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authors,title,source,type,keywords,abstract,times_cited,PY,VL,IS,BP,EP,DI,synergy,antag,additive,check"Sonnier, G; Shipley, B; Navas, ML",quantifying relationships between traits and explicitly measured gradients of stress and disturbance in early successional plant communities,JOURNAL OF VEGETATION SCIENCE,Article,Community weighted mean of trait; Community weighted variance of trait; Environmental filtering; Structural equation model; Trait-environment linkages,"questions how can one explicitly quantify, and separately measure, stress and disturbance gradients? how do these gradients affect functional composition in early successional plant communities and to what extent? can we accurately predict trait composition from knowledge of these gradients? location southern quebec, canada. methods using eight environmental variables measured in 48 early successional plant communities, we estimated stress and disturbance gradients through structural equation modelling. we then measured 10 functional traits on the most abundant species of these 48 communities and calculated their community-level mean and variance weighted by the relative abundance of each species. finally, we related these community-weighted means and variances to the estimated stress and disturbance gradients using general linear models or generalized additive models. results we obtained a well-fitting measurement model of the stress and disturbance gradients existing in our sites. of the 10 studied traits, only average plant reproductive height was strongly correlated with the stress (r2=0.464) and disturbance (r2=0.543) gradients. leaf traits were not significantly related to either the stress or disturbance gradients. conclusions the well-fitting measurement model of the stress and disturbance gradients, combined with the generally weak trait-environment linkages, suggests that community assembly in these early successional plant communities is driven primarily by stochastic processes linked to the history of arrival of propagules and not to trait-based environmental filtering.",19,2010,21,6,1014,1024,10.1111/j.1654-1103.2010.01210.x,0,0,1,1"Bowman, DMJS; Prior, LD; De Little, SC",retreating melaleuca swamp forests in kakadu national park: evidence of synergistic effects of climate change and past feral buffalo impacts,AUSTRAL ECOLOGY,Article,aerial photography; feral animal impact; forest decline; landscape change; multimodel inference,"melaleuca swamp forests form a fringe around seasonally inundated freshwater flood plains of kakadu national park (knp). previous studies based on the analysis of aerial photography reported an increase in woody plant cover on these flood plains, apparently associated with changed fire regimes, increased rainfall and possibly increased atmospheric co2. in opposition to this woody vegetation encroachment past high densities of feral buffalo in the 1960 to mid 1980s changed the hydrology of the knp flood plains, allowing increased penetration of saltwater causing extensive death of melaleuca forests. climate change has increased sea levels and there is concern that this will threaten the freshwater ecosystems of knp. we hypothesized that melaleuca forests that were previously impacted by high densities of feral buffalo have continued to decline because of salinization driven by sea level rise. we examined this hypothesis by overlaying georeferenced aerial photography taken in 1964, 1984 and 2004 in a geographic information environment, and then constructing generalized linear fixed effects and mixed effects models to rank the statistical strength of different drivers of melaleuca forest contraction. we found that there has been a 5% overall contraction of melaleuca forests over the last 50 years on our study sites, although the amount of contraction varied both geographically and temporally. the amount of melaleuca forest contraction was greatest during the 1984-2004 interval, when buffalo densities were low. contraction was greatest on the melaleuca forest edges, at low-lying sites, and where high densities of buffalo were apparent in 1964. these results suggest the enduring legacy effect of past buffalo damage will amplify the effects of sea level rise on the flood plains of knp.",3,2010,35,8,898,905,10.1111/j.1442-9993.2009.02096.x,1,0,0,1"Vaidyanathan, S; Krishnaswamy, J; Kumar, NS; Dhanwatey, H; Dhanwatey, P; Karanth, KU",patterns of tropical forest dynamics and human impacts: views from above and below the canopy,BIOLOGICAL CONSERVATION,Article,Tadoba; Remote sensing; Trend analysis; Spatial regression; NDVI; AVHRR; SPOT; CVI; GIMMS; Rainfall anomalies; Human disturbance,"tropical forests are influenced by regional and global bio-climatic processes as well as local anthropogenic disturbances. most studies have ignored the synergistic influence of bio-physical processes operating at large spatial scales and local human use on forest vegetation and fauna. assessments of forest condition change using time-series of remotely sensed data need to be supported by measurements under the canopy. the tadoba-andhari tiger reserve (tatr) in india is a protected area that has a long history of human resource extraction and settlements. like much of south asia. it has undergone major shifts in rainfall in the last hundred years. we examine trends in forest greenness over two and half decades and assess spatial patterns in rates of change. we also analyze ground based measurements of human impacts on flora and fauna. trends in forest canopy greenness show two distinct phases: a period of decline from 1980s to mid-90s, followed by a recovery. these trends are a function of initial greenness and are best explained by prevailing climatic regimes, feed-backs from human use, and park management practices and protection. negative impacts to flora and fauna on the ground were, however, wide-spread during the recovery period and are influenced by proximity to nearest settlement as well as combined distance from all settlements. remotely sensed data cannot effectively detect these processes under the canopy. there is an urgent need to incorporate monitoring of long-term bio-climatic processes and their interaction with short and long-term effects of human-use and disturbance arising from processes at local, regional and larger spatial scales around protected areas to effectively manage these reserves. (c) 2010 elsevier ltd. all rights reserved.",3,2010,143,12,2881,2890,10.1016/j.biocon.2010.04.027,1,0,0,1"Persha, L; Fischer, H; Chhatre, A; Agrawal, A; Benson, C",biodiversity conservation and livelihoods in human-dominated landscapes: forest commons in south asia,BIOLOGICAL CONSERVATION,Article,Protected areas; Institutions; Decentralization; Tree species richness; Multiple outcomes,"strict protected areas are a critical component in global biodiversity conservation, but the future of biodiversity conservation may well depend upon the ability to experiment successfully with a range of institutional forms, including those that permit human use. here, we focus on forest commons in human-dominated landscapes and their role in biodiversity conservation at the same time as they provide livelihood benefits to users. using a dataset of 59 forest commons located in bhutan, india, and nepal, we estimated tree species richness from plot vegetation data collected in each forest, and drew on interview data to calculate a livelihoods index indicating the overall contribution of each forest to villager livelihoods for firewood, fodder, and timber. we found that tree species richness and livelihoods were positively and significantly correlated (rho = .41, p < 0.001, n = 59). this relationship held regardless of forest type or country, though significance varied somewhat across these two factors. further, both benefits were similarly associated with several drivers of social-ecological change (e.g., occupational diversity of forest users, total number of users, and forest size), suggesting identification of potential synergies and complexes of causal mechanisms for future attention. our analysis shows that forest commons in south asia, explicitly managed to provide livelihoods for local populations, also provide biodiversity benefits. more broadly, our findings suggest that although strict protected areas are effective tools for biodiversity conservation, a singular focus on them risks ignoring other resource governance approaches that can fruitfully complement existing conservation regimes. (c) 2010 elsevier ltd. all rights reserved.",17,2010,143,12,2918,2925,10.1016/j.biocon.2010.03.003,1,0,0,1"Jacob, A; Evanno, G; von Siebenthal, BA; Grossen, C; Wedekind, C",effects of different mating scenarios on embryo viability in brown trout,MOLECULAR ECOLOGY,Article,compatible genes; good genes; melanin-based colours; major histocompatibility complex; pathogen resistance; Salmonid,"mating with attractive or dominant males is often predicted to offer indirect genetic benefits to females, but it is still largely unclear how important such non-random mating can be with regard to embryo viability. we sampled a natural population of adult migratory brown trout (salmo trutta), bred them in vitro in a half-sib breeding design to separate genetic from maternal environmental effects, raised 2098 embryos singly until hatching, and exposed them experimentally to different levels of pathogen stress at a late embryonic stage. we found that the embryos' tolerance to the induced pathogen stress was linked to the major histocompatibility complex (mhc) of their parents, i.e. certain mhc genotypes appeared to provide better protection against infection than others. we also found significant additive genetic variance for stress tolerance. melanin-based dark skin patterns revealed males with 'good genes', i.e. embryos fathered by dark coloured males had a high tolerance to infection. mating with large and dominant males would, however, not improve embryo viability when compared to random mating. we used simulations to provide estimates of how mate choice based on mhc or melanin-based skin patterns would influence embryos' tolerance to the experimentally induced pathogen stress.",18,2010,19,23,5296,5307,10.1111/j.1365-294X.2010.04884.x,0,0,1,1"St Clair, JJH; Garcia-Pena, GE; Woods, RW; Szekely, T",presence of mammalian predators decreases tolerance to human disturbance in a breeding shorebird,BEHAVIORAL ECOLOGY,Article,antipredator behavior; feral cats; human disturbance; introduced predators; natural experiment; nest predation; predation risk; shorebird,"nonlethal disturbance can impose fitness costs, particularly during sensitive life history stages such as reproduction. prey animals are thus expected to assess the costs and benefits of expressing antipredator behavior in different circumstances and to respond optimally according to the perceived risk of predation. one prediction of this hypothesis is that the response to nonlethal disturbance should be elevated when the risk of predation is high, although few studies have tested this prediction with respect to the distribution of actual predators in nature. we used landscape-level variation in the distribution of large mammalian predators (feral cats) to investigate antipredator behavior in a small breeding shorebird, the two-banded plover charadrius falklandicus. we used 8 sites in the falkland islands and argentina and measured the flushing distances of incubating two-banded plovers in response to a controlled human approach to the nest. we found that flushing distances were increased at sites where mammalian predators were present and decreased where exposure to humans was high. these effects were additive, and we interpret them as the effects of generalization and habituation, respectively.",10,2010,21,6,1285,1292,10.1093/beheco/arq144,0,0,1,1"Pedrana, J; Bustamante, J; Travaini, A; Rodriguez, A",factors influencing guanaco distribution in southern argentine patagonia and implications for its sustainable use,BIODIVERSITY AND CONSERVATION,Article,Lama guanicoe; Unregulated hunting; Argentine Patagonia; Distribution models; Predictive cartography; Regional scale,"the guanaco (lama guanicoe) has suffered a progressive decline in numbers because of unregulated hunting and poaching by an assumed competition with sheep. inadequate livestock management, including keeping sheep numbers above carrying capacity, has led to a degradation of the patagonian steppe. recently, interest has grown towards a reduction in sheep density and diversification of extractive activities. guanaco populations could be potentially amenable to a number of sustainable uses. our aim was to investigate the factors that determine guanaco distribution in southern argentine patagonia and to generate a predictive cartography at the regional scale. we hypothesized that guanaco distribution could be determined by primary productivity, terrain ruggedness, human disturbance and poaching, and competition with livestock. guanaco surveys were performed from vehicles using a road survey method. to analyze the relationship between guanaco occurrence and potential predictors we built generalized additive models (gams) using a binomial error and a logistic link. we found that guanaco occurrence increased in the less productive and remote areas, far from cities and oil camps, and decreased in regions with high sheep density. these results suggest that guanacos tend to occur where human pressure is lower. one way to promote guanaco conservation would be to highlight the economic value of guanacos under the regulations imposed by a sustainable exploitation of their populations. the predictive models developed here could be a useful tool for the implementation of conservation and management programs at the regional scale.",12,2010,19,12,3499,3512,10.1007/s10531-010-9910-1,0,0,1,1"Lomba, A; Pellissier, L; Randin, C; Vicente, J; Moreira, F; Honrado, J; Guisan, A",overcoming the rare species modelling paradox: a novel hierarchical framework applied to an iberian endemic plant,BIOLOGICAL CONSERVATION,Article,BIOMOD; Conservation; Ensemble modelling; Hierarchic modelling; Rare species; Species distribution modelling,"rare species have restricted geographic ranges, habitat specialization, and/or small population sizes. datasets on rare species distribution usually have few observations, limited spatial accuracy and lack of valid absences; conversely they provide comprehensive views of species distributions allowing to realistically capture most of their realized environmental niche. rare species are the most in need of predictive distribution modelling but also the most difficult to model. we refer to this contrast as the ""rare species modelling paradox"" and propose as a solution developing modelling approaches that deal with a sufficiently large set of predictors, ensuring that statistical models are not over-fitted. our novel approach fulfils this condition by fitting a large number of bivariate models and averaging them with a weighted ensemble approach. we further propose that this ensemble forecasting is conducted within a hierarchic multi-scale framework. we present two ensemble models for a test species, one at regional and one at local scale, each based on the combination of 630 models. in both cases, we obtained excellent spatial projections, unusual when modelling rare species. model results highlight, from a statistically sound approach, the effects of multiple drivers in a same modelling framework and at two distinct scales. from this added information, regional models can support accurate forecasts of range dynamics under climate change scenarios, whereas local models allow the assessment of isolated or synergistic impacts of changes in multiple predictors. this novel framework provides a baseline for adaptive conservation, management and monitoring of rare species at distinct spatial and temporal scales. (c) 2010 elsevier ltd. all rights reserved.",25,2010,143,11,2647,2657,10.1016/j.biocon.2010.07.007,1,0,0,1"Baer, CF; Joyner-Matos, J; Ostrow, D; Grigaltchik, V; Salomon, MP; Upadhyay, A",rapid decline in fitness of mutation accumulation lines of gonochoristic (outcrossing) caenorhabditis nematodes,EVOLUTION,Article,Caenorhabditis brenneri; Caenorhabditis remanei; mating system; mutation rate; mutational variance,"evolutionary theory predicts that the strength of natural selection to reduce the mutation rate should be stronger in self-fertilizing than in outcrossing taxa. however, the relative efficacy of selection on mutation rate relative to the many other factors influencing the evolution of any species is poorly understood. to address this question, we allowed mutations to accumulate for similar to 100 generations in several sets of ""mutation accumulation"" (ma) lines in three species of gonochoristic (dieocious) caenorhabditis (c. remanei, c. brenneri, c. sp. 5) as well as in a dioecious strain of the historically self-fertile hermaprohodite c. elegans. in every case, the rate of mutational decay is substantially greater in the gonochoristic taxa than in c. elegans (similar to 4x greater on average). residual heterozygosity in the ancestral controls of these ma lines introduces some complications in interpreting the results, but circumstantial evidence suggests the results are not primarily due to inbreeding depression resulting from residual segregating variation. the results suggest that natural selection operates to optimize the mutation rate in caenorhabditis and that the strength (or efficiency) of selection differs consistently on the basis of mating system, as predicted by theory. however, context-dependent environmental and/or synergistic epistasis could also explain the results.",9,2010,64,11,3242,3253,10.1111/j.1558-5646.2010.01061.x,1,0,0,1"Bouwhuis, S; Charmantier, A; Verhulst, S; Sheldon, BC",individual variation in rates of senescence: natal origin effects and disposable soma in a wild bird population,JOURNAL OF ANIMAL ECOLOGY,Article,ageing; cost of reproduction; disposable soma; great tit; immigrant status; life-history; Parus major; senescence; trade-off,"p>1. longitudinal studies of various vertebrate populations have recently demonstrated senescent declines in reproductive performance and/or survival probability with age to be almost ubiquitous in nature. little is known, however, about the extent to which rates of senescence vary between individuals, and about causes or consequences of such variation. quantifying these links in natural populations is important for understanding the constraints and adaptive processes underlying the evolution of senescence. 2. here, we analyse breeding data from 1029 female great tits parus major to quantify the effect of natal conditions and early life reproduction on rates of reproductive senescence, reproductive life span and lifetime reproductive success. 3. although for locally born females we find no evidence that natal conditions influence rates of reproductive senescence, we show that immigrant females suffer from faster rates of senescence than locally born females, and that this difference contributes to immigrants having a lower lifetime reproductive success. 4. additionally, and independently, we find rates of reproductive senescence to increase with rates of early life reproduction, as predicted by the disposable soma hypothesis. despite accelerated senescence late in life, high early life reproduction is, however, positively associated with lifetime reproductive success across individuals. 5. female immigrant status and early life reproduction do not relate to reproductive life span. 6. we thus show that both immigration into our population, and high levels of early life reproduction, are associated with reduced late life reproductive performance in female great tits, but that fitness can be increased by high levels of early life reproduction at the expense of accelerated reproductive senescence. these results suggest disposable soma to be a likely mechanism underlying senescence in these birds, and encourage further study of the genetic basis (i.e. antagonistic pleiotropy) of such an early vs. late life trade-off.",38,2010,79,6,1251,1261,10.1111/j.1365-2656.2010.01730.x,0,1,0,1"Levin, DA",environment-enhanced self-fertilization: implications for niche shifts in adjacent populations,JOURNAL OF ECOLOGY,Review,adaptation; ecological divergence; marginal habitats; niche shifts; phenotypic plasticity; reproductive ecology; reproductive isolation; self-compatibility; speciation,"1. pollen-mediated gene flow from ecological core populations may hamper the ability of populations to invade new, closely adjacent habitats. the potential for the invasion of a new habitat is enhanced when selection against immigrants is augmented by the elevation of self-fertilization. this shift imparts a measure of reproductive isolation to the invader. 2. whereas genetically mediated changes in selfing often accompany niche shifts in plants, the elevation of self-fertilization by plastic responses to novel, stressful, environments has not been explored. here i will show that invaders of novel habitats may have elevated levels of self-fertility mediated by alterations in floral form and self-compatibility. 3. heightened selfing facilitates the evolution of local adaptation by increasing the additive genetic variance for tolerance to the new habitat. heightened selfing also facilitates local adaptation by increasing reproductive assurance. 4. elevated levels of selfing based on developmental responses are immediate, as opposed to that obtained by multigenerational selection. 5. synthesis. the likelihood of a niche shift will be substantially enhanced if the invader is protected from the swamping effect of gene flow from a nearby core population. this protection may be afforded by an environment-induced elevation of self-fertility. the likelihood of a niche shift also is enhanced by an increase in reproductive assurance which may be vital to the survival of an invading population whose reproductive success is density-dependent.",27,2010,98,6,1276,1283,10.1111/j.1365-2745.2010.01715.x,0,0,1,1"Wang, XL; Cumming, SG",configuration dynamics of boreal forest landscapes under recent fire and harvesting regimes in western canada,LANDSCAPE ECOLOGY,Article,Boreal forest; Forest fire; Forest harvesting; Fragmentation; Landscape configuration; Landscape pattern metrics; Landscape dynamics,"harvesting and forest fire change the spatial configurations of forest habitat. we used multivariate statistical models to evaluate the individual and cumulative effects of these two disturbances on habitat configuration in managed boreal forest landscapes in western canada. we evaluated three aspects of configuration (core area, inter-patch distance and shape) using indices normalized for total habitat abundance. the two disturbances types had different effects on the three configuration metrics in terms of both the magnitude and direction of change. we found that the magnitudes of harvesting effects were larger than for fire. the direction of change was the same for core area and shape, but opposite for inter-patch distance which decreased slightly after fire. the combined effects of the two disturbances are distinct from the effects of either disturbance alone, and the effects are not always additive or compensatory for all metrics. pre-treatment configuration was a significant covariate in all models, and total habitat abundance was significant in 4/9 models, but these were often not the most important covariates. in the cumulative disturbance model, covariates for the number or size of cut-blocks were significant.",1,2010,25,9,1419,1432,10.1007/s10980-010-9517-7,0,0,1,1"Knochel, DG; Monson, ND; Seastedt, TR",additive effects of aboveground and belowground herbivores on the dominance of spotted knapweed (centaurea stoebe),OECOLOGIA,Article,Biological control; Herbivory; Compensation; Plant competition; Nutrient limitation,"spotted knapweed (centaurea stoebe) is found in over 3 million ha of rangeland and forests across north america, and evidence supporting the use of biological control as a regional method to reduce infestations and their associated impacts remains inconclusive. several species of insects have been reported to reduce plant densities in some areas; however, rigorous studies that test combinations of these species and the influence of resource availability are lacking. we examined the singular and combined effects of herbivory by a root weevil (cyphocleonus achates) and a flower head weevil (larinus minutus) on the growth and flower production of c. stoebe. we also manipulated soil resource fertility as an additional factor that could explain the outcomes of contradictory biological control herbivore effects on c. stoebe. in a greenhouse study, herbivory by c. achates decreased flower production for plants across all resource environments. in a caged common garden study, the negative effects of herbivory also did not interact with soil nutrient status. however, the presence of plant competition further decreased knapweed growth, and the negative effects of concurrent herbivory by c. achates and l. minutus on plant biomass and flower production were additive. derived within the context of variable levels of soil nutrient availability and competing vegetation, these results support the cumulative stress hypothesis and the contention that combined above- and belowground herbivory can reduce spotted knapweed densities and reduce the ecological and economic impacts of this species in rangelands of western north america.",10,2010,164,3,701,712,10.1007/s00442-010-1708-z,0,0,1,1"Ishii, H; Takashima, A; Makita, N; Yoshida, S","vertical stratification and effects of crown damage on maximum tree height in mixed conifer-broadleaf forests of yakushima island, southern japan",PLANT ECOLOGY,Article,Additive basal area; Disturbance; Height growth; Old-growth; Species coexistence,"we investigated vertical stratification and effects of crown damage on maximum tree height in two mixed conifer-broadleaf forests in yakushima island, southern japan. in both research plots, the conifer trees dominated the upper canopy while the broadleaved trees dominated the middle to lower canopy. most broadleaved trees were shorter than the median crown-base height (h (cb)) of the conifer trees. estimates of the maximum height (h (max)) of the conifer trees were greater than those of the broadleaved trees. crown damage had significant negative effects on maximum height of the conifer trees. crown damage was observed for 72.8-88.7% of the conifer trees, and severe types of damage such as stem breakage and top die-back were the most predominant. the h (max) of the damaged conifer trees was 16-17% shorter than that of the intact trees and as much as 16-28% shorter than the potential maximum height estimated from the diameter-height relationship of the tallest intact trees. we inferred that crown disturbance is an important factor determining the maximum height of the canopy of the two mixed forests. our results suggested that vertical stratification between conifer and broadleaved trees may be an important mechanism contributing to their coexistence and additive basal area of mixed forests on yakushima island.",3,2010,211,1,27,36,10.1007/s11258-010-9768-z,0,0,1,1"Tylianakis, JM; Laliberte, E; Nielsen, A; Bascompte, J",conservation of species interaction networks,BIOLOGICAL CONSERVATION,Article,Food web; Pollination; Global change; Invasion; Climate change; Global warming; Land use change; Parasitoid; Mutualism,"recent work has shown that antagonist (e.g. predator-prey food web) and mutualist (e.g. pollinator-plant) network structure can be altered by global environmental change drivers, and that these alterations may have important ecosystem-level consequences. this has prompted calls for the conservation of network structure, but precisely which attributes of webs should be conserved remains unclear. further, the extent to which network metrics characterise the spatiotemporally-variable dynamic structure of interacting communities is unknown. here, we summarise the attributes of web structure that are predicted to confer stability or increased function to a system, as these may be of greatest interest to conservation biologists. however, empirical evaluation of these effects is lacking in most cases, and we discuss whether stability is even desirable in all contexts. the incorporation of web attributes into conservation monitoring requires that changes in these attributes can be recorded (sampled) with relative ease. we contrast the sensitivity of metrics to sampling effort, and highlight those (such as nestedness and connectance) that could easily be incorporated into conservation monitoring. despite our growing understanding of the characteristics of food webs that confer stability and function, numerous practical challenges need to be overcome before the goal of conserving species interaction networks can be achieved. (c) 2009 elsevier ltd. all rights reserved.",121,2010,143,10,2270,2279,10.1016/j.biocon.2009.12.004,0,1,0,1"Williams, NM; Crone, EE; Roulston, TH; Minckley, RL; Packer, L; Potts, SG",ecological and life-history traits predict bee species responses to environmental disturbances,BIOLOGICAL CONSERVATION,Article,Anthropogenic disturbance; Bees; Functional traits; Landscape change; Life-history response guilds,"the ability to predict the responses of ecological communities and individual species to human-induced environmental change remains a key issue for ecologists and conservation managers alike. responses are often variable among species within groups making general predictions difficult. one option is to include ecological trait information that might help to disentangle patterns of response and also provide greater understanding of how particular traits link whole clades to their environment. although this ""trait-guild"" approach has been used for single disturbances, the importance of particular traits on general responses to multiple disturbances has not been explored. we used a mixed model analysis of 19 data sets from throughout the world to test the effect of ecological and life-history traits on the responses of bee species to different types of anthropogenic environmental change. these changes included habitat loss, fragmentation, agricultural intensification, pesticides and fire. individual traits significantly affected bee species responses to different disturbances and several traits were broadly predictive among multiple disturbances. the location of nests - above vs. below ground - significantly affected response to habitat loss, agricultural intensification, tillage regime (within agriculture) and fire. species that nested above ground were on average more negatively affected by isolation from natural habitat and intensive agricultural land use than were species nesting below ground. in contrast below-ground-nesting species were more negatively affected by tilling than were above-ground nesters. the response of different nesting guilds to fire depended on the time since the burn. social bee species were more strongly affected by isolation from natural habitat and pesticides than were solitary bee species. surprisingly, body size did not consistently affect species responses, despite its importance in determining many aspects of individuals' interaction with their environment. although synergistic interactions among traits remain to be explored, individual traits can be useful in predicting and understanding responses of related species to global change. (c) 2010 elsevier ltd. all rights reserved.",119,2010,143,10,2280,2291,10.1016/j.biocon.2010.03.024,1,0,0,1"Traill, LW; Bradshaw, CJA; Delean, S; Brook, BW",wetland conservation and sustainable use under global change: a tropical australian case study using magpie geese,ECOGRAPHY,Article,,"imminent shifts in environmental parameters due to climatic change might have profound ramifications for wetlands listed under the ramsar convention. although the exact mechanisms by which global change will affect these systems are not known, models that simulate component drivers, particularly at a broad spatial scale, can nevertheless allow for more informed conservation decision making. such general inference is particularly needed for wetlands across the tropics, where less knowledge and fewer resources are available to mitigate the impacts on important conservation sites. here we develop a case study of wetland loss to sea level rise across tropical north australia (including ramsar-listed sites), and link these to a metapopulation model for a keystone endemic waterbird, the magpie goose anseranas semipalmata. we projected published models on sea level rise through to the year 2400, and found a non-linear trajectory of inundation up to 20 m above present levels. digital elevation models were used to simulate sea level rise and the spatially differentiated loss of wetland habitat used by geese. range retraction was linked to decline in ecological carrying capacity, and we coupled wetland-specific habitat loss projections to a spatially explicit demographic metapopulation model. additionally, we included alternate harvest strategies based on present-day estimates of indigenous and non-indigenous offtake of geese, and examined the synergy between wetland loss and hunting on extinction risk. our results suggest that australia's once-abundant and widespread magpie goose will be reduced to a fragmented population of just a few thousand individuals within the next 200-300 yr. harvest could continue for some time, up to a ""tipping point'' at around 5% loss of current wetland habitat, after which the decline of geese is rapid. given the inexorable nature of sea level rise, short-to medium-term conservation of waterbirds across ramsar wetlands must prepare for adaptive wetland management, such as through buffer-placement, and ongoing monitoring of harvest.",14,2010,33,5,818,825,10.1111/j.1600-0587.2009.06205.x,1,0,0,1"Kremer, N; Dedeine, F; Charif, D; Finet, C; Allemand, R; Vavre, F",do variable compensatory mechanisms explain the polymorphism of the dependence phenotype in the asobara tabida-wolbachia association?,EVOLUTION,Article,Apoptosis; oxidative stress; symbiosis; tolerance,"wolbachia are symbiotic intracellular bacteria, which are classified as reproductive parasites. although generally facultative, wolbachia is necessary for asobara tabida (hymenoptera), because aposymbiotic females do not produce any offspring. interestingly, the ovarian phenotype of aposymbiotic females is variable: some females do not produce any eggs, whereas others do produce some eggs, but these are aborted. here, we show that the ovarian phenotype of aposymbiotic females is highly polymorphic within populations, although dependence remains complete in both cases. we also identified some lines in which aposymbiotic females were able to produce a very few viable offspring, further extending the range of variation observed. these results suggest that various factors actively maintain polymorphism. we demonstrated that wolbachia is necessary to trigger oogenetic processes, but that the ovarian phenotype was determined by the host only. phenotypic variation was also correlated with the differential expression of genes controlling iron homeostasis and oxidative stress, which are potentially involved in the evolution of dependence. this suggests that variation in the ovarian phenotype could reflect selection for different levels of compensatory mechanisms in response to wolbachia infection, and that polymorphism is maintained through selection on different antagonist traits influenced by oxidative stress.",11,2010,64,10,2969,2979,10.1111/j.1558-5646.2010.01034.x,0,1,0,1"Bradbury, RB; Stoate, C; Tallowin, JRB",lowland farmland bird conservation in the context of wider ecosystem service delivery,JOURNAL OF APPLIED ECOLOGY,Letter,agri-environment; climate change; ecosystem approach; land-use; multi-objective; multifunctional; regulating; resource protection,"p>1. much policy and research in the uk and elsewhere in europe has been directed towards the conservation of farmland birds. with changes in the drivers of agricultural land management, farmland bird conservation now needs to be considered alongside provision of a range of ecosystem services (es) indicative of environmentally sustainable land-management. 2. we explore the extent to which land management for farmland bird conservation provides 'cultural' es, before assessing the potential consistency between management for bird species conservation and for a suite of es that relate to the regulation of ecosystem processes. 3. we discuss the potential for co-delivery and trade-offs between farmland bird conservation and regulating es, at a range of locations and spatial scales. 4. potentially, action to enhance regulating services could provide some co-benefits for farmland bird conservation. however, more targeted management will still be required for certain species. 5. synthesis and applications. integration of species conservation management practices, in this case in farmland, with provision of other es will be a significant challenge to land management. this will demand careful planning, at multiple scales, to account for the range of synergies and trade-offs between services, the dependence of service provision on time and location of management, and the dependence of service benefit on the number, locations and preferences of human beneficiaries.",14,2010,47,5,986,993,10.1111/j.1365-2664.2010.01843.x,1,0,0,1"O'Farrell, PJ; Reyers, B; Le Maitre, DC; Milton, SJ; Egoh, B; Maherry, A; Colvin, C; Atkinson, D; De Lange, W; Blignaut, JN; Cowling, RM",multi-functional landscapes in semi arid environments: implications for biodiversity and ecosystem services,LANDSCAPE ECOLOGY,Article; Proceedings Paper,Ecosystem service assessment; Grazing; Water; Tourism; Biodiversity hotspots; Climate change,"synergies between biodiversity conservation objectives and ecosystem service management were investigated in the succulent karoo biome (83,000 km(2)) of south africa, a recognised biodiversity hotspot. our study complemented a previous biodiversity assessment with an ecosystem service assessment. stakeholder engagement and expert consultation focussed our investigations on surface water, ground water, grazing and tourism as the key services in this region. the key ecosystem services and service hotspots were modelled and mapped. the congruence between these services, and between biodiversity priorities and ecosystem service priorities, were assessed and considered in relation to known threats. generally low levels of overlap were found between these ecosystem services, with the exception of surface and ground water which had an 80% overlap. the overlap between ecosystem service hotspots and individual biodiversity priority areas was generally low. four of the seven priority areas assessed have more than 20% of their areas classified as important for services. in specific cases, particular service levels could be used to justify the management of a specific biodiversity priority area for conservation. adopting a biome scale hotspot approach to assessing service supply highlighted key management areas. however, it underplayed local level dependence on particular services, not effectively capturing the welfare implications associated with diminishing and limited service provision. we conclude that regional scale (biome level) approaches need to be combined with local level investigations (municipal level). given the regional heterogeneity and varied nature of the impacts of drivers and threats, diverse approaches are required to steer land management towards sustainable multifunctional landscape strategies.",30,2010,25,8,1231,1246,10.1007/s10980-010-9495-9,1,0,0,1"Beckingham, KM",synergy between stresses: an interaction between spaceflight-associated conditions and the microgravity response,MOLECULAR ECOLOGY,Article,Drosophila; micro array analysis; microgravity; stress responses,"gravity is the one constant, ubiquitous force that has shaped life on earth over its 4.8 billion years of evolution. but the sheer inescapability of earth's gravitational pull has meant that its influence on earth's organisms is difficult to study. neutralization of the gravity vector (so-called simulated microgravity) by random movement in three-dimensional space is the best option for earth-based experiments, with spaceflight alone offering the possibility to assess the effects of an extremely reduced gravitational field (microgravity). however, the technical constraints associated with spaceflight introduce complications that can compromise the interpretation of microgravity experiments. it can be unclear whether changes detected in these experiments reflect additional spaceflight-related stresses (temperature shifts, vibrational effects, radiation exposure, and so on) as opposed to the loss of gravitational force per se. in this issue, herranz et al. (2010) report a careful study in which the effects of simulated and actual microgravity on gene expression in drosophila melanogaster were compared and the effects of the flight-associated stresses on the microgravity responses were investigated. a striking finding emerged. the additional stresses associated with the spaceflight experiment altered the response to microgravity. despite controlling for the effects of these stresses/constraints, the group found that responses to microgravity are much stronger in the stressed/constrained background than in its absence. this interaction of gravity with other environmental influences is a novel finding with important implications for microgravity research and other situations where multiple stress factors are combined.",2,2010,19,19,4105,4107,10.1111/j.1365-294X.2010.04799.x,1,0,0,1"Malkinson, D; Tielborger, K",what does the stress-gradient hypothesis predict? resolving the discrepancies,OIKOS,Article,,"in recent years the importance of facilitative interactions in ecological communities is increasingly recognized. this phenomenon has been observed repeatedly, particularly in vegetation communities, in a wide range of environmental conditions. the current hypothesis predicts that the role of facilitation becomes increasingly important in conjunction with increasing stress. several empirical studies, however, failed to detect such patterns, particularly at the extreme ends of the stress gradients. herein, we present a conceptual model that may resolve discrepancies between expected and observed and provides a more precise framework of the existing hypotheses. by relaxing two common assumptions commonly used by the stress-gradient hypothesis (sgh) we are able to demonstrate that under some circumstances the importance of facilitation may be less at the extreme ends of these gradients. namely, we first re-emphasize the notion that physiological response is not linear with respect to environmental changes along stress gradients. second, it is argued that the net outcome of facilitative and competitive interactions is reflected in the fitness of individuals as a product of these two processes, in contrast to the commonly applied assumption of additivity. accordingly, a synthesis of the concepts of population biology (measures of fitness) and plant physiology (nonlinear responses) with the stress gradient hypothesis while retaining the original simplicity of the sgh model contributes to a better specification of the predictions of the stress-gradient hypothesis and the resolution of observed contradictions.",51,2010,119,10,1546,1552,10.1111/j.1600-0706.2010.18375.x,0,0,1,1"Blake, RE; Duffy, JE",grazer diversity affects resistance to multiple stressors in an experimental seagrass ecosystem,OIKOS,Article,,"when multiple stressors act simultaneously, their effects on ecosystems become more difficult to predict. in the face of multiple stressors, diverse ecosystems may be more stable if species respond differently to stressors or if functionally similar species can compensate for stressor effects on focal species. many habitats around the globe are threatened by multiple stressors, including highly productive seagrass habitats. for example, in chesapeake bay, usa, regional climate change predictions suggest that elevated temperature and freshwater inputs are likely to be increasingly important stressors. using seagrass mesocosms as a model system, we tested whether species richness of crustacean grazers buffers ecosystem properties against the impacts of elevated temperature and freshwater pulse stressors in a fully factorial experiment. grazer species responded to pulsed salinity changes differently; abundance of elasmopus levis responded negatively to freshwater pulses, whereas abundance of gammarus mucronatus and erichsonella attenuata responded positively or neutrally. consistent with the hypothesis that biodiversity provides resistance stability, biomass of epiphytic algae that form the base of the food web was less affected by stressors in species-rich grazer treatments than in single-species grazer treatments. stochastic (among-replicate) variation of sessile invertebrate biomass within treatments was also reduced in more diverse grazer treatments. therefore, grazer species richness tended to increase the resistance stability of both major components of the seagrass fouling community, algae and invertebrates, in the face of environmental stressors. finally, in our model system, multi-stressor impacts suggested a pattern of antagonism contrary to previous assumptions of synergistic stressor effects. overall, our results confirm that invertebrate grazer species are functionally diverse in their response to environmental stressors, but are largely functionally redundant in their grazing effects leading to greater resistance stability of certain ecosystem properties in diverse grazer assemblages even when influenced by multiple environmental stressors.",16,2010,119,10,1625,1635,10.1111/j.1600-0706.2010.18419.x,1,1,0,2"Ochoa-Hueso, R; Manrique, E",nitrogen fertilization and water supply affect germination and plant establishment of the soil seed bank present in a semi-arid mediterranean scrubland,PLANT ECOLOGY,Article,Additive effects; Critical load; Mediterranean ecosystems; N fertilization; Rainfall; Seed bank,"anthropogenic nitrogen (n) inputs in terrestrial ecosystems are higher than those that occur naturally and have been related to global biodiversity loss and altered ecosystem functioning. however, its effects on mediterranean-type ecosystems, where production is water-limited and n regulated, remain unclear. we conducted a green-house experiment where we evaluated the effects of four simulated scenarios of n pollution (0, 10, 20 and 50 kg n ha(-1) year(-1)) and two differential water supply regimes on the germination (experiment 1) and early plant establishment (experiment 2) of a seed bank from a semi-arid mediterranean ecosystem of central spain. seed bank density was estimated as 62,374 +/- a 3,279 seeds m(-2). approximately 99.5% of emerged seeds corresponded to only 14 species of a total of 52, the majority of which were the annual forb sagina apetala. the responses for n treatments were species-specific, mainly positive or unimodal, with watering treatments having some interactive effects. n and water supply also affected total and specific productivity; the responses found for n treatments were mainly humpback-shaped and an increased water supply had additive effects on community establishment in terms of total plant biomass. this response was linked to forb responsiveness. contrary to predictions, grass biomass did not change with n supply; however, grass to forb ratio was affected because of changes in the latter. overall, these experiments suggest a critical load for plant biomass production and conclude that n and water availability and supply can modify germination and plant establishment. this should be taken into account when analysing the effects of global change on the dynamics of plant communities where annuals are dominant or vegetation must establish from seed following a natural or anthropogenic disturbance regime.",16,2010,210,2,263,273,10.1007/s11258-010-9755-4,0,0,1,1"Pike, TW; Blount, JD; Metcalfe, NB; Lindstrom, J",dietary carotenoid availability and reproductive effort influence the age-related decline in performance,BEHAVIORAL ECOLOGY,Article,dietary antioxidants; free radical theory of ageing; oxidative stress; three-spined stickleback,"elevated breeding effort is known to increase an individual's rate of senescence, although the underlying mechanisms are not well understood. one possibility is that the ability to resist senescence is limited by the availability of antioxidants, which are necessary to mitigate the deleterious effects of oxidative stress thought to underlie the aging process. susceptibility to oxidative stress is likely to be particularly high during reproduction, and so for a given level of reproductive effort, the rate of senescence should be fastest in those individuals with the poorest antioxidant capacity. we tested this hypothesis in an experimental study of breeding male three-spined sticklebacks (gasterosteus aculeatus) held under a high or low reproduction regime and fed on either high or low levels of carotenoids (potentially limiting dietary compounds with antioxidant properties). fish on the high reproduction regime and those on the low-carotenoid diet both showed an accelerated decline in sustained swimming performance (an indicator of locomotor senescence) compared with males on the low reproduction regime and high-carotenoid diet, respectively. the swimming performance of fish subjected to the high rate of reproduction, but fed a low-carotenoid diet, appeared to decline most rapidly, perhaps because of the additive effects of increased levels of reproduction-induced oxidative stress and lower antioxidant availability. these findings show that both dietary carotenoid intake and breeding effort can impact on the age-related decline in swimming performance and have important implications for female choice and the capacity of males with insufficient antioxidant defenses to adequately perform paternal care.",0,2010,21,5,1048,1053,10.1093/beheco/arq102,0,0,1,1"Mazia, C; Chaneton, EJ; Machera, M; Uchitel, A; Feler, MV; Ghersa, CM",antagonistic effects of large- and small-scale disturbances on exotic tree invasion in a native tussock grassland relict,BIOLOGICAL INVASIONS,Article,Animal burrows; Fire; Gleditsia triacanthos; Seedling recruitment; Seed predation; Tree-grass interactions,"it is generally accepted that disturbances increase community invasibility. yet the role of disturbance in plant invasions may be less predictable than often assumed, due to the influence of environmental stochasticity and interactions between disturbance regimes. we evaluated the single and interactive effects of prescribed burning (large-scale, infrequent event) and animal diggings (small-scale, frequent events) on the invasion success of gleditsia triacanthos l. in a tussock grassland relict of the inland pampa, argentina. tree seedling emergence and survival were monitored over 4 years, after adjusting for propagule pressure through copious seed addition to all disturbance treatments. burning altered community structure by suppressing tussock grasses and promoting exotic forbs, whereas simulated, armadillo-like diggings had little impact on herbaceous composition. overall, seedling emergence rather than survival represented the main demographic bottleneck for tree invasion. tree establishment success varied among seedling cohorts emerged in different climatic years. in a dry year, emergence was only slightly affected by disturbances. in contrast, for two consecutive wet years, initial burning and armadillo-like diggings exerted strong, antagonistic effects on tree recruitment. whereas fire alone increased recruitment, the simulated burrowing regime prevented seedling emergence in both burned and unburned plots. the latter effect might be explained by reduced soil moisture, and increased seed burial and predation in excavated patches. thus, the impact of a single, large-scale perturbation promoting woody plant invasion was overridden by a regime of small-scale, frequent disturbances. our results show that grassland invasibility was contingent on inter-annual climatic variation as well as unexpected interactions between natural and anthropogenic disturbance agents.",12,2010,12,9,3109,3122,10.1007/s10530-010-9702-2,0,1,0,1"Kangas, K; Luoto, M; Ihantola, A; Tomppo, E; Siikamaki, P",recreation-induced changes in boreal bird communities in protected areas,ECOLOGICAL APPLICATIONS,Article,"bird populations; birds; disturbance; national park; nature-based tourism; Oulanka National Park, northeastern Finland; protected area; recreation; species richness; tourism","the impacts of human-induced disturbance on birds have been studied in growing extent, but there are relatively few studies about the effects of recreation on forest bird communities in protected areas. in this paper, the relative importance of recreation as well as environmental variables on bird communities in oulanka national park, in northeastern finland, was investigated using general additive models (gam). bird data collected using the line transect method along hiking trails and in undisturbed control areas were related to number of visits, area of tourism infrastructure, and habitat variables. we further examined the impact of spatial autocorrelation by calculating an autocovariate term for gams. our results indicate that number of visits affects the occurrence and composition of bird communities, but it had no impact on total species richness. open-cup nesters breeding on the ground showed strongest negative response to visitor pressure, whereas the open-cup nesters nesting in trees and shrubs were more tolerant. for cavity-nesting species, recreation had no significant impact. the contribution of the number of visits was generally low also in models in which it was selected, and the occurrence of birds was mainly determined by habitat characteristics of the area. however, our results show that the recreation-induced disturbance with relatively low visitor pressure can have negative impacts on some bird species and groups of species and should be considered in management of protected areas with recreational activities.",13,2010,20,6,1775,1786,10.1890/09-0399.1,0,0,1,1"Shears, NT; Ross, PM",toxic cascades: multiple anthropogenic stressors have complex and unanticipated interactive effects on temperate reefs,ECOLOGY LETTERS,Letter,Behaviourally mediated indirect interactions; climate change; effects of fishing; harmful algal blooms; kelp forests; marine reserves; multiple stressors; non-lethal effects; sea urchin mortality; toxic dinoflagellates; trophic cascades,"in a changing environment multiple anthropogenic stressors can have novel and non-additive effects on interacting species. we investigated the interactive effects of fishing and harmful algal blooms on the predator-sea urchin-macroalgae trophic cascade. fishing of urchin predators had indirect negative effects on macroalgae, whereas blooms of epi-benthic dinoflagellates (ostreopsis siamensis) were found to have strong negative effects on urchins and indirect positive effects on macroalgae. based on these opposing effects, blooms were expected to counteract the cascading effects of fishing. however, a large bloom of ostreopsis led to greater divergence in macroalgae abundance between reserve and fished sites, as urchins declined at reserve sites but remained stable at fished sites. this resulted from enhanced predation rates on bloom-affected urchins at reserve sites rather than direct lethal effects of ostreopsis on urchins. we argue that interacting stressors can facilitate or attenuate trophic cascades depending on stressor intensity and complex non-lethal interactions.",19,2010,13,9,1149,1159,10.1111/j.1461-0248.2010.01512.x,0,0,1,1"Regular, PM; Robertson, GJ; Montevecchi, WA; Shuhood, F; Power, T; Ballam, D; Piatt, JF",relative importance of human activities and climate driving common murre population trends in the northwest atlantic,POLAR BIOLOGY,Article,By-catch mortality; Hunting mortality; Low Arctic; Ocean climate change; Population ecology; Uria aalge,"seabird populations are affected by environmental and anthropogenic influences on a global scale. many population-level responses to climate change have been shown, yet few studies have addressed the additive and/or relative impact of environmental and anthropogenic influences on seabird populations. using a mixed model approach, we analyzed the trends in plot counts of common murres (uria aalge) from a low arctic colony at cape st. mary's, newfoundland, across 26 years (1980-2006). we tested for associations between population change and various environmental and anthropogenic covariates: water temperature, winter north atlantic oscillation, hunting mortality, oil pollution, by-catch in fishing gear, and visitor disturbance. the number of murres occupying central plots decreased from 1980 to 1989 and increased from 1990 to 2006. annual changes in the population were negatively associated with the estimated number of murres killed in the newfoundland murre hunt and the high numbers killed in the early 1980s likely caused the observed population decline. the large number of gillnets set in newfoundland waters during the 1980s, and associated incidence of drowning through by-catch, probably also contributed to the observed decline. though a centennially significant cold-water perturbation in 1991 forced a regime shift in pelagic food webs, the effect of ocean climate variability on the population was not obvious. we conclude that management efforts should focus on assessing and mitigating the effects of human-induced influences and consider the potential additive effects of climate change.",3,2010,33,9,1215,1226,10.1007/s00300-010-0811-2,0,0,1,1"Pechackova, S; Hadincova, V; Munzbergova, Z; Herben, T; Krahulec, F","restoration of species-rich, nutrient-limited mountain grassland by mowing and fertilization",RESTORATION ECOLOGY,Article,competition for nutrients; dominance; multivariate analysis; Polygonum bistorta; spatial scale; species composition; species richness,"mowing suppressed flowering and cover of p. bistorta and promoted target grassland species and richness. fertilization prevented nutrient impoverishment and increased height and dominance of the broad-leaved grasses with which many species-rich grassland herbs could coexist. the additive effect of the mowing/fertilization treatments was strong enough to act as a driver of p. bistorta suppression and associated community change. the litter removal treatment, however, had little effect on plant composition. the experiment demonstrates that in nutrient-limited grasslands, increasing nutrient levels in addition to mowing to manage competition for light can be used to control dominants. this contrasts with restoration of systems where after abandonment increased nutrient levels lead to the establishment of tall dominants that suppress other species by competition for light.",1,2010,18,,166,174,10.1111/j.1526-100X.2009.00615.x,0,0,1,1"Stott, LV; Dougher, TAO; Rew, LJ",developing native multispecies sod: an alternative rehabilitation method for disturbed lands,RESTORATION ECOLOGY,Article,California ecoregions; multispecies sod; native sod; percent cover; population dynamics; revegetation practices; turf,"natural and anthropogenic disturbance provides a mechanism for resetting the species assemblage within natural communities. following anthropogenic disturbance particularly, there are generally more weedy species. restoration of ecosystem structure and function in disturbed areas could aid in the control of these undesirable species. attempts to re-establish vegetation via direct sowing, hydroseeding, drill seeding, imprinting or plugging of either native or non-native species can be effective, but can result in increased erosion and weed proliferation prior to desirable cover of the intended species. the use of native species for rehabilitation can be preferable because non-native species are often less suited to the local environment and can pose a threat to the integrity of adjacent ecosystems. native multispecies sod could become a useful rehabilitation tool, but research is needed to determine which species to use and the appropriate number of species to include. mixtures of 4-7 native species were grown for 7 months, and clipped dry biomass, species percent abundance, and total ground cover were assessed over time in order to determine the suitability of 20 native species for sod production. despite differences between mixtures at some harvests, all mixtures established and produced similar biomass by the end of the study. final percent cover varied widely among species; 16 of the 20 species increased significantly over the course of production. differences in total ground cover between mixtures were explained by the growth of the particular species rather than any synergistic effect of species diversity.",1,2010,18,5,742,752,10.1111/j.1526-100X.2009.00532.x,1,0,0,1"Fridley, JD; Grime, JP",community and ecosystem effects of intraspecific genetic diversity in grassland microcosms of varying species diversity,ECOLOGY,Article,"ecosystem productivity; Festuca ovina; genotypic diversity; limestone grassland; maximum likelihood; neighborhood models; Sheffield, UK; species richness","studies of whether plant community structure and ecosystem properties depend on the genetic diversity of component populations have been largely restricted to species monocultures and have involved levels of genetic differentiation that do not necessarily correspond to that exhibited by neighboring mature individuals in the field. we established experimental communities of varying intraspecific genetic diversity, using genotypes of eight species propagated from clonal material of individuals derived from a small (100-m(2)) limestone grassland community, and tested whether genetic diversity (one, four, and eight genotypes per species) influenced community composition and annual aboveground productivity across communities of one, four, and eight species. eight-species communities were represented by common grass, sedge, and forb species, and four- and one-species communities were represented by four graminoids and the dominant grass festuca ovina, respectively. after three years of community development, there was a marginal increase of species diversity with increased genetic diversity in four- and eight-species communities, and genetic diversity altered the performance of genotypes in monospecific communities of f. ovina. however, shifts in composition from genetic diversity were not sufficient to alter patterns of community productivity. neighborhood models describing pairwise interactions between species indicated that genetic diversity decreased the intensity of competition between species in four-species mixtures, thereby promoting competitive equivalency and enhancing species equitability. in f. ovina monocultures, neighborhood models revealed both synergistic and antagonistic interactions between genotypes that were reduced in intensity on more stressful shallow soils. although the dependence of f. ovina genotype performance on neighborhood genetic composition did not influence total productivity, such dependence was sufficient to uncouple genotype performance in genetic mixtures and monocultures. our results point to an important connection between local genetic diversity and species diversity in this species-rich ecosystem but suggest that such community-level dependence on genetic diversity may not feedback to ecosystem productivity.",36,2010,91,8,2272,2283,10.1890/09-1240.1,1,1,0,2"Swope, SM; Parker, IM",trait-mediated interactions and lifetime fitness of the invasive plant centaurea solstitialis,ECOLOGY,Article,"biological control; California, USA; Centaurea solstitialis; cumulative stress; Eustenopus villosus; indirect interactions; interference; Puccinia jaceae f.s. solstitialis; synergy; yellow starthistle","plants interact with numerous enemies and mutualists simultaneously and sequentially. such multispecies interactions can give rise to trait-mediated indirect effects that are likely to be common in nature but which are also inherently difficult to predict. understanding multispecies interactions is also important in the use of biological control agents to control invasive plants because modern approaches to biocontrol rely on releasing multiple agents for each target weed. centaurea solstitialis is one of the most problematic invasive weeds in california, usa, and the weevil eustenopus villosus is its dominant biological control agent. we conducted a field experiment to quantitatively assess the direct effect of the recently approved biocontrol pathogen puccinia jaceae f.s. solstitialis on plant performance and any indirect effects that might arise by altering the plant's interactions with eustenopus or its pollinators (principally the nonnative apis mellifera). we documented both synergy and interference between the two biocontrol agents depending on the life stage of the weevil. puccinia infection increased the impact of bud-feeding by the adult weevils but reduced the impact of seed-feeding by larval weevils. neither infection nor eustenopus attack had an effect on pollinator visitation. the net effect was that attack by both the pathogen and the weevil did not reduce plant fitness relative to plants attacked only by the weevil. because the consequence to the plant of interacting with one species may depend on the presence or absence of other interacting species, a careful consideration of multispecies interactions may be necessary for the selection of biocontrol agents that act in a complementary manner to reduce plant fitness. likewise, relatively tractable weed-biocontrol systems allow us to examine multispecies interactions that can be difficult to study experimentally in native systems that are composed of numerous species with well-established populations.",11,2010,91,8,2284,2293,10.1890/09-0855.1,1,0,0,1"Kotowski, W; Beauchard, O; Opdekamp, W; Meire, P; van Diggelen, R",waterlogging and canopy interact to control species recruitment in floodplains,FUNCTIONAL ECOLOGY,Article,competition; establishment; functional diversity; functional traits; germination; mesocosm; multivariate analysis; plant community,"p>1. the extent to which seedling recruitment contributes to local functional diversity depends on the environmental filters operating in a plant community. classical community assembly models assume that habitat constraints and competition act like hierarchical filters with habitat filtering as the dominant one. alternative models assume a synergic interaction since responses to environmental stress and competition may impose physiological trade-offs in plants. 2. river floodplains are an ideal system to test the relationship between habitat and competition filtering in community (re)assembly, as flooding causes changes in both habitat stress (waterlogging, resulting in anoxia and toxicity) and competition (dieback of vegetation) on one hand and acts as an effective seed dispersal vector on the other hand. 3. we conducted a mesocosm experiment on early community assembly from a pool of 34 floodplain species covering a wetness gradient. seed mixtures were sown in a full factorial design with water level, canopy and mowing as controlling factors. we measured the biomass of all species after one growing season and determined germination and seedling growth traits, both outside (response to waterlogging/no waterlogging) and in a growth-chamber (response to light/darkness). 4. species recruitment was analysed in relation to the controlling factors and measured functional traits using co-inertia analysis. furthermore we analysed the effects of the controlling factors on several aspects of functional diversity. 5. there was no establishment in grass sward, unless mowing was applied. species-rich communities only developed when germination and early establishment phases occurred on waterlogged bare soil. high water level did not suppress establishment but reduced the total biomass and lowered inter-specific competition. the effect of mowing on species richness depended upon the interplay between waterlogging and canopy. 6. establishment success under canopy required seedling strategies to tolerate shade. the elimination of typical wetland specialists from oxic mesocosms was clearly an effect of their poorer and/or slower germination and lower competitive abilities in comparison to non-wetland plants, leading to their disappearance in this low-stress environment. 7. our results indicate that single stress factors can enhance species richness and functional diversity through limiting competition but a synergic interaction of different stresses can lead to reduced richness.",12,2010,24,4,918,926,10.1111/j.1365-2435.2009.01682.x,1,0,0,1"Clements, WH; Vieira, NKM; Church, SE",quantifying restoration success and recovery in a metal-polluted stream: a 17-year assessment of physicochemical and biological responses,JOURNAL OF APPLIED ECOLOGY,Article,benthic macroinvertebrates; ecological resistance and resilience; heavy metals; long-term assessment; recovery; restoration effectiveness; Salmo trutta,"p>1. evaluating the effectiveness of stream restoration is often challenging because of the lack of pre-treatment data, narrow focus on physicochemical measures and insufficient post-restoration monitoring. even when these fundamental elements are present, quantifying restoration success is difficult because of the challenges associated with distinguishing treatment effects from seasonal variation, episodic events and long-term climatic changes. 2. we report results of one of the most comprehensive and continuous records of physical, chemical and biological data available to assess restoration success for a stream ecosystem in north america. over a 17 year period we measured seasonal and annual changes in metal concentrations, physicochemical characteristics, macroinvertebrate communities, and brown trout salmo trutta populations in the arkansas river, a metal-contaminated stream in colorado, usa. 3. although we observed significant improvements in water quality after treatment, the effectiveness of restoration varied temporally, spatially and among biological response variables. the fastest recovery was observed at stations where restoration eliminated point sources of metal contamination. recovery of macroinvertebrates was significantly delayed at some stations because of residual sediment contamination and because extreme seasonal and episodic variation in metal concentrations prevented recolonization by sensitive species. 4. synthesis and applications. because recovery trajectories after the removal of a stressor are often complex or nonlinear, long-term studies are necessary to assess restoration success within the context of episodic events and changes in regional climate. the observed variation in recovery among chemical and biological endpoints highlights the importance of developing objective criteria to assess restoration success. although the rapid response of macroinvertebrates to reduced metal concentrations is encouraging, we have previously demonstrated that benthic communities from the arkansas river remained susceptible to other novel anthropogenic stressors. we suggest that the resistance or resilience of benthic macroinvertebrate communities to novel stressors may be effective indicators of restoration success that can account for the non-additive (e.g. synergistic) nature of compound perturbations.",15,2010,47,4,899,910,10.1111/j.1365-2664.2010.01838.x,1,0,1,2"Halpern, SL; Adler, LS; Wink, M",leaf herbivory and drought stress affect floral attractive and defensive traits in nicotiana quadrivalvis,OECOLOGIA,Article,Induced defenses; Manduca sexta; Nectar chemistry; Nicotine; Phenotypic plasticity,"adaptive phenotypic plasticity allows sessile organisms such as plants to match trait expression to the particular environment they experience. plasticity may be limited, however, by resources in the environment, by responses to prior environmental cues, or by previous interactions with other species, such as competition or herbivory. thus, understanding the expression of plastic traits and their effects on plant performance requires evaluating trait expression in complex environments, rather than across levels of a single variable. in this study, we tested the independent and combined effects of two components of a plant's environment, herbivory and water availability, on the expression of attractive and defensive traits in nicotiana quadrivalvis in the greenhouse. damage and drought did not affect leaf nicotine concentrations but had additive and non-additive effects on floral attractive and defensive traits. plants in the high water treatment produced larger flowers with more nectar than in the low water treatment. leaf damage induced greater nectar volumes in the high water treatment only, suggesting that low water limited plastic responses to herbivore damage. leaf damage also tended to induce higher nicotine concentrations in nectar, consistent with other studies showing that leaf damage can induce floral defenses. our results suggest that there are separate and synergistic effects of leaf herbivory and drought on floral trait expression, and thus plasticity in response to complex environments may influence plant fitness via effects on floral visitation and defense.",19,2010,163,4,961,971,10.1007/s00442-010-1651-z,1,0,1,2"Cobb, RC",species shift drives decomposition rates following invasion by hemlock woolly adelgid,OIKOS,Article,,"insect and disease outbreak is an important cause of selective species removal and accompanying functional change in north american forests. outbreak of hemlock woolly adelgid, adelgies tsugae - hwa, is causing selective removal of eastern hemlock tsuga canadensis at a regional scale. impacts of outbreak-caused canopy mortality and shifts in dominant species on litter decay were compared across sites that range in hwa-caused canopy damage and subsequent canopy dominance by black birch betula lenta. senescent litter from eastern hemlock, black birch, and equal litter mixes were decomposed in the field for 36 months within nine sites in connecticut and massachusetts usa. mass loss and % n accumulation of black birch was 65% and 52% greater compared to eastern hemlock. in contrast, outbreak related canopy damage increased litter mass loss by 11.5% in high mortality stands relative to uninfested stands but canopy damage had no impact on % n dynamics. non-additive effects of litter mixing influenced chemical dynamics of decaying litter; black birch accumulated less n and eastern hemlock accumulated more n compared to each species decaying alone. however, these changes offset and mixed litter bags overall showed no differences in n dynamics compared to values from each species decaying alone. in eastern hemlock stands invaded by hemlock woolly adelgid, canopy damage influences the rates and dynamics of decay but species differences between hemlock and black birch leaf litter are the dominant mechanisms of decomposition changes and a long-lasting driver of increased n cycling rates. species shifts may be the dominant driver of altered ecosystem processes for other insect outbreaks, particularly when replacement species have very different characteristics regulating decomposition and n cycling.",13,2010,119,8,1291,1298,10.1111/j.1600-0706.2009.18308.x,0,0,1,1"Carboni, M; Thuiller, W; Izzi, F; Acosta, A",disentangling the relative effects of environmental versus human factors on the abundance of native and alien plant species in mediterranean sandy shores,DIVERSITY AND DISTRIBUTIONS,Article,Biological invasions; coastal dunes; diversity patterns; environmental and human determinants; exotic species; inference-based model,"aim mediterranean coastal sand dunes are characterized by both very stressful environmental conditions and intense human pressure. this work aims to separate the relative contributions of environmental and human factors in determining the presence/abundance of native and alien plant species in such an extreme environment at a regional scale. location 250 km of the italian tyrrhenian coast (region lazio). methods we analysed alien and native plant richness and fitted generalized additive models in a multimodel-inference framework with comprehensive randomizations to evaluate the relative contribution of environmental and human correlates in explaining the observed patterns. results native and alien richness are positively correlated, but different variables influence their spatial patterns. for natives, human population density is the most important factor and is negatively related to richness. numbers of natives are unexpectedly lower in areas with a high proportion of natural land cover (probably attributable to local farming practices) and, to a lesser degree, affected by the movement of the coastline. on the other hand, alien species richness is strongly related to climatic factors, and more aliens are found in sectors with high rainfall. secondarily, alien introductions appear to be related to recent urban sprawl and associated gardening. main conclusions well-adapted native species in a fragile equilibrium with their natural environment are extremely sensitive to human-driven modifications. on the contrary, for more generalist alien species, the availability of limited resources plays a predominant role.",20,2010,16,4,537,546,10.1111/j.1472-4642.2010.00677.x,0,0,1,1"Poulter, B; Aragao, L; Heyder, U; Gumpenberger, M; Heinke, J; Langerwisch, F; Rammig, A; Thonicke, K; Cramer, W",net biome production of the amazon basin in the 21st century,GLOBAL CHANGE BIOLOGY,Article,carbon cycle; climate change; deforestation; dynamic global vegetation model; fire; LPJmL,"global change includes multiple stressors to natural ecosystems ranging from direct climate and land-use impacts to indirect degradation processes resulting from fire. humid tropical forests are vulnerable to projected climate change and possible synergistic interactions with deforestation and fire, which may initiate a positive feedback to rising atmospheric co(2). here, we present results from a multifactorial impact analysis that combined an ensemble of climate change models with feedbacks from deforestation and accidental fires to quantify changes in amazon basin carbon cycling. using the lpjml dynamic global vegetation model, we modelled spatio-temporal changes in net biome production (nbp); the difference between carbon fluxes from fire, deforestation, soil respiration and net primary production. by 2050, deforestation and fire (with no co(2) increase or climate change) resulted in carbon losses of 7.4-20.3 pg c with the range of uncertainty depending on socio-economic storyline. during the same time period, interactions between climate and land use either compensated for carbon losses due to wetter climate and co(2) fertilization or exacerbated carbon losses from drought-induced forest mortality (-20.1 to +4.3 pg c). by the end of the 21st century, depending on climate projection and the rate of deforestation (including its interaction with fire), carbon stocks either increased (+12.6 pg c) or decreased (-40.6 pg c). the synergistic effect of deforestation and fire with climate change contributed up to 26-36 pg c of the overall decrease in carbon stocks. agreement between climate projections (n=9), not accounting for deforestation and fire, in 2050 and 2098 was relatively low for the directional change in basin-wide nbp (19-37%) and aboveground live biomass (13-24%). the largest uncertainty resulted from climate projections, followed by implementation of ecosystem dynamics and deforestation. our analysis partitions the drivers of tropical ecosystem change and is relevant for guiding mitigation and adaptation policy related to global change.",18,2010,16,7,2062,2075,10.1111/j.1365-2486.2009.02064.x,1,0,0,1"Dmitriew, C; Blows, MW; Rowe, L",ontogenetic change in genetic variance in size depends on growth environment,AMERICAN NATURALIST,Article,compensatory growth; quantitative genetics; ontogeny; G x E; canalization; mutational target size,"within populations, the amount of environmental and genetic variation present may differ greatly among traits measured at multiple times over ontogeny. brief periods of food deprivation are often followed by a period of accelerated (compensatory) growth. early laboratory studies likewise reported a contraction of genetic variance in size as maturation approached. however, studies of wild populations often contradict these laboratory results. one possibility is that environmentally imposed stress is exposing genetic variance not seen in the laboratory. we tested the effect of rearing environment (high or low food) on genetic variance in size traits measured at two ages in the ladybird beetle harmonia axyridis. a substantial amount of genetic variance was present in all combinations of rearing environment by ontogenetic stage among males. the pattern of change in male variance in mass over ontogeny was of opposite sign in the two food treatments, which may reflect cryptic genetic variance that is apparent only under stress. the proportion of overall variance that was due to additive genetic effects was much lower in females than in males, which suggests that the underlying genetics of female growth trajectories differs from that males. our experimental design afforded an initial exploration of the genetics of compensatory growth.",15,2010,175,6,640,649,10.1086/652470,0,0,1,1"Duman, F; Ozturk, F; Aydin, Z",biological responses of duckweed (lemna minor l.) exposed to the inorganic arsenic species as(iii) and as(v): effects of concentration and duration of exposure,ECOTOXICOLOGY,Article,Arsenite; Arsenate; Lemna minor; Bioaccumulation; Exposure; Duration,"the accumulation of arsenic (as) and physiological responses of lemna minor l. under different concentration (0, 1, 4, 16 and 64 mu m) and duration (1, 2, 4 and 6 days) of two species as, naaso(2) and na(2)haso(4)center dot 7h(2)o, were studied in hydroponics. the accumulation of both as species depended on as concentration and exposure duration. the highest accumulation of as was found as 17408 and 8674 mu g g(-1), for plants exposed to 64 mu m of as(iii) and as(v), respectively, after 6 days. two-way anova analyses indicated that, for plants exposed to arsenite (as(iii)), exposure duration had a greater effect than concentration on as accumulation. conversely, exposure concentration had a greater effect on as accumulation in plants exposed to arsenate (as(v)). arsenic exposure levels, approaching 16 mu m for as(iii) and 64 mu m for as(v), did not significantly affect ec values. beyond these exposure concentrations, ec values increased in a manner that depended on duration. significant effect of as(iii) on lipid peroxidation was observed at 1 mu m application whereas, this effect started to be significant after an exposure to 16 mu m as(v). for both as(iii) and as(v), photosynthetic pigment levels slightly increased for the first day with respect to the control, followed by a gradual decline at higher concentrations and durations. an increase in protein content and enzyme activity was observed at moderate exposure conditions, followed by a decrease. significant positive correlations were determined between accumulated as and ion leakage and lipid peroxidation. negative correlations were found between accumulated as and total chlorophyll and protein content. our results suggested that exposure duration and concentration had a strong synergetic effect on antioxidant enzyme activity. the findings of the present study may be useful when this plant is used as a phytoremediator in arsenic-polluted water.",20,2010,19,5,983,993,10.1007/s10646-010-0480-5,1,0,0,1"Mitchell, KA; Hoffmann, AA",thermal ramping rate influences evolutionary potential and species differences for upper thermal limits in drosophila,FUNCTIONAL ECOLOGY,Article,knockdown time; thermal tolerance; phylogenetic contrasts; Drosophila; ramping,"p>1. thermal tolerance is a key factor limiting insect distributions, but there is limited information on the ability of species to evolve different thermal limits. recent studies indicate that the experimental protocol influences upper limits, with slower but ecologically relevant rates of warming lowering estimates of tolerance. these effects could also influence genetic and environmental variances that define evolutionary potential. 2. to determine the influence of experimental protocol on estimates of narrow sense heritability (h2(n)) and other measures of evolutionary potential in drosophila melanogaster, we conducted family studies on knockdown time when flies were immediately exposed to a high temperature (static) or when temperature was increased to an upper limit (ramping). 3. estimates of variance components in two populations were obtained using the animal model approach that incorporates information from all relationships among relatives. coefficients of variation were higher when flies were exposed to a static stress, as were estimates of additive genetic variance and measures of evolvability where genetic variances were standardized by trait means. in contrast, levels of environmental variance were higher under ramping conditions. these effects mean that the narrow sense heritability of thermal resistance was low under slow ramping and did not differ significantly from zero. 4. differences in thermal limits under both methods were detected among drosophila species. there was a significant positive relationship between the fast and slow ramping estimates of thermal resistance across species after correction for phylogeny, suggesting similar underlying mechanisms or a history of correlated evolution. however, this result was caused by the strong influence of two taxa. 5. these results suggest that natural populations exhibit lower adaptive potential for upper thermal limits under ramping than estimated from traditional (static) estimates of heat resistance. even the highly adaptable drosophila melanogaster appears to have little evolutionary potential to extend its upper thermal range under ramping conditions although species have diverged for this measure.",63,2010,24,3,694,700,10.1111/j.1365-2435.2009.01666.x,0,0,1,1"Pajares, JA; Alvarez, G; Ibeas, F; Gallego, D; Hall, DR; Farman, DI","identification and field activity of a male-produced aggregation pheromone in the pine sawyer beetle, monochamus galloprovincialis",JOURNAL OF CHEMICAL ECOLOGY,Article,Aggregation pheromone; Bursaphelenchus xylophilus; Cerambycidae; Ethers; Gas chromatography-electroantennographic recording; Kairomone; Lamiinae; Monochaminae; Monochamus galloprovincialis; Pine sawyer; Pine wilt disease; Pine wood nematode; Trapping; 2-Undecyloxy-1-ethanol,"the pine sawyer beetle, monochamus galloprovincialis, is a pest of pine trees in europe and north africa. previously considered a secondary pest of stressed and dying trees, it is now receiving considerable attention as a vector of the pine wood nematode, bursaphelenchus xylophilus, the causal agent of a lethal wilting disease in susceptible species of pines. adult beetles are attracted to traps baited with a kairomone blend consisting of a host volatile, alpha-pinene, and two bark beetle pheromone components, ipsenol and 2-methyl-3-buten-2-ol. more recently it has been shown that mature male m. galloprovincialis produce a pheromone that attracts mature females in a laboratory bioassay. here, volatiles were collected from mature male and female m. galloprovincialis, and a compound produced specifically by mature males was identified as 2-undecyloxy-1-ethanol from its gas chromatographic retention times, its mass spectrum, and by comparison with synthetic standards. the naturally-derived and synthetic compounds elicited electroantennographic responses from both females and males. sealed polyethylene vials and polyethylene sachets were shown to be effective dispensers with zero-order release, the latter giving a higher release rate than the former. in two field tests, multiple-funnel traps baited with synthetic 2-undecyloxy-1-ethanol caught both female and male m. galloprovincialis, with higher catches at the higher release rate. this compound also synergized the attractiveness of the kairomone blend, the combined mixture catching 80-140% more beetles than the sum of the catches to each bait separately and luring up to two beetles/trap/d in a moderate-density population. we conclude that 2-undecyloxy-1-ethanol is a male-produced aggregation pheromone of m. galloprovincialis. this is the first example of a sex-specific compound in the cerambycid subfamily lamiinae with significant behavioral activity in the field at a range sufficient to make it a useful trap bait. the possible roles of this pheromone in the chemical ecology of m. galloprovincialis and its potential use in pine wilt disease management are discussed.",36,2010,36,6,570,583,10.1007/s10886-010-9791-5,1,0,0,1"Westley, PAH; Schindler, DE; Quinn, TP; Ruggerone, GT; Hilborn, R","natural habitat change, commercial fishing, climate, and dispersal interact to restructure an alaskan fish metacommunity",OECOLOGIA,Article,Aquatic metacommunities; Dispersal; Disturbance response; Chignik Lake; Climate change,"the metacommunity concept has recently been described to account for the roles of dispersal in regulating community structure. despite its strong theoretical basis, there exist few large-scale and long-term examples of its applicability in aquatic ecosystems. in this study we used a long-term dataset (1961-2007) on the relative abundances of the dominant limnetic fishes from two interconnected lakes to investigate the synergistic effects of naturally declining lake volume (approximately 50% in 50 years), climate variation, fishery management, and dispersal on community composition. we found a marked shift in fish community composition and variability during a period of rapid natural habitat change; however, the change was most apparent in the downstream, more stable lake of the system rather than at the site of disturbance. multivariate analysis suggested significant shifts in community composition and variability in the downstream lake. results indicated that the community composition in both lakes was best explained by habitat loss in the upper watershed and the number of spawning adult sockeye salmon the previous year (reflecting both natural processes and commercial fishing). furthermore, communities exhibited site-specific responses to climatic conditions (e.g., index of the pacific decadal oscillation), whereby the upper lake responded to climate within a given year and with a 1-year time lag, whereas the downstream community responded only with a 1-year lag. we attribute this difference largely to downstream dispersal and recruitment of fish from the upper lake. thus, we suggest that the interconnected nature of the communities in this system provides a useful and large-scale example of the metacommunity concept, whereby the effects of environmental disturbance on community structure ultimately depend on the effects of these disturbances on dispersal among ecosystems.",12,2010,163,2,471,484,10.1007/s00442-009-1534-3,1,0,0,1"Sundback, K; Alsterberg, C; Larson, F",effects of multiple stressors on marine shallow-water sediments: response of microalgae and meiofauna to nutrient-toxicant exposure,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,Benthic microalgae; Grazing; Meiofauna; Multiple-stressors; Nutrients; PAH,"two types of common stressors acting simultaneously on shallow coastal ecosystems include increased anthropogenic nutrient loading and exposure to toxicants. nutrients (inorganic nitrogen and phosphorus) and the polyaromatic hydrocarbon (pah) pyrene were added singly and in combination, to study the combined effects of nutrients and toxicants on the base of the food web of a shallow-water illuminated sediment. the microbenthic community of natural sieved, sediment was used in a in a flow-through laboratory experiment lasting 28 days. variables measured included benthic microalgal and meiofaunal biomass and composition, and meiofaunal grazing rates. the hypotheses were that (i) pyrene exposure affects meiofauna and their grazing rate, resulting in increased benthic microalgal biomass, and that (ii) pyrene effects depend on nutrient status, as found in previous mesocosm experiments. our results showed that exposure to a low, environmentally realistic concentration of pyrene had a general negative effect on meiofauna and their grazing rates, although major taxonomical groups differed in response. a concomitant increase in benthic microalgal biomass suggested a cascading effect on the primary producers. whether there was a significant interaction between pyrene and nutrient status depended on the variable measured. while toxicant effects on total meiofaunal grazing rate, chlorophyll a content of the sediment and microalgal composition depended on nutrient status, the effects on meiofaunal and algal biomass (based on cell counts) did not. we found only partial support for our specific hypothesis that pyrene effects were greater when nutrient concentrations were high. the mode of nutrient-toxicant interaction appeared to vary with variable: non-additive effects (antagonistic or synergistic) were more common than additive effects, but some effects could also be interpreted according to a comparative model. this apparent variation in interaction mode highlights the complexity of nutrient-toxicant interactions - and of multiple stressors in general - in the marine benthic environment, emphasizing the need to consider both structural and functional variables when assessing effects of stressor interactions. moreover, the presence of potential indirect, food web-mediated effects underlines the need to test multiple-stressor effects using multitrophic communities. (c) 2010 elsevier b.v. all rights reserved.",17,2010,388,02-Jan,39,50,10.1016/j.jembe.2010.03.007,1,1,1,3"Atalah, J; Crowe, TP","combined effects of nutrient enrichment, sedimentation and grazer loss on rock pool assemblages",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,Multiple stressors; Synergies; Disturbance; Hard-bottom communities; Top-down; Bottom-up; Macroalgae,"coastal areas around the world are experiencing increasing disturbance from multiple stressors caused by anthropogenic activities. although there is good knowledge about the impacts of individual stressors, there is less understanding of the consequences of several stressors acting simultaneously. eutrophication and sediment deposition are widely recognized as major problems for the functioning of coastal systems, and they are expected to increase during the next decades. in a field experiment, using rock pools as a model system, different levels of nutrients and sedimentation were applied in a factorial experimental design that also accounted for the influence of molluscan grazers. sedimentation significantly changed assemblage structure, mainly owing to an increase in turfing and filamentous algae and a decrease in crustose algae. nutrients also caused an increase in the cover of green filamentous algae, which in turn was synergistically magnified by the removal of grazers. here we showed that these stressors can individually alter the structure of rock pools assemblages; and that in this system top-down control (by grazers) is more important than bottom-up factors (nutrients) in controlling macroalgal assemblage structure. the combined effect of grazers loss and nutrients was larger than the sum of their individual effects. this study enhanced mechanistic understanding of the impacts of multiple stressors on coastal ecosystems, which will help to develop management strategies and conservation of the marine environment. (c) 2010 elsevier b.v. all rights reserved.",19,2010,388,02-Jan,51,57,10.1016/j.jembe.2010.03.005,1,0,0,1"Ashe, E; Noren, DP; Williams, R",animal behaviour and marine protected areas: incorporating behavioural data into the selection of marine protected areas for an endangered killer whale population,ANIMAL CONSERVATION,Article,disturbance; marine protected area; habitat conservation; behaviour; spatial model; hotspot,"like many endangered wildlife populations, the viability and conservation status of 'southern resident' killer whales orcinus orca in the north-east pacific may be affected by prey limitation and repeated disturbance by human activities. marine protected areas (mpas) present an attractive option to mitigate impacts of anthropogenic activities, but they run the risk of tokenism if placed arbitrarily. notwithstanding recreational and industrial marine traffic, the number of commercial vessels in the local whalewatching fleet is approaching the number of killer whales to be watched. resident killer whales have been shown to be more vulnerable to vessel disturbance while feeding than during resting, travelling or socializing activities, therefore protected-areas management strategies that target feeding 'hotspots' should confer greater conservation benefit than those that protect habitat generically. classification trees and spatially explicit generalized additive models were used to model killer whale habitat use and whale behaviour in inshore waters of washington state (usa) and british columbia (bc, canada). here we propose a candidate mpa that is small (i.e. a few square miles), but seemingly important. killer whales were predicted to be 2.7 times as likely to be engaged in feeding activity in this site than they were in adjacent waters. a recurring challenge for cetacean mpas is the need to identify areas that are large enough to be biologically meaningful while being small enough to allow effective management of human activities within those boundaries. our approach prioritizes habitat that animals use primarily for the activity in which they are most responsive to anthropogenic disturbance.",11,2010,13,2,196,203,10.1111/j.1469-1795.2009.00321.x,0,0,1,1"Carilli, JE; Norris, RD; Black, B; Walsh, SM; McField, M",century-scale records of coral growth rates indicate that local stressors reduce coral thermal tolerance threshold,GLOBAL CHANGE BIOLOGY,Article,climate change; coral bleaching; Mesoamerican reef; Montastraea faveolata; resilience; sclerochronology,"coral bleaching, during which corals lose their symbiotic dinoflagellates, appears to be increasing in frequency and geographic extent, and is typically associated with abnormally high water temperatures and solar irradiance. a key question in coral reef ecology is whether local stressors reduce the coral thermal tolerance threshold, leading to increased bleaching incidence. using tree-ring techniques, we produced master chronologies of growth rates in the dominant reef builder, massive montastraea faveolata corals, over the past 75-150 years from the mesoamerican reef. our records indicate that the 1998 mass bleaching event was unprecedented in the past century, despite evidence that water temperatures and solar irradiance in the region were as high or higher mid-century than in more recent decades. we tested the influence on coral extension rate from the interactive effects of human populations and thermal stress, calculated here with degree-heating-months (dhm). we find that when the effects of chronic local stressors, represented by human population, are taken into account, recent reductions in extension rate are better explained than when dhm is used as the sole predictor. therefore, the occurrence of mass bleaching on the mesoamerican reef in 1998 appears to stem from reduced thermal tolerance due to the synergistic impacts of chronic local stressors.",31,2010,16,4,1247,1257,10.1111/j.1365-2486.2009.02043.x,1,0,0,1"Kelly, DW; Poulin, R; Tompkins, DM; Townsend, CR",synergistic effects of glyphosate formulation and parasite infection on fish malformations and survival,JOURNAL OF APPLIED ECOLOGY,Article,disease; fish populations; glyphosate; malformation; multiple stressors; parasite; Roundup; toxicity tests,"p>1. anthropogenic pollution and disease can cause both lethal and sub-lethal effects in aquatic species but our understanding of how these stressors interact is often not known. contaminants can reduce host resistance to disease, but whether hosts are impacted at environmentally relevant concentrations is poorly understood. 2. we investigated the independent and combined effects of exposure to the common herbicide glyphosate and the trematode parasite telogaster opisthorchis on survival and the development of spinal malformations in juvenile galaxias anomalus, a new zealand freshwater fish. we then investigated how exposure to a glyphosate concentration gradient (0 center dot 36, 3 center dot 6, 36 mg active ingredient (a.i.) l-1) affected the production and release of the infective cercarial stage of the parasite by its snail intermediate host potamopyrgus antipodarum. 3. survival of juvenile fish was unaffected by exposure to glyphosate alone (at an environmentally relevant concentration; 0 center dot 36 mg a.i. l-1) or by t. opisthorchis infection alone. however, simultaneous exposure to infection and glyphosate significantly reduced fish survival. 4. juvenile fish developed spinal malformations when exposed either to infections alone or to infections and glyphosate, with a trend towards greater severity of spinal malformation after exposure to both stressors. 5. all snails exposed to the highest glyphosate concentration (36 mg a.i. l-1) died within 24 h. snails exposed to a moderate concentration (3 center dot 6 mg a.i. l-1) produced significantly more t. opisthorchis cercariae than snails in the control group or the low concentration group (0 center dot 36 mg a.i. l-1; the same concentration as in the fish experiment). 6. synthesis and applications. this is the first study to show that parasites and glyphosate can act synergistically on aquatic vertebrates at environmentally relevant concentrations, and that glyphosate might increase the risk of disease in fish. our results have important implications when identifying risks to aquatic communities and suggest that threshold levels of glyphosate currently set by regulatory authorities do not adequately protect freshwater systems.",17,2010,47,2,498,504,10.1111/j.1365-2664.2010.01791.x,1,0,0,1"Rubio-Casal, AE; Leira-Doce, P; Figueroa, ME; Castillo, JM",contrasted tolerance to low and high temperatures of three tree taxa co-occurring on coastal dune forests under mediterranean climate,JOURNAL OF ARID ENVIRONMENTS,Article,Chilling; Chlorophyll fluorescence; Drought; Photosynthesis; Thermal stress,"this work compares the tolerance to low and high temperatures of the photosynthetic apparatus of the tree species pinus pinea, juniperus oxycedrus subsp. macrocarpa and juniperus phoenicea subsp. turbinata, which co-occur on coastal dunes under mediterranean climate on sw iberian peninsula. chlorophyll (chl) fluorescence, gas exchange and water potential (w) measurements were recorded for over two years in the field and in a controlled-temperature study. p. pinea showed a high sensitivity to the combined effects of drought and high temperatures at the end of the drier and warmer summers. in addition, its net photosynthetic rate decreased with warmer temperatures. the lower thermotolerance of r pinea to higher temperatures was supported by the laboratory results. j. oxycedrus showed the lowest tolerance to chilling stress with its highest chronic photoinhibition levels during wetter and colder periods and its lower net photosynthetic rates at lower temperatures. the photosynthetic apparatus of j. phoenicea showed a suboptimal state during summertime denoted as high chronic photoinhibition levels that increased with lower w. these results show that air temperature, with its synergic effects in combination with drought and solar radiation, is a key climatic factor conditioning stress levels of tree species growing on coastal sand dunes under mediterranean climate. (c) 2009 elsevier ltd. all rights reserved.",9,2010,74,4,429,439,10.1016/j.jaridenv.2009.10.004,1,0,0,1"Lejeusne, C; Chevaldonne, P; Pergent-Martini, C; Boudouresque, CF; Perez, T","climate change effects on a miniature ocean: the highly diverse, highly impacted mediterranean sea",TRENDS IN ECOLOGY & EVOLUTION,Review,,"little doubt is left that climate change is underway, strongly affecting the earth's biodiversity. some of the greatest challenges ahead concern the marine realm, but it is unclear to what extent changes will affect marine ecosystems. the mediterranean sea could give us some of the answers. data recovered from its shores and depths have shown that sea temperatures are steadily increasing, extreme climatic events and related disease outbreaks are becoming more frequent, faunas are shifting, and invasive species are spreading. this miniature ocean can serve as a giant mesocosm of the world's oceans, with various sources of disturbances interacting synergistically and therefore providing an insight into a major unknown: how resilient are marine ecosystems, and how will their current functioning be modified?",154,2010,25,4,250,260,,1,0,0,1"Saona, NM; Albrectsen, BR; Ericson, L; Bazely, DR",environmental stresses mediate endophyte-grass interactions in a boreal archipelago,JOURNAL OF ECOLOGY,Article,antagonist-mutualist continuum; endophyte; Epichloe festucae; Festuca rubra; grass; herbivory; nutrient stress; Sweden; symbiosis; water stress,"1. both evolutionary theory and empirical evidence from agricultural research support the view that asexual, vertically transmitted fungal endophytes are typically plant mutualists that develop high infection frequencies within host grass populations. in contrast, endophyte-grass interactions in natural ecosystems are more variable, spanning the range from mutualism to antagonism and comparatively little is known about their range of response to environmental stress. 2. we examined patterns in endophyte prevalence and endophyte-grass interactions across nutrient and grazing (from greylag and canada geese) gradients in 15 sites with different soil moisture levels in 13 island populations of the widespread grass festuca rubra in a boreal archipelago in sweden. 3. in the field, endophyte prevalence levels were generally low (range = 10-53%) compared with those reported from agricultural systems. under mesic-moist conditions endophyte prevalence was constantly low (mean prevalence = 15%) and was not affected by grazing pressure or nutrient availability. in contrast, under conditions of drought, endophyte prevalence increased from 10% to 53% with increasing nutrient availability and increasing grazing pressure. 4. in the field, we measured the production of flowering culms, as a proxy for host fitness, to determine how endophyte-infected plants differed from uninfected plants. at dry sites, endophyte infection did not affect flowering culm production. in contrast, at mesic-moist sites production of flowering culms in endophyte-infected plants increased with the covarying effects of increasing nutrient availability and grazing pressure, indicating that the interaction switched from antagonistic to mutualistic. 5. a concurrent glasshouse experiment showed that in most situations, the host appears to incur some costs for harbouring endophytes. uninfected grasses generally outperformed infected grasses (antagonistic interaction), while infected grasses outperformed uninfected grasses (mutualistic interaction) only in dry, nutrient-rich conditions. nutrient and water addition affected tiller production, leaf number and leaf length differently, suggesting that tillers responded with different strategies. this emphasizes that several response variables are needed to evaluate the interaction. 6. synthesis. this study found complex patterns in endophyte prevalence that were not always correlated with culm production. these contrasting patterns suggest that the direction and strength of selection on infected plants is highly variable and depends upon a suite of interacting environmental variables that may fluctuate in the intensity of their impact, during the course of the host life cycle.",16,2010,98,2,470,479,10.1111/j.1365-2745.2009.01613.x,0,1,0,1"Vuleta, A; Jovanovic, SM; Seslija, D; Tucic, B",seasonal dynamics of foliar antioxidative enzymes and total anthocyanins in natural populations of iris pumila l.,JOURNAL OF PLANT ECOLOGY,Article,SOD; CAT; POD; anthocyanins; seasonal variation,"aims plants in their natural habitats frequently cope with a multitude of abiotic stresses, such as high light intensity, extreme temperatures and water deficit, which often co-occur during periods of drought, especially in semi-arid and arid regions exposure of plants to stressful environmental conditions usually induce overproduction of reactive oxygen species (ros) that, as highly toxic derivatives of o-2, can assault all cell macromolecules, leading to the disruption of cellular homeostasis and, consequently, the uncoupling of major metabolic processes, the photosynthesis and photorespiration in order to minimize ros-mediated cellular damage, plants have evolved highly efficient antioxidative defense systems that include both enzymatic and non-enzymatic components since abiotic stress call also operate as a strong evolutionary force that shapes adaptations in natural plant populations, the aim of this study was to examine the seasonal variation patterns of two distinct antioxidative systems, ros-scavenging enzymes and anthocyanin pigments, in the leaf tissue of a steppe plant, iris pumila, as expressed under contrasting light conditions that the species regularly experiences in the wild methods we selected two natural populations of i pumila inhabiting the alternative radiation environments in the deliblato sands, a sun-exposed dune site and a woodland understory the specific activity of three antioxidative enzymes, superoxide dismutase (sod) catalase (cat) and peroxidase (pod) and the content of total anthocyanins were examined in leaves of i pumila plants collected from each of the 31 iris clones (17 in the exposed popula tion and 14 in the shaded population) once during each of the three seasons, spring, summer and autumn in 2004 specifically, a fully expanded leaf was cut from each clonal plant between 15 00 and 16 00 h, immediately frozen in liquid nitrogen and stored at -70 degrees c until preparation important findings generally, all three antioxidative enzymes were up-regulated in summer-harvested leaves compared to their spring or autumn counterparts, as was observed for the concentration of foliar anthocyanins, indicating that strengthening of antioxidant systems was the key mechanism for long-term acclimatization of i pumila plants to stressful environmental conditions within their natural ecological niches when plants from contrasting radiation environments were compared, sod and cat activities appeared to be greater in shade-exposed than in sun-exposed leaves conversely, pod activity and the content of foliar anthocyanins were notably higher in foliage experiencing full sunlight relative to those developed under vegetation canopy, suggesting the synergistic function of these two molecules in protecting leaf cells against photoinhibitory and photooxidative effects of strong light",6,2010,3,1,59,69,10.1093/jpe/rtp019,1,0,0,1"Overgaard, J; Sorensen, JG; Jensen, LT; Loeschcke, V; Kristensen, TN",field tests reveal genetic variation for performance at low temperatures in drosophila melanogaster,FUNCTIONAL ECOLOGY,Article,candidate genes; cold tolerance; field fitness; genetic variation; laboratory vs; field comparison; transcriptomics,"p>1. physiological and evolutionary responses underlying thermal adaptation and acclimation are often investigated under controlled laboratory conditions. such studies may fail to assess ecologically relevant parameters as they do not account for the complexity of the natural environment. 2. we investigated a population of drosophila melanogaster for performance at low temperature conditions in the field using release recapture assays and in the laboratory using standard cold resistance assays. the aim of the study was to get a better understanding of the nature and underlying mechanisms of the trait measured in field recapture studies and the association between field performance and fitness measures estimated in the laboratory. 3. we performed one generation of selection on the ability to reach a resource at low temperature under field conditions. flies that reached a resource ('mobile') and those that never left the release site ('stationary') were reared to the f1 and f2 generation in the laboratory. subsequent field releases with these flies demonstrated a clear genetic differentiation between mobile and stationary flies in their ability to reach resources at low temperatures in the field. this indicates that mobility at low temperature is under additive genetic influence. in contrast mobile and stationary flies were generally indistinguishable when tested in standard laboratory tests of cold performance. the genetic differentiation between the two sub-populations was not linked to allelic variation in known candidate genes for cold adaptation. however, using transcriptomics we identified new candidate genes (transcripts) and pathways that differed between the mobile and stationary flies. 4. the current study reveals an irregular relationship between cold performance in the field and in the laboratory. based on these results, we suggest that the ecological relevance of laboratory assays should be evaluated more critically in studies of thermal adaptation and hardening/acclimation.",13,2010,24,1,186,195,10.1111/j.1365-2435.2009.01615.x,0,0,1,1"Alton, LA; Wilson, RS; Franklin, CE",risk of predation enhances the lethal effects of uv-b in amphibians,GLOBAL CHANGE BIOLOGY,Article,amphibian declines; chemical cues; multiple stressors; predation; ultraviolet-B radiation,"amphibian declines are a prominent part of the global biodiversity crisis and have received special consideration because they have occurred relatively recently, on a global scale, and in seemingly pristine habitats where no obvious anthropogenic cause is apparent. although several causes for declines have been implicated, the isolation of a singular cause has proven elusive. consequently, it has been hypothesized that complex interactions between multiple environmental stressors, particularly those associated with global change, may be responsible. increasing ultraviolet-b radiation (uv-b) associated with stratospheric ozone depletion is one such stressor that has received considerable attention. uv-b causes enhanced lethal effects when combined with other factors such as aquatic ph, contaminants, temperature and pathogens, but little is known of how uv-b interacts with pervasive biological stressors, such as risk of predation. we exposed limnodynastes peronii tadpoles to uv-b and predatory chemical cues in a controlled laboratory experiment to determine their independent and interactive effects on survival and morphology. we show that uv-b and risk of predation interact synergistically to enhance mortality above the additive effects of the independent stressors, and that exposure to uv-b affects the ability of tadpoles to morphologically respond to predatory chemical cues (i.e. predator-induced phenotypic plasticity), which has implications for their survival in an environment with predators. this highlights the importance of considering both anthropogenic and naturally occurring stressors when examining the underlying causes of amphibian declines.",17,2010,16,2,538,545,10.1111/j.1365-2486.2009.02010.x,1,0,1,2"Wittmer, MHOM; Auerswald, K; Bai, YF; Schaufele, R; Schnyder, H",changes in the abundance of c3/c4 species of inner mongolia grassland: evidence from isotopic composition of soil and vegetation,GLOBAL CHANGE BIOLOGY,Article,delta 13C; carbon isotope discrimination; crossover temperature; geostatistics; precipitation; semivariogram; soil organic carbon; Suess effect; wool,"global warming, increasing co(2) concentration, and environmental disturbances affect grassland communities throughout the world. here, we report on variations in the c3/c4 pattern of inner mongolian grassland derived from soil and vegetation. soil samples from 149 sites covering an area of approximately 250 000 km2 within inner mongolia, people's republic of china were analyzed for the isotopic composition (delta 13c) of soil organic carbon (soc). the contrast in delta 13c between c3 and c4 plants allowed for calculation of the c3/c4 ratio from delta 13c of soc with a two-member mixing model, which accounted for influences of aridity and altitude on delta 13c of the c3 end-member and for changes in delta 13c of atmospheric co(2). maps were created geostatistically, and showed a substantially lower c4 abundance in soil than in recent vegetation (-10%). the difference between soil and vegetation varied regionally and was most pronounced within an e-w belt along 44 degrees n and in a mountainous area, suggesting a spread of c4 plants toward northern latitudes (about 1 degrees) and higher altitudes. the areas of high c4 abundance for present vegetation and soc were well delineated by the isotherms of crossover temperature based on the climatic conditions of the respective time periods. our study indicates that change in the patterns of c3/c4 composition in the inner mongolia grassland was mainly triggered by increasing temperature, which overrode the antagonistic effect of rising co(2) concentrations.",34,2010,16,2,605,616,10.1111/j.1365-2486.2009.02033.x,0,1,0,1"Hoorens, B; Coomes, D; Aerts, R",neighbour identity hardly affects litter-mixture effects on decomposition rates of new zealand forest species,OECOLOGIA,Article,Litter chemistry; Nutrient transfer; Phenolics; Soil fertility,"the mass loss of litter mixtures is often different than expected based on the mass loss of the component species. we investigated if the identity of neighbour species affects these litter-mixing effects. to achieve this, we compared decomposition rates in monoculture and in all possible two-species combinations of eight tree species, widely differing in litter chemistry, set out in two contrasting new zealand forest types. litter from the mixed-species litter bags was separated into its component species, which allowed us to quantify the importance of litter-mixing effects and neighbour identity, relative to the effects of species identity, litter chemistry and litter incubation environment. controlling factors on litter decomposition rate decreased in importance in the order: species identity (litter quality) >> forest type >> neighbour species. species identity had the strongest influence on decomposition rate. interspecific differences in initial litter lignin concentration explained a large proportion of the interspecific differences in litter decomposition rate. litter mass loss was higher and litter-mixture effects were stronger on the younger, more fertile alluvial soils than on the older, less-fertile marine terrace soils. litter-mixture effects only shifted percentage mass loss within the range of 1.5%. there was no evidence that certain litter mixtures consistently showed interactive effects. contrary to common theory, adding a relatively fast-decomposing species generally slowed down the decomposition of the slower decomposing species in the mixture. this study shows that: (1) species identity, litter chemistry and forest type are quantitatively the most important drivers of litter decomposition in a new zealand rain forest; (2) litter-mixture effects-although statistically significant-are far less important and hardly depend on the identity and the chemical characteristics of the neighbour species; (3) additive effects predominate in this ecosystem, so that mass dynamics of the mixtures can be predicted from the monocultures.",22,2010,162,2,479,489,10.1007/s00442-009-1454-2,0,0,1,1"Montesinos, D; Garcia-Fayos, P; Verdu, M",relictual distribution reaches the top: elevation constrains fertility and leaf longevity in juniperus thurifera,ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY,Article,Altitude; Parthenocarpy; Treeline; Leaf longevity; Leaf growth; Seed predation; Migration,"juniperus thurifera populations are scattered throughout the western mediterranean basin and are relictual from its tertiary distribution due to progressive climatic warming since the last glacial period. to disentangle the factors responsible for its extremely low fertility we combined a microscale experimental design with a macroscale study. at the microscale we experimentally alleviated environmental stress by watering and fertilizing during two years a set of trees in one population. at macroscale we selected 11 populations across a geographical range and sampled them for three years. macroscale patterns evidenced that both plant fertility and leaf longevity diminished with increasing elevation. both microscale and macroscale illustrated the importance of water and nutrient availability on leaf growth and plant fertility: on the microscale experiments, regular supply of water and nutrients increased fruit-set by 300%. macroscale showed that increases in resource availability (precipitation) resulted in reductions of seed abortion, although paralleled by increases in seed predation. altogether, our results indicate that fertility is constrained both by elevation and by resource limitation. therefore any potential lift in the elevational distribution limits will result in synergistic fertility reductions due to harder physical conditions and lower water and nutrient availability. both will compromise future regeneration of this relictual species, although population decline might be buffered temporary thanks to longevity of adult trees. (c) 2009 elsevier masson sas. all rights reserved.",10,2010,36,1,120,125,10.1016/j.actao.2009.10.010,1,0,0,1"Yoshihara, Y; Okuro, T; Buuveibaatar, B; Undarmaa, J; Takeuchi, K",complementary effects of disturbance by livestock and marmots on the spatial heterogeneity of vegetation and soil in a mongolian steppe ecosystem,AGRICULTURE ECOSYSTEMS & ENVIRONMENT,Article,Grazing; Mongolian steppe; Multiple spatial scales; Degradation-indicator species; Ecosystem engineers,"in the mongolian steppes, livestock and burrowing rodents are the main animal modifiers of the habitat. although grazing lands and rodent habitats overlap, the combined effects of livestock and rodent disturbance on spatial heterogeneity of plants and soil have rarely been evaluated. we established study plots at each of four sites: sites heavily grazed by livestock, with and without marmots, and ungrazed sites, with and without marmots. we subdivided each plot into quadrats to survey the plant species composition and soil nutrient properties, and calculated the spatial heterogeneity of vegetation at three spatial scales using non-metric multidimensional scaling analysis. we also calculated the coefficient of variance among the soil samples. the vegetation's spatial heterogeneity did not differ significantly between grazed and ungrazed plots; however, it was higher under marmot disturbance than in the absence of marmots at a fine scale, but lower under marmot disturbance at a coarse scale, irrespective of livestock grazing. at a fine scale, unique habitats were formed by each combination of livestock grazing (presence/absence) and marmots (presence/absence). in addition, the plant species composition in the grazed plots was distinct from that in the ungrazed plots at the coarser scale. the occurrence of degradation-indicator plant species depended on the presence of grazing rather than on the additive effect of grazing and marmots. marmots increased the abundance of degradation-indicator species only in the ungrazed plots. each herbivore group increased the spatial heterogeneity of soil nutrients at coarser scales, but these influences were lost when both herbivore groups coexisted. these results show that the ecological roles of livestock and marmots are complementary, not functionally equivalent. that is, livestock modified the overall vegetation composition, and thereby modified spatial heterogeneity at the landscape scale, whereas marmots modified spatial heterogeneity at the local scale. proper manipulation of the livestock grazing regime can maintain species-rich communities without serious land degradation in the mongolian steppe. (c) 2009 elsevier b.v. all rights reserved.",8,2010,135,02-Jan,155,159,10.1016/j.agee.2009.09.009,0,0,1,1"Hofmann, GE; Barry, JP; Edmunds, PJ; Gates, RD; Hutchins, DA; Klinger, T; Sewell, MA",the effect of ocean acidification on calcifying organisms in marine ecosystems: an organism-to-ecosystem perspective,"ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS, VOL 41",Review; Book Chapter,acclimation; adaptation; calcification; carbon dioxide; climate change; synergistic stressors,"ocean acidification (oa), a consequence of anthropogenic carbon dioxide emissions, poses a serious threat to marine organisms in tropical, open-ocean, coastal, deep-sea, and high-latitude sea ecosystems the diversity of taxonomic groups that precipitate calcium carbonate from seawater are at particularly high risk here we review the rapidly expanding literature concerning the biological and ecological impacts of oa on calcification, using a cross-scale, process-oriented approach in comparison to calcification, we find that areas such as fertilization, early life-history stages, and interaction with synergistic stressors are understudied although understanding the long-term consequences of oa are critical, available studies are largely short-term experiments that do not allow for tests of long-term acclimatization or adaptation future research on the phenotypic plasticity of contemporary organisms and interpretations of performance in the context of current environmental heterogeneity of pco(2) will greatly aid in our understanding of how organisms will respond to oa in the future",141,2010,41,,127,147,10.1146/annurev.ecolsys.110308.120227,1,0,0,1"Balsamo, M; Albertelli, G; Ceccherelli, VU; Coccioni, R; Colangelo, MA; Curini-Galletti, M; Danovaro, R; D'Addabbo, R; De Leonardis, C; Fabiano, M; Frontalini, F; Gallo, M; Gambi, C; Guidi, L; Moreno, M; Pusceddu, A; Sandulli, R; Semprucci, F; Todaro, MA; Tongiorgi, P",meiofauna of the adriatic sea: present knowledge and future perspectives,CHEMISTRY AND ECOLOGY,Article,meiofauna; Adriatic Sea; biodiversity; ecology; bioindicator; conservation,"owing to technical problems and difficult taxonomic identification, meiofauna have been generally less studied than macrofauna. however, the role of meiofauna in marine ecosystem functioning, and their effective and rapid response to anthropogenic alterations and climatic changes have recently been acknowledged, leading to increasing scientific and applied interest. at present, systematic and biogeographic knowledge of the meiofauna of the adriatic sea is extremely heterogeneous, because most of the data are limited to a few taxa and the sampled areas are scattered, being located mainly in the coastal areas of the northern basin. analysis of the composition and distribution of meiobenthic groups in the adriatic sea highlights the presence of several endemisms. meiofauna also include bioindicator taxa, which allow assessment of the quality of marine sediments; this is particularly useful in systems characterised by the synergistic effect of different forms of anthropogenic impact, such as the adriatic basin. current knowledge about the ecology of the meiofauna and use of this component in applied ecological studies, along with the availability of a standardised protocol for the analysis of meiofaunal assemblages, allows us to recommend formal acknowledgement of the need to integrate information derived from the analysis of macrofauna with information derived from the study of meiofauna. future research based on the simultaneous use of both of these benthic components will allow faster and more accurate evaluation of the response of coastal marine ecosystems to anthropogenic disturbance.",13,2010,26,,45,63,10.1080/02757541003705492,1,0,0,1"Marion, B; Bonis, A; Bouzille, JB",how much does grazing-induced heterogeneity impact plant diversity in wet grasslands?,ECOSCIENCE,Article,additive partitioning; grazing intensity; management; patchiness; species richness,"the positive impact of grazing herbivores on plant diversity has been frequently reported in fertile grasslands. grazing-induced heterogeneity is often evoked as an explanation for this influence. however, the relative importance of plant community heterogeneity induced by herbivores compared to other mechanisms linked to grazing remains unclear. we investigated this question by looking at 3 plant communities found in wet grasslands situated along the french atlantic coast and traditionally grazed by horses and cattle. an experimental design set up in 1995 allowed us to compare the consequences of cattle-grazing, horse-grazing, and grazing abandonment on plant community diversity and heterogeneity. floristic measurements made in 2007 showed that cattle and horses both had a positive impact on species richness and shannon diversity index and that patchiness only occurred in grazed situations. the relative importance of grazing-induced patchiness within the overall positive effect of grazing on plant diversity was assessed by partitioning the diversity gain due to grazing into its additive within-and among-patch components. grazing-induced patchiness entirely explained the increase in plant richness, whereas it accounted for only a small part of shannon diversity. grazing-related processes operating at the patch scale explained the main part of the increase in shannon diversity. these processes make only a limited contribution to species recruitment, but they result in a more even species abundance distribution.",12,2010,17,3,229,239,10.2980/17-3-3315,0,0,1,1"Ravolainen, VT; Yoccoz, NG; Brathen, KA; Ims, RA; Iversen, M; Gonzalez, VT",additive partitioning of diversity reveals no scale-dependent impacts of large ungulates on the structure of tundra plant communities,ECOSYSTEMS,Article,grazing; tundra ecosystem; shrub dominance; abundant reindeer; productivity gradients; landscape elements; management scale; Fennoscandia,"large herbivores can change ecosystem functioning by impacting plant diversity. however, although such impacts are expected to be scale-dependent in ecosystems with wide-roaming ungulates, scaling issues rarely enter empirical assessments. we here test the hypothesis that the impact of increased reindeer abundance on plant diversity in alpine tundra is scale-dependent. based on potentially high productivity of the focal habitat units and hence the possibility of positive grazer impacts on plant diversity we predicted higher alpha and beta diversity at the habitat scale where reindeer densities are high. we also explored whether there were differences in diversity patterns at larger scales, including the scale of reindeer management districts. we estimated grazing disturbance as high versus low reindeer density in selected districts (a total extent of 7421 km(2)) of northern norway where reindeer-induced vegetation shifts are debated. we focus on dominance patterns because they can quantify the vegetation state and thus performed additive partitioning of simpson diversity on multiple scales assessing also species' contributions to diversity. contrary to our predictions, we found only weak scale-dependent effects of reindeer grazing on plant diversity. under high reindeer densities there was evidence for a landscape-scale homogenization of the vegetation, but the predicted alpha and beta diversity increases at the habitat scale were not found. consistently through all scales considered, four shrub species contributed the most to plant diversity. these results contradict the idea that reindeer at high stocking densities induce shifts in plant species dominance in productive habitats. we conclude that context-dependencies such as spatial scales of management units and habitat types need to be explicitly considered in evaluations of the impacts of large ungulates on plant diversity.",15,2010,13,1,157,170,10.1007/s10021-009-9308-7,0,0,1,1"Ahmed, MZ; Khan, MA","tolerance and recovery responses of playa halophytes to light, salinity and temperature stresses during seed germination",FLORA,Article,Dormancy; Germination; Playa; Opportunity window; Stress release; Novel crops,"halogeton glomeratus (m. bieb.) c.a. mey., lepidium tantalum linn. and peganum harmala linn. are distributed in temperate salt playa habitats of upper hunza, pakistan. seeds were germinated under various salinity (0-500 mm nacl), light (12 h-light: 12 h-dark and 24 h-dark) and temperature (5/15, 10/20, 15/25, 20/30, and 25/35 degrees c, dark/light) regimes for 20 days to determine the optimal conditions for germination and recovery of seeds from these factors when exposed to less than optimal conditions. seeds that failed to germinate in dark were transferred successively to 12 h-photoperiod, salinity to distilled water and from various temperature regimes to 20/30 degrees c. to determine the effect of these stresses and the ability of these seeds to recover respectively. highest seed germination (h. glomeratus and l latifolium: 100%; p. harmala: 80%) was obtained in non-saline control at 20/30 degrees c in 12 h-photoperiod, however, increase in salinity progressively inhibited seed germination. seed germination of h. glomeratus and p. harmala was substantially inhibited and that of l. latifolium was prevented in dark. salinity and dark treatments have a synergistic effect in inhibiting seed germination of all species. no seed of any species germinated at 5/15 degrees c; germination was substantially inhibited at 25/35 degrees c both for h. glomeratus and p. harmala while l latifolium failed to germinate at 25/35 degrees c. rate of germination also decreased with an increase in salinity at all temperature regimes but this effect was minimal at optimal temperature regime of 20/30 degrees c. after successive elimination of light, salinity and temperature stresses, final seed germination was identical to respective controls. the results indicate that seeds of these temperate halophytes could endure environmental stresses without losing viability and germinate readily when these stresses are removed. under the extremely variable conditions of the playa habitat these species are highly opportunistic exploiting the windows of opportunity available during spring or early summer. (c) 2010 elsevier gmbh. all rights reserved.",12,2010,205,11,764,771,10.1016/j.flora.2009.10.003,1,0,0,1"Duquesne, S; Liess, M",indirect effects of pesticides on mosquito larvae via alterations of community structure,ISRAEL JOURNAL OF ECOLOGY & EVOLUTION,Article,mosquito larvae; associated communities; pesticide treatment; biological interactions; prediction; pest management; risk assessment,"we describe how pesticides used for mosquito control alter communities in mosquito breeding sites, and how these alterations affect larval populations of mosquitoes. lethal and sublethal toxic effects modify biological interactions through density- and trait-mediated changes. density-mediated effects due to pesticide treatment can lead to indirect positive effects on the target species. for example, recolonization of pests can be amplified due to disturbances of antagonistic species. trait-mediated effects can result in lethal effects of originally sublethal exposure when the pesticide is combined with additional stress. such lethal effects can result from changes of behavior or sensitivity. also the immune capacity and resistance of individuals to parasitic infection could be decreased. furthermore, pesticide treatment can act independently of toxic effects. for example, habitat and oviposition site selection can be influenced. these examples highlight the diversity of processes to be considered when determining the overall consequences of pesticide treatment. we show that a better understanding of these processes is needed to predict effects of pesticides on population dynamics. such knowledge would have direct benefits in designing mosquito control strategies.",2,2010,56,04-Mar,433,447,10.1560/IJEE.56.3-4.433,0,1,0,1"Munguia, P; Osman, RW; Hamilton, J; Whitlatch, RB; Zajac, RN",modeling of priority effects and species dominance in long island sound benthic communities,MARINE ECOLOGY PROGRESS SERIES,Article,Community threshold; Dispersal; Life history; Model,"spatially structured communities are common in many systems, including the marine benthos where sessile species compete for substrate. which species colonizes a habitat first may determine species coexistence or dominance. the strength of this priority effect will vary as a function of the interaction between life history processes and disturbance events at different spatial and temporal scales. on a local scale, disturbance tends to open up space, allowing new propagules to arrive, while on a regional scale, it has the potential to reduce source populations and the colonization ability of dispersal-limited species. differences in larval longevity will have a direct influence on dispersal distance, the relative timing of colonization, and the impact of priority effects, especially when interacting with different disturbance regimes. this study presents a modeling exercise to highlight this synergy and its implications for invasive species and ecosystem management. four life histories were simulated, representing species from the 4 common community states of long island sound, usa: resident bryozoans, invasive ascidians, mussels, and the ascidian diplosoma listerianum that is restricted to years with abnormally warm winters. brooding species took longer to exert dominance than broadcast spawners, but were more resilient to disturbance, having less local extinctions. simulations showed that the combined effects of dispersal ability and disturbance could allow the maintenance of diversity on a regional scale regardless of the identity of locally dominant species. priority effects are only present when the system experiences localized disturbance regimes, such as predation.",5,2010,413,,229,240,10.3354/meps08764,1,0,0,1"Foden, J; Rogers, SI; Jones, AP",recovery of uk seabed habitats from benthic fishing and aggregate extraction-towards a cumulative impact assessment,MARINE ECOLOGY PROGRESS SERIES,Article,Towed bottom-fishing; Recovery; Cumulative effects; Fishing intensity; Marine habitats; Aggregate extraction; UK seabed; Vessel monitoring system,"assessing cumulative impacts of multiple pressures on the marine environment can help inform management response. this requires understanding of the spatial and temporal distribution of human pressures and their impacts. quantifying seabed recovery rates from 2 significant pressures in european waters, benthic fishing and aggregate extraction, is a significant step towards assessing sensitivity and cumulative impacts. vessel monitoring system data were used to estimate the distribution and intensity of benthic fishing in uk (england and wales) marine waters (2006 to 2007). data were separated by towed bottom-fishing gears (scallop dredges, beam and otter trawls) and linked to habitat in a geographic information system. recovery periods of seabed habitats were estimated by literature review, for gear types and fishing intensity. recovery rates generally increased with sediment hardness, and habitats required longer periods of recovery from scallop dredging than from otter or beam trawling. fishing pressure across the habitat-gear combinations was such that 80% of the bottom-fished area was estimated to be able to recover completely before repeat trawling, based on mean annual trawl frequencies. however, in 19% of the uk's bottom-fished seabed, scallop dredging in sand and gravel and otter trawling in muddy sand and reef habitats occurred at frequencies that prevented full habitat recovery. in 2007, benthic fishing and aggregate extraction occurred together in an estimated 40 km(2) (<0.02%) of the uk seabed. cumulative impacts were estimated as total recovery time under 4 scenarios: greatest, additive, antagonistic and synergistic impacts. recovery from aggregate extraction required much greater periods than from benthic fishing, and gravel was identified as a more sensitive habitat than sand.",17,2010,411,,259,270,10.3354/meps08662,1,1,1,3"Searle, CL; Belden, LK; Bancroft, BA; Han, BA; Biga, LM; Blaustein, AR",experimental examination of the effects of ultraviolet-b radiation in combination with other stressors on frog larvae,OECOLOGIA,Article,Rana cascadae; Batrachochytrium; dendrobatidis; Temperature; UVB,"ultraviolet-b radiation (uvb) is a ubiquitous stressor with negative effects on many aquatic organisms. in amphibians, ambient levels of uvb can result in impaired growth, slowed development, malformations, altered behavior and mortality. uvb can also interact with other environmental stressors to amplify these negative effects on individuals. in outdoor mesocosm and laboratory experiments we studied potential synergistic effects of uvb, a pathogenic fungus, batrachochytrium dendrobatidis (bd), and varying temperatures on larval cascades frogs (rana cascadae). first, we compared survivorship, growth and development in two mesocosm experiments with uvb- and bd-exposure treatments. we then investigated the effects of uvb on larvae in the laboratory under two temperature regimes, monitoring survival and behavior. we found reduced survival of r. cascadae larvae with exposure to uvb radiation in all experiments. in the mesocosm experiments, growth and development were not affected in either treatment, and no effect of bd was found. in the laboratory experiment, larvae exposed to uvb demonstrated decreased activity levels. we also found a trend towards reduced survival when uvb and cold temperatures were combined. our results show that amphibian larvae can suffer both lethal and sublethal effects when exposed to uvb radiation.",9,2010,162,1,237,245,10.1007/s00442-009-1440-8,1,0,0,1"Borowicz, VA",the impact of arbuscular mycorrhizal fungi on strawberry tolerance to root damage and drought stress,PEDOBIOLOGIA,Article,Fragaria virginiana; Belowground herbivory; Mycorrhiza; Symbiosis; Tolerance,"individually, arbuscular mycorrhizal fungi (amf), drought stress, and root damage can alter terrestrial plant performance but the joint effects of these three factors have not been explored. because amf can improve water relations, colonization by these root symbionts may increase the host's tolerance of drought especially when roots have been compromised by herbivory. this full factorial study examined effects of amf, water deficit, and artificial root herbivory in three genotypes of wild strawberry, fragaria virginiana duchesne that originated from the same restored tallgrass prairie as the amf inoculum. drought stress and root damage altered allocation to roots vs. shoots but the effects were not additive and the interaction did not depend on amf treatment. effects of amf were absent with one exception: root damage significantly reduced belowground mass only in plants inoculated with amf. although drought stress did not interact with the amf treatment, both drought stress and root damage reduced the abundance of arbuscules, and especially vesicles, and colonization varied among genotypes. failure to detect strong effects of amf on host growth could be due to variable responses of individual amf species summing to no net effects. functionally, amf were primarily commensals of strawberry in this study. (c) 2010 elsevier gmbh. all rights reserved.",9,2010,53,4,265,270,10.1016/j.pedobi.2010.01.001,0,0,1,1"Bamforth, SS",distribution of and insights from soil protozoa of the olympic coniferous rain forest,PEDOBIOLOGIA,Article,Protozoa; Ciliates; Testate amoebae; Biodiversity; Temperate rain forest; Neutral theory,"decomposition occurs in the surface litter and soil to support temperate rainforests, but little is known about the protozoa that stimulate bacterial activity and turnover. i examined surface litter and top soils, fallen logs, and epiphytes within 2 m from the soil surface in olympic national park, usa, of the pacific northwest temperate coniferous rain forest. ciliates in surface litter numbered 180-580 g(-1) dry weight, but were reduced by 20-60% in the underlying soils. testate amoebae numbered 18,000-77,000 g(-1) dry weight in both litter and soil although they were often more abundant in underlying soils. rotting logs, essential for tree regeneration, supported similar numbers of ciliates, but twice the numbers of testate amoebae. in three epiphytic soils, ciliates numbered 350-550, and testate amoebae 35,000-195,000 g(-1) dry weight of soil. in these soils, 26 species of gymnamoebae, 64 species of ciliates, and 113 species of testate amoebae were found. about 65% of the individuals in ciliate and 45% in testate amoebae populations were small, r-selected taxa. rain forest soil protozoa have distinct testate amoebae populations, and are characterized by enormous biodiversity, the dominance of acrostome species, the proliferation of euglypha and nebela species, and the appearance of aquatic taxa. ecological succession of ciliates and testate amoebae follows an additive (non-replacement) pattern according to a neutral model. the large numbers of persistent r-selected species respond to ecosystem disturbances by mobilizing quickly to resume the bacterivory necessary to help restore the recovering above-ground plant community. (c) 2010 elsevier gmbh. all rights reserved.",4,2010,53,6,361,367,10.1016/j.pedobi.2010.05.001,0,0,1,1"Caujape-Castells, J; Tye, A; Crawford, DJ; Santos-Guerra, A; Sakai, A; Beaver, K; Lobin, W; Florens, FBV; Moura, M; Jardim, R; Gomes, I; Kueffer, C",conservation of oceanic island floras: present and future global challenges,PERSPECTIVES IN PLANT ECOLOGY EVOLUTION AND SYSTEMATICS,Review,World islands; Threat factors; Endangerment; Conservation research; Conservation policies; Global network,"current threats to the planet's biodiversity are unprecedented,.and they particularly imperil insular floras. in this investigation, we use the threat factors identified by the millennium ecosystem assessment as the main drivers of biodiversity loss on islands to define and rank 13 current, continuing threats to the plant diversity of nine focal archipelagos where volcanic origin (or in the seychelles a prolonged isolation after a continental origin) has produced a high degree of endemicity and fragility in the face of habitat alteration. we also conduct a global endangerment assessment based on the numbers of insular endemic plants in the endangered (en) and critically endangered (cr) iucn categories for 53 island groups with an estimated 9951 endemic plant species, providing a representative sample of the world's insular systems and their floristic richness. our analyses indicate that isolation does not significantly influence endangerment, but plant endemics from very small islands are more often critically endangered. we estimate that between 3500 and 6800 of the estimated 70,000 insular endemic plant species worldwide might be highly threatened (cr+en) and between ca. 2000 and 2800 of them in critical danger of extinction (cr). based on these analyses, and on a worldwide literature review of the biological threat factors considered, we identify challenging questions for conservation research, asking (i) what are the most urgent priorities for the conservation of insular species and floras, and (ii) with the knowledge and assets available, how can we improve the impact of conservation science and practice on the preservation of island biodiversity? our analysis indicates that the synergistic action of many threat factors can induce major ecological disturbances, leading to multiple extinctions. we review weaknesses and strengths in conservation research and management in the nine focal archipelagos, and highlight the urgent need for conservation scientists to share knowledge and expertise, identify and discuss common challenges, and formulate multi-disciplinary conservation objectives for insular plant endemics worldwide. to our knowledge, this is the most up-to-date and comprehensive survey yet to review the threat factors to native plants on oceanic islands and define priority research questions. (c) 2009 rubel foundation, eth zurich. published by elsevier gmbh. all rights reserved.",77,2010,12,2,107,129,10.1016/j.ppees.2009.10.001,1,0,0,1"Tu, WG; Gao, XF; Wu, N; Liu, SH",altitudinal patterns of vascular plant richness in high mountains: applying of generative additive model,POLISH JOURNAL OF ECOLOGY,Article,altitudinal gradient; plant species richness; patterns; growth form; Mt. Jiuding,"to explore and describe the species richness patterns along altitudinal, high mountain gradients, two transects - northern exposure (yg) and southern exposure (td) at mt. jiuding (1200-4200 m) in western china (31 degrees 13 '-31 degrees 46 ' n, 103 degrees 29 '-104 degrees 05 ' e) were selected. they differ from south to north in climate conditions and vegetation zonation, and each transect was sampled according to a uniform method. every 200 m along the altitudinal gradient we set a sampling belt of 3000 m x 5 m to record the tree species, and 30 plots of 5 m x 5 m within every vegetation belt were used to investigate shrub and herb species. we compared the composition of plant species and calculated the coefficient of similarity between the two transects. a generalized additive model (gam) was used to describe the richness patterns. for the whole mt. jiuding, the richness at all three levels (species, genus and family) showed a monotonically decreasing pattern. as for the different growth forms, richness of the trees, shrubs and pteridophytes showed hump-shaped patterns; and herbs showed a slow decreasing pattern along the altitudinal gradients. in td transect, the richness of species, genus and family also showed monotonically decreasing patterns; tree richness decreased with the increase of altitude; the shrub richness showed a humpshaped pattern; but pteridophytes and other herbs showed wave-like patterns. in yg transect, altitudinal gradient of richness at different taxonomic levels all showed hump-shaped patterns; and the species richness patterns for different growth forms peaked at middle attitude except for the graminoids and other herbs. the evolutionary history of the vegetation in mt. jiuding was quite consistent, and different richness patterns along altitudinal gradients might be resulted from different contemporary ecological conditions. human disturbance and different range of altitudinal gradients were also important factors for different richness patterns between the two transects. in our study, species in different growth forms showed different altitudinal patterns, but those species with similar requirements to environmental conditions showed similar richness patterns along altitudinal gradients.",1,2010,58,2,231,240,,0,0,1,1"D'Amen, M; Pietrangeli, B; Bologna, MA",human-provoked amphibian decline in central italy and the efficacy of protected areas,WILDLIFE RESEARCH,Article,amphibian extinction; climate change; land cover; natural reserves,"context. today, more than 32% of amphibian species are threatened and more than 43% face a steep decline in numbers. most species are being affected simultaneously by multiple stressors and habitat protection is often inadequate to prevent declines. aims. the main goal of the present research was to understand the consequences of alternative human land use in producing landscape disturbance for amphibians. at the same time, we also evaluated the effect of changing climatic conditions as additional potential drivers of population decline. another goal was to determine whether and to what extent the existing nature reserves have been effective in protecting species in recent decades. methods. we used generalised additive models (gams) to investigate the association between the state (stable/decline) of amphibian populations in 5 x 5 km cells in central italy and proxies of different typology of anthropogenic stressors, climatic variables and protection measures. key results. we found a significant association between anthropogenic landscape modifications and species decline. this negative relationship was revealed with agricultural predictors for the majority of the species, whereas urban fabrics had a slightly smaller impact. we found significant associations between amphibian declines and climatic variation, particularly the increasing number of dry days. protected areas protected declines of two species only. conclusions. our results showed that the status of amphibians in this region warrants greater attention than has been given previously. the detrimental effect of agricultural practices, combined with increasing aridity, makes amphibian populations particularly susceptible to extinction, and the conservation measures applied till now are inadequate for species protection in this region. implications. our results should stimulate the implementation of environmental policies that focus not only on the protection of single habitats, but also on ensuring the environmental quality of the surrounding landscapes. moreover, an adaptive management approach should be applied to take into account future modification of hydrology and climate.",1,2010,37,7,547,557,10.1071/WR09167,0,0,1,1"Laurance, WF; Useche, DC",environmental synergisms and extinctions of tropical species,CONSERVATION BIOLOGY,Review,climatic change; endangered species; environmental synergisms; extinction; fire; habitat fragmentation; hunting; IUCN Red Data Book; logging; species invasions; tropical forests,"environmental synergisms may pose the greatest threat to tropical biodiversity. using recently updated data sets from the international union for conservation of nature (iucn) red list, we evaluated the incidence of perceived threats to all known mammal, bird, and amphibian species in tropical forests. vulnerable, endangered, and extinct species were collectively far more likely to be imperiled by combinations of threats than expected by chance. among 45 possible pairwise combinations of 10 different threats, 69%, 93%, and 71% were significantly more frequent than expected for threatened mammals, birds, and amphibians, respectively, even with a stringent bonferroni-corrected probability value (p = 0.003). based on this analysis, we identified five key environmental synergisms in the tropics and speculate on the existence of others. the most important involve interactions between habitat loss or alteration (from agriculture, urban sprawl, infrastructure, or logging) and other anthropogenic disturbances such as hunting, fire, exotic-species invasions, or pollution. climatic change and emerging pathogens also can interact with other threats. we assert that environmental synergisms are more likely the norm than the exception for threatened species and ecosystems, can vary markedly in nature among geographic regions and taxa, and may be exceedingly difficult to predict in terms of their ultimate impacts. the perils posed by environmental synergisms highlight the need for a precautionary approach to tropical biodiversity conservation.",42,2009,23,6,1427,1437,10.1111/j.1523-1739.2009.01336.x,1,0,0,1"Henriquez, P; Donoso, DS; Grez, AA","population density, sex ratio, body size and fluctuating asymmetry of ceroglossus chilensis (carabidae) in the fragmented maulino forest and surrounding pine plantations",ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY,Article,Biological conservation; Ceroglossus chilensis; Chile; Demographical changes; Habitat fragmentation; Morphological changes,"habitat fragmentation results in new environmental conditions that may stress resident populations. such stress may be reflected in demographical or morphological changes in the individuals inhabiting those landscapes. this study evaluates the effects of fragmentation of the maulino forest on population density, sex ratio, body size, and fluctuating asymmetry (fa) of the endemic carabid ceroglossus chilensis. individuals of c chilensis were collected during 2006 in five locations at los queules national reserve (continuous forest), in five forest fragments and in five areas of surrounding pine plantations (matrix). in each location, once a season, 40 pitfall traps (20 in the centre, 20 in the edge), were opened for 72 h. population density of c. chilensis was higher in the small fragments than in the pine matrix, with intermediate densities in the continuous forest; sex ratio did not differ significantly from 1: 1 in the three habitats. individuals from the centre of fragments were smaller than those from the centre of continuous forest, and fa did not vary significantly among habitats. these results suggest that small forest fragments maintain dense populations of c chilensis and therefore they must be considered in conservation strategies. although the decrease of the body size suggests that small remnants should be connected by managing the structure of the surrounding matrix, facilitating the dispersion of this carabid across the landscape and avoiding possible antagonistic interactions inside small fragments. (c) 2009 elsevier masson sas. all rights reserved.",12,2009,35,6,811,818,10.1016/j.actao.2009.08.012,0,1,0,1"Puurtinen, M; Ketola, T; Kotiaho, JS",the good-genes and compatible-genes benefits of mate choice,AMERICAN NATURALIST,Review,female choice; genetic compatibility; indirect benefits; sexual selection,"genetic benefits from mate choice could be attained by choosing mates with high heritable quality (""good genes"") and that are genetically compatible (""compatible genes""). we clarify the conceptual and empirical framework for estimating genetic benefits of mate choice, stressing that benefits must be measured from offspring fitness because there are no unequivocal surrogates for genetic quality of individuals or for compatibility of parents. we detail the relationship between genetic benefits and additive and nonadditive genetic variance in fitness, showing that the benefits have been overestimated in previous verbal treatments. we point out that additive benefits readily arise from nonadditive gene action and that the idea of ""heritable nonadditive benefits"" is a misconception. we review the empirical evidence of the magnitude of benefits of good genes and compatible genes in animal populations, and we outline the most promising future directions for empirical research on the genetic benefits of mate choice.",50,2009,174,5,741,752,10.1086/606024,0,0,1,1"Williams-Linera, G; Lorea, F","tree species diversity driven by environmental and anthropogenic factors in tropical dry forest fragments of central veracruz, mexico",BIODIVERSITY AND CONSERVATION,Article,Anthropogenic disturbance; Beta diversity; Environmental factors; Tree diversity; Tropical dry forest; Veracruz,"we examined vegetation structure and woody species diversity in relation to 14 environmental and anthropogenic factors in ten tropical dry forest (tdf) fragments in central veracruz, mexico. the basal area of the canopy (30.2 +/- a 2.11 m(2)/ha) and understory (1.96 +/- a 0.12 m(2)/ha) trees was similar, but density (1,014 +/- a 104 and 2,532 +/- a 227 individuals/ha, respectively) differed among sites. we recorded 98 canopy, 77 understory, and 60 seedling species. richness was 24-45 species per site, fisher's alpha and shannon's indices increased with site altitude. chao jaccard indices revealed high species turnover, and a consistently higher similarity within the sites at the lowest and within the highest elevation sites. ordination identified altitude, aspect, slope, water proximity, cattle and trails as significant explanatory variables of species patterns, and showed that sites at lower elevations were clearly separated from the other sites. environmental heterogeneity alone did not control species diversity distribution, but species were affected by environmental filters at different stages in their life cycle, e.g., water proximity was significant for saplings and seedlings but not for adults. anthropogenic disturbances act synergistically, e.g., trails played a key role in determining structure and tree diversity patterns. an important finding is that human disturbance diminishes species diversity in this tdf, but sites at lower elevations were more disturbed and less diverse, therefore we need to study how environmental factors would act if there were no anthropogenic disturbance.",15,2009,18,12,3269,3293,10.1007/s10531-009-9641-3,1,0,0,1"Costa, PM; Caeiro, S; Diniz, MS; Lobo, J; Martins, M; Ferreira, AM; Caetano, M; Vale, C; DelValls, TA; Costa, MH",biochemical endpoints on juvenile solea senegalensis exposed to estuarine sediments: the effect of contaminant mixtures on metallothionein and cyp1a induction,ECOTOXICOLOGY,Article; Proceedings Paper,Senegalese sole; Contaminated sediments; Bioaccumulation; Metallothionein; CYP1A; Sado estuary,"juvenile solea senegalensis were exposed to fresh sediments from three stations of the sado estuary (portugal) in 28-day laboratory assays. sediments revealed distinct levels of total organic matter, fine fraction, redox potential, trace elements (arsenic, cadmium, chromium, copper, nickel, lead and zinc) and organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls and a pesticide: dichloro diphenyl trichloroethane). organisms were surveyed for contaminant bioaccumulation and induction of two hepatic biochemical biomarkers: metallothionein (mt) and cytochrome p450 (cyp1a), as potential indicators of exposure to metallic and organic contaminants, respectively. using an integrative approach it was established that, although bioaccumulation is in general accordance with sediment contamination, lethality and biomarker responses are not linearly dependent of the cumulative concentrations of sediment contaminants but rather of their bioavailability and synergistic effects in organisms. it is concluded that metals and organic contaminants modulate both mt and cyp1a induction and it is suggested that reactive oxygen species may be the link between responses and effects of toxicity.",19,2009,18,8,988,1000,10.1007/s10646-009-0373-7,1,0,0,1"Naug, D",nutritional stress due to habitat loss may explain recent honeybee colony collapses,BIOLOGICAL CONSERVATION,Article,Habitat loss; Nutritional stress; Honeybees; Colony collapse disorder; Pollinator habitat; Conservation,"in spite of the tremendous public interest in the recent large honeybee losses attributed to colony collapse disorder, there is still no definitive explanation for the phenomenon. with the hypothesis that nutritional stress due to habitat loss has played an important role in honeybee colony collapse, i analyze the land use data in united states to show that the colony loss suffered by each state is significantly predicted by the extent of its open land relative to its developed land area. i provide further support for this hypothesis by showing that states with the largest areas of open land have a significantly higher honey yield on a per colony basis. 1 discuss how increasing loss of foraging resources could be synergistically acting with emerging diseases to stress honeybee populations and the importance therefore for preserving natural areas that act as important pollinator habitats. (c) 2009 elsevier ltd. all rights reserved.",57,2009,142,10,2369,2372,10.1016/j.biocon.2009.04.007,1,0,0,1"Coors, A; De Meester, L","synergistic, antagonistic and additive effects of multiple stressors: predation threat, and pesticide exposure in daphnia magna (vol 45, pg 1820, 2008)",JOURNAL OF APPLIED ECOLOGY,Correction,,,0,2009,46,5,1138,1138,,1,1,1,3"Wolfle, S; Trienens, M; Rohlfs, M",experimental evolution of resistance against a competing fungus in drosophila melanogaster,OECOLOGIA,Article,Animal-fungus interactions; Antimicrobial strategies; Fecundity; Survival; Trade-off,"competition between microorganisms and arthropods has been shown to be an important ecological interaction determining animal development and spatial distribution patterns in saprophagous communities. in fruit-inhabiting drosophila, variation in insect developmental success is not only determined by species-specific effects of various noxious filamentous fungi but, as suggested by an earlier study, also by additive genetic variation in the ability to successfully withstand the negative impact of the fungi. if this variation represents a direct adaptive response to the degree to which insect breeding substrates are infested with harmful fungi, genetic variation for successful development in the presence of fungi could be maintained by variation in infestation of resource patches with fungi. we selected for the ability to resist the negative influence of mould by maintaining replicated drosophila melanogaster populations on substrates infested with aspergillus nidulans. after five cycles of exposure to the fungus during the larval stage, the selected populations were compared with unselected control populations regarding adult survival and reproduction to reveal an evolved resistance against the fungal competitor. on fungus-infested larval feeding substrates, emerged adults from mould-selected populations had higher survival rates and higher early fecundity than the control populations. in the unselected populations, females had higher mortality rates than males, and a high proportion of both females and males appeared to be unable to lay eggs or fertilise eggs, respectively. when larvae developed on non-infested food we found indications of a loss of resistance to abiotic and starvation stress in the adult stage in flies from the selected populations. this suggests that there are costs associated with an increase in resistance against the microbial competitor. we discuss the underlying mechanisms that might have selected for increased resistance against harmful fungi.",8,2009,161,4,781,790,10.1007/s00442-009-1414-x,0,0,1,1"Dunn, RR; Harris, NC; Colwell, RK; Koh, LP; Sodhi, NS",the sixth mass coextinction: are most endangered species parasites and mutualists?,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Review,mass extinction; coextinction; chains of extinction; secondary extinctions; climate change; emerging diseases,"the effects of species declines and extinction on biotic interactions remain poorly understood. the loss of a species is expected to result in the loss of other species that depend on it (coextinction), leading to cascading effects across trophic levels. such effects are likely to be most severe in mutualistic and parasitic interactions. indeed, models suggest that coextinction may be the most common form of biodiversity loss. paradoxically, few historical or contemporary coextinction events have actually been recorded. we review the current knowledge of coextinction by: (i) considering plausible explanations for the discrepancy between predicted and observed coextinction rates; (ii) exploring the potential consequences of coextinctions; (iii) discussing the interactions and synergies between coextinction and other drivers of species loss, particularly climate change; and (iv) suggesting the way forward for understanding the phenomenon of coextinction, which may well be the most insidious threat to global biodiversity.",113,2009,276,1670,3037,3045,10.1098/rspb.2009.0413,1,0,0,1"Galvan, I; Alonso-Alvarez, C",the expression of melanin-based plumage is separately modulated by exogenous oxidative stress and a melanocortin,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,melanocortin system; eumelanin; glutathione; oxidative stress; pheomelanin,"melanin-based traits involved in animal communication have been traditionally viewed as occurring under strict genetic control. however, it is generally accepted that both genetic and environmental factors influence melanin production. medical studies suggest that, among environmental factors influencing melanization, oxidative stress could play a relevant role. on the other hand, genetic control would be exerted by the melanocortin system, and particularly by the alpha-melanocyte-stimulating hormone (alpha-msh), which triggers the production of eumelanins (black pigments). to determine how the melanocortin system and an exogenous source of oxidative stress interact in the expression of melanin-based plumage, developing red-legged partridges (alectoris rufa) were manipulated. some partridges were injected with alpha-msh, while other birds received a pro-oxidant molecule (diquat) in drinking water. controls and birds receiving both treatments were also studied. both alpha-msh- and diquat-treated individuals presented larger eumelanin-based traits than controls, but alpha-msh+diquat-treated birds showed the largest traits, suggesting that oxidative stress and melanocortins promote additive but independent effects. diquat also induced a decline in the level of a key intracellular antioxidant (glutathione), which is associated with high expression of eumelanin-based signals in other bird species. some scenarios for the evolution of melanin-based traits in relation to oxidative stress are proposed.",49,2009,276,1670,3089,3097,10.1098/rspb.2009.0774,0,0,1,1"Wooldridge, SA; Done, TJ",improved water quality can ameliorate effects of climate change on corals,ECOLOGICAL APPLICATIONS,Article,"bleaching threshold; CO(2) limitation; coral reef; dissolved inorganic nitrogen (DIN); Great Barrier Reef, Australia; zooanthellae species","the threats of wide-scale coral bleaching and reef demise associated with anthropogenic climate change are widely known. moreover, rates of genetic adaptation and/or changes in the coral-zooxanthella partnerships are considered unlikely to be sufficiently fast for corals to acquire increased physiological resistance to increasing sea temperatures and declining ph. however, it has been suggested that coral reef resilience to climate change may be improved by good local management of coral reefs, including management of water quality. here, using major data sets from the great barrier reef (gbr), australia, we investigate geographic patterns of coral bleaching in 1998 and 2002 and outline a synergism between heat stress and nutrient flux as a major causative mechanism for those patterns. the study provides the first concrete evidence for the oft-expressed belief that improved coral reef management will increase the regional-scale survival prospects of coral reefs to global climate change.",67,2009,19,6,1492,1499,10.1890/08-0963.1,1,0,0,1"Matesanz, S; Escudero, A; Valladares, F",impact of three global change drivers on a mediterranean shrub,ECOLOGY,Article,Centaurea hyssopifolia; changes in habitat quality; climate change; fitness; fragmentation; global change; gypsophile; interactions; Mediterranean ecosystem; phenology,"global change is not restricted to climate change, and plant species generally face multiple human-driven disturbances constraining their viability. most importantly, interactions among these drivers frequently generate nonadditive effects that cannot be predicted based on single-factor studies. our goal was to assess the joint effects of three global change drivers that are especially relevant in mediterranean ecosystems, namely, fragmentation, reduced habitat quality, and climate change on centaurea hyssopifolia, a gypsum specialist plant. we carried out a two-year study (2005-2006) in natural populations of this plant in large (>11 ha) and small (<1.5 ha) fragments. within each fragment, we identified areas of contrasting habitat quality as revealed by plant cover and nutrient content, and within each combination of habitat quality and fragment size we performed a rainfall manipulation experiment simulating the most likely future climate scenario for the region. survival, growth, phenology, and reproductive success of selected plants were monitored. the three drivers profoundly affected responses of centaurea hyssopifolia in both study years, phenology being mainly affected by changes in habitat quality and reductions in rainfall and reproductive traits being mainly affected by fragmentation. plants in sites of poor habitat quality and plants in the dry treatment advanced most of their phenophases (flowering and dispersing earlier) and showed reduced growth rate and increased fraction of senescent leaves. plants growing in small fragments had lower survival, lower number of viable seeds, and a reduced seed set compared to those from large fragments. we found significant synergistic interactions among drivers. for example, the interaction between fragmentation and habitat quality led to lower survival and lower relative growth in plants from small and poor-quality habitat sites. our results highlight the importance of studies addressing simultaneously all relevant drivers of global change potentially affecting plant performance under natural conditions. in addition, the complex responses of phenology and reproductive traits of c. hyssopifolia emphasize the need for studies integrating traits from vegetative to reproductive and from the organ to the whole-plant level.",31,2009,90,9,2609,2621,10.1890/08-1558.1,1,0,1,2"Russell, BD; Thompson, JAI; Falkenberg, LJ; Connell, SD",synergistic effects of climate change and local stressors: co2 and nutrient-driven change in subtidal rocky habitats,GLOBAL CHANGE BIOLOGY,Article,carbon dioxide; climate change; CO2; coralline algae; habitat resilience; turf-forming algae,"climate-driven change represents the cumulative effect of global through local-scale conditions, and understanding their manifestation at local scales can empower local management. change in the dominance of habitats is often the product of local nutrient pollution that occurs at relatively local scales (i.e. catchment scale), a critical scale of management at which global impacts will manifest. we tested whether forecasted global-scale change [elevated carbon dioxide (co2) and subsequent ocean acidification] and local stressors (elevated nutrients) can combine to accelerate the expansion of filamentous turfs at the expense of calcifying algae (kelp understorey). our results not only support this model of future change, but also highlight the synergistic effects of future co2 and nutrient concentrations on the abundance of turfs. these results suggest that global and local stressors need to be assessed in meaningful combinations so that the anticipated effects of climate change do not create the false impression that, however complex, climate change will produce smaller effects than reality. these findings empower local managers because they show that policies of reducing local stressors (e.g. nutrient pollution) can reduce the effects of global stressors not under their governance (e.g. ocean acidification). the connection between research and government policy provides an example whereby knowledge (and decision making) across local through global scales provides solutions to some of the most vexing challenges for attaining social goals of sustainability, biological conservation and economic development.",91,2009,15,9,2153,2162,10.1111/j.1365-2486.2009.01886.x,1,0,0,1"Meinke, CW; Knick, ST; Pyke, DA",a spatial model to prioritize sagebrush landscapes in the intermountain west (usa) for restoration,RESTORATION ECOLOGY,Article,Artemisia; Cheatgrass; Greater Sage-Grouse; Intermountain West; Sagebrush; spatial modeling,"the ecological integrity of sagebrush (artemisia spp.) ecosystems in the intermountain west (u.s.a.) has been diminished by synergistic relationships among human activities, spread of invasive plants, and altered disturbance regimes. an aggressive effort to restore sagebrush habitats is necessary if we are to stabilize or improve current habitat trajectories and reverse declining population trends of dependent wildlife. existing economic resources, technical impediments, and logistic difficulties limit our efforts to a fraction of the extensive area undergoing fragmentation, degradation, and loss. we prioritized landscapes for restoring sagebrush habitats within the intermountain western region of the united states using geographic information system (gis) modeling techniques to identify areas meeting a set of conditions based on (1) optimum abiotic and biotic conditions favorable for revegetation of sagebrush; (2) potential to increase connectivity of sagebrush habitats in the landscape to benefit wildlife; (3) location of population strongholds for greater sage-grouse (centrocercus urophasianus, a species of conservation concern); and (4) potential impediments to successful restoration created by cheatgrass (bromus tectorum, an invasive exotic annual grass). approximately 5.8 million ha in southwestern idaho, northern nevada, and eastern oregon met our criteria for restoring wyoming big sagebrush (artemisia tridentata ssp. wyomingensis) and 5.1 million ha had high priority for restoring mountain big sagebrush (a. tridentata ssp. vaseyana). our results represent an integral component in a hierarchical framework after which site-specific locations for treatments can be focused within high-priority areas. using this approach, long-term restoration strategies can be implemented that combine local-scale treatments and objectives with large-scale ecological processes and priorities.",16,2009,17,5,652,659,10.1111/j.1526-100X.2008.00400.x,1,0,0,1"Goodson, JL; Kabelik, D; Schrock, SE",dynamic neuromodulation of aggression by vasotocin: influence of social context and social phenotype in territorial songbirds,BIOLOGY LETTERS,Article,vasotocin; vasopressin; aggression; songbird,"the homologous neuropeptides vasotocin (vt) and vasopressin (vp) influence agonistic behaviours across many taxa, but peptide-behaviour relationships are complex and purportedly species- specific. putative species- specific effects in songbirds are confounded with context, however, such that territorial species have been tested only in resident-intruder paradigms and gregarious species have been tested only in a mate competition paradigm. using the territorial violet-eared waxbill (estrildidae: uraeginthus granatina), we now show that a v(1a) receptor antagonist reduces male aggression during mate competition (as in gregarious finches), but does not affect resident-intruder aggression in dominant males. however, the v(1a) antagonist disinhibits aggression in less aggressive (typically subordinate) males. these results are consistent with recent data on the activation of different vt cell groups during positive and negative social interactions. thus, vt influences aggression similarly across territorial and gregarious species, but in context- and phenotype-specific ways that probably reflect the differential activation of discrete vt cell groups.",31,2009,5,4,554,556,10.1098/rsbl.2009.0316,0,1,0,1"Ayroles, JF; Hughes, KA; Rowe, KC; Reedy, MM; Rodriguez-Zas, SL; Drnevich, JM; Caceres, CE; Paige, KN","a genomewide assessment of inbreeding depression: gene number, function, and mode of action",CONSERVATION BIOLOGY,Article,additivity; inbreeding; inbreeding depression; microarray; overdominance; transcriptional variation,"although the genetic basis of inbreeding depression is still being debated, most fitness effects are thought to be the result of increased homozygosity for recessive or partially recessive deleterious alleles rather than the loss of overdominant genes. it is unknown how many loci are associated with inbreeding depression, the genes or gene pathways involved, or their mode of action. to uncover genes associated with variation in fitness following inbreeding, we generated a set of inbred lines of drosophila melanogaster for which only the third chromosome varied among lines and measured male competitive reproductive success among these lines to estimate inbreeding depression. male competitive reproductive success for different lines validated our prediction that equally inbred lines show variation in inbreeding depression. to begin to assess the molecular basis of inbreeding depression for male competitive reproductive success, we detected variation in whole-genome gene expression across these inbred lines with commercially available high-density oligonucleotide microarrays. a total of 567 genes were differentially expressed among these inbred lines, indicating that inbreeding directly or indirectly affects a large number of genes: genes that are disproportionately involved in metabolism, stress and defense responses. subsequently, we generated a set of outbred lines by crossing the highest inbreeding depression lines to each other and contrasted gene expression between parental inbred lines and f(1) hybrids with transcript abundance as a quantitative phenotype to determine the mode of action of the genes associated with inbreeding depression. although our results indicated that approximately 75% of all genes involved in inbreeding depression were additive, partially additive, or dominant, about 25% of all genes expressed patterns of overdominance. these results should be viewed with caution given that they may be confounded by issues of statistical inference or associative overdominance.",35,2009,23,4,920,930,10.1111/j.1523-1739.2009.01186.x,0,0,1,1"Angelier, F; Clement-Chastel, C; Welcker, J; Gabrielsen, GW; Chastel, O",how does corticosterone affect parental behaviour and reproductive success? a study of prolactin in black-legged kittiwakes,FUNCTIONAL ECOLOGY,Article,corticosterone; kittiwake; parental care; prolactin; seabird; stress,"p>an emergency life-history stage is expressed in breeding vertebrates when the immediate survival is threatened by poor energetic conditions (i.e. allostatic overload). this emergency life-history stage shifts energy investment away from reproduction and redirects it toward immediate survival. in birds, this emergency life-history stage is promoted by a release of the stress hormone corticosterone. however, how corticosterone reduces the expression of parental cares remains to be clarified. one hypothesis is that the release of corticosterone may also affect prolactin levels, a pituitary hormone widely involved in regulating parental behaviours. we tested this hypothesis by experimentally increasing corticosterone levels of chick-rearing black-legged kittiwakes (rissa tridactyla) over a 2-day period and by monitoring prolactin levels over an 8-day period. we also investigated whether this hormonal manipulation affected nest attendance, the motivation to come back to the nest after a short-term stress and breeding success. corticosterone treatment resulted in a significant increase in plasma corticosterone levels during the first 2 days, which returned to pre-treatment values at day 3. this short-term corticosterone increase was accompanied by a 30% decrease in prolactin levels. prolactin levels were reduced in a progressive and persistent manner and did not return to their initial levels when corticosterone levels returned to pre-treatment levels. moreover, although corticosterone levels had returned to pre-treatment values, low prolactin levels were associated with a reduced nest attendance and a greater latency to come back to the nest after a short-term stress. this hormonal treatment also significantly reduced breeding success. this experimental treatment strongly supports the idea that the secretion of these two hormones might be mechanistically linked. thus, we showed that even a relatively short-term increase in corticosterone levels can durably affect plasma prolactin levels. therefore, the well-established suppressive action of corticosterone on parental behaviour is probably mediated and reinforced through an effect on prolactin levels. this study highlights the need to consider the potential synergistic effects of these two hormones when studying on the hormonal basis of parental decisions.",58,2009,23,4,784,793,10.1111/j.1365-2435.2009.01545.x,1,0,0,1"Humair, B; Gonzalez, N; Mossialos, D; Reimmann, C; Haas, D",temperature-responsive sensing regulates biocontrol factor expression in pseudomonas fluorescens cha0,ISME JOURNAL,Article,biocontrol; GacS/GacA; Pseudomonas; RetS; small RNAs; temperature control,"in the plant-beneficial, root-colonizing strain pseudomonas fluorescens cha0, the gac/rsm signal transduction pathway positively regulates the synthesis of biocontrol factors (mostly antifungal secondary metabolites) and contributes to oxidative stress response via the stress sigma factor rpos. the backbone of this pathway consists of the gacs/gaca two-component system, which activates the expression of three small regulatory rnas (rsmx, rsmy, rsmz) and thereby counters translational repression exerted by the rsma and rsme proteins on target mrnas encoding biocontrol factors. we found that the expression of typical biocontrol factors, that is, antibiotic compounds and hydrogen cyanide (involving the phla and hcna genes), was significantly lower at 35 degrees c than at 30 degrees c. the expression of the rpos gene was affected in parallel. this temperature control depended on rets, a sensor kinase acting as an antagonist of the gacs/gaca system. an additional sensor kinase, lads, which activated the gacs/gaca system, apparently did not contribute to thermosensitivity. mutations in gacs or gaca were epistatic to (that is, they overruled) mutations in rets or lads for expression of the small rnas rsmxyz. these data are consistent with a model according to which rets-gacs and lads-gacs interactions shape the output of the gac/rsm pathway and the environmental temperature influences the rets-gacs interaction in p. fluorescens cha0. the isme journal (2009) 3, 955-965; doi: 10.1038/ismej.2009.42; published online 7 may 2009",26,2009,3,8,955,965,10.1038/ismej.2009.42,0,1,0,1"Szuroczki, D; Richardson, JML",the role of trematode parasites in larval anuran communities: an aquatic ecologist's guide to the major players,OECOLOGIA,Review,Echinostoma trivolvis; Emerging infectious disease; Ribeiroia ondatrae; Tadpoles,"conservation strategies depend on our understanding of the ecosystem and community dynamics. to date, such understanding has focused mostly on predator-prey and competitor interactions. it is increasingly clear, however, that parasite-host interactions may represent a large, and important, component of natural communities. the need to consider multiple factors and their synergistic interactions if we are to elucidate the contribution of anthropogenic factors to loss in biodiversity is exemplified by research into present-day amphibian declines. only recently has the role of factors such as trematode parasite infections been incorporated into studies of the population and community dynamics of aquatic systems. we argue that this is due, at least in part, to difficulties faced by aquatic ecologists in sifting through the complex systematics that pervade the parasite literature. we note that two trematode species are of dominant importance with regard to north american larval anuran communities, and provide in this review a clear explanation of how to distinguish between the infective stages of these two parasites. we describe the general biology and life history of these parasites, as well as what is known about their effect on larval anurans, and the interactive effects of environmental stressors (typically anthropogenic in nature) and parasites on larval anurans. we hope that this review will convince the reader of the potential importance of these parasites to aquatic communities in general, and to amphibian communities specifically, and will also provide the information necessary for aquatic ecologists to more frequently consider the role of these parasites in their studies of aquatic ecology.",22,2009,161,2,371,385,10.1007/s00442-009-1388-8,1,0,0,1"Csergo, AM; Nemes, S; Gafta, D; Demeter, L; Jakab, S",two-scale modelling of saponaria bellidifolia sm. (caryophyllaceae) abundance on limestone outcrops from its northern range periphery (southeastern carpathians),PLANT ECOLOGY,Article,Rare plants; Generalized additive models; Binomial logistic regression; Habitat heterogeneity; Disturbance; Regeneration niche,"we modelled the effect of habitat heterogeneity on the abundance of the submediterranean saponaria bellidifolia, a red list species in romania. the study was designed at two scales: 100 and 0.5 m(2). at larger scale, generalized additive models and canonical correspondence analysis were used to model the density of ramets, whereas at microscale, binomial logistic regression was employed to model the species' occurrence. s. bellidifolia abundance responded sensitively to habitat type (classified as ""grassy"", ""rocky"" and ""scree""), rather than to microclimatic variables. at both scales, habitat type was the best predictor of ramet abundance, followed by slope and vegetation cover. at 0.5 m(2), soil depth was also a good predictor of species occurrence. the data revealed that screes are the most suitable habitats for hosting relatively large populations of this rare species, because of occasional natural disturbances and presumably lower interspecific competition.",2,2009,203,2,229,242,10.1007/s11258-008-9539-2,0,0,1,1"Blomquist, GE",environmental and genetic causes of maturational differences among rhesus macaque matrilines,BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY,Article,Social dominance; Breeding value; Quantitative genetics; Heritability; Female maturation; Cayo Santiago,"females of many cercopithecine primates live in stable dominance hierarchies that create long-term asymmetries among sets of female relatives (matrilines) in access to limiting resources and shelter from psychosocial stress. rank-related differences in fitness components are widely documented, but their causes are unclear. predicted breeding values from an animal model for female age of first reproduction are used to discriminate between shared additive genetic and shared environmental effects among the members of matrilines in a population of free-ranging rhesus macaques (macaca mulatta). while age of first reproduction has a modest heritability (a parts per thousand 0.2), breeding values are distributed in a largely random fashion among matrilines and contribute little to the observed rank-related differences in average age of first reproduction. these results support the long-held, but previously unverified, contention that rank-related life history differences in female cercopithecine primates are the result of environmental rather than genetic differences among them.",8,2009,63,9,1345,1352,10.1007/s00265-009-0792-8,0,0,1,1"Traill, LW; Bradshaw, CJA; Field, HE; Brook, BW",climate change enhances the potential impact of infectious disease and harvest on tropical waterfowl,BIOTROPICA,Review,Anseranas semipalmata; avian disease; global warming; population viability analysis; tropical Australia,"global warming exacerbates threats to biodiversity as ecological systems shift in response to altered climatic conditions. yet the long-term survival of populations at direct risk from climate change may also be undermined by local factors such as infectious disease or anthropogenic harvest, which leave smaller and more isolated populations increasingly vulnerable to the rapid pace of global change. we review current and future threats to an exemplar tropical waterfowl species, magpie geese anseranas semipalmata, and focus on the potential synergies between infectious diseases, harvest, and climate change. we outline viral, bacterial, and fungal pathogens likely to cause disease in geese, and give mention to parasites. further, we elaborate on a previously developed, spatially explicit population viability model to simulate demographic responses to hunting and novel or enhanced disease outbreaks due to climate change. with no harvest, the simulated disease epizootics only threatened metapopulation viability when both mortality rate was high and outbreaks were regular (a threshold response). however, when contemporary site-specific harvest is included as an additive impact, the response to disease severity and probability was linear. we recommend field research to test these hypotheses linking drivers of waterfowl population decline to disease-climate change interactions.",5,2009,41,4,414,423,10.1111/j.1744-7429.2009.00508.x,1,0,1,2"Normand, S; Treier, UA; Randin, C; Vittoz, P; Guisan, A; Svenning, JC",importance of abiotic stress as a range-limit determinant for european plants: insights from species responses to climatic gradients,GLOBAL ECOLOGY AND BIOGEOGRAPHY,Article,Biotic interactions; climate; Europe; HOF models; physiological tolerance; plant species; response curves; spatial scale; Swiss Alps,"aim we examined whether species occurrences are primarily limited by physiological tolerance in the abiotically more stressful end of climatic gradients (the asymmetric abiotic stress limitation (aasl) hypothesis) and the geographical predictions of this hypothesis: abiotic stress mainly determines upper-latitudinal and upper-altitudinal species range limits, and the importance of abiotic stress for these range limits increases the further northwards and upwards a species occurs. location europe and the swiss alps. methods the aasl hypothesis predicts that species have skewed responses to climatic gradients, with a steep decline towards the more stressful conditions. based on presence-absence data we examined the shape of plant species responses (measured as probability of occurrence) along three climatic gradients across latitudes in europe (1577 species) and altitudes in the swiss alps (284 species) using huisman-olff-fresco, generalized linear and generalized additive models. results we found that almost half of the species from europe and one-third from the swiss alps showed responses consistent with the predictions of the aasl hypothesis. cold temperatures and a short growing season seemed to determine the upper-latitudinal and upper-altitudinal range limits of up to one-third of the species, while drought provided an important constraint at lower-latitudinal range limits for up to one-fifth of the species. we found a biome-dependent influence of abiotic stress and no clear support for abiotic stress as a stronger upper range-limit determinant for species with higher latitudinal and altitudinal distributions. however, the overall influence of climate as a range-limit determinant increased with latitude. main conclusions our results support the aasl hypothesis for almost half of the studied species, and suggest that temperature-related stress controls the upper-latitudinal and upper-altitudinal range limits of a large proportion of these species, while other factors including drought stress may be important at the lower range limits.",62,2009,18,4,437,449,10.1111/j.1466-8238.2009.00451.x,0,0,1,1"Corenblit, D; Steiger, J; Gurnell, AM; Naiman, RJ",plants intertwine fluvial landform dynamics with ecological succession and natural selection: a niche construction perspective for riparian systems,GLOBAL ECOLOGY AND BIOGEOGRAPHY,Review,Biogeomorphic succession; ecosystem engineers; niche construction; riparian conservation; riparian plants; riparian systems,"aim to contribute to the development of a macroevolutionary framework for riparian systems, reinforcing conceptual linkages between earth surface processes and biological and ecological processes. location riparian systems. methods literature review leading to an original proposition for perceiving the functioning of riparian systems in a new and different way. results riparian systems provide diverse landforms, habitats and resources for animals and plants. certain organisms, defined as 'ecosystem engineers', significantly create and modify the physical components of riparian systems. many studies have highlighted such engineering effects by animals on riparian systems, but the identification and understanding of the effects and responses of plants within fluvial corridors have emerged only recently. the modulation of matter, resources and energy flows by engineering plants helps establish characteristic sequences of fluvial landform creation and maintenance associated with synergetic ecological successions. we relate this process to the concept of niche construction, developed mainly by evolutionary biologists. feedbacks between adaptive responses of riparian plants to flow regime and adjusting effects on biostabilization and bioconstruction are discussed in the context of niche construction at the scale of ecological succession and the evolution of organisms. main conclusions our conceptualization forges an integrated approach for understanding vegetated fluvial systems from a macroevolutionary perspective, for elucidating riparian ecosystem dynamics and potentially for establishing long-term stream conservation and restoration strategies.",36,2009,18,4,507,520,10.1111/j.1466-8238.2009.00461.x,1,0,0,1"Zerger, A; Gibbons, P; Seddon, J; Briggs, S; Freudenberger, D",a method for predicting native vegetation condition at regional scales,LANDSCAPE AND URBAN PLANNING,Article,Vegetation condition; GIS; Landsat; SPOT4; GAMs,"regional-scale mapping of vegetation characteristics such as extent, configuration, composition and condition are critical for managing native vegetation. the extent and configuration of native vegetation is typically mapped using remote sensing, and plant species and communities are typically mapped using statistical models built with explanatory variables derived from gis layers. such research has paid limited attention to the 'condition' of native vegetation and rarely are explanatory variables derived from satellite remote sensing and gis layers used together to spatially predict vegetation characteristics. we calculated two independent metrics of vegetation condition using field data measured at each of 239 0.1 ha plots. these metrics of vegetation condition were used to develop two continuous maps of vegetation condition across an area of 260,000 ha using statistical models (generalised additive models, gams) built with explanatory variables derived from a range of sources including digital elevation models (dems), metrics of landscape connective, land use mapping and satellite remote sensing. both models included significant explanatory variables that were derived from satellite remote sensing and gis layers. using a cross-validation technique based on bootstrapping, correlations between observed plot data and predicted data for the two measures of vegetation condition were only reasonable (0.47-0.56). improved stratified sampling which captures disturbance gradients is a priority for improving models of this type. crown copyright (c) 2008 published by elsevier b.v. all rights reserved.",15,2009,91,2,65,77,10.1016/j.landurbplan.2008.11.011,0,0,1,1"Fredersdorf, J; Muller, R; Becker, S; Wiencke, C; Bischof, K","interactive effects of radiation, temperature and salinity on different life history stages of the arctic kelp alaria esculenta (phaeophyceae)",OECOLOGIA,Article,Climate change; Germination; Life cycle; Multiple stress; Photosynthesis,"to estimate the potential effects of climate change on polar marine macroalgae, studies on interactive stress effects of multiple climate-related parameters are essential. interactions of temperature, radiation and salinity on two different life history stages of alaria esculenta (l.) greville from the kongsfjord (spitsbergen) were investigated for the first time within this study. adult macroscopic sporophytes of a. esculenta were exposed to different temperatures between 4 and 21a degrees c combined with artificial irradiation conditions [photosynthetically active radiation, ultraviolet (uv) radiation: uv-a/uv-b, first experiment] and with different salinities [34, 28, 20 practical salinity units (p.s.u.) second experiment]. effects of photosynthetic activity were determined by measuring variable chlorophyll fluorescence of photosystem ii. germination success of young microscopic zoospores of a. esculenta was studied under multifactorial stress. zoospore suspensions were exposed to the three different salinities and irradiation conditions at four temperatures between 2 and 16a degrees c. overall, a. esculenta exhibited a highly stage-specific susceptibility towards the experimental treatments. in both experiments using sporophytes, photosynthetic activity showed significant temperature effects and only very few significant radiation and salinity effects. microscopic stages of a. esculenta were shown to be more sensitive than the adult macroscopic stages, since germination capacity of zoospores was significantly affected by temperature and salinity changes, and interactions of both. these results suggest that multiple stress factors interact synergistically. temperature seems to be a predominant environmental parameter for the kelp a. esculenta. overall, a. esculenta proved to be relatively tolerant and adaptable to increasing temperature and uv radiation, as well as to diluted salinities, but only up to a specific limit.",25,2009,160,3,483,492,10.1007/s00442-009-1326-9,1,0,0,1"Johnson, DS; Fleeger, JW",weak response of saltmarsh infauna to ecosystem-wide nutrient enrichment and fish predator reduction: a four-year study,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,Bottom-up; Ecosystem experiments; Multiple stressors; Salt marsh; Top-down,"we examined the effect of whole-ecosystem manipulations of predator removal and nutrient enrichment on saltmarsh macroinfauna in the plum island estuary, massachusetts. nitrate and phosphate loading rates were increased 10x above background levels in experimental creeks, and we significantly reduced (by 60%) the abundance of the killifish, fundulus heteroclitus, a key predator in this system. two creek pairs were manipulated; creek pair 1 for three growing seasons and creek pair 2 for one. infaunal responses were examined in four habitats along the inundation gradient: mudflat, creek wall, spartina alterniflora, and s. patens habitats. although benthic microalgae increased synergistically in our treatments, we detected no long-term, population-level numerical response by any taxon. similarly, no long-term species diversity or community responses were observed. however, nutrient enrichment increased the population biomass of the polychaete manayunkia aestuarina in the creek wall habitat and the oligochaete cernosvitoviella immota in the s. alterniflora habitat. no numerical or biomass responses of infauna were detected in predator removal treatments although indirect effects associated with killifish reduction may have contributed to an ephemeral interaction between nutrient addition and predator reduction in s. patens habitat. our data suggest that population and community responses between benthic microalgae and macroinfauna are not tightly coupled even though some species benefit from increased benthic algae biomass by achieving larger body size. (c) 2009 elsevier b.v. all rights reserved.",11,2009,373,1,35,44,10.1016/j.jembe.2009.03.003,1,0,0,1"Cornaglia, PS; Schrauf, GE; Deregibus, VA",flooding and grazing promote germination and seedling establishment in the perennial grass paspalum dilatatum,AUSTRAL ECOLOGY,Article,disturbances; fluctuating temperatures; gaps; grasslands; light quality; Paspalum dilatatum; seed dormancy,"seed germination and seedling emergence are key processes for population recruitment. flooding and grazing are disturbances forming gaps that may strongly influence recruitment patterns in space and time, but their combined effects and action mechanisms have rarely been addressed. in this study we analysed the effects of microhabitat conditions associated with winter flooding and spring-summer defoliation on seed germination and seedling establishment of paspalum dilatatum, a dominant perennial c(4) grass in native grasslands of the flooding pampa, argentina. the dynamics of seedling emergence from natural seed banks and buried seeds was studied in a factorial experiment with flooding and defoliation treatments applied to soil monoliths (mesocosms) collected from natural grassland. additional laboratory experiments were applied to investigate seed germination under different combinations of temperature, light quality and simulated flooding. seed germination and seedling emergence of p. dilatatum were promoted by flooding and high intensity defoliation. gaps generated by flooding were maintained by high intensity defoliation exercising a synergistic effect on survival seedlings. flooding resulted in the breaking of seed dormancy and higher germination rates associated with alternating temperature and the activation of the phytochrome system. our results indicate that microhabitat conditions associated with the disturbances forming gaps, such as flooding and heavy grazing, synergistically promote the recruitment process of this dominant grass species.",6,2009,34,3,343,350,10.1111/j.1442-9993.2009.01935.x,1,0,0,1"Ainouche, ML; Fortune, PM; Salmon, A; Parisod, C; Grandbastien, MA; Fukunaga, K; Ricou, M; Misset, MT","hybridization, polyploidy and invasion: lessons from spartina (poaceae)",BIOLOGICAL INVASIONS,Article,Spartina; Allopolyploidy; Hybridization; Invasion; Genome evolution; Phylogeny,"in this paper, we examine how the spartina system has helped our understanding of the genomic aspects of allopolyploid speciation in the context of biological invasion. more specifically the respective roles of hybridization and genome duplication in the success of newly formed allopolyploid species are explored. hybridization appears to have triggered genetic and epigenetic changes in the two recently formed european homoploid hybrids s. x towsendii and s. x neyrautii. deviation from parental structural additivity is observed in both hybrids, with different patterns when considering transposable element insertions or aflp and methylation alteration. no important changes are observed in the invasive allopolyploid spartina anglica that inherited the identical genome to s. x townsendii. the repeated rrna genes are not homogenized in the allopolyploid, and both parental repeats are expressed in the populations examined. transcriptomic changes suggest possible gene silencing in both hybrids and allopolyploid. in the long-term of evolutionary time, older hexaploid spartina species (spartina alterniflora, spartina maritima and spartina foliosa) appear to have selectively retained differential homeologous copies of nuclear genes. waxy gene genealogies suggest a hybrid (allopolyploid) origin of this hexaploid lineage of spartina. finally, nuclear and chloroplast dna data indicate a reticulate origin (alloheptaploid) of the invasive spartina densiflora. all together these studies stress hybridization as a primary stimulus in the invasive success of polyploid spartina species.",62,2009,11,5,1159,1173,10.1007/s10530-008-9383-2,0,0,1,1"Talloen, W; Van Dongen, S; Van Dyck, H; Lens, L",environmental stress and quantitative genetic variation in butterfly wing characteristics,EVOLUTIONARY ECOLOGY,Article,Environmental stress; Genetic variation; Canalization; Butterfly wing pattern; Pararge aegeria,"butterfly wing characteristics are extensively used as model system in studies of development, quantitative genetics and phenotypic plasticity. in spite of its evolutionary relevance, however, the effect of stress on the expression of genetic variation itself has only rarely been studied. in this paper, we explore genetic variation of wing characteristics of the speckled wood pararge aegeria along a host plant drought stress gradient. forewing area, basal and distal degree of melanization and the area of five yellow wing spots were measured. we found an increase in (additive) genetic variation in degree of melanization at higher drought stress, and a similar, yet non-significant, relationship for forewing size. as a result, both the upper limits of the narrow-sense heritability and the coefficient of additive genetic variation of wing size and melanization increased with drought stress. patterns for the different yellow wing spots were less consistent, suggesting trait-specificity in the relationships between genetic variation and environmental stress.",8,2009,23,3,473,485,10.1007/s10682-008-9246-4,0,0,1,1"Hegaret, H; da Silva, PM; Sunila, I; Shumway, SE; Dixon, MS; Alix, J; Wikfors, GH; Soudant, P","perkinsosis in the manila clam ruditapes philippinarum affects responses to the harmful-alga, prorocentrum minimum",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,Bivalve; Harmful algal bloom; Hemocyte; Perkinsus olseni; Prorocentrum minimum; Ruditapes philippinarum,"the dinoflagellate prorocentrum minimum is increasingly recognized as a harmful algal bloom (hab) species that affects filter-feeding shellfish. an experiment was done to investigate possible interactions between parasitic diseases and exposure to p. minimum in manila clams, ruditapes philippinarum. manila clams, with variable levels of infection with perkinsus olseni, were exposed for three or six days to the benign phytoplankton species chaetoceros neogracile or a mixed diet of c. neogracile and p minimum. after three or six days of exposure, clams were assessed individually for condition index, parasite status, and plasma and hemocyte parameters (morphological and functional) using flow-cytometry. histological evaluation was also performed on individual clams to assess prevalence and intensity of parasitic infection, as well as other pathological conditions. prorocentrum minimum caused several changes in manila clams, especially after six days of exposure, such as decreased hemocyte phagocytosis and size and clam condition index. pathological conditions observed in manila clams exposed to p. minimum were hemocyte infiltration in the intestine and gonad follicles, myopathy, and necrosis of the intestine epithelial cells. the parasite p. olseni alone had no significant effect on manila clams, nor did it modulate the hemocyte variables in clams exposed to p. minimum; however, the parasite did affect the pathological status of manila clams exposed to the p. minimum culture, by causing atrophy and degeneration of residual ova in the gonadal follicles and hyaline degeneration of the muscle fibers, indicating synergistic effects of both stressors on the host over a short period of time. additionally, an in vitro experiment also demonstrated detrimental effects of p. minimum and exudates upon r olseni cells, thus suggesting hab antagonistic suppression of transmission and proliferation of the parasite in the natural environment over a longer period of time. the results of this experiment demonstrate the complexity of interactions between host, parasite, and hab. (c) 2009 elsevier b.v. all rights reserved.",22,2009,371,2,112,120,10.1016/j.jembe.2009.01.016,1,1,0,2"Madden, JR; Clutton-Brock, TH",manipulating grooming by decreasing ectoparasite load causes unpredicted changes in antagonism,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,antagonism; ectoparasites; grooming; meerkats; social networks; stress,"it is thought that allogrooming is practised strategically in order to establish, maintain and reinforce social bonds between group members, exchanging one altruistic behaviour for a different form of reciprocated benefit at a later date. correlational evidence supports this, but evidence of causality is lacking. we reduced parasite loads in eight meerkat suricata suricatta groups, generating a substantial decrease in grooming. contrary to the predictions, overall antagonism did not increase. however, within group networks, grooming increased towards individuals who increased their antagonism. this was restricted to antagonism focused on social position, rather than access to physical resources. the treatment also increased an alternative placatory behaviour: unprompted submissions. following treatment, individuals performed higher rates of guarding and marking behaviours, suggesting that they were stressed. a reduction in opportunity to mediate stress through grooming may explain local rises in antagonism and corresponding increases in placatory behaviours. we suggest that meerkats use allogrooming (and submissions) as a facultative response to antagonism, rather than a pre-emptive strategy to avert it by establishing a network of associations, as has been suggested for primates.",16,2009,276,1660,1263,1268,10.1098/rspb.2008.1661,0,1,0,1"Nicholson, E; Keith, DA; Wilcove, DS",assessing the threat status of ecological communities,CONSERVATION BIOLOGY,Review,classification protocols; conservation status; IUCN; NatureServe; red list; threat categories; threatened species lists,"conservationists are increasingly interested in determining the threat status of ecological communities as a key part of their planning efforts. such assessments are difficult because of conceptual challenges and a lack of generally accepted criteria. we reviewed 12 protocols for assessing the threat status of communities and identified conceptual and operational issues associated with developing a rigorous, transparent, and universal set of criteria for assessing communities, analogous to the international union for conservation of nature (iucn) red list standards for species. we examined how each protocol defines a community and its extinction and how each applies 3 overarching criteria: decline in geographic distribution, restricted geographic distribution, and changes to ecological function. the protocols vary widely in threshold values used to assess declines and distribution size and the time frames used to assess declines, leading to inconsistent assessments of threat status. few of the protocols specify a scale for measuring distribution size, although assessment outcomes are highly sensitive to scale. protocols that apply different thresholds for species versus communities tend to require greater declines and more restricted distributions for communities than species to be listed in equivalent threat categories. eleven of the protocols include a reduction in ecological function as a criterion, but almost all assess it qualitatively rather than quantitatively. we argue that criteria should be explicit and repeatable in their concepts, parameters, and scale, applicable to a broad range of communities, and address synergies between types of threats. such criteria should focus on distribution size, declines in distribution, and changes to key ecological functions, with the latter based on workable proxies for assessing the severity, scope, and immediacy of degradation. threat categories should be delimited by thresholds that are assessed at standard scales and are logically consistent with the viability of component species and important ecological functions.",24,2009,23,2,259,274,10.1111/j.1523-1739.2008.01158.x,1,0,0,1"Scheil, V; Kienle, C; Osterauer, R; Gerhardt, A; Kohler, HR","effects of 3,4-dichloroaniline and diazinon on different biological organisation levels of zebrafish (danio rerio) embryos and larvae",ECOTOXICOLOGY,Article,Fish; Multi-level approach; Pesticides; Stress proteins; Behaviour; DarT,"in this study the effects of 3,4-dichloroaniline (3,4-dca), a decomposition product of the herbicides propanil and diuron (and other pesticides), and diazinon, a neurotoxic insecticide, on early life stages of zebrafish danio rerio were assessed. the toxicity of these substances with different modes of action (acetylcholine esterase inhibitor vs. polar narcosis) was tested for single substances as well as in binary mixtures. to study effects on different biological organisation levels (from the molecular up to the whole organism level) the molecular stress response regarding hsp70, the embryonic and larval development and the locomotor activity were investigated as integrative biomarkers. in single substance tests 3,4-dichloroaniline elicited deformations at a parts per thousand yen0.25 mg/l during the 11 days subchronic test, whereas locomotor activity and mortality were impaired at a parts per thousand yen0.5 mg/l. diazinon effects on those parameters were obvious at a parts per thousand yen2 mg/l, except for the deformation rate (11 days:1 mg/l). in equitoxic mixtures of both substances concentration additivity was observed for deformation rate and mortality (11 days). an increase in the hsp70 content occurred in zebrafish exposed to 0.25 mg 3,4-dca/l as well as to 0.05 mg diazinon/l; in mixtures concentration additivity could be shown. the investigated endpoints varied in respect to their sensitivity, with deformations and hsp70 levels as most sensitive parameters concerning 3,4-dca and hsp70 as most sensitive parameter concerning diazinon. accordingly, for an integrated understanding of the effects of chemicals and their mixtures on fish, a battery of different test methods should be applied.",12,2009,18,3,355,363,10.1007/s10646-008-0291-0,0,0,1,1"Dowling, DK; Maklakov, AA; Friberg, U; Hailer, F",applying the genetic theories of ageing to the cytoplasm: cytoplasmic genetic covariation for fitness and lifespan,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,ageing; antagonistic pleiotropy; cytoplasm; Drosophila melanogaster; mitochondria; mtDNA; mutation accumulation; senescence,"two genetic models exist to explain the evolution of ageing - mutation accumulation (ma) and antagonistic pleiotropy (ap). under ma, a reduced intensity of selection with age results in accumulation of late-acting deleterious mutations. under ap, late-acting deleterious mutations accumulate because they confer beneficial effects early in life. recent studies suggest that the mitochondrial genome is a major player in ageing. it therefore seems plausible that the ma and ap models will be relevant to genomes within the cytoplasm. this possibility has not been considered previously. we explore whether patterns of covariation between fitness and ageing across 25 cytoplasmic lines, sampled from a population of drosophila melanogaster, are consistent with the genetic associations predicted under ma or ap. we find negative covariation for fitness and the rate of ageing, and positive covariation for fitness and lifespan. notably, the direction of these associations is opposite to that typically predicted under ap.",4,2009,22,4,818,827,10.1111/j.1420-9101.2009.01692.x,0,1,0,1"Herrera, LP; Laterra, P",do seed and microsite limitation interact with seed size in determining invasion patterns in flooding pampa grasslands?,PLANT ECOLOGY,Article,Paspalum quadrifarium; Ground cover; Disturbance; Recruitment; Litter,"additive influences of the invasion ability of species (invasiveness) and the characteristics of the habitat which make it invasible (invasibility) cannot fully explain grassland invasion patterns. we tested the hypothesis that different species assemblages of grassland communities may partly result from interactive influences between the relative invasiveness of available species and community invasibility. during 10 months, we evaluated seed and microsite limitation of seedling emergence, survival, and recruitment of plants belonging to species with different seed size (large-seeded species vs. small-seeded species), with in a two-phase community mosaic typical of semi-natural grasslands in the southern flooding pampa of argentina. seeds of large versus small-seeded species were sown either in species-poor patches dominated by a tall tussock grass (""pajonal"") or in species-rich patches dominated by short grasses (""matrix""), subjected to different levels of canopy disturbance (cut vs. uncut). seed addition promoted seedling emergence for 7 out of the 10 species sown, and this effect was higher for large than for small-seeded species. after seed limitations were removed, interactive effects among seed size, community state and canopy disturbance reflected a strong positive influence of seed size on plant recruitment only in cut pajonal patches. therefore, according to the stage of invasion process, relative species success may depend on non-interactive (seed-size effect on seed limitation to seedling emergence) or interactive influences among species invasibility and community invasiveness (from seedling emergence to plant recruitment). as a general conclusion, different assemblages of species are expected to successfully colonize spatially close grassland patches, according to both the available invasible species (seed size) and the community state and stage (species composition and canopy disturbance).",8,2009,201,2,457,469,10.1007/s11258-008-9542-7,0,0,1,1"Gallet, R; Tully, T; Evans, MEK",ecological conditions affect evolutionary trajectory in a predator-prey system,EVOLUTION,Article,Antagonistic coevolution; Bdellovibrio bacteriovorus; disturbance; experimental evolution; Pseudomonas fluorescens; trade-off evolution,"the arms race of adaptation and counter adaptation in predator-prey interactions is a fascinating evolutionary dynamic with many consequences, including local adaptation and the promotion or maintenance of diversity. although such antagonistic coevolution is suspected to be widespread in nature, experimental documentation of the process remains scant, and we have little understanding of the impact of ecological conditions. here, we present evidence of predator-prey coevolution in a long-term experiment involving the predatory bacterium bdellovibrio bacteriovorus and the prey pseudomonas fluorescens, which has three morphs (sm, fs, and ws). depending on experimentally applied disturbance regimes, the predator-prey system followed two distinct evolutionary trajectories, where the prey evolved to be either super-resistant to predation (sm morph) without counter-adaptation by the predator, or moderately resistant (fs morph), specialized to and coevolving with the predator. although predation-resistant fs morphs suffer a cost of resistance, the evolution of extreme resistance to predation by the sm morph was apparently unconstrained by other traits (carrying capacity, growth rate). thus we demonstrate empirically that ecological conditions can shape the evolutionary trajectory of a predator-prey system.",8,2009,63,3,641,651,10.1111/j.1558-5646.2008.00559.x,0,1,0,1"Relva, MA; Westerholm, CL; Kitzberger, T",effects of introduced ungulates on forest understory communities in northern patagonia are modified by timing and severity of stand mortality,PLANT ECOLOGY,Article,Austrocedrus chilensis; Browsing; Disturbance; Exotic deer; Forest decline,"natural disturbances such as fires, windstorms, floods, and herbivory often act on plant communities, affecting their structure and the abundance and composition of their species. most research has focused on the effects of single disturbances on plant communities whereas the synergistic effects of several disturbances have received less attention. in this study, we evaluated how timing and severity of tree mortality modified plant use by introduced deer and early post-mortality successional trajectories in northern patagonian conifer forests. we sampled understory composition and deer use in austrocedrus chilensis (cipr,s de la cordillera) forest stands undergoing varying timing and severity of forest mortality as reconstructed using dendroecological techniques. in addition, we evaluated the effect of fallen logs on plant composition and deer use of plants by monitoring areas of massive dieback where fallen logs had been removed for fire hazard reduction, and nearby control areas not subjected to such removal. stepwise regression analyses showed that history and severity of tree mortality strongly influence plant composition and deer use of plants. for deer use (with pellet counts and browsing index as response variables), results showed a positive relationship with degree of stand mortality and a negative relationship with cover of fallen logs. similarly, cover of unpalatable shrub species was explained by canopy mortality history, whereas cover of palatable shrub species was positively associated with severity of canopy mortality. in areas where fallen logs had been removed, pellet counts were six times higher than those in control areas. though total shrub species cover was similar between log removal and control areas, proportion of unpalatable shrubs increased in areas where fallen logs had been removed. in conclusion, deer use of plants was strongly limited by tall fallen logs, allowing palatable species to establish and grow. fallen log removal accelerated deer entrance and changed understory composition toward more browse-resistant and unpalatable species. these results underscore the importance of considering the dynamics (timing, severity, and extent) of fallen woody debris influencing understory herbivory and post-disturbance succession. in addition, experimental results underpin the importance of maintaining snags and large woody debris in disturbed landscapes where salvage logging is a routine procedure.",14,2009,201,1,11,22,10.1007/s11258-008-9528-5,1,0,0,1"Caro, SP; Charmantier, A; Lambrechts, MM; Blondel, J; Balthazart, J; Williams, TD",local adaptation of timing of reproduction: females are in the driver's seat,FUNCTIONAL ECOLOGY,Article,gonadal development; heritability; local adaptation; Parus; Parus caeruleus; timing of breeding; yolk precursors,"breeding at the right time of the year is crucial for many temperate zone organisms, as any mismatch with their optimal breeding period leads to a reduction in fitness. the roles of the breeding partners in these adaptive decisions have, however, only rarely been studied. in blue tits (cyanistes caeruleus) that breed in heterogenous mediterranean habitats, nearby populations show up to 1-month differences in breeding time. this difference is adaptive as the optimal time for breeding varies by the same amount due to habitat characteristics. but which sex is determining this large difference in timing? we show here that the seasonal development of female reproductive activity (yolk precursor production) closely matches the local optimal breeding time in these two highly contrasted landscapes, while previous studies have demonstrated that male gonadal development does not. in accordance with this, quantitative genetic analyses reveal that timing for breeding is determined by the female only, with no evidence for an additive genetic male effect on laying date. our results strongly suggest that the adaptive inter-population difference in the laying periods has been driven by females. the central role of females in the determination of breeding period needs to be included when studying how micro-evolutionary processes are affected by global climate change.",42,2009,23,1,172,179,10.1111/j.1365-2435.2008.01486.x,0,0,1,1"Garcia-Fayos, P; Bochet, E",indication of antagonistic interaction between climate change and erosion on plant species richness and soil properties in semiarid mediterranean ecosystems,GLOBAL CHANGE BIOLOGY,Article,climate change; interaction models; Mediterranean; plant cover; semiarid; soil erosion; soil fertility; Spain; species richness; water holding capacity,"we analyzed the consequences of climate change and the increase in soil erosion, as well as their interaction on plant and soil properties in semiarid mediterranean shrublands in eastern spain. current models on drivers of biodiversity change predict an additive or synergistic interaction between drivers that will increase the negative effects of each one. we used a climatic gradient that reproduces the predicted climate changes in temperature and precipitation for the next 40 years of the wettest and coldest end of the gradient; we also compared flat areas with 20 degrees steep hillslopes. we found that plant species richness and plant cover are negatively affected by climate change and soil erosion, which in turn negatively affects soil resistance to erosion, nutrient content and water holding capacity. we also found that plant species diversity correlates weakly with plant cover but strongly with soil properties related to fertility, water holding capacity and resistance to erosion. conversely, these soil properties correlate weaker with plant species cover. the joint effect of climate change and soil erosion on plant species richness and soil characteristics is antagonistic. that is, the absolute magnitude of change is smaller than the sum of both effects. however, there is no interaction between climate change and soil erosion on plant cover and their effects fit the additive model. the differences in the interaction model between plant cover and species richness supports the view that several soil properties are more linked to the effect that particular plant species have on soil processes than to the quantity and quality of the plant cover and biomass they support. our findings suggest that plant species richness is a better indicator than plant cover of ecosystems services related with soil development and protection to erosion in semiarid mediterranean climates.",14,2009,15,2,306,318,10.1111/j.1365-2486.2008.01738.x,1,1,1,3"Morgan, AD; Maclean, RC; Buckling, A",effects of antagonistic coevolution on parasite-mediated host coexistence,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,antagonistic coevolution; bacteria; bacteriophage; host; parasite; parasite-mediated coexistence,"parasites can promote diversity by mediating coexistence between a poorer and superior competitor, if the superior competitor is more susceptible to parasitism. however, hosts and parasites frequently undergo antagonistic coevolution. this process may result in the accumulation of pleiotropic fitness costs associated with host resistance, and could breakdown coexistence. we experimentally investigated parasite-mediated coexistence of two genotypes of the bacterium pseudomonas fluorescens, where one genotype underwent coevolution with a parasite (a virulent bacteriophage), whereas the other genotype was resistant to the evolving phages at all time points, but a poorer competitor. in the absence of phages, the resistant genotype was rapidly driven extinct in all populations. in the presence of the phages, the resistant genotype persisted in four of six populations and eventually reached higher frequencies than the sensitive genotype. the coevolving genotype showed a reduction in the growth rate, consistent with a cost of resistance, which may be responsible for a decline in its relative fitness. these results demonstrate that the stability of parasite-mediated coexistence of resistant and susceptible species or genotypes is likely to be affected if parasites and susceptible hosts coevolve.",12,2009,22,2,287,292,10.1111/j.1420-9101.2008.01642.x,0,1,0,1"Gillson, L",landscapes in time and space,LANDSCAPE ECOLOGY,Article,Landscape mosaics; Biocomplexity; Resilience; Thresholds; Adaptive cycles; Palaeo-invasions,"landscape ecology has a temporal dimension, and the role of past processes in shaping landscapes is increasingly recognised. to date, the interface between landscape ecology and palaeoecology has proved most productive in understanding the impacts of climate change and in discovering the extent of past human impacts on ecosystems. further areas of synergy are emerging. this perspective gives selected examples of five main areas of synergy between palaeoecology and landscape ecology: dynamic landscape mosaics; resilience and thresholds; biocomplexity; adaptive cycles; and in the landscape ecology of invasive spread.",15,2009,24,2,149,155,10.1007/s10980-008-9315-7,1,0,0,1"Piessens, K; Adriaens, D; Jacquemyn, H; Honnay, O",synergistic effects of an extreme weather event and habitat fragmentation on a specialised insect herbivore,OECOLOGIA,Article,Calcareous grassland; Climate change; Trophic interaction; Cupido minimus; Anthyllis vulneraria,"habitat fragmentation is considered to be one of the main causes of population decline and species extinction worldwide. furthermore, habitat fragmentation can decrease the ability of populations to resist and to recover from environmental disturbances such as extreme weather events, which are expected to occur at an increasing rate as a result of climate change. in this study, we investigated how calcareous grassland fragmentation affected the impact of the climatically extreme summer of 2003 on egg deposition rates, population size variation and survival of the blue butterfly cupido minimus, a specialist herbivore of anthyllis vulneraria. immediately after the 2003 summer heat wave, populations of the host plant declined in size; this was paralleled with decreases in population size of the herbivore and altered egg deposition rates. in 2006 at the end of the monitoring period, however, most a. vulneraria populations had recovered and only one population went extinct. in contrast, several butterfly populations had gone extinct between 2003 and 2006. extinction probability was significantly related to initial population size, with small populations having a higher risk of extinction than large populations. these results support the prediction that species of higher trophic levels are more susceptible to extinction due to habitat fragmentation and severe disturbances.",25,2009,159,1,117,126,10.1007/s00442-008-1204-x,1,0,0,1"Kay, KM; Sargent, RD","the role of animal pollination in plant speciation: integrating ecology, geography, and genetics",ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS,Review; Book Chapter,floral isolation; reproductive isolation; specialization; syndromes trade-offs,"although animal pollination is often proposed as a major driver of floral divergence, questions remain about its importance in plant speciation. one issue is whether pollinator specialization, traditionally thought necessary for floral isolation, is prevalent enough to have played a major role in speciation. furthermore, the ecological and geographic scenarios under which pollinator transitions occur are poorly understood, and the underlying genetic factors are just beginning to be uncovered for a few systems. nevertheless, macroevolutionary studies consistently show that transitions to animal pollination are accompanied by an increase in diversification rate. here we consider several models and diverse empirical data on how pollinators could influence speciation. we conclude that floral isolation is rarely, if ever, sufficient to cause speciation on its own, but that it acts synergistically with other isolating mechanisms. a more comprehensive approach is the key to an improved understanding of the role of pollinators in angiosperm speciation.",86,2009,40,,637,656,10.1146/annurev.ecolsys.110308.120310,1,0,0,1"Kendall, WL; Converse, SJ; Doherty, PF; Naughton, MB; Anders, A; Hines, JE; Flint, E",sampling design considerations for demographic studies: a case of colonial seabirds,ECOLOGICAL APPLICATIONS,Article,albatross; buffer area; capture-recapture; dead recoveries; double banding; incidental observations; less invasive robust design; multistate models; Phoebastria immutabilis; Phoebastria nigripes; robust design; tag loss,"for the purposes of making many informed conservation decisions, the main goal for data collection is to assess population status and allow prediction of the consequences of candidate management actions. reducing the bias and variance of estimates of population parameters reduces uncertainty in population status and projections, thereby reducing the overall uncertainty under which a population manager must make a decision. in capture recapture studies, imperfect detection of individuals, unobservable life-history states, local movement outside study areas, and tag loss can cause bias or precision problems with estimates of population parameters. furthermore, excessive disturbance to individuals during capture-recapture sampling may be of concern because disturbance may have demographic consequences. we address these problems using as an example a monitoring program for black-footed albatross (phoebastria nigripes) and laysan albatross (phoebastria immutabilis) nesting populations in the northwestern hawaiian islands. to mitigate these estimation problems, we describe a synergistic combination of sampling design and modeling approaches. solutions include multiple capture periods per season and multistate, robust design statistical models, dead recoveries and incidental observations, telemetry and data loggers, buffer areas around study plots to neutralize the effect of local movements outside study plots, and double banding and statistical models that account for band loss. we also present a variation on the robust capture-recapture design and a corresponding statistical model that minimizes disturbance to individuals. for the albatross case study, this less invasive robust design was more time efficient and, when used in combination with a traditional robust design, reduced the standard error of detection probability by 14% with only two hours of additional effort in the field. these field techniques and associated modeling approaches are applicable to studies of most taxa being marked and in some cases have individually been applied to studies of birds, fish, herpetofauna, and mammals.",18,2009,19,1,55,68,10.1890/07-1072.1,1,0,0,1"Holdo, RM; Holt, RD; Fryxell, JM","grazers, browsers, and fire influence the extent and spatial pattern of tree cover in the serengeti",ECOLOGICAL APPLICATIONS,Article,Acacia; elephants (Loxodonta africana); GIS; migration; savanna dynamics; SD model; spatial coupling; spatial heterogeneity; Tanzania; tree-grass interactions; wildebeest (Connochaetes taurinus),"vertebrate herbivores and fire are known to be important drivers of vegetation dynamics in african savannas. it is of particular importance to understand how changes in herbivore population density, especially of elephants, and fire frequency will affect the amount of tree cover in savanna ecosystems, given the critical importance of tree cover for biodiversity, ecosystem function, and human welfare. we developed a spatially realistic simulation model of vegetation,fire, and dominant herbivore dynamics, tailored to the serengeti ecosystem of east africa. the model includes key processes such as tree-grass competition, fire, and resource-based density dependence and adaptive movement by herbivores. we used the model to project the ecosystem 100 years into the future from its present state under different fire, browsing (determined by elephant population density), and grazing (with and without wildebeest present) regimes. the model produced the following key results: (1) elephants and fire exert synergistic negative effects on woody cover; when grazers are excluded, the impact of fire and the strength of the elephant-fire interaction increase; (2) at present population densities of 0.15 elephants/km(2), the total amount of woody cover is predicted to remain stable in the absence of fire, but the mature tree population is predicted to decline regardless of the fire regime; without grazers present to mitigate the effects of fire, the size structure of the tree population will become dominated by seedlings and mature trees; (3) spatial heterogeneity in tree cover varies unimodally with elephant population density fire increases heterogeneity in the presence of grazers and decreases it in their absence; (4) the marked rainfall gradient in the serengeti directly affects the pattern of tree cover in the absence of fire; with fire, the woody cover is determined by the grazing patterns of the migratory wildebeest, which are partly rainfall driven. our results show that, in open migratory ecosystems such as the serengeti, grazers can modulate the impact of fire and the strength of the interaction between fire and browsers by altering fuel loads and responding to the distribution of grass across the landscape, and thus exert strong effects on spatial patterns of tree cover.",62,2009,19,1,95,109,10.1890/07-1954.1,1,0,0,1"Fyllas, NM; Troumbis, AY",simulating vegetation shifts in north-eastern mediterranean mountain forests under climatic change scenarios,GLOBAL ECOLOGY AND BIOGEOGRAPHY,Article,Climate change; fire regimes; forest gap dynamics models; Greece; Mediterranean forests; plant functional types,"to explore potential shifts in vegetation and fire regime in some dominant forest types in the north-eastern part of the mediterranean basin under climate change. two altitudinal gradients in the continental part of greece. we developed a forest gap dynamics simulator that provides feedback from the stand to its water balance and flammability status. the model is used to simulate vegetation dynamics in two mountainous areas, currently found under different aridity conditions. two climatic change scenarios (intergovernmental panel on climate change a1 and b2) were applied to explore differences in the response of the established forest types. in addition we explicitly accounted for the role of fire, under both current and altered climate patterns. fire was identified to play a significant role in low-altitude sites. its significance increased with the severity of the climate change scenario. elevational shifts of the dominant species were simulated for each site, while in some cases these changes were associated with a shorter fire cycle and a frequent resetting of processes of vegetation change. our simulations suggest a greater vulnerability of mountainous mediterranean drier areas regarding compositional alteration and flammability trends. changes in vegetation could take place through both a discrete and synergistic realization of changes in the drought stress and fire frequency.",10,2009,18,1,64,77,10.1111/j.1466-8238.2008.00419.x,1,0,0,1"Theodorou, K; Souan, H; Couvet, D",metapopulation persistence in fragmented landscapes: significant interactions between genetic and demographic processes,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,conservation; deleterious mutation; dispersal; disturbance; extinction; matrix; metapopulation,"we formulated a mathematical model in order to study the joint influence of demographic and genetic processes on metapopulation viability. moreover, we explored the influence of habitat structure, matrix quality and disturbance on the interplay of these processes. we showed that the conditions that allow metapopulation persistence under the synergistic action of genetic and demographic processes depart significantly from predictions based on a mere superposition of the effects of each process separately. moreover, an optimal dispersal rate exists that maximizes the range of survival rates of dispersers under which metapopulation persists and at the same time allows the largest sustainable patch removal and patch-size reduction. the relative impact of patch removal and patch-size reduction depends both on matrix quality and the dispersal strategy of the species: metapopulation persistence is more affected by patch-size reduction (patch removal) for low (high)-dispersing species, in presence of a low (high) quality matrix. avoidance of inbreeding, through increased dispersal when the rate of inbreeding in a population is large, has positive effects on low-dispersing species, but impairs the persistence of high-dispersing species. finally, size heterogeneity between patches largely influences metapopulation dynamics; the presence of large patches, even at the expense of other patches being smaller, can have positive effects on persistence in particular for species of low dispersing ability.",9,2009,22,1,152,162,10.1111/j.1420-9101.2008.01634.x,1,0,0,1"Meyer, E; Davies, S; Wang, S; Willis, BL; Abrego, D; Juenger, TE; Matz, MV",genetic variation in responses to a settlement cue and elevated temperature in the reef-building coral acropora millepora,MARINE ECOLOGY PROGRESS SERIES,Article,Global climate change; Adaptation; Coral reefs; Thermal tolerance,"reef-building corals are threatened by increasing sea surface temperatures resulting from global climate change. whether corals can adapt to increasing temperatures over the course of generations will depend in part on heritable variation in thermal physiology and dispersal potential, which may serve as the raw material for natural selection. to investigate whether such variation exists in coral populations, and build a framework for identifying the coral-specific genetic factors involved, we performed controlled crosses between 3 genetically distinct colonies of the branching coral acropora millepora. we compared the families of larvae (which in this species naturally lack symbionts) for several physiological traits, and observed between-family differences in nearly every case. using larvae cultured at standard and elevated temperatures, we measured the developmental decrease in protein content and the expression of candidate heat response genes. we used an in vivo assay for mitochondrial enzyme activity to evaluate the metabolic response to temperature changes in individual larvae. we also compared the responsiveness of larvae from different families to a natural settlement cue to gain insights into long-range dispersal potential. partitioning the components of total phenotypic variance confirmed the existence of additive genetic effects for settlement rates and beta gamma-crystallin expression, while variance in mitochondrial q(10) and the expression of actin and hsp16 were driven by non-additive effects. the phenotypic variance observed among the small number of families analyzed here suggests the existence of considerable heritable variation in natural coral populations, which supports the possibility of effective adaptive responses to climate change.",37,2009,392,,81,92,10.3354/meps08208,0,0,1,1"Somerfield, PJ; Arvanitidis, C; Faulwetter, S; Chatzigeorgiou, G; Vasileiadou, A; Amouroux, JM; Anisimova, N; Cochrane, SJ; Craeymeersch, J; Dahle, S; Denisenko, S; Dounas, K; Duineveld, G; Gremare, A; Heip, CHR; Herrmann, M; Karakassis, I; Kedra, M; Kendall, MA; Kingston, P; Kotwicki, L; Labrune, C; Laudien, J; Nevrova, H; Nicolaidou, A; Occhipinti-Ambrogi, A; Palerud, R; Petrov, A; Rachor, E; Revkov, N; Rumohr, H; Sarda, R; Janas, U; Vanden Berghe, E; Wlodarska-Kowalczuk, M",assessing evidence for random assembly of marine benthic communities from regional species pools,MARINE ECOLOGY PROGRESS SERIES,Article,Benthos; Soft sediment; Community assembly; Local-regional relationships; Species pools; Taxonomic distinctness,"local species diversity may be determined by processes operating locally, such as disturbance, predation and competition, or by regional processes, such as environmental structuring or history. classical theory focusing on competition predicts that the species combining to form communities will be less similar to each other than they would be if they were assembled at. random from a regional species pool, theory focusing on environmental structuring predicts that species will be more similar to each other than expected by chance. a randomisation test that determines the extent to which local species lists represent random selections from a regional list, based on the average relatedness between species, was applied to data held in the macroben database. little or no evidence was found for species lists of whole faunas at any scale being random subsets of species lists at larger scales. species tend to be more closely related to each other than would be expected if they were assembled at random. thus marine soft-sediment macrofauna are not locally assembled at random from regional species pools and it is likely that regional processes determine the assembly of communities. focusing on the most abundant class within the macrofauna, a different pattern emerges, in that there is a much stronger tendency for local polychaete composition to be a random subset from regional pools at all scales. thus it is not possible to determine whether local polychaete diversity is independent of both local and regional processes, or determined by a combination of both acting antagonistically.",8,2009,382,,279,286,10.3354/meps07934,0,1,0,1"Johnson, DS; Fleeger, JW; Deegan, LA",large-scale manipulations reveal that top-down and bottom-up controls interact to alter habitat utilization by saltmarsh fauna,MARINE ECOLOGY PROGRESS SERIES,Article,Ecosystem experiments; Multi-stressors; Parasites; Epifauna; Salt marsh,"we used ecosystem-wide predator removal and nutrient enrichment to examine top-own and bottom-up forces on saltmarsh fauna. we reduced the killifish fundulus heteroclitus by similar to 60%, which elicited significant increases (2 to 4 x) in hydrobiid snails hydrobia spp., suggesting top-own control. the talitrid amphipod uhlorchestia spartinophila was the most abundant species of epifauna in the creek-bank spartina alterniflora habitat. our elevated water column nutrients (similar to 70 mu mol 1(-1) , similar to 10x background) and predator reduction treatments alone both yielded nonsignificant increases in amphipod abundance, suggesting weak top-down and bottom-up control over this species. however, treatments interacted antagonistically in this habitat such that amphipod abundances were lower than would be expected by an additive response to both treatments. we found corresponding amphipod abundance increases in the adjoining creek-wall habitat, suggesting that amphipods move under the influence of our treatments from the marsh edge onto the creek wall, possibly as a result of an increased incidence of a parasitic (i.e. trematode levinseniella sp.) infection. coincident to increased amphipods on creek walls, semipalmated sandpipers calidris pusilla, amphipod predators, increasingly foraged in creek channels in combined treatments (similar to 30x higher than controls based on unreplicated creek systems). our results suggest that top-down and bottom-up effects may at times be difficult to detect in small, single-factor studies because of inter-habitat movements of target species and redundant predation. because the effects of stressors may not be limited to one part of the landscape even for small, motile fauna, landscape-level studies may generally be needed to capture responses to anthropogenic activities.",11,2009,377,,33,41,10.3354/meps07849,0,1,1,2"Darling, ES; Cote, IM",quantifying the evidence for ecological synergies,ECOLOGY LETTERS,Letter,Meta-analysis; mortality; multiple stressors; non-additive effects; synergy,"there is increasing concern that multiple drivers of ecological change will interact synergistically to accelerate biodiversity loss. however, the prevalence and magnitude of these interactions remain one of the largest uncertainties in projections of future ecological change. we address this uncertainty by performing a meta-analysis of 112 published factorial experiments that evaluated the impacts of multiple stressors on animal mortality in freshwater, marine and terrestrial communities. we found that, on average, mortalities from the combined action of two stressors were not synergistic and this result was consistent across studies investigating different stressors, study organisms and life-history stages. furthermore, only one-third of relevant experiments displayed truly synergistic effects, which does not support the prevailing ecological paradigm that synergies are rampant. however, in more than three-quarters of relevant experiments, the outcome of multiple stressor interactions was non-additive (i.e. synergies or antagonisms), suggesting that ecological surprises may be more common than simple additive effects.",184,2008,11,12,1278,1286,10.1111/j.1461-0248.2008.01243.x,1,1,1,3"Crain, CM; Kroeker, K; Halpern, BS",interactive and cumulative effects of multiple human stressors in marine systems,ECOLOGY LETTERS,Letter,Antagonisms; cumulative stressors; cumulative threat models; ecosystem-based management; interactions; synergisms; threat-analysis,"humans impact natural systems in a multitude of ways, yet the cumulative effect of multiple stressors on ecological communities remains largely unknown. here we synthesized 171 studies that manipulated two or more stressors in marine and coastal systems and found that cumulative effects in individual studies were additive (26%), synergistic (36%), and antagonistic (38%). the overall interaction effect across all studies was synergistic, but interaction type varied by response level (community: antagonistic, population: synergistic), trophic level (autotrophs: antagonistic, heterotrophs: synergistic), and specific stressor pair (seven pairs additive, three pairs each synergistic and antagonistic). addition of a third stressor changed interaction effects significantly in two-thirds of all cases and doubled the number of synergistic interactions. given that most studies were performed in laboratories where stressor effects can be carefully isolated, these three-stressor results suggest that synergies may be quite common in nature where more than two stressors almost always coexist. while significant gaps exist in multiple stressor research, our results suggest an immediate need to account for stressor interactions in ecological studies and conservation planning.",290,2008,11,12,1304,1315,10.1111/j.1461-0248.2008.01253.x,1,1,1,3"Tylianakis, JM; Didham, RK; Bascompte, J; Wardle, DA",global change and species interactions in terrestrial ecosystems,ECOLOGY LETTERS,Review,Climate change; CO(2); competition; disease; food web; global warming; interaction effect; land-use change; mycorrhiza; nitrogen deposition; parasite; pollination; seed dispersal,"the main drivers of global environmental change (co(2) enrichment, nitrogen deposition, climate, biotic invasions and land use) cause extinctions and alter species distributions, and recent evidence shows that they exert pervasive impacts on various antagonistic and mutualistic interactions among species. in this review, we synthesize data from 688 published studies to show that these drivers often alter competitive interactions among plants and animals, exert multitrophic effects on the decomposer food web, increase intensity of pathogen infection, weaken mutualisms involving plants, and enhance herbivory while having variable effects on predation. a recurrent finding is that there is substantial variability among studies in both the magnitude and direction of effects of any given gec driver on any given type of biotic interaction. further, we show that higher order effects among multiple drivers acting simultaneously create challenges in predicting future responses to global environmental change, and that extrapolating these complex impacts across entire networks of species interactions yields unanticipated effects on ecosystems. finally, we conclude that in order to reliably predict the effects of gec on community and ecosystem processes, the greatest single challenge will be to determine how biotic and abiotic context alters the direction and magnitude of gec effects on biotic interactions.",545,2008,11,12,1351,1363,10.1111/j.1461-0248.2008.01250.x,0,1,0,1"Coors, A; De Meester, L","synergistic, antagonistic and additive effects of multiple stressors: predation threat, parasitism and pesticide exposure in daphnia magna",JOURNAL OF APPLIED ECOLOGY,Article,aquatic ecotoxicology; Chaoborus crystallinus; immunomodulation; independent action; intrinsic rate of natural increase; joint effects; natural antagonists; non-additive interactions; Pasteuria ramose; population growth rate,"1. predation and parasitism are important factors in the ecology and evolution of natural populations and may, along with other environmental factors, interact with the impact of anthropogenic pollutants. 2. our study aimed at identifying potential interactions between three stressors (predation threat, parasitism and pesticide exposure) and at exploring the predictability of their joint effects by using the model of independent action. we assessed in a full-factorial design the impacts of these stressors on key life-history traits and population growth rate of the water flea daphnia magna. 3. when applied as single stressors, predation threat and parasite challenge induced varying stressor-specific adaptive responses. the pesticide carbaryl was applied at a generally sublethal concentration, which caused low mortality only in first-brood offspring. 4. pesticide exposure interacted synergistically with parasite challenge regarding survival, which suggests immunomodulatory activity of the pesticide. predation threat by phantom midge larvae showed antagonistic interactions for amount of first-brood offspring with both parasite challenge and carbaryl exposure. all stressors additively affected age and size at maturity, which added up to a considerable delay in the onset of reproduction in the three-stressor combination. the intrinsic rate of natural increase, r, reflected the non-additive and additive effects on single endpoints and showed significant synergistic interactions for all two-stressor combinations. the combination of all stressors resulted in a dramatic reduction of r compared to the stressor-free control. 5. the model of independent action proved useful in quantitatively predicting effects of additively acting stressors, and in visualizing the occurrence and magnitude of non-additive effects in accordance with results of analysis of variances. 6. synthesis and applications. cumulative additive effects and non-additive interactions of natural antagonists and pollutants are shown to result in considerable impacts on ecologically relevant parameters. as a starting point for an environmentally more realistic risk assessment of chemicals, it may be a valuable strategy to screen for non-additive effects among many stress factors simultaneously in simplified experimental designs by using the model of independent action.",82,2008,45,6,1820,1828,10.1111/j.1365-2664.2008.01566.x,1,1,1,3"Coors, A; Decaestecker, E; Jansen, M; De Meester, L",pesticide exposure strongly enhances parasite virulence in an invertebrate host model,OIKOS,Article,,"parasites are a common and constant threat to organisms at all levels of phyla. the virulence of a parasite, defined as the impact on survival and reproduction of its host, depends on the specific host-parasite combination and can also be influenced by environmental conditions. environmental pollution might be an additional factor influencing host-parasite interactions. we here aimed to test whether the combined stress of pollutant exposure and parasite challenge results in stronger impacts on host organisms than expected from the single stressors applied alone. we used the water flea daphnia magna and two of its endoparasites, the bacterium pasteuria ramosa and the microsporidium flabelliforma magnivora, as invertebrate host-parasite models. for each parasite, we tested in a full-factorial design for interactions between parasitism and pollution using the neurotoxic pesticide carbaryl as a model substance. sublethal concentrations of the pesticide synergistically enhanced the virulence of both parasites by increasing host mortality. furthermore, host castration induced by p. ramosa was accelerated by carbaryl exposure. these effects likely reflect decreased host resistance due to direct or indirect immunosuppressive activity of carbaryl. the present study provides experimental evidence that the in vivo development of infectious diseases can be influenced by a pesticide at environmentally realistic concentrations. this implies that host-parasite interactions and subsequently co-evolution might be influenced by environmental pollution at toxicant concentrations being sublethal to parasite-free hosts. standard toxicity testing as employed in the current way of conducting ecological risk assessments for anthropogenic substances does not consider natural antagonists such as infectious diseases, and thereby likely underestimates the impact these substances may pose to natural populations in the environment.",33,2008,117,12,1840,1846,10.1111/j.1600-0706.2008.17028.x,1,1,0,2"Fincher, CL; Thornhill, R","assortative sociality, limited dispersal, infectious disease and the genesis of the global pattern of religion diversity",PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,cross-cultural psychology; ethnocentrism; limited dispersal; religion; social behaviour; xenophobia,"why are religions far more numerous in the tropics compared with the temperate areas? we propose, as an answer, that more religions have emerged and are maintained in the tropics because, through localized coevolutionary races with hosts, infectious diseases select for three anticontagion behaviours: in-group assortative sociality; out-group avoidance; and limited dispersal. these behaviours, in turn, create intergroup boundaries that effectively fractionate, isolate and diversify an original culture leading to the genesis of two or more groups from one. religion is one aspect of a group's culture that undergoes this process. if this argument is correct then, across the globe, religion diversity should correlate positively with infectious disease diversity, reflecting an evolutionary history of antagonistic coevolution between parasites and hosts and subsequent religion genesis. we present evidence that supports this model: for a global sample of traditional societies, societal range size is reduced in areas with more pathogens compared with areas with few pathogens, and in contemporary countries religion diversity is positively related to two measures of parasite stress.",59,2008,275,1651,2587,2594,10.1098/rspb.2008.0688,0,1,0,1"Thrush, SF; Hewitt, JE; Hickey, CW; Kelly, S",multiple stressor effects identified from species abundance distributions: interactions between urban contaminants and species habitat relationships,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,Differential-effects; Estuaries; Macrofauna habitat requirements; Multiple Stressors; New Zealand; Species-environment relationships; Urban contaminants,"the potential for stressors to interact or elicit different responses depending on ecological setting can confound the use of contaminant guidelines or predictions from laboratory-based ecotoxicological studies. however, predicting and identifying multiple stressor effects is challenging because of the wide range of treatment combinations needed for laboratory experiments and the difficulty of conducting field experiments across a range of conditions that may influence stress responses. in this study we analyse density responses apparent in the natural populations of 46 macrofaunal taxa to stressors representing habitat requirements (sediment particle size), food (sediment organic content) and heavy metal contamination (copper, zinc and lead). simple responses to either a single stressor or stressors acting additively were less apparent in our regression-based models than multiplicative effects. we also investigated whether species that exhibited a unimodal abundance distribution in response to a habitat factor were more likely to exhibit differential responses to contaminants than species that exhibited monotonic responses to habitat factors. this proved to be the case, although not all unimodal abundance distributions were related to differential responses. the results of this study suggest that regression analysis, together with well-designed, large-scale, field surveys, offer a good method for describing and predicting effects of multiple stressors and helping to both target experiments and scale-up their results. (c) 2008 elsevier b.v. all rights reserved.",37,2008,366,02-Jan,160,168,10.1016/j.jembe.2008.07.020,0,0,1,1"Ferrari, MCO; Vavrek, MA; Elvidge, CK; Fridman, B; Chivers, DP; Brown, GE",sensory complementation and the acquisition of predator recognition by salmonid fishes,BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY,Article,Disturbance cues; Chemical alarm cues; Anti-predator behaviour; Learned predator recognition; Juvenile rainbow trout,"following disturbance, some aquatic prey species release chemicals that act as a warning cue and increase vigilance in nearby conspecifics. such disturbance cues evoke consistent low intensity anti-predator responses. in contrast, alarm cues from injured conspecifics often evoke stronger intensity responses in prey animals. in this study, we test the sensory complement hypothesis, which suggests that multiple cues act in an additive or synergistic fashion to provide additional information for risk assessment by prey. in the first experiment, we showed that juvenile rainbow trout pre-exposed to disturbance cues respond to a given concentration of damage-released alarm cues with a higher intensity of response than the trout that were pre-exposed to cues from undisturbed conspecifics. the two cues acted in an additive fashion. in the second experiment, we demonstrated that disturbance cues alone were not enough to elicit a conditioned response to the odour of a novel predator. we also showed that while disturbance cues elicit an increase in the response of trout to alarm cues, this increase does not translate into a stronger learned response to the predator when the predator odour is paired with alarm cues. future studies should take into account sensory complementation to avoid underestimating the responses of prey to predators.",26,2008,63,1,113,121,10.1007/s00265-008-0641-1,1,0,1,2"Bussotti, F","functional leaf traits, plant communities and acclimation processes in relation to oxidative stress in trees: a critical overview",GLOBAL CHANGE BIOLOGY,Review,acclimation; functional groups; functional leaf traits; oxidative stress; ozone; stress resilience,"tropospheric ozone exercises pressure on vegetation in combination with other oxidative factors such as strong sunlight, uv-b radiation, high temperatures and water shortage. the relationship established between these factors and the plants can be either antagonistic (cross-resistance) or synergistic. response mechanisms are activated involving physiological, chemical and morphological features. overall sensitivity (or resistance) is determined by the amount of total oxidative pressure in relation to the plant's physiological plasticity [i.e. its ability (within its own resilience potential) to alter its structure and functions in order to react to the oxidative pressure]. within different populations of the same species, functional leaf traits (leaf area and thickness, leaf mass per area or specific leaf area, tissue thickness) may vary in relation to the extent that the plant succeeds in acclimating to ambient oxidative pressure. the behaviour of a tree in an oxidative environment can be interpreted by means of leaf structure analysis. leaves presenting high tissue density (and thus low intercellular space content) display a high degree of acclimation to stressors, react little to environmental changes and are characterized by remarkable longevity. leaves of this type also have a high photosynthesis capacity per surface unit (due to the n content per surface unit) and a high p-n/g(w) (or water use efficiency, wue). thus, they are able to support detoxification processes. these morphological traits are to be found in adult plants in late successional stands and, above all, in ambients that have already been subjected to oxidative pressure. however, in early successional species and during the dynamic stages of growth (e.g. in the renewal occurring along forest edges), it is the opposite leaf traits that prevail: low leaf density, high photosynthesis capacity per dry weight unit, low wue, low leaf longevity. these traits make plants far more reactive to environmental changes (e.g. they exploit the light from sun flecks much more effectively), but enable them to achieve only a low degree of acclimation and a poor ability to support detoxification processes. whereas adult forests display a high level of ecological resilience and have a relatively good tolerance of ozone, the renewal stages are (at least potentially) more vulnerable. in these environments, ozone can alter the competition among genotypes and favour more resistant ones. among the sectors most at risk, we must include communities growing at the edge of their ecological range, for whom even a slight increase in oxidative pressure can trigger substantial degenerative processes.",40,2008,14,11,2727,2739,10.1111/j.1365-2486.2008.01677.x,1,1,0,2"Martone, RG; Wasson, K",impacts and interactions of multiple human perturbations in a california salt marsh,OECOLOGIA,Article,multiple stressor; synergistic interactions; fluctuating resource hypothesis; invasion; resilience,"multiple disturbances to ecosystems can influence community structure by modifying resistance to and recovery from invasion by non-native species. predicting how invasibility responds to multiple anthropogenic impacts is particularly challenging due to the variety of potential stressors and complex responses. using manipulative field experiments, we examined the relative impact of perturbations that primarily change abiotic or biotic factors to promote invasion in coastal salt marsh plant communities. specifically we test the hypotheses that nitrogen enrichment and human trampling facilitate invasion of upland weeds into salt marsh, and that the ability of salt marsh communities to resist and/or recover from invasion is modified by hydrological conditions. nitrogen enrichment affected invasion of non-native upland plants at only one of six sites, and increased aboveground native marsh biomass at only two sites. percent cover of native marsh plants declined with trampling at all sites, but recovered earlier at tidally flushed sites than at tidally restricted sites. synergistic interactions between trampling and restricting tidal flow resulted in significantly higher cover of non-native upland plants in trampled plots at tidally restricted sites. percent cover of non-native plants recovered to pre-trampling levels in fully tidal sites, but remained higher in tidally restricted sites after 22 months. thus, perturbations that reduce biotic resistance interact with perturbations that alter abiotic conditions to promote invasion. this suggests that to effectively conserve or restore native biodiversity in altered systems, one must consider impacts of multiple human disturbances, and the interactions between them.",14,2008,158,1,151,163,10.1007/s00442-008-1129-4,1,0,0,1"Jonsson, M; Wardle, DA",context dependency of litter-mixing effects on decomposition and nutrient release across a long-term chronosequence,OIKOS,Article,,"litter decomposition is an important driver of terrestrial systems, and factors that determine decomposition rate for individual litter species have been widely studied. fewer studies have explored the factors that regulate how mixing litters of multiple species affects litter decomposition and nutrient dynamics, and only a handful of studies have investigated how litter-mixing effects may differ among different habitats or ecosystems, or how they respond to environmental gradients. we used a well-established retrogressive chronosequence involving thirty lake islands in northern sweden in which time since fire disturbance increases with decreasing island size; smaller islands therefore have reduced rates of aboveground and belowground ecosystem processes. on each of these islands we utilized plots with and without the long-term experimental removal of shrubs. litters from the six most common plant species on the islands were prepared in single-, three- and six-species litterbags, and placed on both the shrub-removal and non-removal plots on each island to decompose for one year. we found significant non-additive effects of litter mixing on litter decomposition rates, on final litter n and p concentrations, and on litter n loss, but these non-additive effects varied both in direction and magnitude with changed number of species, and even among litter mixtures with the same number of species. further, the magnitude of non-additive effects of litter mixing on both litter decomposition and nutrient dynamics was significantly influenced by both island size and the interaction between island size and shrub-removal treatment. when shrubs were present, there was a u-shaped relationship between these non-additive effects and island size, while the relationship was positive when shrubs were removed. hence, our results support previous findings that litter mixing may produce non-additive effects on litter decomposition and nutrient dynamics, and that these effects tend to be idiosyncratic due to the importance of effects of individual species in the mixture. most importantly, our results show that non-additive litter-mixing effects change greatly across environmental gradients, meaning that the biotic and abiotic characteristics of an ecosystem can be a powerful driver of the magnitude and even the direction of litter-mixing effects on ecosystem processes.",35,2008,117,11,1674,1682,10.1111/j.1600-0706.2008.16810.x,0,0,1,1"Linke, S; Norris, RH; Pressey, RL",irreplaceability of river networks: towards catchment-based conservation planning,JOURNAL OF APPLIED ECOLOGY,Article,complementarity; freshwater conservation; macroinvertebrates; rivers; systematic conservation planning,"1. this study has adapted a complementarity-based area-selection method to estimate conservation value/irreplaceability for river systems. irreplaceability represents the likelihood that an area will be required as part of a conservation system that achieves all conservation targets. we adapt this measure - often used in marine or terrestrial planning - to consider whole-of-catchment protection in a riverine setting. 2. after dividing the australian state of victoria into 1854 subcatchments, we successfully modelled distributions of 400 benthic macroinvertebrate taxa using generalized additive models. we calculated the minimum area required to protect all taxa using three different heuristic selection algorithms. the algorithms were modified to consider the entire upstream catchment for any subcatchment. 3. a summed rarity algorithm, corrected for upstream area, proved to be the most efficient, requiring 100 000 hectares less total catchment area to represent all taxa than the second most efficient algorithm. we calculated irreplaceability by running the algorithm 1000 times and randomly removing 90% of the catchments in each run. from this analysis, we estimated two metrics: fs (the frequency of selection) and average c (average contribution to conservation targets). 4. four groups of catchments were identified: (i) catchments that have high contributions and are always or very frequently selected; (ii) catchments that have high contributions and are infrequently selected; (iii) catchments that are always or very frequently selected but contribute few taxa; and (iv) catchments that are infrequently selected and contribute few taxa. 5. synthesis and applications. for the first time, a complementarity-based algorithm has been adapted to a riverine setting. this algorithm acknowledges the connected nature of rivers by considering not only the local assemblages, but also upstream areas that need to be protected. we demonstrated that using standard algorithms in these connected systems would lead to two mistakes, namely: (i) not all taxa would be covered by reserves that were buffered from potential human disturbances upstream; and (ii) the standard algorithms would not lead to the most efficient solution, potentially costing additional millions of dollars to any conservation scheme. we therefore recommend the use of our algorithm or a similar riverine adaptation of reserve design algorithms to ensure adequate and efficient conservation planning.",30,2008,45,5,1486,1495,10.1111/j.1365-2664.2008.01520.x,0,0,1,1"Kristensen, TN; Barker, JSF; Pedersen, KS; Loeschcke, V",extreme temperatures increase the deleterious consequences of inbreeding under laboratory and semi-natural conditions,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,inbreeding x environment interactions; inbreeding depression; temperature stress; phenotypic variance; semi-natural environments,"the majority of experimental studies of the effects of population bottlenecks on fitness are performed under laboratory conditions, which do not account for the environmental complexity that populations face in nature. in this study, we test inbreeding depression in multiple replicates of inbred when compared with non-inbred lines of drosophila melanogaster under different temperature conditions. egg-to-adult viability, developmental time and sex ratio of emerging adults are studied under low, intermediate and high temperatures under laboratory as well as semi-natural conditions. the results show inbreeding depression for egg-to-adult viability. the level of inbreeding depression is highly dependent on test temperature and is observed only at low and high temperatures. inbreeding did not affect the developmental time or the sex ratio of emerging adults. however, temperature affected the sex ratio with more females relative to males emerging at low temperatures, suggesting that selection against males in pre-adult life stages is stronger at low temperatures. the coefficient of variation (cv) of egg-to-adult viability within and among lines is higher for inbred flies and generally increases at stressful temperatures. our results contribute to knowledge on the environmental dependency of inbreeding under different environmental conditions and emphasize that climate change may impact negatively on fitness through synergistic interactions with the genotype.",37,2008,275,1646,2055,2061,10.1098/rspb.2008.0426,1,0,0,1"Marsden, SJ; Symes, CT","bird richness and composition along an agricultural gradient in new guinea: the influence of land use, habitat heterogeneity and proximity to intact forest",AUSTRAL ECOLOGY,Article,agricultural mosaic; bird; forest alteration; habitat heterogeneity; New Guinea; tropical forest,"we examined variation in bird species richness, abundance and guild composition along an agricultural gradient in new guinea, and looked for any additive influence of habitat heterogeneity on these variables. the study was based on a grid of survey plots, six plots wide and 24 plots long with the long axis running from a settlement 2.4 km through active and abandoned agricultural plots towards a large area of forest. each circular survey plot (25 m radius) was assigned to a broad habitat type, ten habitat measures taken, and birds counted for 1 h in each plot. principal component analysis (pca) habitat axis 1 described an axis of decreasing forest alteration (larger trees, greater tree densities, fuller canopy) that was positively correlated with distance from the settlement. bird richness and abundance were highest at intermediate disturbance levels (plots with mid-range axis 1 scores). proportions of insectivores and frugivores increased with decreasing forest alteration, while proportions of nectarivores decreased. we calculated three measures of habitat heterogeneity by comparing each plot's pca score to those of eight neighbouring plots (50-110 m away). these measures reflected how different the plot was to its neighbours, how variable the habitat was around the plot, and the degree to which the plot bordered less disturbed forest. we related these measures to plot bird variable scores independently, and to residuals following regressions of bird scores against pca scores. heterogeneity measures had no significant influence on abundance or richness measures, but there were greater proportions of frugivores in plots showing a given degree of habitat alteration if they bordered more pristine habitat. while we readily identified differences in bird communities along the agricultural gradient, the influences of habitat heterogeneity were not striking for birds at this fine scale.",7,2008,33,6,784,793,10.1111/j.1442-9993.2008.01850.x,0,0,1,1"Gross, K",positive interactions among competitors can produce species-rich communities,ECOLOGY LETTERS,Article,facilitation; interaction component; resource competition; species coexistence; theoretical ecology,"although positive interactions between species are well documented, most ecological theory for investigating multispecies coexistence remains rooted in antagonistic interactions such as competition and predation. standard resource-competition models from this theory predict that the number of coexisting species should not exceed the number of factors that limit population growth. here i show that positive interactions among resource competitors can produce species-rich model communities supported by a single limiting resource. simulations show that when resource competitors reduce each others' per capita mortality rate (e.g. by ameliorating an abiotic stress), stable multispecies coexistence with a single resource may be common, even while the net interspecific interaction remains negative. these results demonstrate that positive interactions may provide an important mechanism for generating species-rich communities in nature. they also show that focusing on the net interaction between species may conceal important coexistence mechanisms when species simultaneously engage in both antagonistic and positive interactions.",65,2008,11,9,929,936,10.1111/j.1461-0248.2008.01204.x,0,1,0,1"Ducrest, AL; Keller, L; Roulin, A","pleiotropy in the melanocortin system, coloration and behavioural syndromes",TRENDS IN ECOLOGY & EVOLUTION,Review,,"in vertebrates, melanin-based coloration is often associated with variation in physiological and behavioural traits. we propose that this association stems from pleiotropic effects of the genes regulating the synthesis of brown to black eumelanin. the most important regulators are the melanocortin 1 receptor and its ligands, the melanocortin agonists and the agouti-signalling protein antagonist. on the basis of the physiological and behavioural functions of the melanocortins, we predict five categories of traits correlated with melanin-based coloration. a review of the literature indeed reveals that, as predicted, darker wild vertebrates are more aggressive, sexually active and resistant to stress than lighter individuals. pleiotropic effects of the melanocortins might thus account for the widespread covariance between melanin-based coloration and other phenotypic traits in vertebrates.",229,2008,23,9,502,510,10.1016/j.tree.2008.06.001,0,1,0,1"Matesanz, S; Eseudero, A; Valladares, F",additive effects of a potentially invasive grass and water stress on the performance of seedlings of gypsum specialists,APPLIED VEGETATION SCIENCE,Article,Biological invasion; Climate change; Competition; Global change; Gypsum habitat; Microcosm; Water stress,"question: what is the combined effect of two drivers of local biodiversity changes (presence of a potentially invasive species and seasonal drought) oil the performance of seedlings of plants front gypsum habitats under experimental conditions'? location: a controlled microcosm reconstruction of natural assemblages of gypsum plant communities from central spain. methods: we evaluated the effects of a potentially invasive grass (lolium rigidum) and water stress oil the survival, height growth and biomass of five woody species (colutea hispanica, gypsophila struthium, thymus lacaitae, lepidium subulatum and helianthemum squamatum) from semi-arid gypsum ecosystems. seedlings of the five species were grown with or without the potential invader and under three watering regimes: early stress - simulating an advanced summer, late stress - simulating the characteristic timing of current summer drought and well-watered. results: seedling survival and performance were negatively affected by the presence of the potential invader. early stress had larger impacts on the gypsum species than late stress, no interactions were found between factors for any of the study variables, and responses to both factors were found to be species-specific. conclusions: the lack of interactions between factors indicates that the presence of the potentially invasive grass and water stress had additive effects in our study system. the negative impact of early water stress draws attention to the possible consequences of the advances of summer drought predicted for mediterranean ecosystems. finally, the differential responses found for the study species suggest that plant communities will not respond as a unit to global change, leading to significant changes in species composition and dominance.",11,2008,11,3,287,296,10.3170/2008-7-18425,0,0,1,1"Bancroft, BA; Baker, NJ; Blaustein, AR","a meta-analysis of the effects of ultraviolet b radiation and its synergistic interactions with ph, contaminants, and disease on amphibian survival",CONSERVATION BIOLOGY,Article,anura; caudata; life-history stage; meta-analysis; synergistic; UVB radiation,"human alterations to natural systems have resulted in a loss of biological diversity around the world. amphibian population losses have been more severe than those of birds and mammals. amphibian population declines are likely due to many factors including habitat loss, disease, contaminants, introduced species and ultraviolet-b (uvb) radiation. the effect of uvb, however, varies widely among species and can vary within populations of the same species or at different life-history stages. this variation has often led to opposing conclusions about how uvb affects amphibians. we used meta-analysis techniques to explore the overall effects of uvb radiation on survival in amphibians. we also used recently developed factorial meta-analytic techniques to quantify potential interactions between uvb radiation and other stressors on amphibians. ultraviolet-b radiation reduced survival of amphibians by 1.9-fold compared with shielded controls. larvae were more susceptible to damage from uvb radiation compared with embryos, and salamanders were more susceptible compared with frogs and toads. furthermore, uvb radiation interacted synergistically with other environmental stressors and resulted in greater than additive effects on survival when 2 stressors were present. our results suggest that uvb radiation is an important stressor in amphibians, particularly in light of potential synergisms between uvb and other stressors in amphibian habitats.",50,2008,22,4,987,996,10.1111/j.1523-1739.2008.00966.x,1,0,1,2"Forde, SE; Thompson, JN; Holt, RD; Bohannan, BJM",coevolution drives temporal changes in fitness and diversity across environments in a bacteria-bacteriophage interaction,EVOLUTION,Article,bacteria; bacteriophage; competition; fitness costs; genotype-by-environment interactions; host-parasite; productivity; resistance,"coevolutionary interactions are thought to play a crucial role in diversification of hosts and parasitoids. furthermore, resource availability has been shown to be a fundamental driver of species diversity. yet, we still do not have a clear understanding of how resource availability mediates the diversity generated by coevolution between hosts and parasitoids over time. we used experiments with bacteria and bacteriophage to test how resources affect variation in the competitive ability of resistant hosts and temporal patterns of diversity in the host and parasitoid as a result of antagonistic coevolution. bacteria and bacteriophage coevolved for over 150 bacterial generations under high and low-resource conditions. we measured relative competitive ability of the resistant hosts and phenotypic diversity of hosts and parasitoids after the initial invasion of resistant mutants and again at the end of the experiment. variation in relative competitive ability of the hosts was both time- and environment-dependent. the diversity of resistant hosts, and the abundance of host-range mutants attacking these phenotypes, differed among environments and changed over time, but the direction of these changes differed between the host and parasitoid. our results demonstrate that patterns of fitness and diversity resulting from coevolutionary interactions can be highly dynamic.",33,2008,62,8,1830,1839,10.1111/j.1558-5646.2008.00411.x,0,1,0,1"Gillson, L; Ekblom, A; Willis, KJ; Froyd, C","holocene palaeo-invasions: the link between pattern, process and scale in invasion ecology?",LANDSCAPE ECOLOGY,Review,climate change; disturbance; landscape connectivity; multi-factor hypothesis; homogenisation,"invasion ecology has made rapid progress in recent years through synergies with landscape ecology, niche theory, evolutionary ecology and the ecology of climate change. the palaeo-record of holocene invasions provides a rich but presently underexploited resource in exploring the pattern and process of invasions through time. in this paper, examples from the palaeo-literature are used to illustrate the spread of species through time and space, also revealing how interactions between invader and invaded communities change over the course of an invasion. the main issues addressed are adaptation and plant migration, ecological and evolutionary interactions through time, disturbance history and the landscape ecology of invasive spread. we consider invasions as a continuous variable, which may be influenced by different environmental or ecological variables at different stages of the invasion process, and we use palaeoecological examples to describe how ecological interactions change over the course of an invasion. finally, the use of palaeoecological information to inform the management of invasions for biodiversity conservation is discussed.",16,2008,23,7,757,769,10.1007/s10980-008-9243-6,1,0,0,1"Brook, BW; Sodhi, NS; Bradshaw, CJA",synergies among extinction drivers under global change,TRENDS IN ECOLOGY & EVOLUTION,Review,,"if habitat destruction or overexploitation of populations is severe, species loss can occur directly and abruptly. yet the final descent to extinction is often driven by synergistic processes (amplifying feedbacks) that can be disconnected from the original cause of decline. we review recent observational, experimental and metaanalytic work which together show that owing to interacting and self-reinforcing processes, estimates of extinction risk for most species are more severe than previously recognised. as such, conservation actions which only target single-threat drivers risk being inadequate because of the cascading effects caused by unmanaged synergies. future work should focus on how climate change will interact with and accelerate ongoing threats to biodiversity, such as habitat degradation, overexploitation and invasive species.",425,2008,23,8,453,460,10.1016/j.tree.2008.03.011,1,0,0,1"Laurance, WF",theory meets reality: how habitat fragmentation research has transcended island biogeographic theory,BIOLOGICAL CONSERVATION,Review,area effects; edge effects; extinction; fragmentation; island biogeography theory; matrix effects; species turnover,"island biogeography theory (ibt) provides a basic conceptual model for understanding habitat fragmentation. empirical studies of fragmented landscapes often reveal strong effects of fragment area and isolation on species richness, although other predictions of the theory, such as accelerated species turnover in fragments, have been tested less frequently. as predicted by ibt, biota in fragments typically 'relax' over time towards lower species richness. beyond these broad generalizations, however, the relevance of ibt for understanding fragmented ecosystems is limited. first, ibt provides few predictions about how community composition in fragments should change over time, and which species should be most vulnerable. second, edge effects can be an important driver of local species extinctions and ecosystem change, but are not considered by ibt. third, the matrix of modified vegetation surrounding fragments-also ignored by ibt-can strongly influence fragment connectivity, which in turn affects the demography, genetics, and survival of local populations. fourth, most fragmented landscapes are also altered by other anthropogenic changes, such as hunting, logging, fires, and pollution, which can interact synergistically with habitat fragmentation. finally, fragmentation often has diverse impacts on ecosystem properties such as canopy-gap dynamics, carbon storage, and the trophic structure of communities that are not considered by ibt. i highlight these phenomena with findings from fragmented ecosystems around the world. published by elsevier ltd.",155,2008,141,7,1731,1744,10.1016/j.biocon.2008.05.011,1,0,0,1"Hurteau, M; North, M","mixed-conifer understory response to climate change, nitrogen, and fire",GLOBAL CHANGE BIOLOGY,Article,biomass; climate change; disturbance; diversity; fire; forest fuels; mixed-conifer; nitrogen deposition; Sierra Nevada,"california's sierra nevada mountains are predicted to experience greater variation in annual precipitation according to climate change models, while nitrogen deposition from pollution continues to increase. these changes may significantly affect understory communities and fuels in forests where managers are attempting to restore historic conditions after a century of altered fire regimes. the objective of this research was to experimentally test the effects of increasing and decreasing snowpack depth, increasing nitrogen, and applying prescribed fire to mixed-conifer forest understories at two sites in the central and southern sierra nevada. understory response to treatments significantly differed between sites with herb biomass increasing in shrub-dominated communities when snowpack was reduced. fire was a more important factor in post-treatment species richness and cover than either snowpack addition or reduction. nitrogen additions unexpectedly increased herbaceous species richness. these varied findings indicate that modeling future climatic influences on biodiversity may be more difficult than additive prediction based on increasing the ecosystem's two limiting growth resources. increasing snowpack and nitrogen resulted in increased shrub biomass production at both sites and increased herb production at the southern site. this additional understory biomass has the potential to increase fuel connectivity in patchy sierran mixed-conifer forests, increasing fire severity and size.",11,2008,14,7,1543,1552,10.1111/j.1365-2486.2008.01584.x,0,0,1,1"Davidson, AD; Lightfoot, DC",burrowing rodents increase landscape heterogeneity in a desert grassland,JOURNAL OF ARID ENVIRONMENTS,Article,banner-tailed kangaroo rats; biodiversity ecosystem engineers; gunnison's prairie dogs; keystone species,"animals that modify their environment through engineering and herbivory have important impacts on ecosystems, yet the interactive roles of such species have rarely been studied. we studied the comparative and interactive effects of two burrowing herbivorous rodents, gunnison's prairie dogs (cynomys gunnisoni) and banner-tailed kangaroo rats (dipodomys spectabilis), on vegetation where they co-occurred in a chihuahuan desert grassland. we found that their effects remained distinct and, thus, non-substitutable, where they co-occurred. the rodents differentially altered plant community structure relative to their different mound types, herbivory, and spatial scales of disturbance. vegetation structure and plant species assemblages differed between mound and landscape patches occupied by prairie dogs and kangaroo rats. where both species co-occurred, there was more soil disturbance, organic material from-their fecal pellets, forb cover, and activity by other animals. the combined effect of these rodents increased the landscape heterogeneity and plant species richness by creating a mosaic of different habitat patches on the landscape. our results demonstrate that these rodents had complementary, additive effects where they co-occurred, and suggest that multiple habitat-modifying species, especially those that play large ecological roles, can have important interactive effects on community structure and biodiversity. (c) 2007 elsevier ltd. all rights reserved.",25,2008,72,7,1133,1145,10.1016/j.jaridenv.2007.12.015,0,0,1,1"Catterall, CP; McKenna, S; Kanowski, J; Piper, SD",do cyclones and forest fragmentation have synergistic effects? a before-after study of rainforest vegetation structure at multiple sites,AUSTRAL ECOLOGY,Article,damage; hurricane; remnant; tree; vine,"ecological degradation within areas of remnant forest may be amplified if the effects of fragmentation interact with the effects of other environmental disturbances such as wind storms. we used before-after comparisons to assess the effects of tropical cyclone larry on remnant and continuous rainforest in the wet tropics uplands of north-eastern australia. vegetation structure was measured 3 years before the cyclone and 6 months afterwards, at eight continuous forest sites and eight remnants (6-37 ha), within 20 km of the cyclone's track. the cyclone caused extensive defoliation, felling and breakage of stems and branches (greatest among the trees > 100 cm diameter which had around 50% stem loss), and increased litter and woody debris. cyclone effects were strongly influenced by a site's spatial position (p = 0.005, 0.001 in multivariate analyses of overall damage). maximum damage occurred 10-15 km south of the cyclone track, perhaps because of the additive effects of the west-moving air at the southern eyewall combined with the cyclone's own rapid westward movement. most fragments were south of the cyclone track, as a consequence of spatially selective deforestation practices, and therefore, showed greatest damage. however, once the effects of spatial position were considered, the independent differences in cyclone effects between fragments and continuous forest were lost (p = 0.23, 0.41 when north-south distance was included as a covariate in analyses). the expected protection afforded by a continuous forest canopy seems to have disappeared in the face of extremely strong cyclonic winds and down-draughts. nevertheless, an interaction between fragmentation and disturbance may yet occur, during the period of post-cyclone recovery, owing to the effects of landscape context on plant recruitment. for example, there was a higher diversity of exotic seedling germination in fragments, independent of the extent of cyclone damage.",10,2008,33,4,471,484,10.1111/j.1442-9993.2008.01902.x,1,0,1,2"Corney, PM; Kirby, KJ; Le, DMG; Smart, SM; McAllister, HA; Marrs, RH",changes in the field-layer of wytham woods - assessment of the impacts of a range of environmental factors controlling change,JOURNAL OF VEGETATION SCIENCE,Article,ancient woodland; deer browsing; HOF modelling; long-term monitoring; management history; multivariate analysis of variance; nitrogen deposition,"question: what are the impacts of factors controlling patterns of change in woodland field-layer vegetation, through time? location: wytham woods, oxford, uk (51 degrees 41' n, 1 degrees 19' w). methods: species occurrence was monitored in 163 permanent plots three times between 1973 and 2002 and related to management compartment and history. the dataset was analysed using a combination of ordination methods, univariate and multivariate analysis of variance and hof modelling. results: the two key findings of this paper are: ( 1) that the species composition of ancient woodlands ( often cited as a conservation goal), may be moving along an 'undesirable' trajectory, from a conservation viewpoint; and ( 2) that the impact of a synergistic effect of changing canopy dynamics, nitrogen deposition and a rising deer population has resulted in an increase in grass species, at the expense of woodland herbs. these findings have significant implications for the practical conservation of similar habitats across europe. conclusions: the analytical methodology presented here allowed detailed assessment of the potential roles of a range of environmental factors controlling change. the methodology may be applicable to other long-term studies of vegetation, and is particularly appropriate for identification of cross-site drivers, such as pollutant load and climate change.",10,2008,19,3,287,U15,10.3170/2008-8-18383,1,0,0,1"Gross, K",fusing spatial resource heterogeneity with a competition-colonization trade-off in model communities,THEORETICAL ECOLOGY,Article,Biodiversity; Dispersal; Resource competition; Spatial dynamics,"two commonly cited mechanisms of multispecies coexistence in patchy environments are spatial heterogeneity in competitive abilities caused by variation in resources and a competition-colonization trade-off. in this paper, a model that fuses these mechanisms together is presented and analyzed. the model suggests that spatial variation in resource ratios can lead to multispecies coexistence, but this mechanism by itself is weak when the number of resources for which species compete is small. however, spatial resource heterogeneity is a powerful mechanism for multispecies coexistence when it acts synergistically with a competition-colonization trade-off. the model also shows how resource supply can control the competitive balance between species that are weak competitors but superior colonizers and strong competitors/inferior colonizers. this provides additional theoretical support for a possible explanation of empirically observed hump-shaped relationships between species diversity and ecological productivity.",2,2008,1,2,65,75,10.1007/s12080-007-0005-x,1,0,0,1"Zhu, J; Lu, YT; Chen, WC",single and joint toxic effects of cadmium and phenanthrene on enchytraeid fridericia bulbosa,EUROPEAN JOURNAL OF SOIL BIOLOGY,Article,Cd; Phe; enchytraeid Fridericia bulbosa; toxic effect; joint pollution,"the toxic effects of single and joint stress of cd (cadmium) and phe (phenanthrene) on enchytraeid fridericia bulbosa were investigated by natural soil tests. mortality of single and joint stress of cd and phe was significant (p < 0.01) except the lowest concentration of single pollutant. there was a positive correlation between mortality and the concentration of pollutant added to soil. also, the more exposed to single or joint cd and phe, the more morality. for joint pollution, cd was the main contributive factor of toxic effects, the different concentration and interaction of cd and phe significantly influenced mortality (p < 0.01). the joint effects of cd and phe were additive, after a 14-d exposure. when phe was 0.1 mg kg(-1) and 1.6 mg kg(-1), the interactive effects between cd and phe were synergistic. when phe was 25.6 mg kg(-1), the interactive effects were antagonistic. it suggested that morality may be considered as a valuable and sensitive biomarker to diagnose adverse effects of cd or phe in soil environment. (c) 2008 elsevier masson sas. all rights reserved.",8,2008,44,3,260,265,10.1016/j.ejsobi.2008.03.002,1,1,1,3"Schlipalius, DI; Chen, W; Collins, P; Nguyen, T; Reilly, P; Ebert, P","gene interactions constrain the course of evolution of phosphine resistance in the lesser grain borer, rhyzopertha dominica",HEREDITY,Article,pesticide resistance; fitness; methyl bromide; oxidative stress; linkage mapping; RAF,"phosphine, a widely used fumigant for the protection of stored grain from insect pests, kills organisms indirectly by inducing oxidative stress. high levels of heritable resistance to phosphine in the insect pest of stored grain, rhyzopertha dominica have been detected in asia, australia and south america. in order to understand the evolution of phosphine resistance and to isolate the responsible genes, we have undertaken genetic linkage analysis of fully sensitive (qrd14), moderately resistant (qrd369) and highly resistant (qrd569) strains of r. dominica collected in australia. we previously determined that two loci, rph1 and rph2, confer high-level resistance on strain qrd569, which was collected in 1997. we have now confirmed that rph1 is responsible for the moderate resistance of strain qrd369, which was collected in 1990, and is shared with a highly resistant strain from the same geographical region, qrd569. in contrast, rph2 by itself confers only very weak resistance, either as a heterozygote or as a homozygote and was not discovered in the field until weak resistance (probably due to rph1) had become ubiquitous. thus, high-level resistance against phosphine has evolved via stepwise acquisition of resistance alleles, first at rph1 and thereafter at rph2. the semi-dominance of rph2 together with the synergistic interaction between rph1 and rph2 would have led to rapid selection for homozygosity. a lack of visible fitness cost associated with alleles at either locus suggests that the resistance phenotype will persist in the field.",27,2008,100,5,506,516,10.1038/hdy.2008.4,1,0,0,1"Bussell, JA; Gidman, EA; Causton, DR; Gwynn-Jones, D; Malham, SK; Jones, MLM; Reynolds, B; Seed, R","changes in the immune response and metabolic fingerprint of the mussel, mytilus edulis (linnaeus) in response to lowered salinity and physical stress",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,aquaculture; climate change; immune response; mussel; salinity; stress,"mussels, such as mytilus edulis, are common keystone species on open coasts and in estuaries and are frequently used in environmental monitoring programmes. mussels experience a wide range of environmental conditions at these locations, including rapid changes in salinity and physical disturbance (both natural and from aquaculture practices). this paper addressed the hypothesis that reduced salinity will lower mussel blood immune function and influence mussel blood metabolic responses, and that this will in turn increase the susceptibility of mussels to other stresses such as physical disturbance. to test these hypotheses, experiments were conducted in controlled laboratory tank conditions and mussel blood was analysed using a combination of metabolic fingerprinting with ft-ir and immunological assay techniques. reducing seawater salinity to half that of normal caused a significant reduction in several measures of immune function, including the concentration of haemocytes, percentage of eosinophilic haemocytes and phagocytosis. mechanical shaking of mussels for 10 min caused a reduction in the level of respiratory burst activity. however, there was no evidence of additive or interactive effects of lowered salinity with shaking on the immune response. analysis of mussel blood metabolic fingerprints revealed differences in response to half salinity (vs. full salinity) but there were no detectable effects of shaking. increasing frequency and magnitude of flood events at coastal sites due to climate change could lead to longer, and more frequent, periods of reduced salinity. the potential impact on the immune function of this keystone species within or near estuaries could have knock-on effects on the wider ecosystem including altered nutrient cycling, changes in biodiversity and aquaculture production. (c) 2008 elsevier b.v. all rights reserved.",32,2008,358,1,78,85,10.1016/j.jembe.2008.01.018,0,0,1,1"Sovada, MA; Pietz, PJ; Conuerse, KA; King, DT; Hofmeister, EK; Scherr, P; Ip, HS",impact of west nile virus and other mortality factors on american white pelicans at breeding colonies in the northern plains of north america,BIOLOGICAL CONSERVATION,Article,American white pelican; late breeding season mortality; mortality factors; Pelecanus erythrorhynchos; west Nile virus,"american white pelicans (pelecanus erythrorhynchos) are colonial-nesting birds and their breeding sites are concentrated in a few small areas, making this species especially vulnerable to factors that can influence productivity, such as disease, disturbance, predation, weather events and loss of nesting habitat. nearly half of the american white pelican population breeds at four colonies in the northern plains: chase lake national wildlife refuge (nwr) in north dakota, bitter lake (waubay nwr) in south dakota, medicine lake nwr in montana, and marsh lake in minnesota. thus, sustained productivity at these colonies is crucial to the health of the entire species. during the latter half of the 2002 and 2003 breeding seasons, unusually high mortality of pelican chicks was observed at these colonies. west nile virus (wnv) was identified as one source of these losses. in 2004-2007 we monitored three major colonies in the northern plains to assess mortality of chicks during the late breeding season. we documented severe weather events, disturbance, and wnv as factors contributing to chick mortality. before wnv arrived in the region in 2002, chick mortality after mid-july was <= 4%, and then jumped to as high as 44% in the years since wnv arrived. wnv kills older chicks that are no longer vulnerable to other common mortality factors (e.g., severe weather, gull predation) and typically would have survived to fledge; thus wnv appears to be an additive mortality factor. persistence of lower productivity at american white pelican colonies in the northern plains might reduce the adult breeding population of this species in the region. published by elsevier ltd.",18,2008,141,4,1021,1031,10.1016/j.biocon.2008.01.019,0,0,1,1"Bishop, MJ; Kelaher, BP","non-additive, identity-dependent effects of detrital species mixing on soft-sediment communities",OIKOS,Article,,"accelerating rates of species extinction and invasion have sparked recent interest in how changes in plant community composition can be propagated through food webs. research in this area has, however, been largely restricted to considerations of how detrital species mixing affects litter decay processes. the consequences of changing detrital resources for whole assemblages of sediment-dwelling invertebrates remain largely unknown. we manipulated the availability of three detrital sources, avicennia marina leaves, posidonia australis blades and sargassum sp. thalli, on an australian mudflat to test hypotheses about how changes in the type and number of macrophytes contributing to detrital resources might impact benthic invertebrate assemblages of estuarine soft-sediments. by controlling for changes in total detrital biomass and ensuring that each detrital source was present in two- and three-species mixes as well as monocultures, our experimental design was able to distinguish among effects of mixing, identity and biomass. three months after detrital manipulation, macroinvertebrate abundance and species richness differed among treatments according to the biomass of detritus added and non-additive effects of detrital species mixing. whereas the mixing of two detrital species generally had an antagonistic effect on macroinvertebrate abundance and richness, faunal assemblages did not appreciably differ between three-species mixes and monocultures. generally negative effects of two-species mixes on macroinvertebrates were opposed by positive effects on microphytobenthos, an important food-source for many of the animals. non-additive effects on sediment communities were particularly apparent when sargassum sp., the most labile of the three detrital sources considered, was included in two-species mixes. this demonstration of non-additive and identity-dependent effects of detrital species mixing on soft-sediment communities suggests that predicted compositional changes to aquatic macrophyte communities, resulting from coastal development and climate change, will flow on to effect other components of the estuarine food-web.",12,2008,117,4,531,542,10.1111/j.2008.0030-1299.16418.x,0,1,1,2"Allen, SM; Burnett, LE","the effects of intertidal air exposure on the respiratory physiology and the killing activity of hemocytes in the pacific oyster, crassostrea gigas (thunberg)",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,Crassostrea gigas; hemocyte immune function; hypercapnia physiology; hypoxia; summer mortality,"the occurrence of summer mortalities of the commercially important pacific oyster, crassostrea gigas, has increased in recent years. these mortality events occur during the late summer when water temperatures are at their highest. many theories have been proposed concerning the causes including reproductive stress, environmental stress, disease, or synergistic interactions of these factors. c gigas are grown intertidally and are exposed to the air (emersed) for hours at a time. these organisms can experience extreme changes in temperature during the course of a day. an oyster closed during emersion depletes the oxygen stores to near zero within the shell and builds up co2 causing a decrease in tissue ph. the focus of this study is to determine the respiratory (ph, po2, p-co2 and total co2) and immune responses of oysters exposed to air at normal seasonal temperatures, and to determine whether these stresses associated with emersion inhibit the immune system of the oyster and contribute to the summer mortalities. the respiratory variables of the hemolymph of oysters submerged at 18 degrees c (ph- 7.52 +/- 0.04 s.e.m., po2 - 7.09 +/- 0.53 s.e.m. kpa and p-co2 = 0.20 +/- 0.03 s.e. m. kpa) varied significantly from oysters emersed for four hours at 22 degrees c (ph= 7.11 +/- 0.03 s.e.m., po2 = 3.83 +/- 0.15 s.e.m. kpa, pco2 = 0.36 +/- 0.03 s.e. m. kpa) and those emersed for four hours at 30 degrees c (ph = 6.84 +/- 0.02 s.e.m., po2 = 3.10 +/- 0.12 s.e.m. kpa, p-co2 = 1.31 +/- 0.06 s.e.m. kpa). the ability of hemocytes to kill the bacterium vibrio campbellii was assessed using an in vitro assay to generate a killing index. there was no significant difference in the killing index between ph treatment groups (p = 0.856): at ph 7.6 killing index = 50.2% +/- 2.33 s.e.m., at ph 6.6 killing index = 52.3% +/- 3.67 s.e.m.. temperature was the only factor to significantly affect the killing indices among temperature and oxygen treatment groups. the killing index was lowest (29.3% +/- 3.25 s.e.m.) at 30 degrees c and 7% oxygen, simulating in vivo oxygen pressure in well-aerated conditions and 30 degrees c and 3% oxygen, simulating in vivo oxygen pressure in hypoxia (30.5% +/- 13.25 s.e.m.), compared with the index in 7% oxygen at low temperature (18 degrees c (44.4% +/- 4.50 s.e.m.) or compared with low oxygen (3%) at low temperature (18 degrees c) (39.7%:1:+/- 2.51 s.e.m.). the seasonal and diurnal rise in temperature may, therefore, be an important factor contributing to summer mortalities of c. gigas. (c) 2008 elsevier b.v. all rights reserved.",11,2008,357,2,165,171,10.1016/j.jembe.2008.01.013,1,0,0,1"Deblauwe, I; Dibog, L; Missoup, AD; Dupain, J; Van Elsacker, L; Dekoninck, W; Bonte, D; Hendrickx, F",spatial scales affecting termite diversity in tropical lowland rainforest: a case study in southeast cameroon,AFRICAN JOURNAL OF ECOLOGY,Article,heterogeneity; lowland rainforest; southeast Cameroon; spatial scales; species richness; termite assemblage,"termites play a prominent role in the decomposer food web as 'ecosystem engineers'. however, the effect of spatial scales on termite assemblages has, to date, been poorly studied. here, we evaluate the contribution of two spatial levels [transects (100 m x 2 m) and sections within transects (5 m x 2 m)] on the local termite assemblage of a continuous mixed secondary lowland rainforest in southeast cameroon. standardized 100 m x 2 m transects were run in five vegetation types to cover more of the heterogeneity of this forest. the additive partitioning of the species richness of all species, soil- and wood-feeder species was statistically tested with sample-based randomization. the average species richness per transect (61) was the highest ever recorded. the section scale significantly influenced the observed species richness of all groups. this suggests that physical complexity and heterogeneity exist on a small scale within each transect and create a variety of microhabitats for different termites. still, soil-feeder species were less influenced by this scale than wood-feeder species. although different vegetation types were sampled, transect scale did not enhance observed termite species diversity. overall, as a wide variety and high density of microhabitats is inherent to large primary or regenerating forests, conservation programmes should focus on interconnecting large tropical rainforest blocks in central africa to maintain biodiversity hot spots of termites and optimal ecosystem functioning.",3,2008,46,1,5,18,10.1111/j.1365-2028.2007.00790.x,0,0,1,1"Mahecha, MD; Schmidtlein, S",revealing biogeographical patterns by nonlinear ordinations and derived anisotropic spatial filters,GLOBAL ECOLOGY AND BIOGEOGRAPHY,Article,anisotropic spatial autocorrelation; floristic survey; FLORKART; Germany; hierarchical variance partitioning; Isomap; nonlinear dimensionality reduction; PC(An)NM; sampling artefacts,"aim spatial floristic and faunistic data bases promote the investigation of biogeographical gradients in relation to environmental determinants on regional to continental scales. our aim was to extract major gradients in the distribution of vascular plant species from a grid-based inventory (the german florkart data base) and relate them to long-term precipitation and temperature records as well as soil conditions. we present an ordination technique capable of coping with this complex data array. the goal was also to sort out the influence of spatial autocorrelation, assuming floristic autocorrelation is anisotropic. location germany, at a spatial resolution of 6' x 10'. methods isometric feature mapping (isomap) was applied as a nonlinear ordination method. isomap was coupled to 'eigenvector-based filters' for generating spatial reference models representing spatial autocorrelation. what is novel here is that the derived filters are not based on the assumption of equidirectional autocorrelation. instead, the so-called 'principal coordinates of anisotropic neighbour matrices' build filters to test the influence of geographical vicinity in directions of high similarity among observations. results the isomap ordination of floristic data explained more than 95% of the data variance in six dimensions. the leading two dimensions (representing about 80% of the florkart data variance) revealed clear spatial gradients that could be related to independent effects of temperature, precipitation and soil observations. by contrast, the third and higher florkart dimensions were dominated by an antagonism of anisotropic spatial autocorrelation and soil conditions. a subsequent cluster analysis of the floristic isomap coordinates educed the spatial organization of the floristic survey, indicating a considerable sampling bias. conclusions we showed that isomap provides a consistent methodical framework for both ordination and derived spatial filters. the technique is useful for tracing the often nonlinear features of species occurrence data to environmental drivers, taking into account anisotropic spatial autocorrelation. we also showed that sampling biases are a conspicuous source of variance in a frequently used floristic data base.",21,2008,17,2,284,296,10.1111/j.1466-8238.2007.00368.x,0,1,0,1"Carrillo, P; Delgado-Molina, JA; Medina-Sanchez, JM; Bullejos, FJ; Villar-Argaiz, M",phosphorus inputs unmask negative effects of ultraviolet radiation on algae in a high mountain lake,GLOBAL CHANGE BIOLOGY,Article,extracellular carbon release; high mountain lakes; primary production; sestonic C : P ratio; UVR x P interactive effects,"ultraviolet solar radiation (uvr) and atmospheric nutrient loads to pristine ecosystems are global climate change phenomena that simultaneously affect aquatic organisms in ways not easily predicted by single factor studies. plankton in a high mountain lake was exposed in situ to increasing phosphorus (p) concentrations (mimicking atmospheric pulses) in absence or presence of uvr in order to identify their interactive effect on functional [primary production, organic carbon (c) release (eoc), and percentage of c released (%eoc)], growth rate, structural-physiological (algal biomass, sestonic c, p content, chlorophyll a (chl a), and chl a:c ratio, p cell quota, cell-specific chl a), and stoichiometric (autotroph c: p ratio) traits. the availability of p after the pulse determined the intensity of responses by primary producers to uvr stress. all structural-physiological and functional variables significantly increased by up to two orders of magnitude in response to p enrichment. uv radiation, over a long-term scale, exerted significant deleterious effects on most structural-physiological variables when inorganic p was added at high levels (>= 30 mu g pl-1). the subsequent unexpected negative synergistic uvr x p effect on algal development did not support our initial hypothesis that p input might buffer the harmful uvr effect. uvr exerted a weak negative effect on primary production but strongly enhanced the absolute and percentage excretion of c (up to 60%), mechanism responsible of a significant reduction in autotroph c: p ratios. we propose that low sestonic c:p ratios are the outcome of an adaptive strategy of algae in environments with high uvr exposure and extreme nutrient limitation and have important implications for c flux through grazing vs. microbial food webs in oligotrophic systems.",29,2008,14,2,423,439,10.1111/j.1365-2486.2007.01496.x,1,0,0,1"Ferguson, CA; Carvalho, L; Scott, EM; Bowman, AW; Kirika, A",assessing ecological responses to environmental change using statistical models,JOURNAL OF APPLIED ECOLOGY,Article,climate change; freshwater; Loch Leven; seasonality; statistical model; trend,"1. there is a clear need to improve our ability to assess the ecological consequences of environmental change. because of the complexity of ecosystems and a need to disentangle the effects of multiple pressures, predictions are often reliant on models and expert opinion. these require validation with observed data; in this respect, long-term data sets are particularly valuable. 2. innovative statistical methods (nonparametric regression and additive models) are presented for identifying nonparametric ecological trends and changes in seasonality in response to environmental change. these are illustrated through the example of loch leven, a shallow freshwater lake. monitoring data for 35 years are examined, spanning periods of enrichment, ecological recovery and changing climate. 3. models are developed for phosphorus and nitrogen; temperature and rainfall; daphnia grazers; and chlorophyll a, with the ecological objectives of examining trends in water quality and the corresponding trends in nutrient availability, grazer abundance and climate. 4. the analysis highlighted a generally decreasing availability of p over the study period, and generally increasing nonparametric trends in nitrate concentration and rainfall. increasing spring temperatures were also evident, as were significant nonparametric changes in density of summer grazers. 5. significant reductions are highlighted in spring and summer chlorophyll a, related to the return of daphnia to the loch. however, no response in chorophyll a to the later declining trends in p is apparent, but seasonality has changed. 6. synthesis and applications. the analysis highlights the value of nonparametric statistical models for assessing complex ecological responses to environmental change. the models outlined can examine key ecological impacts of climate change, particularly effects on the timing of seasonal events and processes. the models are illustrated using long-term water-quality data from loch leven to explore patterns in key environmental drivers and ecological responses affecting freshwater ecosystems. analysis of chlorophyll a, in particular, highlighted the value of examining the seasonal trends separately, with different trends evident for winter and spring and a changing seasonal pattern.",34,2008,45,1,193,203,10.1111/j.1365-2664.2007.01428.x,0,0,1,1"Gonzalez, WL; Negritto, MA; Suarez, LH; Gianoli, E",induction of glandular and non-glandular trichomes by damage in leaves of madia sativa under contrasting water regimes,ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY,Article,drought; herbivory; induced responses; mechanical defenses; plant resistance; tarweed,"plant traits may play multiple functional roles simultaneously. leaf trichomes have been related to resistance against herbivores as well as to enhanced water economy in the plant. in a greenhouse study, we evaluated the interactive effect of damage (control vs. mechanical damage) and water availability (control vs. low watering) on the expression of glandular and non-glandular leaf trichomes in the annual chilean tarweed madia sativa (asteraceae). we found that the overall trichome density increased both after damage and when plants were grown under water shortage. interestingly, the type of trichome induced after damage varied with each water environment. while damage induced glandular trichomes only under control watering, non-glandular trichomes were induced by damage only under experimental drought. results indicate that in m. sativa glandular trichomes are equally induced by drought or damage but there is no additive effect of these factors. in both cases glandular trichome density apparently reached a limit, which may be interpreted in terms of constraint or efficacy. on the other hand, the synergistic effect of damage and drought on non-glandular trichomes might suggest that, compared to glandular ones, these trichomes are less responsive to each stress factor separately. thus, for plants to induce non-glandular trichomes they must be subjected to a degree of stress above a threshold that was not reached for each individual factor in our experimental setting. we did not detect a significant correlation between trichome types. thus, the contrasting patterns observed likely reflect independent responses of trichomes to the evaluated factors. (c) 2007 elsevier masson sas. all rights reserved.",22,2008,33,1,128,132,10.1016/j.actao.2007.10.004,1,0,1,2"Aguirre, AA; Tabor, GM",global factors driving emerging infectious diseases impact on wildlife populations,Animal Biodiversity and Emerging Diseases: Prediction and Prevention,Article; Proceedings Paper,conservation medicine; ecological health; emerging infectious disease; extinction; globalization; habitat fragmentation; sentinel species; wildlife,"the extinction of species across the globe is accelerating directly or indirectly from human activities. biological impoverishment, habitat fragmentation, climate change, increasing toxification, and the rapid global movement of people and other living organisms have worked synergistically to diminish ecosystem function. this has resulted in unprecedented levels of disease emergence driven by human-induced environmental degradation, which poses a threat to the survival and health of biodiversity. what is often overlooked in the discussion of the health consequences to humans is that critically endangered wildlife species are at grave risk of extinction by disease outbreaks. as habitat becomes more compressed and with migration routes cut off, gene pools of small species are stranded in isolated habitat fragments. species now are vulnerable to encroachment, malnutrition, environmental pollutants, and epidemics from domestic animals and humans. furthermore, the continuous degradation of ecosystems is leading to increased stress, immunosuppression, and greater susceptibility to disease. disease can be catastrophic to a diminished stressed population, becoming in some instances the leading factor of local, regional, and global extinctions. the strategies of the new field of conservation medicine include long-term monitoring, health assessment, and interventions to protect species at risk. we particularly must minimize the threat of any potentially catastrophic disease outbreaks resulting from anthropogenic changes to the environment. current and future diagnostic molecular techniques offer new opportunities to identify tools for the management and possible treatment of diseases in imperiled species.",24,2008,1149,,1,3,10.1196/annals.1428.052,1,0,0,1"Trusilova, K; Churkina, G","the response of the terrestrial biosphere to urbanization: land cover conversion, climate, and urban pollution",BIOGEOSCIENCES,Article,,"although urban areas occupy a relatively small fraction of land, they produce major disturbances of the carbon cycle through land use change, climate modification, and atmospheric pollution. in this study we quantify effects of urban areas on the carbon cycle in europe. among urbanization-driven environmental changes, which influence carbon sequestration in the terrestrial biosphere, we account for: (1) proportion of land covered by impervious materials, (2) local urban meteorological conditions, (3) urban high co(2) concentrations, and (4) elevated atmospheric nitrogen deposition. we use the terrestrial ecosystem model biome-bgc to estimate fluxes of carbon exchange between the biosphere and the atmosphere in response to these urban factors. we analysed four urbanization-driven changes individually, setting up our model in such a way that only one of the four was active at a time. from these model simulations we found that fertilization effects from the elevated co(2) and the atmospheric nitrogen deposition made the strongest positive contributions to the carbon uptake (0.023 pg c year(-1) and 0.039 pg c year(-1), respectively), whereas, the impervious urban land and local urban meteorological conditions resulted in a reduction of carbon uptake (-0.005 pg c year(-1) and -0.007 pg c year(-1), respectively). the synergetic effect of the four urbanization-induced changes was an increase of the carbon sequestration in europe of 0.058 pg c year(-1).",14,2008,5,6,1505,1515,,1,0,0,1"Hendrickx, F; Maelfait, JP; Lens, L",effect of metal stress on life history divergence and quantitative genetic architecture in a wolf spider,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,animal model; Bayesian statistics; ecological divergence; egg size; heavy metal; stress resistance; trade-off,"effects and consequences of stress exposure on life history strategies and quantitative genetic variation in wild populations remain poorly understood. we here study whether long-term exposure to heavy metal pollution may result in alternative life history strategies and alter quantitative genetic properties in natural populations of the wolf spider pirata piraticus. offspring originating from a reference and a metal contaminated population and their reciprocal hybrid cross were bred in a half-sib mating scheme and subsequently reared in cadmium contaminated vs. clean environment. results from this experiment provided evidence for a genetically based reduced growth rate and increased egg size in the contaminated population. growth rate reduction in response to cadmium contamination was only observed for the reference population. animal model analysis revealed that heritability for growth rate was large for the reference population under reference conditions, but much lower under metal stressed conditions, caused by a strong decrease in additive genetic variance. heritability for growth of the metal contaminated population was very low, even under reference conditions. initial size of the offspring was primarily determined by maternal effects, whereas egg size produced by the offspring was determined by both sire and dam effects, indicating that egg size determination is under control of the female genotype. in conclusion, these results show that metal stress can not only affect life history variation in natural populations, but also decreases the expression as well as the of the amount of genetic variation for particular life history traits.",17,2008,21,1,183,193,10.1111/j.1420-9101.2007.01452.x,0,0,1,1"Portner, HO",ecosystem effects of ocean acidification in times of ocean warming: a physiologist's view,MARINE ECOLOGY PROGRESS SERIES,Article,Ocean acidification; Global change; Temperature effects; Calcification; Metabolic performance; Acclimation; Ecosystems; Hypoxia,"ocean warming and acidification occur at global scales and, in the case of temperature, have already caused shifts in marine ecosystem composition and function. in the case of co2-induced ocean hypercapnia and acidification, however, effects may still be so small that evidence for changes in the field is largely lacking, future scenarios indicate that marine life forms are threatened by the specific or synergistic effects of factors involved in these processes. the present paper builds on the view that development of a cause and effect understanding is required beyond empirical observations, for a more accurate projection of ecosystem effects and for quantitative scenarios. identification of the mechanisms through which temperature- and co2-related ocean physicochemistry affect organism fitness, survival and success, is crucial with this research strategy. i suggest operation of unifying physiological principles, not only of temperature but also co2 effects, across animal groups and phyla. thermal windows of optimized performance emerge as a basic character defining species fitness and survival, including their capacity to interact with other species. through effects on performance at the level of reproduction, behaviour and growth, ocean acidification acts especially on lower marine invertebrates, which are characterized by a low capacity to compensate for disturbances in extracellular ion and acid-base status and sensitivity of metabolism to such disturbances. available data suggest that one key consequence of these features is a narrowing of thermal tolerance windows, as well as a reduced scope for performance at ecosystem level. these changes in bioenvelopes may have major implications for the ranges of geographical distribution of these organisms and in species interactions.",247,2008,373,,203,217,10.3354/meps07768,1,0,0,1"Jones, OAH; Dondero, F; Viarengo, A; Griffin, JL",metabolic profiling of mytilus galloprovincialis and its potential applications for pollution assessment,MARINE ECOLOGY PROGRESS SERIES,Article,Antagonism; Metabonomics; Metabolomics; Mussels; Pollution; Nickel; Chlorpyrifos,"monitoring of the marine environment is crucial for determining the impact of environmental stressors and/or pollution on ecosystem health. classical assays that traditionally focus on a limited number of selected endpoints have thus far proven to be of limited success in this regard. here, we apply h-1-nuclear magnetic resonance (nmr)-based chemometric analysis to the marine mussel mytilus galloprovincialis to investigate changes in the metabolic profile of digestive gland tissue as a response to exposure to nickel and chlorpyrifos, both as single chemicals and as a mixture. the multivariate data was analysed by principal component analysis and partial least-squares discriminant analysis. the major metabolite changes responsible for the spectral differences observed were related to amino acid, nucleotide and methylamine metabolism in all 3 cases. in addition, novel metabolic profiles were associated with exposure to each chemical and the mixture. nickel produced changes in energy metabolism while chlorpyrifos resulted in an increase in acetylcholine levels. mussels exposed to a single compound demonstrated a significantly different response to those given the mixture, where a small antagonistic effect was evident. the study demonstrates the potential of nmr-based metabolomics to provide a rapid and cost-effective screening tool for monitoring the aquatic environment.",36,2008,369,,169,179,10.3354/meps07654,0,1,0,1"Brun, FG; Olive, I; Malta, EJ; Vergara, JJ; Hernandez, I; Perez-Llorens, JL",increased vulnerability of zostera noltii to stress caused by low light and elevated ammonium levels under phosphate deficiency,MARINE ECOLOGY PROGRESS SERIES,Article,ammonium toxicity; carbohydrates; eutrophication; fluorescence; net production; phosphate limitation; seagrass,"the effects of light and ammonium levels on net production, fluorescence parameters and non-structural carbohydrates of the seagrass zostera noltii under different phosphate conditions were studied. a fully factorial design was used with light (low/high levels), ammonium supply and phosphate preculture conditions of the plants as the experimental variables. both ammonium supply and low light caused negative and synergistic effects on net production, while ammonium toxicity was more severe at high light levels; in this case, it was independent of the non-structural carbohydrate (sucrose and starch) content. preculturing of plant with added phosphate alleviated the ammonium toxicity, and also attenuated the negative production balance of plants grown at low light levels. the results indicated that phosphate preculture ameliorated the plant's short-term response against the assayed stressors (low light, high ammonium) significantly. an overall consumption of non-structural carbohydrates in response to environmental stressors was recorded throughout the experiment, indicating the importance of carbon and phosphorus reserves to cope with adverse conditions. ln addition, phosphate deficiency increased the vulnerability of plants, which could have negative ecological consequences for seagrass species thriving under phosphate deficiency conditions, or in developing seagrass transplantation programs.",13,2008,365,,67,75,10.3354/meps07512,1,0,0,1"Carroll, SP",facing change: forms and foundations of contemporary adaptation to biotic invasions,MOLECULAR ECOLOGY,Article; Proceedings Paper,adaptation; biological control; conservation; contemporary evolution; invasion; soapberry bug,"ongoing adaptation in native populations to anthropogenic change both facilitates and challenges ecologically appropriate and sustainable management. human disturbance promotes adaptive responses at the genomic, individual and population levels. traits vary widely in whether adaptation occurs through plasticity or evolution, and these modes interact within and among traits. for example, plasticity in one trait may be adaptive because it permits homeostasis and lessens the intensity of selection in another. both opportunity and catastrophe generate adaptive responses. recently evolved adaptations characterize the responses of many native species to biotic invasions. several well-known examples involve native phytophagous insects colonizing introduced plants. for example, our studies of north american and australian soapberry bugs on nonindigenous plants demonstrate both diversifying and homogenizing contemporary evolution. modes of adaptation differ among traits and populations and as a function of the host on which they develop. the genetic architecture of the evolving adaptations involves a substantial degree of nonadditive genetic variation. one important consequence of contemporary adaptation may be an enhanced capacity of native communities to provide adaptive biological control of invasive species. conservation scientists may manipulate adaptation to achieve conservation goals, but must also decide how deeply they wish to attempt to control the phenotypes and genotypes of other species.",34,2008,17,1,361,372,10.1111/j.1365-294X.2007.03484.x,0,0,1,1"Rixen, C; Huovinen, C; Huovinen, K; Stockli, V; Schmid, B",a plant diversity x water chemistry experiment in subalpine grassland,PERSPECTIVES IN PLANT ECOLOGY EVOLUTION AND SYSTEMATICS,Article,artificial snow; biodiversity experiment; ecosystem functioning; fertilization; skiing; snow additives,"plant diversity has been shown to drive important ecosystem functions such as productivity. at the same time, plant diversity and species composition are altered in alpine ecosystems by human impacts such as skiing. therefore, we investigated impacts of decreased species richness and ski piste treatments on ecosystem functions in subalpine grassland. species richness manipulations were combined with nutrient input from snow cover treated with snow additives that are commonly used on ski pistes. three different species richness levels containing 1, 3 or 9 species randomly selected from a larger pool plus unmanipulated meadow plots were treated with four water types to simulate melt water. one water type contained the snow additive ammonium nitrate. invasion into the communities was prevented by weeding during 2 years and allowed in three subsequent years. higher species richness increased plant cover and biomass and decreased their variation. the number of functional groups in a plant assemblage had a positive effect on plant growth. ammonium nitrate strongly increased biomass and plant cover after a single application but decreased species richness in originally diverse meadow plots. there was no significant interaction between species richness and water-type treatments. after the cessation of weeding, the species richness of different plot types converged within 3 years due to invasion. nevertheless, relationships between initial species richness and plant cover remained positive. the results suggest that the diversity and species composition of alpine vegetation are important factors influencing cover and biomass, in particular during re-colonization of bare ground after disturbances such as ski-piste construction. in slow-growing alpine vegetation, initially positive diversity effects may remain even after successional convergence of species richness due to invasion. the negative effect of ammonium nitrate on species richness suggests the snow additives should only be used with care. (c) 2007 rubel foundation, eth zurich. published by elsevier gmbh. all rights reserved.",8,2008,10,1,51,61,10.1016/j.ppees.2007.09.003,0,0,1,1"Salvat, B; Aubanel, A; Adjeroud, M; Bouisset, P; Calmet, D; Chancerelle, Y; Cochennec, N; Davies, N; Fougerousse, A; Galzin, R; Lagouy, E; Lo, C; Monier, C; Ponsonnet, C; Remoissenet, G; Schneider, D; Stein, A; Tatarata, M; Villiers, L",monitoring of french polynesia coral reefs and their recent development,REVUE D ECOLOGIE-LA TERRE ET LA VIE,Article,,"monitoring of french polynesia coral reefs and their recent development.-french polynesia, consisting of 118 islands in the centre of the pacific ocean, has more than 15 000 km(2) of reefs and lagoons managed by the local government. tourism and pearl culture are the two main economic resources of the country. polynesian coral reefs are extremely diverse and are among those for which we have thorough knowledge. the exploitation of local resources has been recorded for multiple decades and includes : coral materials, fishing, harvest and export of mother-of-pearl molluscs, pearl production, and ornamental fish. all over the country, many monitoring programmes have been launched to measure the health of reefs and the natural and anthropogenic perturbations that they suffer : hurricanes and seismic events, water quality, health of benthic and fish communities, pearl oyster pathology and radiobiology. these data, collected over the last few decades, allowed to define the relative importance of natural and anthropogenic degradation on reefs and lagoons, and to explain the present status of reefs at different spatial scales. devastating hurricanes are rare (1903-1906, 1982-1983 and occasionally at other times), but they may annihilate outer slope coral communities on some islands. bleaching events with considerable coral mortality at different geographical scales occurred mainly in 1991, 1994 and 2003. outbreaks of acanthaster destroyed numerous reefs (lagoons and outer slopes) from 1978-1982 and a new demographic wave began in 2006 at many society islands. eutrophication events only occurred occasionally and only in some lagoons. whereas natural catastrophic events degrade the coral reef ecosystem across many islands, at the archipelago or even regional scale, anthropogenic degradation is limited to a few society islands, occurring rarely on atolls and not at all on those (one third) which are uninhabited. the main causes of reef degradation in some areas of tahiti and moorea include the embankment of fringing zones, coral mining, overfishing, absence of urban sewage treatment and the development of leisure and tourism activities. because of its large geographical extent, one may conclude that major reef degradation in french polynesia is caused by catastrophic natural events. on the other hand, anthropogenic degradation is more localized. unfortunately, the synergistic effects of these causes of degradation prevent reefs from recovering. optimum coral cover on french polynesian outer reef slopes is between 50-60%. after a major destructive impact (hurricane, bleaching, acanthaster) a reef is reduced to less than 10% coral cover, however if no more major disturbance events occur a reef will recover in about 12 years. most of the 15 000 km(2) of reefs and lagoons in french polynesia are in good health, and along with their neighbouring reefs in east and central pacific they are considered as the least degraded reefs worldwide and at a low risk of becoming degraded in the few next decades. however, we are more and more anxious about the future of reefs in the world particularly because present simulations predict that major impacts of climate change would include : elevation of sea surface temperatures, increase in the strength of hurricanes and acidification of seawater which will affect the formation of coral structures.",7,2008,63,02-Jan,145,177,,1,0,0,1"Brook, BW","synergies between climate change, extinctions and invasive vertebrates",WILDLIFE RESEARCH,Article,,"there is mounting evidence for the direct ecological impacts of recent climate change, and for amplifying feedbacks, in both directions, with other drivers of biodiversity loss, such as habitat fragmentation and overexploitation. surprisingly, however, empirical and experimental data on the links between climate change and species introductions are scant, especially for invasive vertebrates. because the theoretical basis for their mutually reinforced impact is strong, this dearth of evidence likely reflects the difficulty in studying such interactions, and insufficient attention to this topic, rather than a genuine lack of association. given the unprecedented rate of recent and predicted future climate change, and the continued exponential rise in species invasions worldwide, it is imperative that we sharpen our scientific focus so as to best equip wildlife managers with the knowledge to tackle this inevitable synergy of threats.",23,2008,35,3,249,252,10.1071/WR07116,1,0,0,1"Stangeland, T; Remberg, SF; Lye, KA",antioxidants in some ugandan fruits,AFRICAN JOURNAL OF ECOLOGY,Article,antioxidant activity; dietary plants; FRAP; assay; fruits; Uganda,"several studies indicate that a plant-based diet protects against the development of some serious diseases. it is assumed that the antioxidant content in food is an important reason for this protection. dietary plants contain several hundred antioxidants, many of which are believed to act in a synergistic way to protect the body against oxidative stress. berries, fruits, spices and some nuts have proved to be excellent sources of antioxidants. in this preliminary study, many fruits and some seeds from ugandan plants have been analysed for total antioxidant activity using the frap (ferric reducing ability of plasma) assay. our results demonstrate that there is a large variation in antioxidant activity between the samples analysed. the plants with highest activity in decreasing order were found to be: african black olive (canarium sweinfurthii), pomegranate, guava, java plum (syzygium cuminii), sweet banana, tamarind, mango, orange and passion fruits, with antioxidant values in the range of 47.25 to 0.77 mmol per 100 g fresh weight. we believe that increased awareness of antioxidant activity in food and resulting change in food intake can be of importance for an improved health situation.",3,2007,45,,29,30,10.1111/j.1365-2028.2007.00853.x,1,0,0,1"Michalski, F; Peres, CA",disturbance-mediated mammal persistence and abundance-area relationships in amazonian forest fragments,CONSERVATION BIOLOGY,Article,Amazonian forest; forest disturbance; forest fragmentation; mammal abundance; species abundance; species richness,"few researchers have investigated the synergistic effects of tropical forest fragmentation and disturbance on species persistence and abundance. we examined effects of both forest-patch metrics and forest disturbance in determining richness and abundance of midsized to large-bodied mammal species in a highly fragmented amazonian forest landscape. twenty-one forest fragments, ranging from 2 to 14,480 ha, and two continuous forest sites were sampled based on sightings, tracks, line-transect censuses, armadillo burrow censuses, and camera trapping. patch occupancy of 37 species recorded ranged from 4% to all forest sites surveyed. forest fragment size was the strongest predictor of species persistence, explaining 90% of the variation in species richness. information-theoretic analysis confirmed that fragment area was the most important explanatory variable for the overall species richness and abundance of mammal species, followed by surface fires, which affected the abundance of seven species. large mammal species were typically absent from fragments < 100 ha, whereas some ubiquitous species were favored by fragmentation, exhibiting hyperabundance in small patches. our findings highlight the importance of large (> 10,000 ha), relatively undisturbed forest patches to maximize persistence and maintain baseline abundances of neotropical forest mammal species.",47,2007,21,6,1626,1640,10.1111/j.1523-1739.2007.00797.x,1,0,0,1"Galletly, BC; Blows, MW; Marshall, DJ",genetic mechanisms of pollution resistance in a marine invertebrate,ECOLOGICAL APPLICATIONS,Article,ascidians; copper stress; genotype x environment interactions; marine invertebrates; pollution resistance; reaction norms; Styela plicata,"pollution is a common stress in the marine environment and one of today's most powerful agents of selection, yet we have little understanding of how anthropogenic toxicants influence mechanisms of adaptation in marine populations. due to their life history strategies, marine invertebrates are unable to avoid stress and must adapt to variable environments. we examined the genetic basis of pollution resistance across multiple environments using the marine invertebrate, styela plicata. gametes were crossed in a quantitative genetic breeding design to enable partitioning of additive genetic variance across a concentration gradient of a common marine pollutant, copper. hatching success was scored as a measure of stress resistance in copper concentrations of 0, 75, 150, and 350 mu g/l. there was a significant genotype 3 environment interaction in hatching success across copper concentrations. further analysis using factor analytic modeling confirmed a significant dimension of across-environment genetic variation where the genetic basis of resistance to stress in the first three environments differed from that in the environment of highest copper concentration. a second genetic dimension further differentiated between the genetic basis of resistance to low and high stress environments. these results suggest that marine organisms use different genetic mechanisms to adapt to different levels of pollution and that the level of genetic variation to adapt to intense pollution stresses may be limited.",22,2007,17,8,2290,2297,10.1890/06-2079.1,0,0,1,1"James, PMA; Fortin, MJ; Fall, A; Kneeshaw, D; Messier, C",the effects of spatial legacies following shifting management practices and fire on boreal forest age structure,ECOSYSTEMS,Article,stochastic spatially explicit model; landscape pattern metrics; ordination; simulation modeling; landscape legacies; forest disturbance; forest management; forest age structure,"forest age structure and its spatial arrangement are important elements of sustainable forestry because of their effects on biodiversity and timber availability. forest management objectives that include specific forest age structure may not be easily attained due to constraints imposed by the legacies of historical management and natural disturbance. we used a spatially explicit stochastic model to explore the synergetic effects of forest management and fire on boreal forest age structure. specifically, we examined (1) the duration of spatial legacies of different management practices in the boreal forest, (2) how multiple shifts in management practices affect legacy duration and the spatial trajectories of forest age structure, and (3) how fire influences legacy duration and pattern development in combination with harvesting. results based on 30 replicates of 500 years for each scenario indicate that (1) spatial legacies persist over 200 years and the rate at which legacies are overcome depends on whether new management targets are in synchrony with existing spatial pattern; (2) age specific goals were met faster after multiple management shifts due to the similar spatial scale of the preceding management types; (3) because large fires can erase the spatial pattern created by smaller disturbances, scenarios with fire had shorter lags than scenarios without fire. these results suggest that forest management goals can be accelerated by applying management at a similar spatial scale as existing spatial patterns. also, management planning should include careful consideration of historical management as well as current and likely future disturbances.",24,2007,10,8,1261,1277,10.1007/s10021-007-9095-y,1,0,0,1"Pauli, JN; Buskirk, SW","risk-disturbance overrides density dependence in a hunted colonial rodent, the black-tailed prairie dog cynomys ludovicianus",JOURNAL OF APPLIED ECOLOGY,Article,Allee effect; coloniality; density dependence; hunting; prairie dog; risk-disturbance; Wyoming,"traditional understanding of how hunting affects vertebrate populations emphasizes competitive release and density dependence of vital rates, but more recent thinking has proposed complex non-lethal responses to hunting disturbance and predation risk. colonial species have been proposed to be more vulnerable than dispersed, solitary species to disturbance and perceived risk from hunting. however, empirical comparisons of density dependence vs. risk disturbance in hunted species are few. to compare density dependence with risk-disturbance effects of hunting on individuals and populations of a colonial species, we tested the response of black-tailed prairie dogs cynomys ludovicianus to shooting in a before-after, treatment-control experiment. we subjected five colonies to a pulse of shooting, and compared individual and colony attributes to those of five control colonies, protected from shooting. surviving prairie dogs increased alert behaviours eightfold and reduced both above-ground activity and time spent foraging by 66%. changes in behaviour lowered the body condition of surviving adults by 35%. survivors of shooting, especially juveniles, exhibited elevated stress levels; faecal corticosterone concentrations increased by 80% among juveniles. unexpectedly, overwinter survival rates did not increase in response to reduced prairie dog density. colonies subjected to shooting experienced reproductive near-collapse the summer after shooting; pregnancy rates declined by 50% and reproductive output fell by 82%. risk-disturbance overwhelmed any possible density-dependent effects of shooting in prairie dogs, which exhibited additive mortality in response to hunting, and reproductive failure 1 year after shooting. risk-disturbance was the predominant mechanism whereby individuals and colonies were affected by hunting. synthesis and applications. because of their coloniality, prairie dogs possess certain life-history traits that predisposed them to be particularly susceptible to hunting-associated disturbances, which had cascading effects on population-level processes. our findings contradict the general belief that small-bodied mammals quickly rebound from hunting exploitation via compensatory mortality and reproduction. managers should consider measures to reduce recreational shooting intensity and duration in regions where black-tailed prairie dog colony growth and persistence is desired, yet allow shooting in areas where colonies conflict with landowner interests.",18,2007,44,6,1219,1230,10.1111/j.1365-2664.2007.01337.x,0,0,1,1"Morritt, D; Leung, KMY; De Pirro, M; Yau, C; Wai, TC; William, GA","responses of the limpet, cellana grata (gould 1859), to hypo-osmotic stress during simulated tropical, monsoon rains",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,freshwater; limpet; monsoon; physiology; rain; tropical shores,"although heat stress is often cited as the dominant physical stress on tropical shores, intertidal organisms in regions with monsoonal climates are also regularly exposed to prolonged periods of heavy rainfall. such events are predicted to have adverse physiological effects on individuals and may result in mortality. in a series of laboratory experiments, the impact of simulated monsoonal rains was investigated on the patellid limpet, cellana grata. sub-lethal responses in terms of body water content, body fluid osmolality and heart rate were measured in two different size cohorts maintained on horizontal and vertical substrata. limpets were unable to achieve any effective behavioural isolation, and exposure to either simulated rainfall or diluted seawater resulted in both large and small c grata gaining water with subsequent dilution of mantle water and haemolymph osmolalities. with increased duration of rainfall, dilution of body fluids increased with little difference between individuals on horizontal and vertical surfaces. body fluids generally showed proportional dilution during prolonged rain, but in some individuals there was evidence for regulation of the haemolymph relative to the mantle fluid. overall, smaller limpets were more susceptible to prolonged rainfall than large animals in terms of swelling of soft tissues and detachment and also had higher heart rates than large limpets. both cohorts reduced heart rates with prolonged rainfall, suggesting a degree of metabolic depression, especially on horizontal surfaces. in small limpets, no difference in heart rate was found with substratum orientation, whereas large limpets had elevated heart rates on vertical as compared to horizontal substrata, when exposed to either simulated rainfall or washed with dilute seawater. this may reflect the increased energetic costs required to maintain a relatively larger body on a vertical surface under stressful conditions. monsoonal rainfall during emersion, and subsequent dilution of seawater, therefore, have sub-lethal physiological and possible lethal effects on intertidal limpets. this influence has been largely overlooked, but coupled with the possible synergistic effects of thermal stress, monsoon rains are likely to play an important role in community dynamics on tropical shores. (c) 2007 elsevier b.v. all rights reserved.",8,2007,352,1,78,88,10.1016/j.jembe.2007.07.002,1,0,0,1"Li, J; Duggin, JA; Loneragan, WA; Grant, CD","grassland responses to multiple disturbances on the new england tablelands in nsw, australia",PLANT ECOLOGY,Article,fire; grazing; plant community; resilience; soil cultivation; soil amendment,"disturbances have played a significant role in shaping vegetation patterns following european settlement and agricultural development in australia, particularly over the last 100 years. however, little is known about the temporal dynamics of plant communities in relation to disturbances and their interactions. in this study we examined the response and recovery of temperate grassland communities to disturbance, using a multi-factorial experiment involving grazing exclusion (absent and present), fire (absent and present), soil cultivation (none, 5 and 20 cm) and soil amendment (none, fertiliser and fertiliser plus clover seeds) on the new england tablelands in nsw, australia. temporal patterns of plant communities were analysed using detrended correspondence analysis for eight surveys over 24 months. vegetation patterns at each survey were analysed using principal components analysis. the effects of treatments on malleability (bray-curtis dissimilarity) of plant communities were analysed using a linear mixed model, and the relationships between malleability and plant species groups were depicted using a generalised additive model and further analysed using a linear model. perennial native grasses and a non-native forb (hypochaeris radicata) initially dominated the vegetation, but after the disturbances h. radicata and other non-native species dominated. compositional changes from the initial states were greatest in the first spring (7 months after treatment application), and then the vegetation tended to recover towards its original state. soil cultivation resulted in the greatest deviation in community composition, followed by soil amendment, fire, with grazing exclusion the least. the recovery process and rate of recovery varied with treatment reflecting the dominance of soil cultivation and its interactions with other forms of disturbances. soil amendment and grazing exclusion tended to reduce the effects of soil cultivation. malleability was negatively related to perennial native grasses; positively to other non-native species, annual native grasses and perennial native sedges/rushes; and negatively to h. radicata when its cover was below 18%, but positively when above 18%. the degree of malleability reflected the high resilience of the vegetation to disturbance, and was mainly due to the recovery of perennial native grasses and h. radicata. this resilience demonstrated that the small-scale disturbances did not cause vegetation to cross an ecological threshold and that the present vegetation is resilient to common disturbances occurring at small scales. the results also suggest (1) that the present vegetation has developed mechanisms to adapt to these disturbances, (2) the importance of disturbance scale or (3) that the ecological threshold had already been crossed and the present vegetation is in a degraded state compared with its original state before the end of the 19th century.",5,2007,193,1,39,57,10.1007/s11258-006-9247-8,0,0,1,1"Ricklefs, RE; Cadena, CD",lifespan is unrelated to investment in reproduction in populations of mammals and birds in captivity,ECOLOGY LETTERS,Article,aging; antagonistic pleiotropy; disposable soma; senescence; survival; trade-off; zoo populations,"we examined the relationship between number of offspring produced to a certain age and subsequent longevity in captive zoo populations of 18 species of mammal and 12 species of bird. the age cut-offs in each analysis were set to include 50%, 75% and 90% of the offspring produced in each of the population samples. only one of 68 regressions was significant, and its slope was positive. in addition, we examined the relationship between age at first reproduction up to a certain age and longevity after that age, generally 5 years (3-8), among 17 species of mammal and 12 species of bird. only one of these regressions had a significantly positive slope, indicating that early reproduction rarely reduces lifespan. overall, we found no evidence that producing offspring in a zoo environment influences the age at death. thus, although trade-offs might apply in natural populations under resource limitation, neither pregnancy, growth of the foetus and lactation in mammals, nor egg production in birds, reduces lifespan in the absence of such stress. if genetically based or other intrinsic antagonistic pleiotropy underlies the evolution of senescence, it was not evident in our analyses.",36,2007,10,10,867,872,10.1111/j.1461-0248.2007.01085.x,0,1,0,1"Smith, CA; Wilson, WG",evolutionarily stable dispersal with pattern formation in a mutualist-antagonist system,EVOLUTIONARY ECOLOGY RESEARCH,Article,disperse; evolutionarily stable state; heterogeneity; host-parasitoid; individual-based simulation; mathematical model; metapopulation dynamics; obligate mutualism; patches,"question: how does the evolution of dispersal distance affect the persistence, distribution, and population dynamics of a mutualist-antagonist system capable of endogenous pattern formation? modelling approach: we let dispersal distance evolve within an individual-based model involving an obligate plant-pollinating seed parasite pair and a parasitoid that preys upon pollinator larvae. the model incorporates demographic parameters for ovule production, pollinator oviposition, pollinator and parasitoid visitation rates, in addition to background mortality probabilities for each of the three species. a corresponding non-spatial mathematical model verifies our representation of the interspecific dynamics. key assumptions: individuals move over a homogeneous underlying environment with dispersal distances drawn from probability distribution kernels. each species is subject to density-dependent reproduction. pollinators and parasitoids make multiple visits per time step that are poisson distributed. conclusions: dependent on demographic parameter values, there is a spectrum of outcomes, including: (1) runaway selection for increased dispersal distance resulting in homogeneous distributions of all three species; (2) an evolutionarily stable state with pattern formation and metapopulation-like dynamics; and (3) rapid extinction of one or more species. interestingly, a weak relaxation of the obligacy between the plants and the pollinators erodes the evolutionarily stable state with pattern formation. we argue that this dependence upon and sensitivity to obligacy may explain the lack of empirical observations of endogenous pattern formation in nature.",0,2007,9,6,987,1004,,0,1,0,1"Reusch, TBH; Wood, TE",molecular ecology of global change,MOLECULAR ECOLOGY,Review,ecogenomics; genetic architecture; genome scan; global change; photoperiod; range shift; selection experiment; stress tolerance; transcription profiling,"global environmental change is altering the selection regime for all biota. the key selective factors are altered mean, variance and seasonality of climatic variables and increase in co2 concentration itself. we review recent studies that document rapid evolution to global climate change at the phenotypic and genetic level, as a response to shifts in these factors. among the traits that have changed are photoperiod responses, stress tolerance and traits associated with enhanced dispersal. the genetic basis of two traits with a critical role under climate change, stress tolerance and photoperiod behaviour, is beginning to be understood for model organisms, providing a starting point for candidate gene approaches in targeted nonmodel species. most studies that have documented evolutionary change are correlative, while selection experiments that manipulate relevant variables are rare. the latter are particularly valuable for prediction because they provide insight into heritable change to simulated future conditions. an important gap is that experimental selection regimes have mostly been testing one variable at a time, while synergistic interactions are likely under global change. the expanding toolbox available to molecular ecologists holds great promise for identifying the genetic basis of many more traits relevant to fitness under global change. such knowledge, in turn, will significantly advance predictions on global change effects because presence and polymorphism of critical genes can be directly assessed. moreover, knowledge of the genetic architecture of trait correlations will provide the necessary framework for understanding limits to phenotypic evolution; in particular as lack of critical gene polymorphism or entire pathways, metabolic costs of tolerance and linkage or pleiotropy causing negative trait correlations. synergism among stressor impacts on organismal function may be causally related to conflict among transcriptomic syndromes specific to stressor types. because adaptation to changing environment is always contingent upon the spatial distribution of genetic variation, high-resolution estimates of gene flow and hybridization should be used to inform predictions of evolutionary rates.",138,2007,16,19,3973,3992,10.1111/j.1365-294X.2007.03454.x,1,0,0,1"Lewison, R",population responses to natural and human-mediated disturbances: assessing the vulnerability of the common hippopotamus (hippopotamus amphibius),AFRICAN JOURNAL OF ECOLOGY,Article,catastrophe; environmental stochasticity; habitat loss; hippopotamus; multi-matrix population model; population persistence; sensitivity to disturbance,"vulnerable wildlife populations can face a suite of anthropogenic activities that may threaten their persistence. however, human-mediated disturbances are likely to be coincident with natural disturbances that also influence a population. this synergism is often neglected in population projection models. here i evaluate the effects of natural (rainfall fluctuation) and human disturbances (habitat loss and unregulated hunting) using a multi-matrix environmental state population model for the common hippopotamus (hippopotamus amphibius). by evaluating each disturbance type (natural and human) alone and then together, i explicitly consider the importance of incorporating realistic environmental variability into population projection models. the model population was most strongly affected by moderate habitat loss, which yielded the highest probability of crossing the risk thresholds over the 60 year time period, although these probabilities were relatively low (<= 0.31). however, the likelihood of crossing the risk thresholds were two to five times as high when human-mediated and natural disturbances were considered together. when these probabilities were calculated per year of the simulation, the results suggested that even relatively mild human disturbances, when considered in conjunction with realistic natural disturbance, resulted in a high probability (> 0.50) of substantial declines within decades. the model highlights the importance of integrating realistic natural disturbances into population models, and suggests that, despite locally abundant populations, protected hippopotamus populations may decline over the next 60 years in response to a combination of environmental fluctuations and human-mediated threats.",6,2007,45,3,407,415,10.1111/j.1365-2028.2006.00747.x,1,0,0,1"Butler, LG; Kielland, K; Rupp, TS; Hanley, TA","interactive controls of herbivory and fluvial dynamics on landscape vegetation patterns on the tanana river floodplain, interior alaska",JOURNAL OF BIOGEOGRAPHY,Article,Alaska; boreal forest; fluvial dynamics; herbivory; landscape dynamics; spatially explicit models; succession,"aim we examined the interactive effects of mammalian herbivory and fluvial dynamics on vegetation dynamics and composition along the tanana river in interior alaska. location model parameters were obtained from field studies along the tanana river, alaska between fairbanks (64 degrees 50.50' n, 147 degrees 43.30' w) and manley hot springs (65 degrees 0.0' n, 150 degrees 36.0' w). methods we used a spatially explicit model of landscape dynamics (alfresco) to simulate vegetation changes on a 1-year time-step. the model was run for 250 years and was replicated 100 times. results increases in herbivory decreased the proportion of early successional vegetation and increased the proportion of late successional vegetation on the simulated landscape. erosion and accretion worked as antagonists to herbivory, increasing the amount of early successional vegetation and decreasing the amount of late successional vegetation. however, the interactive effects of herbivory and erosion/accretion were especially important in determining system response, particularly in early seral vegetation types. high erosion rates, when coupled with low herbivory, greatly increased the proportion of willow on the landscape. when coupled with high herbivory, however, they greatly increased the proportion of alder on the landscape. at low levels of herbivory, alder abundance peaked at intermediate levels of erosion/accretion. main conclusions neither erosion/accretion nor herbivory produced consistent landscape patterns that could be predicted independently of the other. these findings underscore the importance of the interactive effects of biotic and abiotic disturbances in shaping large-scale landscape vegetation patterns in boreal floodplain ecosystems - systems traditionally thought to be driven primarily by abiotic disturbance alone.",10,2007,34,9,1622,1631,10.1111/j.1365-2699.2007.01713.x,0,1,0,1"Didham, RK; Tylianakis, JM; Gemmell, NJ; Rand, TA; Ewers, RM",interactive effects of habitat modification and species invasion on native species decline,TRENDS IN ECOLOGY & EVOLUTION,Review,,"different components of global environmental change are often studied and managed independently, but mounting evidence points towards complex non-additive interaction effects between drivers of native species decline. using the example of interactions between land-use change and biotic exchange, we develop an interpretive framework that will enable global change researchers to identify and discriminate between major interaction pathways. we formalise a distinction between numerically mediated versus functionally moderated causal pathways. despite superficial similarity of their effects, numerical and functional pathways stem from fundamentally different mechanisms of action and have fundamentally different consequences for conservation management. our framework is a first step toward building a better quantitative understanding of how interactions between drivers might mitigate or exacerbate the net effects of global environmental change on biotic communities in the future.",243,2007,22,9,489,496,10.1016/j.tree.2007.07.001,0,0,1,1"Liu, W; Au, DWT; Anderson, DM; Lam, PKS; Wu, RSS","effects of nutrients, salinity, ph and light : dark cycle on the production of reactive oxygen species in the alga chattonella marina",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,Chattonella marina; iron; nutrient; PH; physical parameters; plasma membrane; reactive oxygen species; redox,"experiments were carried out to investigate the effects of nutrients, salinity, ph and light:dark cycle on growth rate and production of reactive oxygen species (ros) by chattonella marina, a harmful algal bloom (hab) species that often causes fish kills. different nitrogen forms (organic-n and inorganic-n), n:p ratios, light:dark cycles and salinity significantly influenced algal growth, but not ros production. however, iron concentration and ph significantly affected both growth and ros production in c marina. kcn (an inhibitor of mitochondrial respiration) and 3-(3,4-dichlorophenyt)-1,1-dimethylurea (an inhibitor of photosynthesis) had no significant effects on ros production. vitamin k-3 (a plasma membrane electron shuttle) enhanced ros production while its antagonist, dicumarol, decreased ros production. taken together, our results suggest that ros production by c marina is related to a plasma membrane enzyme system regulated by iron availability but is independent of growth, photosynthesis, availability of macronutrients, salinity and irradiance. (c) 2007 elsevier b.v. all rights reserved.",32,2007,346,02-Jan,76,86,10.1016/j.jembe.2007.03.007,0,1,0,1"Norry, FM; Gomez, FH; Loeschcke, V",knockdown resistance to heat stress and slow recovery from chill coma are genetically associated in a quantitative trait locus region of chromosome 2 in drosophila melanogaster,MOLECULAR ECOLOGY,Article,cold-stress resistance; Drosophila; heat-stress resistance; Hsp70 expression; QTL; thermal adaptation,"in insects, two ecologically relevant traits of thermal adaptation are knockdown resistance to high temperature (krht) and chill-coma recovery (ccr). chromosome 2 of drosophila melanogaster was tested for quantitative trait loci (qtl) affecting both ccr and krht in backcrosses between homosequential lines that are fixed for the standard (noninverted) sequence of this autosome. these lines were obtained by artificial selection on krht and subsequent inbreeding from a stock that was derived from a single wild population. heat-induced expression of the 70kd heat-shock protein (hsp70) was also examined for variation between the lines. composite interval mapping was performed for each trait on each reciprocal backcross, identifying one qtl region in the middle of chromosome 2 for both krht and ccr. the largest estimates of additive effects were found in pericentromeric regions of chromosome 2, accounting for 10-14% (ccr) and 10-17% (krht) of the phenotypic variance in bc populations. no qtl was found in the region of the heat-shock factor (hsf) gene. however, the two parental lines have diverged in the heat-induced hsp70 expression. distribution of krht qtl on chromosome 2 was similar between this study based on crosses between lines selected from a single wild population and previous work based on crosses between selection lines from different continents. colocalized qtl showed a trade-off association between ccr and krht, which should be the result of either multiple, tightly linked trait-specific genes or a single gene with pleiotropic effects on the traits. we discuss candidate loci contained within the qtl regions.",34,2007,16,15,3274,3284,10.1111/j.1365-294X.2007.03335.x,0,0,1,1"Dormann, CF","competition hierarchy, transitivity and additivity: investigating the effect of fertilisation on plant-plant interactions using three common bryophytes",PLANT ECOLOGY,Article,bryophytes; community matrix; competition; facilitation; Lotka-Volterra; stability; transitivity,"the way competition structures plant communities has been investigated intensely over many decades. dominance structures due to competitive hierarchies, with consequences for species richness, have not received as much experimental attention, since their manipulation is a large logistic undertaking. here the data from a model system based on bryophytes are presented to investigate competition structure in a three-species system. grown in monocultures, pairwise and three-species mixtures under no and high nitrogen supply, the three moss species responded strongly to treatment conditions. one of them suffered from nitrogen fertilisation and hence performed better in mixtures, where the dominant species provided physical shelter from apparently toxic nitrogen spray. accordingly, no linear competitive hierarchy emerged and qualitative transitivity remains restricted to the unfertilised treatments. faciliation also affected other properties of the competition structure. the reciprocity of competition effects could not be observed. moreover, the performances in three-species mixtures were not well predictable from the knowledge of monocultures and pairwise mixtures because competitive effects were not additive. this had implications for community stability at equilibrium: all two-species systems were stable, both fertilised and unfertilised, while the three-species system was only stable when fertilised. this stability under fertilisation has probably to do with the facilitative effect of the two dominant species on the third. in this experiment, little support for commonly held ideas was found about the way competition in plant communities is structured. on the other hand, this study shows that moss communities are ideal model systems to test predictions of theoretical models concerning properties and consequences of competition in plant communities.",4,2007,191,2,171,184,10.1007/s11258-006-9235-z,0,0,1,1"Deegan, LA; Bowen, JL; Drake, D; Fleeger, JW; Friedrichs, CT; Galvan, KA; Hobble, JE; Hopkinson, C; Johnson, DS; Johnson, JM; Lemay, LE; Miller, E; Peterson, BJ; Picard, C; Sheldon, S; Sutherland, M; Vallino, J; Warren, RS",susceptibility of salt marshes to nutrient enrichment and predator removal,ECOLOGICAL APPLICATIONS,Article; Proceedings Paper,bottom-up; eutrophication; Fundulus heteroclitus; multiple stressors; nutrient loading; salt marsh; Spartina alterniflora; Spartina patens; species change; top-down,"salt marsh ecosystems have been considered not susceptible to nitrogen overloading because early studies suggested that salt marshes adsorbed excess nutrients in plant growth. however, the possible effect of nutrient loading on species composition, and the combined effects of nutrients and altered species composition on structure and function, was largely ignored. failure to understand interactions between nutrient loading and species composition may lead to severe underestimates of the impacts of stresses. we altered whole salt marsh ecosystems (similar to 60 000 m(2)/treatment) by addition of nutrients in flooding waters and by reduction of a key predatory fish, the mummichog. we added nutrients (n and p; 15-fold increase over ambient conditions) directly to the flooding tide to mimic the way anthropogenic nutrients are delivered to marsh ecosystems. despite the high concentrations (70 mmol n/l) achieved in the water column, our annual n loadings (15-60 g n.m(-2).yr(-1)) were an order of magnitude less than most plot-level fertilization experiments, yet we detected responses at several trophic levels. preliminary calculations suggest that 30-40% of the added n was removed by the marsh during each tidal cycle. creek bank spartina alterniflora and high marsh s. patens production increased, but not stunted high marsh s. alterniflora. microbial production increased in the fertilized creek bank s. alterniflora habitat where benthic microalgae also increased. we found top-down control of benthic microalgae by killifish, but only under nutrient addition and in the opposite direction (increase) than that predicted by a fish-invertebrate-microalgae trophic cascade. surprisingly, infauna declined in abundance during the first season of fertilization and with fish removal. our results demonstrate ecological effects of both nutrient addition and mummichog reduction at the whole-system level, including evidence for synergistic interactions.",40,2007,17,5,S42,S63,10.1890/06-0452.1,1,0,0,1"Tercero-Bucardo, N; Kitzberger, T; Veblen, TT; Raffaele, E",a field experiment on climatic and herbivore impacts on post-fire tree regeneration in north-western patagonia,JOURNAL OF ECOLOGY,Article,Austrocedrus; climate change; disturbances; fire; livestock; Nothofagus; Patagonia; seedling survival; tree regeneration,"1. wildfires are predicted to increase in many ecosystems in relation to globally increasing temperatures but future patterns of post-fire vegetation change are largely unknown, particularly when there are synergistic effects from introduced biota. in the late 1990s northern patagonia, argentina, experienced extreme droughts which led to severe wildfires affecting a range of andean ecosystems. 2. we experimentally examined how variations in moisture, temperature and herbivory by livestock affect post-1999 fire patterns of the three main tree species. over two years we monitored, in three forest types, the survival and growth of tree seedlings in a factorial warming (+2 degrees c)/livestock exclosure/watering experiment. 3. seedling survival in the warmed treatments and in the controls was nil for the evergreen nothofagus dombeyi and the conifer austrocedrus chilensis at the two low-elevation experimental sites. survival of the subalpine nothofagus pumilio in the warmed treatments at high elevation tended to be lower than in the control; for all treatments of warming alone there were no significant differences compared with the controls. 4. in all three forest types, increased water availability was essential for higher rates of tree seedling survival. doubling water availability during the growing season resulted in up to fourfold increases in seedling survival and up to threefold increases in seedling biomass. 5. in the subalpine forest, livestock reduced seedling survival by c. 30% in non-watered treatments compared with watered treatments, probably due mainly to soil desiccation and to consumption of or damage to facilitating plants. in contrast, at lower elevation, where livestock pressure was lower, seedling survival of n. dombeyi and a. chilensis tended to be higher in unfenced sites, possibly due to reduced competition from highly palatable shrub species. 6. general circulation models predict a warming-drying trend in northern patagonia during the twenty-first century. the resulting increase in wildfire is likely to be followed by inadequate tree regeneration and conversion from forest to shrubland cover types. this and similar studies suggest that under relatively slight changes in regional climate, increased fire occurrence interacting synergistically with moisture limitations will result in long-lasting displacements of forest by more xeric vegetation shrublands.",17,2007,95,4,771,779,10.1111/j.1365-2745.2007.01249.x,1,0,0,1"Eriksson, BK; Rubach, A; Hillebrand, H",dominance by a canopy forming seaweed modifies resource and consumer control of bloom-forming macroalgae,OIKOS,Article,,"degradation of ecological resources by large-scale disturbances highlights the need to demonstrate biological properties that increase resistance to change and promote the resilience of ecosystem regimes. coastal eutrophication is a global-scale disturbance that drives ecosystem change by increasing primary production and favouring ephemeral and bloom-forming life-forms. recent synthesis indicates that consumption processes increase the resistance of coastal communities to nutrient loading by controlling the responses of ephemeral macroalgae. here we suggest a similar ecological function for canopy cover by demonstrating that the presence of a canopy species modifies both resource and consumer control of bloom-forming algae associated with nutrient enrichment. we tested effects of canopy presence on the interaction between consumer and resource control, by field-manipulations of a dominant canopy forming seaweed (fucus vesiculosus), grazer presence (dominated by the gastropod littorina littorea) and nutrient enrichment (common agricultural npk fertilizer). canopy cover and grazers jointly controlled strong increases of ephemeral bloom-forming algae (dominated by ulva spp) from nutrient enrichment; nutrients increased ephemeral recruitment almost 10-fold, but only in the absence of both grazers and canopy cover. recruitment success of the canopy-forming seaweed itself decreased additively with 56.1, 71.3 and 50.5% from independent effects of canopy cover, grazers and nutrient enrichment, respectively. a meta-analysis of nine nutrient enrichment experiments including seaweed, seagrass and stream communities, showed that in the presence of canopies average nutrient effects were reduced by more than 90% compared to without canopies. this corroborates the generality of our finding that dominating canopy species are important for aquatic ecosystems by increasing community resistance to the propagation of nutrient effects.",19,2007,116,7,1211,1219,10.1111/j.2007.0030-1299.15666.x,0,0,1,1"Sargian, P; Mas, S; Pelletier, E; Demers, S",multiple stressors on an antarctic microplankton assemblage: water soluble crude oil and enhanced uvbr level at ushuaia (argentina),POLAR BIOLOGY,Article,ultraviolet-B radiation; water soluble crude oil; marine bacteria and phytoplankton; synergistic effects; Cryptomonas sp,"changes in phytoplankton pigment content, in vivo fluorescence as well as in abundance and cell characteristics of phyto- and bacterioplankton were investigated on a field-collected microplankton assemblage from ushuaia bay (southern argentina). effects of different experimental treatments were examined: natural and enhanced ultraviolet-b radiation (uvbr: 280-320 nm) exposures, and water soluble fraction (wsf) of crude oil contamination under both uvbr exposures. after a 5-day exposure to experimental treatments in microcosms, significant uvbr-induced deleterious effects were observed with afternoon depression of the photochemical yield followed by night-time recovery. a significant increase in photoprotective pigments (ppcs) was also observed. due to their smaller size, picophytoplankton cells appeared to be more impacted than nanophytoplankton cells as revealed by their increasing mean cell size and decreasing growth rate implying a perturbation of the cell cycle. on the other hand, the differential response between the two bacterial sub-populations identified (i.e., as sub-populations 1 and 2 according to their cellular characteristics) suggests a higher vulnerability for only one of these sub-populations to uvbr stress. wsf alone was also shown to induce deleterious effects on phytoplankton assemblage. nevertheless, bacteria were positively affected, and particularly bacterial sub-population 2. the combination of wsf and enhanced uvbr exposure resulted in an exacerbation of these individual effects, demonstrating a synergistic effect of both stresses. moreover, cryptomonas sp. were observed to develop only under dual stresses in response to their capacity to switch between phototrophic and mixotrophic states following stressed conditions. in situ studies with natural communities provided a unique tool for determining the short-term biological response of microplankton assemblages exposed to multiple stressors.",13,2007,30,7,829,841,10.1007/s00300-006-0243-1,1,0,0,1"Krausman, PR",ruffed grouse population ecology in the appalachian region,WILDLIFE MONOGRAPHS,Review,,"the appalachian cooperative grouse research project (acgrp) was a multistate cooperative effort initiated in 1996 to investigate the apparent decline of ruffed grouse (bonasa umbellus) and improve management throughout the central and southern appalachian region (i.e., parts of ohio, pennsylvania, rhode island, kentucky, west virginia, virginia, and north carolina, usa). researchers have offered several hypotheses to explain the low abundance of ruffed grouse in the region, including low availability of early-successional forests due to changes in land use, additive harvest mortality, low productivity and recruitment, and nutritional stress. as part of the acgrp, we investigated ruffed grouse population ecology. our objectives were to estimate reproductive rates, estimate survival and cause-specific mortality rates, examine if ruffed grouse harvest in the appalachian region is compensatory, and estimate ruffed grouse finite population growth. we trapped > 3,000 ruffed grouse in autumn (sep-nov) and spring (feb-mar) from 1996 to september 2002 on 12 study areas. we determined the age and gender of each bird and fitted them with necklace-style radiotransmitters and released them at the trap site. we tracked ruffed grouse >= 2 times per week using handheld radiotelemetry equipment and gathered data on reproduction, recruitment, survival, and mortality. ruffed grouse population dynamics in the appalachian region differed from the central portion of the species' range (i.e., northern united states and canada). ruffed grouse in the appalachian region had lower productivity and recruitment, but higher survival than reported for populations in the great lakes region and southern canada. population dynamics differed between oak (quercus spp.)-hickory (carya spp.) and mixed-mesophytic forest associations within the southern and central appalachian region. productivity and recruitment were lower in oak-hickory forests, but adult survival was higher than in mixed-mesophytic forests. furthermore, ruffed grouse productivity and recruitment were more strongly related to hard mast (i.e., acorn) production in oak-hickory forests than in mixed-mesophytic forests. the leading cause of ruffed grouse mortality was avian predation (44% of known mortalities). harvest mortality accounted for 12% ofall known mortalities and appeared to be compensatory. population models indicated ruffed grouse populations in the appalachian region are declining (lambda = 0.7-0.95), but differences in model estimates highlighted the need for improved understanding of annual productivity and recruitment. we posit ruffed grouse in the appalachian region exhibit a clinal population structure characterized by changes in life-history strategies. changes in life history strategies are in response to gradual changes in forest structure, quality of food resources, snowfall and accumulation patterns, and predator communities. management efforts should focus on creating a mosaic of forest stand ages across the landscape to intersperse habitat resources including nesting and brood cover, adult escape cover, roosting sites, and, most importantly, food resources. land managers can intersperse habitat resources through a combination of clearcutting, shelterwood harvests, group selection, and timber stand improvement (including various thinnings and prescribed fire). managers should maintain current ruffed grouse harvest rates while providing high quality hunting opportunities. we define high quality hunting as low hunting pressure, low vehicle traffic, and high flush rates. managers ca provide high quality hunting opportunities through use of road closures in conjunction with habitat management.",10,2007,NA,168,1,36,10.2193/0084-0173.168,0,0,1,1"Elith, J; Leathwick, J",predicting species distributions from museum and herbarium records using multiresponse models fitted with multivariate adaptive regression splines,DIVERSITY AND DISTRIBUTIONS,Article; Proceedings Paper,MARS; presence-only; multiresponse; habitat model; pseudo-absence; community,"current circumstances - that the majority of species distribution records exist as presence-only data (e.g. from museums and herbaria), and that there is an established need for predictions of species distributions - mean that scientists and conservation managers seek to develop robust methods for using these data. such methods must, in particular, accommodate the difficulties caused by lack of reliable information about sites where species are absent. here we test two approaches for overcoming these difficulties, analysing a range of data sets using the technique of multivariate adaptive regression splines (mars). mars is closely related to regression techniques such as generalized additive models (gams) that are commonly and successfully used in modelling species distributions, but has particular advantages in its analytical speed and the ease of transfer of analysis results to other computational environments such as a geographic information system. mars also has the advantage that it can model multiple responses, meaning that it can combine information from a set of species to determine the dominant environmental drivers of variation in species composition. we use data from 226 species from six regions of the world, and demonstrate the use of mars for distribution modelling using presence-only data. we test whether (1) the type of data used to represent absence or background and (2) the signal from multiple species affect predictive performance, by evaluating predictions at completely independent sites where genuine presence-absence data were recorded. models developed with absences inferred from the total set of presence-only sites for a biological group, and using simultaneous analysis of multiple species to inform the choice of predictor variables, performed better than models in which species were analysed singly, or in which pseudo-absences were drawn randomly from the study area. the methods are fast, relatively simple to understand, and useful for situations where data are limited. a tutorial is included.",107,2007,13,3,265,275,10.1111/j.1472-4642.2007.00340.x,0,0,1,1"Aiba, S; Hanya, G; Tsujino, R; Takyu, M; Seino, T; Kimura, K; Kitayama, K",comparative study of additive basal area of conifers in forest ecosystems along elevational gradients,ECOLOGICAL RESEARCH,Article; Proceedings Paper,ecosystem function; litterfall; Mount Kinabalu; tree life form; Yakushima Island,"we examined the basal area of two life forms (conifers vs. broadleaf trees) along elevational gradients on yakushima island, japan and on two series of geological substrate on mount kinabalu, borneo. on yakushima, total stand basal area abruptly increased from 700 to 1,050 m in accordance with the high dominance of conifers, indicating the presence of additive basal area of conifers in conifer-broadleaf mixed forests at higher elevations (1,050-1,300 m). along two substrate series on kinabalu, some forests at higher elevations (1,860-3,080 m) showed relatively high dominance of conifers, but conifer basal area did not appear to be additive. conifers were emergents above the canopy of broadleaf trees in mixed forests on yakushima, but two life forms usually coexisted in the single-story canopy in mixed forests on kinabalu. litterfall rate as a surrogate of productivity decreased with decreasing temperature along elevation on both the sites, but the rate of decrease was slower on yakushima, where mixed forests at higher elevations showed relatively high rates. thus, we suggest that additive basal area of conifers was linked to their emergent status, and that it enhanced productivity by complementary use of light by two life forms that occupy different stories. on yakushima, typhoons are a major disturbance, but do not severely limit the height growth of conifers, allowing the development of two-story mixed forests. on kinabalu, a major disturbance is el nino-driven drought, and hydraulic limitation to tree height may explain the non-additive and non-emergent nature of conifers.",18,2007,22,3,439,450,10.1007/s11284-007-0338-3,0,0,1,1"McKinney, ML; La Sorte, FA",invasiveness and homogenization: synergism of wide dispersal and high local abundance,GLOBAL ECOLOGY AND BIOGEOGRAPHY,Article,biotic homogenization; exotic species; invasive species; native species; plants; USA,"aim to determine whether invasive and locally abundant non-native species have a more homogenizing effect on plant communities than non-invasive and less abundant non-native species. location california and florida counties, conservation areas in the usa, and eight us cities. methods species lists among counties, conservation areas and cities were compared to see whether invasive and abundant non-native species increased the jaccard index of similarity between localities beyond any increases caused by non-invasive and less abundant non-native species. results for all comparisons, we found that invasive non-native species have a significantly greater homogenizing effect than non-invasive non-native species. for the us conservation areas, we found that locally abundant invasive species tend to be more widespread and more widely shared than less abundant invasive species. there is also a positive relationship between homogenization by invasive species and the magnitude of human disturbance. main conclusions invasive non-native species tend to be disproportionately shared among communities relative to non-invasive non-native species. this effect is enhanced by human disturbance, as measured by the ratio of non-native to native species. there is a synergism between abundance and geographical range which enhances the homogenizing effects of abundant species. invasive species, with wide ecological niches, are more widely shared among communities and more locally abundant. abundant invasive species are thus more spatially homogenizing, and more ecologically dominant (functionally homogenizing). also, 'perceived homogenization' is probably greater than homogenization measured by the increase in shared species. the abundant species typically seen by the casual observer in a biological community are probably more commonly shared between communities than less common species. studies that lack abundance data and measure homogenization only on the basis of shared species, which includes most homogenization studies to date, probably underestimate the homogenizing impacts of non-native species as perceived by people.",24,2007,16,3,394,400,10.1111/j.1466-8238.2007.000296.x,1,0,0,1"Keller, JM; Allen, DE; Davis, CR; Leamy, LJ","2,3,7,8-tetrachlorodibenzo-p-dioxin affects fluctuating asymmetry of molar shape in mice, and an epistatic interaction of two genes for molar size",HEREDITY,Article,TCDD; fluctuating asymmetry; molars; QTL,"fluctuating asymmetry ( fa), random variation between left and right sides in a bilaterally symmetrical character, is a commonly used measure of developmental instability that is expected to increase with increasing environmental stress. one potential stressor is 2,3,7,8-tetrachlorodibenzo-p-dioxin ( tcdd), a powerful toxicant known to disturb tooth development. in this study, mice in the f-2 generation produced from an intercross between two inbred strains ( c57bl/ 6j and akr/ j) were exposed in utero to tcdd. we hypothesized that tcdd would increase fa in the molars of exposed mice over that of the control mice. in addition, we hypothesized that we would discover genes for molar size, shape or asymmetry whose expression would be affected by tcdd. we detected a very small, but significant, increase in fa of molar shape ( but not size) in the tcdd-exposed mice compared to the control mice, although molar size and shape did not differ between these groups. although we did not uncover any genes that acted differently in the tcdd exposed and control groups, we did identify two genes whose dominance by additive epistatic effect on molar size was affected by tcdd. we concluded that although tcdd may be affecting the expression of some genes governing the development of molars in our population of mice, fa of molar size and shape is not a particularly sensitive indicator of this effect.",7,2007,98,5,259,267,10.1038/sj.hdy.6800928,0,0,1,1"Pueyo, Y; Alados, CL",abiotic factors determining vegetation patterns in a semi-arid mediterranean landscape: different responses on gypsum and non-gypsum substrates,JOURNAL OF ARID ENVIRONMENTS,Article,aridity; ebro valley; environmental factors; gypsophily; gypsophytes; topography,"in arid and semi-arid regions water availability is the main factor determining vegetation patterns. on gypsum outcrops, vegetation is also conditioned by soil physical (i.e. surface crust) and chemical (i.e. ion unbalance) restrictions, which promote a highly specialist and endemic gypsophile flora. topographical and climatic variability affect the rigors of gypsum soil environment, and thus, plant community distribution along environmental gradients can differ between gypsum and non-gypsum substrates. the aim of the paper was to evaluate the relative importance of different abiotic factors as drivers of plant communities in gypsum and non-gypsum substrates. while non-gypsophile vegetation is expected to be determined mainly by aridity, gypsophile vegetation could show more. complex patterns, following the relaxation of the rigors of gypsum soil under environmental gradients such as steep slopes and mesic conditions. we compared the relationships between presence and cover of three plant communities (open woodland, dwarf-shrubland and garrigue) on gypsum and non-gypsum substrates with environmental factors, after removing the effect of human use. generalized additive models (gam) and generalized linear models (glm) were employed. results showed that xeric conditions inhibited development and recovery of vegetation, but plant communities on gypsum substrate did not always respond in the same way as non-gypsum vegetation. while the degree of aridity (determined by precipitation and temperature) conditioned non-gypsum vegetation strongly, favouring less developed plant communities, topographical factors (slope aspect and angle) were the main determinants of gypsum plant community patterns. we conclude that gypsum substrate determines strongly the plant community patterns in a semi-arid mediterranean landscape, as it can be observed by the strong response of gypsophile vegetation to the relaxation of the rigors of gypsum soils with topography (i.e. steep and north oriented slopes). (c) 2006 elsevier ltd. all rights reserved.",24,2007,69,3,490,505,10.1016/j.jaridenv.2006.10.008,0,0,1,1"Ricciardi, A",are modern biological invasions an unprecedented form of global change?,CONSERVATION BIOLOGY,Article,biotic interchange; dispersal; exotic species; global change; homogenization; nonindigenous,"the uniqueness of the current, global mass invasion by nonindigenous species has been challenged recently by researchers who argue that modem rates and consequences of nonindigenous species establishment are comparable to episodes in the geological past. although there is a fossil record of species invasions occurring in waves after geographic barriers had been lifted, such episodic events differ markedly from human-assisted invasions in spatial and temporal scales and in the number and diversity of organisms involved in long-distance dispersal. today, every region of the planet is simultaneously affected and modern rates of invasion are several orders of magnitude higher than prehistoric rates. in terms of its rate and geographical extent, its potential for synergistic disruption and the scope of its evolutionary consequences, the current mass invasion event is without precedent and should be regarded as a unique form of global change. prehistoric examples of biotic interchanges are nonetheless instructive and can increase our understanding of species-area effects, evolutionary effects, biotic resistance to invasion, and the impacts of novel functional groups introduced to naive biotas. nevertheless, they provide only limited insight into the synergistic effects of invasions and other environmental stressors, the effect of frequent introductions of large numbers of propagules, and global homogenization, all of which characterize the current mass invasion event.",152,2007,21,2,329,336,10.1111/j.1523-1739.2006.00615.x,1,0,0,1"Doroszuk, A; Brake, ET; Crespogonzalez, D; Kammenga, JE",response of secondary production and its components to multiple stressors in nematode field populations,JOURNAL OF APPLIED ECOLOGY,Article,Acrobeloides nanus; biomass turnover; copper; environmental stressors; life history; mean relative growth rate; pH,"realistic measures of the impact of individual or multiple stressors are important for ecological risk assessment. although multiple anthropogenic stressors are common in human-dominated environments, knowledge of their influence on functional population parameters such as secondary production (p) and biomass turnover (p/b) is very limited. secondary production integrates population characteristics such as biomass, size-frequency distribution and body growth rate, and provides a link between population and system ecologies. the influence of copper and ph stress on yearly secondary production and biomass turnover of field populations of the nematode acrobeloides nanus was investigated by using a randomized factorial block design. the responses of the components of secondary production were also analysed in order to elucidate the mechanisms underlying the change in secondary production. secondary production and biomass turnover showed reduced values in soil of low ph. a negative effect of copper on both parameters was observed only when the copper load was combined with low ph, otherwise higher copper concentrations resulted in higher secondary production and biomass turnover. the observed response of production and biomass turnover was mainly driven by changes in mean relative growth rate (mrgr), a measure of body growth rate estimated in a laboratory soil experiment. the biomass was higher on average in the plots with high copper load, while no significant response to ph was found. synthesis and applications. our results demonstrate that populations of soil organisms may experience strong synergistic effects of combined stressors (acidification and copper stress) on functional population parameters while showing no detrimental effects on biomass. moreover, the effects on secondary production and biomass turnover rate are predominantly driven by effects on body growth rate. we recommend that ecological risk assessment methodologies should include consideration of soil contamination on the basis of conservation of functional properties of ecosystems and their key components.",10,2007,44,2,446,455,10.1111/j.1365-2664.2007.01257.x,1,0,0,1"Martorell, C",detecting and managing an overgrazing-drought synergism in the threatened echeveria longissima (crassulaceae): the role of retrospective demographic analysis,POPULATION ECOLOGY,Article,anthropogenic disturbance; erosion; type II error; LTRE; matrix population models; Mexico,"echeveria longissima, a threatened herb whose habitat has been severely overgrazed and eroded, was studied for three years in a currently grazed and a fenced area. matrix population models were used to assess if livestock elimination provides a proper management strategy. the merits of retrospective perturbation analyses in terms of management planning have been debated. nevertheless, they may prove useful when applied in combination with exclosures because they may detect the effects of anthropogenic disturbance on population dynamics. thus, the results of retrospective and prospective methods were compared. a rapid decrease in population size was projected in both areas, even though it was faster in the exposed one. the demographic processes that were favourable or detrimental in a given year were magnified outside of the fence, but buffered in the exclosure, showing a strong drought-disturbance synergism. thus, the largest difference in the population growth rate lambda between areas was observed in the driest year. higher nurse-plant density inside the fence seems to alleviate drought effects. the use of prospective analysis alone may lead to erroneous management decisions, since the highest elasticities corresponded to transitions that were favoured by human activities. while allowing for an increased lambda in the short term, intervention aimed at increasing these transitions further without attending others that are lessened by disturbance may introduce large changes in the population dynamics, with negative long-term consequences. retrospective methods can detect which processes have been altered by disturbance and its synergisms, so we may more efficiently restore healthy population dynamics.",11,2007,49,2,115,125,10.1007/s10144-006-0027-z,1,0,0,1"Davidson, C; Knapp, RA",multiple stressors and amphibian declines: dual impacts of pesticides and fish on yellow-legged frogs,ECOLOGICAL APPLICATIONS,Article,amphibian declines; generalized additive models; introduced fish; mountain yellow-legged frog; multiple stressors; pesticide drift; Rana muscosa; Sierra Nevada,"more than 40% of earth's 5700+ amphibian species have undergone recent declines. despite the likely involvement of multiple factors in driving these declines, most studies continue to focus on single stressors. in california ( usa), separate studies have implicated either introduced. sh or pesticides as causal agents. to date, however, no study has simultaneously evaluated the respective roles of these two potential stressors nor attempted to assess their relative importance, information critical for the development of effective conservation efforts and environmental policies. we examined the role and relative effect of. sh and pesticides on the mountain yellow-legged frog ( rana muscosa) using unusually detailed data sets for a large portion of r. muscosa's historic range in california's sierra nevada. habitat characteristics and presence/ absence of r. muscosa and. sh were quantified at each of 6831 sites during field surveys. pesticide use upwind of each site was calculated from pesticide application records and predominant wind directions. using generalized additive models, we found that, after accounting for habitat effects, the probability of r. muscosa presence was significantly reduced by both. sh and pesticides, with the landscape-scale effect of pesticides much stronger than that of. sh. the degree to which a site was sheltered from the predominant wind ( and associated pesticides) was also a significant predictor of r. muscosa presence. taken together, these results represent the strongest evidence to date that windborne pesticides are contributing to amphibian declines in pristine locations. our results suggest that amphibian declines may have complex multi-factorial causes, and caution that single-factor studies that demonstrate the importance of one factor should not be used as evidence against the importance of other factors.",51,2007,17,2,587,597,10.1890/06-0181,0,0,1,1"Moller, AP",senescence in relation to latitude and migration in birds,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,actuarial senescence; anti-oxidants; bird banding; evolutionary theories of senescence; longevity,"senescence is the age-related deterioration of the phenotype, explained by accumulation of mutations, antagonistic pleiotropy, free radicals or other mechanisms. i investigated patterns of actuarial senescence in a sample of 169 species of birds in relation to latitude and migration, by analysing longevity records adjusted for sampling effort, survival rate and body mass. senescence might decrease at low latitudes because of elevated adult survival rates and generally slow life histories. alternatively, the rate of senescence might increase at low latitudes because of the greater impact of biological interactions such as parasitism, predation and competition on fitness through differential effects of age-specific mortality (e.g. because immunologically naive young individuals and immuno-senescent old individuals might die more frequently than individuals belonging to intermediate age classes). bird migration entails extensive exercise twice annually, with migrants spending more time in benign environments with little abiotic mortality than residents, migrants having higher adult survival rate and lower annual fecundity than residents, and migrants suffering more from the consequences of oxidative stress than residents. the rate of senescence increased with latitude, as expected because of slow life histories at low latitudes. independently, rate of senescence decreased with increasing migration distance. these findings were robust to control for potentially confounding effects of body mass, age of first reproduction and phenotypic similarity among species because of common descent.",35,2007,20,2,750,757,10.1111/j.1420-9101.2006.01236.x,0,1,0,1"Oneal, E; Connallon, T; Knowles, LL",conflict between direct and indirect benefits of female choice in desert drosophila,BIOLOGY LETTERS,Article,sexual selection; sexual antagonism; female mate choice; direct benefits; indirect benefits,"identifying the factors that contribute to the adaptive significance of mating preferences is one major goal of evolutionary research and is largely unresolved. both direct and indirect benefits can contribute to mate choice evolution. failure to consider the interaction between individual consequences of mate choice may obscure the opposing effects of individual costs and benefits. we investigate direct and indirect fitness effects of female choice in a desert fly (drosophila mojavensis), a species where mating confers resistance to desiccation stress. females prefer males that provide a direct benefit: greater resistance to desiccation stress. mating preferences also appear to have indirect consequences: daughters of preferred males have lower reproductive success than daughters of unpreferred males, although additional experimentation will be needed to determine if the indirect consequences of female preferences actually arise from 'sexually antagonistic' variation. nevertheless, the results are intriguing and are consistent with the hypothesis that an interaction between direct and indirect benefits maintains sexually antagonistic variation in these desert flies: increased desiccation resistance conferred by mating might offset the cost of producing low-fecundity daughters.",13,2007,3,1,29,32,10.1098/rsbl.2006.0565,0,1,0,1"Koch, MS; Schopmeyer, S; Kyhn-Hansen, C; Madden, CJ",synergistic effects of high temperature and sulfide on tropical seagrass,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,dissolved organic carbon; Florida Bay; glucose; Halodule wrightii; Thalassia testudinum,"to examine the synergism of high temperature and sulfide on two dominant tropical seagrass species, a large-scale mesocosm experiment was conducted in which sulfide accumulation rates (sar) were increased by adding labile carbon (glucose) to intact seagrass sediment cores across a range of temperatures. during the initial 10 d of the 38 d experiment, porewater sar in cores increased 2- to 3-fold from 44 and 136 mu mol l(-1) d(-1) at 28-29 degrees c to 80 and 308 mu mol l(-1) d(-1) at 34-35 degrees c in halodule wrightii and thalassia testudinum cores, respectively. labile c additions to the sediment resulted in sar of 443 and 601 mu mol l(-1) d(-1) at 28-29 degrees c and 758 to 1,557 mu mol l(-1) d(-1) at 34-35 degrees c in h. wrightii and t testudinton cores, respectively. both t testudinum and h. wrightii were highly thermal tolerant, demonstrating their tropical affinities and potential to adapt to high temperatures, while plants survived the 38 d temperature treatments, there was a clear thermal threshold above 33 degrees c where t testudinum growth declined and leaf quantum efficiencies (fv/fm) fell below 0.7. at this threshold temperature, h. wrightii maintained shoot densities and leaf quantum efficiencies. although h. wrigghtii showed a greater tolerance to high temperature, t testudinum had a greater capacity to sustain biomass and short shoots under thermal stress with labile c enrichment, regardless of the fact that sulfide levels in the t testudium cores were 2 times higher than in the h. wrightii cores. tropical seagrass tolerance to elevated temperatures, predicted in the future with global warming, should be considered in the context of the sediment-plant complex which incorporates the synergism of plant physiological responses and shifts in sulfur biogeochemistry leading to increased plant exposure to sulfides, a known toxin. (c) 2006 elsevier b.v. all rights reserved.",36,2007,341,1,91,101,10.1016/j.jembe.2006.10.004,1,0,0,1"Bruvo, R; Schulenburg, H; Storhas, M; Michiels, NK",synergism between mutational meltdown and red queen in parthenogenetic biotypes of the freshwater planarian schmidtea polychroa,OIKOS,Article,,"do parasites and accumulation of deleterious mutations act synergistically in balancing the costs of sex? we addressed this possibility in the freshwater planarian flatworm schmidtea polychroa. sexual and parthenogenetic forms of this species sometimes coexist but show no ecological separation. previous studies indicate that in a mixed sexual/ parthenogenetic population in lago di caldonazzo (n. italy) parthenogens get more frequently infected with parasites. at the same time, they suffer from higher embryo mortality, which has been interpreted as a sign of accumulation of deleterious mutations. in the present study, we test whether these two factors are correlated, by focusing on the differences among the clonal lineages of a predominantly parthenogenetic subpopulation. our results suggest that, for two out of three parasite types found, the infections are positively associated with the indirect measure of host mutation load.",10,2007,116,2,313,323,10.1111/j.2006.0030-1299.15388.x,1,0,0,1"Torregiani, JH; Lesser, MP",the effects of short-term exposures to ultraviolet radiation in the hawaiian coral montipora verrucosa,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,corals; DNA damage; MAAs; quantum yields; ultraviolet radiation,"exposure to ultraviolet radiation (uvr, 290-400 nm) is an important abiotic factor that tropical marine organisms have been exposed to over evolutionary time. additionally, uvr is known to cause coral bleaching independently and is an important synergistic factor in bleaching caused by thermal stress. corals can avoid some of the damage associated with exposure to uvr by producing ltvr-absorbing compounds such as mycosporine-like amino acids (maas). to examine the role of maas in the uvr photobiology of corals we conducted experiments on the hawaiian coral montipora verrucosa. m. verrucosa colonies were collected from 1, 5 and 10 m and exposed to three different uvr treatments for 3 days under constant visible irradiances equivalent to a depth of 0.15 m depth in kane'ohe bay. in addition to quantifying the maa concentration of these corals several types of uvr-induced damage were measured to assess whether maas were providing protection. quantum yields of photosystem ii (psii) fluorescence and excitation pressure on psii were measured for each coral, and the formation of direct uvr damage to dna was measured as cyclobutane pyrimidine dimers (cpds) and (6-4) pyrimidine-pyrimidone photoproducts for the holobiont. all corals exhibited midday depressions in quantum yields, developed dna photoproducts, and increased their maa concentrations significantly as a result of uvr exposures. cpd accumulation in m. verrucosa was highest in corals from i m, which had the lowest maa concentrations at the end of the experiment. corals originally from 10 m showed the highest maa concentration and lowest dna damage in response to exposure to uvr. while corals from all collection depths displayed some sensitivity to increased irradiances of uvr, their respective levels of tolerance were clearly dependant on their previous light history. (c) 2006 elsevier b.v. all rights reserved.",21,2007,340,2,194,203,10.1016/j.jembe.2006.09.004,1,0,0,1"Ashman, TL; Penet, L",direct and indirect effects of a sex-biased antagonist on male and female fertility: consequences for reproductive trait evolution in a gender-dimorphic plant,AMERICAN NATURALIST,Article,dioecy; florivory; natural selection; plant-animal interactions; pollination; sexual dimorphism,"gender-dimorphic plants are often subject to sex-differential enemy attack, but whether and how this contributes to trait evolution is unknown. to address this gap, we documented the spatiotemporal prevalence of sex-biased weevil damage in a gynodioecious strawberry. we then conducted path analysis to evaluate the direct and indirect pathways for weevils to affect female and male fertility and to mediate selection in two experimental gardens. direct effects of weevils significantly reduced fertility and mediated selection on reproductive traits, even in the nonpreferred sex (females). weevils significantly reduced floral display size in hermaphrodites in both gardens, and this translated into a substantial negative indirect effect on male fertility in the garden where the pathway to fertility via display was stronger. thus, indirect effects of weevils can contribute to selection in hermaphrodites, which gain the majority of their fitness via male function. our results also indicate that weevils often play a larger role than pollinators in shaping reproductive phenotype and thus raise the intriguing possibility that antagonists may be drivers of sexual dimorphism. finally, our results support the view that mutualists, antagonists, and the abiotic environment should be considered when attempting to understand reproductive trait evolution in gender-dimorphic species.",34,2007,169,5,595,608,10.1086/513150,0,1,0,1"Pueyo, Y; Alados, CL","effects of fragmentation, abiotic factors and land use on vegetation recovery in a semi-arid mediterranean area",BASIC AND APPLIED ECOLOGY,Article,aridity; dispersal ability; grazing; landscape; secondary succession; seed sources; topography,"recent vegetation dynamics in the northern and western mediterranean region are mainly the result of socio-economical changes. old-field succession and the cessation of extensive grazing have enhanced reforestation. however, vegetation recovery after disturbance can be impaired in and environments. here we analysed recent vegetation dynamics (1957-98) in a northern, semi-arid area of the mediterranean region: the middle ebro valley. centuries of timber harvesting, cropping and grazing in this region have produced a highly fragmented landscape. recently, socio-economic changes have led to intensified use of productive areas. traditional land use in marginal areas has been abandoned. in this study, we examined the main factors related to vegetation recovery in a fragmented, semi and landscape. we used aerial photographs from 1957 and 1998 to produce vegetation maps. a transition matrix showed that vegetation recovery was very scarce. generalized additive models (gam) and generalized linear models (glm) were used to study the relationships between vegetation dynamics, fragmentation, water availability, present land use and land use changes in the area. we found a strong negative relationship between distance from seed or propagule source and vegetation recovery. this indicates that fragmentation contributes to limiting recovery. in addition, we observed that aridity limited vegetation recovery. however, current land use and topography showed weaker relationships with vegetation recovery than those reported in other mediterranean and semi-arid landscapes. we conclude that fragmentation and aridity are the main determinants of vegetation recovery in the middle ebro valley, white current land use plays a secondary role. (c) 2006 gesellschaft fur okologie. published by elsevier gmbh. all rights reserved.",23,2007,8,2,158,170,10.1016/j.baae.2006.03.009,0,0,1,1"Ruesink, JL",biotic resistance and facilitation of a non-native oyster on rocky shores,MARINE ECOLOGY PROGRESS SERIES,Article,invasion; non-indigenous species; competition; predation; survival; intertidal; Pacific oyster; Crassostrea gigas,"the pacific oyster crassostrea gigas varies dramatically in density throughout its introduced range in the northeast pacific; this could be driven by environmental constraints or by species interactions that change across habitats. i studied the effects of native species on this invader across a range of environmental contexts where it is common (mid-intertidal zone, low wave exposure) vs. where it is rare (low intertidal zone, high wave exposure) in barkley sound, vancouver island, canada. i carried out factorial manipulations of 2 guilds of native species (neighbors, i.e. filter feeders such as mussels and barnacles, and predators such as crabs and whelks) and recorded survival and linear shell growth of transplanted, newly settled oysters (juveniles similar to 1 cm in size). c. gigas responded dramatically to tidal elevation: growth improved but survival declined at lower elevations, where feeding time and predation were greater. wave exposure reduced shell growth over 2 mo from 11.4 mm at protected sites to 7.2 mm at exposed sites, but variation in survival was not statistically significant. both guilds of native species exerted biotic resistance: predators reduced oyster survival and neighbors reduced growth. surprisingly, neighbors improved oyster survival at some wave-exposed sites, thereby facilitating one demographic variable related to invasion while restricting another. finally, predation had equivalent effects on survival at wave-exposed and protected sites, although different predators were probably involved. post-recruitment phenomena were unable to account for variation in oyster density across sites, and propagule pressure is a likely driver instead. abiotic and biotic factors jointly contributed to the risk of proliferation of a non-native species, and in this case their influence was often (on growth) but not always (on survival) additive.",29,2007,331,,1,9,10.3354/meps331001,0,0,1,1"Salbu, B; Skipperud, L",challenges in radioecotoxicology,MULTIPLE STRESSORS: A CHALLENGE FOR THE FUTURE,Proceedings Paper,ecotoxicology; multiple stressors; radiation,"radioecotoxicology refers to responses, usually negative and detrimental responses, in living organisms exposed to radionuclides in ecosystems contaminated with artificially produced radionuclides or enriched with naturally occurring radionuclides. the key focus is put on the link between radionuclide exposures and the subsequent biological effects in flora and fauna. radioecotoxicology is therefore an essential ingredient in impact and risk assessments associated with radioactive contaminated ecosystems. the radionuclide exposure depends on the source, release scenarios, transport, deposition and ecosystem characteristics as well as processes influencing the radionuclide speciation over time, in particular bioavailability, biological uptake, accumulation and internal distributions. radionuclides released from a source may be present in different physico-chemical forms (e.g. low molecular mass species, colloids, pseudocolloids, particles) influencing biological uptake, accumulation, doses and biological effects in flora and fauna. following releases from severe nuclear events, a major fraction of refractory radionuclides such as plutonium will be present as particles, representing point sources if inhaled or ingested. when organisms, and especially sensitive history life-stages, are exposed to radionuclides, free radicals are induced and subsequently, effects in several umbrella biological endpoints (e.g. reproduction and immune system failures, genetic instability and mutation, increased morbidity and mortality) may occur. however, radionuclides released into the environment rarely occur alone, but may co-occur in a mixture of other contaminants (e.g. metals, pesticides, organics, endocrine disruptors), which potentially could lead to synergisms or antagonisms. thus, the relationships between radionuclide exposure and especially long-term effects are difficult to document and quantify, reflecting that the challenges within radioecotoxicology are multiple.",5,2007,NA,,3,12,10.1007/978-1-4020-6335-0_1,1,1,0,2"Mitchel, REJ; Audette-Stuart, M; Yankovich, T","effects of ionizing radiation combined with other stressors, on non-human biota",Multiple Stressors: A Challenge for the Future,Proceedings Paper,combined stressors; radiation; heat; chlorine; non-human biota,"exposure of organisms in the environment to ionizing radiation is generally considered to be harmful, regardless of the dose. this assumption derives directly from the basic assumption used for human radiation protection, that harm is directly proportional to dose, without a threshold. the consequence of combined exposures is generally unknown, but is assumed to be either additive or multiplicative. we have examined the in vivo and in vitro responses of a variety of cells and organisms. we show that exposure to one stressor can influence the outcome of a subsequent exposure to the same or another stressor. in many cases, pre-exposure to one stressor appeared to induce an adaptive response that mitigated the harm from a second stressor. these observations challenge the basic assumptions used in environmental protection strategies, suggesting that new approaches are needed.",3,2007,NA,,31,38,10.1007/978-1-4020-6335-0_3,0,0,1,1"Geras'kin, SA; Oudalova, AA; Dikarev, VG; Dikareva, NS; Evseeva, TI",effects of multipollutant exposures on plant populations,Multiple Stressors: A Challenge for the Future,Proceedings Paper,radioactive and chemical contamination; multipollutant exposure; bioindication; plant populations; environment quality assessment,"results of laboratory, ""green-house"" and long-term field experiments carried out on different plant species to study ecotoxical effects of low doses and concentrations of most common environmental pollutants are presented. special attention is paid to ecotoxic effects of chronic low dose exposures, synergistic and antagonistic effects of multipollutant exposure. plant populations growing in areas with relatively low levels of pollution are characterized by the increased level of both cytogenetic disturbances and genetic diversity. the chronic low dose exposure appears to be an ecological factor creating preconditions for possible changes in the genetic structure of a population. a long-term existence of some factors (either of natural origin or man-made) in the plants environment activates genetic mechanisms, changing a population's resistance to exposure. however, in different radioecological situations, genetic adaptation of plant populations to extreme edaphic conditions could be achieved at different rates. the findings presented indicate clearly that an adequate environment quality assessment cannot rely only on information about pollutant concentrations. this conclusion emphasizes the need to update some current principles of ecological standardization, which are still in use today.",0,2007,NA,,73,89,10.1007/978-1-4020-6335-0_6,1,1,0,2"Mothersill, C; Seymour, C",radiation risks in the context of multiple stressors in the environment-issues for consideration,Multiple Stressors: A Challenge for the Future,Proceedings Paper,multiple stressors; radiation; low dose exposure; biomarkers,"the field of multiple stressors is highly complex. agents can interact in an additive, antagonist or synergistic manner. the outcome following low dose multiple stressor exposure also is impacted by the context in which the stressors are received or perceived by the organism or tissue. modem biology has given us very sensitive tools to access change following stressor interaction with biological systems at several levels of organization but the effect-harm-risk relationship remains difficult to resolve. this paper reviews some of the issues, using low dose ionizing radiation as a common stressor and chemicals known to act through similar mechanisms, as examples since multiple stressor exposure is the norm in the environment, it is essential to move away from single stressor based protection and to develop tools, including legal instruments, which will enable us to use response-based risk assessment. the problem of radiation protection in the context of multiple stressors includes consideration of humans and non-humans as separate groups requiring separate assessment frameworks. this is because for humans, individual survival and prevention of cancer are paramount but for animals, it is considered sufficient to protect populations and cancer is not of concern. the need to revisit this position is discussed not only from the environmental perspective but because the importance of pollution as a cause of non-cancer disease is increasingly being recognized. finally a way forward involving experimental assessment of biomarker performance coupled with modeling is discussed.",0,2007,NA,,235,246,10.1007/978-1-4020-6335-0_15,1,1,1,3"Durante, M",cytogenetic biomarkers for exposure to multiple stressors,Multiple Stressors: A Challenge for the Future,Proceedings Paper,chromosomal aberrations; fish; densely ionizing radiation,"risk associated to exposure to a single genotoxic agent can be assessed from the dose or concentration of the pollutant. for instance, radiation risk is estimated from physical dose (energy per mass unit), using radiation and tissue weighting factors and risk coefficients derived from epidemiology. however, for exposure to multiple stressor this approach is complicated, and deviations from simple additive models are common. chromosomal aberrations in peripheral blood lymphocytes have long been considered a biomarker of cancer risk. in fact, cytogenetic damage in blood cells reflect similar events occurring in target organs, and take into account the interaction of different clastogenic agents, individual sensitivity, genetic background, physiological status, synergisms, etc. new molecular techniques allow a careful and unequivocal identification of several chromosomal rearrangements and can be used to provide biologically motivated risk estimates, to be compared with the estimates coming from field measurements of dose, concentration, etc. one example of exposure to multiple stressors where cytogenetic biomarkers have been widely used is manned space exploration. during space flight, astronauts are exposed to cosmic radiation while sustaining several other stresses, primarily weightlessness. it is well known that spaceflight environment has large effects on the immune system and produce several physiological alterations. the interaction of these stresses, especially microgravity, with radiation exposure has been long studied in vitro, with contradictory results. however, measurements of cytogenetic biomarkers in astronauts have demonstrated that the radiation risk is not higher than expected from ground-based studies. the use of biomarkers is therefore particularly useful for the exposure to multiple stressors.",0,2007,NA,,287,293,10.1007/978-1-4020-6335-0_19,1,0,1,2"Dugonik, M; Goricanec, D; Krope, J",pressure drop in aqueous surfactant solution flow through pipes in sis structure degradation zone,Proceedings of the 2nd IASME/WSEAS International Conference on Energy & Environment,Proceedings Paper,fluid dynamics; surfactants; pressure drop; shear stress; drag coefficient; drag reduction,"the paper describes chemical and rheologic properties of solutions of polymer additives and cationic surfactants while they flow though pipes in a laminar and turbulent zone and their influence on drag reduction. surface active additives or aqueous solutions of surfactants form rod-like micelles, associated into an intermolecular sis structure that absorbs the turbulence energy at the passage through a pipe, thus influencing the reduction in pressure drop or drag reduction. the influence of the velocity of aqueous solution of surface active additives is analysed in pipes in the re number range, where high shear stress leads to a degradation of the surfactant intermolecular sis structure and the drag reduction effect disappears. the pressure drop and drag reduction rate diagrams as functions of aqueous surfactant solution flow velocity and re number are based on computer calculations.",0,2007,NA,,50,55,,0,0,1,1"Spromberg, JA; Meador, JP",relating chronic toxicity responses to population-level effects: a comparison of population-level parameters for three salmon species as a function of low-level toxicity,ECOLOGICAL MODELLING,Article; Proceedings Paper,life history modeling; chronic toxicity; salmon; population-level effects,"standard laboratory toxicity tests assess the physiological responses of individual organisms to exposure to toxic substances under controlled conditions. time and space restrictions often prevent the assessment of population-level responses to a toxic substance. contaminants can affect various biological functions (e.g. growth, fecundity or behavior), which may alter different demographic traits, leading to population-level impacts. in this study, immune suppression, reproductive dysfunction and somatic growth impairment were examined using life history matrix models for coho salmon (oncorhynchus kisutch), sockeye salmon (oncorhynchus nerka) and chinook salmon (oncorhynchus tshawytscha). our intent was to gauge the relative magnitude of response to toxic effects among species and between life history stages, not provide a specific estimate of population growth rate or abundance. effects due to immune suppression were modeled as reductions in age-specific survival. toxic impacts on reproductive function were modeled as a 10% reduction in reproductive contribution for all reproductively mature age groups. model runs that examined the effect of somatic growth reduction on population parameters incorporated both survival and reproductive impacts. all impacts were modeled as 10% reductions in the affected population demographic parameters. first-year survival and reproductive impacts produced similar population growth rates (lambda), but resulted in different sensitivity and stable age distributions. modeled somatic growth reduction produced additive effects on survival and reproduction. toxic stressors producing similar changes in; did not necessarily produce similar changes in the age distributions. sensitivity and elasticity analyses demonstrated that changes to the first-year survival rate produced the greatest per-unit effect on; for each species. alteration in abundance of mature females also strongly influenced l differences observed between species showed that the number of reproductive ages and time to reproductive maturity were important components for population-level responses. these results emphasize the importance of linking toxicity responses at low concentrations to the demographic traits they affect, and help to highlight the toxicity tests that are more suitable for assessing impacts on the focal species. additionally, life history modeling is a useful tool for developing testable hypotheses regarding impacts on specific populations as well as for conducting comparisons between populations. (c) 2006 elsevier b.v. all rights reserved.",20,2006,199,3,240,252,10.1016/j.ecolmodel.2006.05.007,0,0,1,1"Pertoldi, C; Sorensen, JG; David, JR; Loeschcke, V","lerner's theory on the genetic relationship between heterozygosity, genomic co-adaptation, and developmental instability revisited",EVOLUTIONARY ECOLOGY RESEARCH,Article,admixture analysis; developmental instability; environmental variability; homeostasis; Lerner's conjecture,"question: what is the genetic relationship between heterozygosity and developmental instability? methods: using a new method for the quantification of developmental instability, we compare homozygous strains of drosophila mereatorum (either parthenogenetic or highly inbred) and of their f1 progeny for the analysis of a symmetrical meristic trait (sternopleural bristle number). the method also implies the choice of samples in which the left-right correlation is close to zero. conclusions: in the parthenogenetic strain, developmental instability was seven times greater than in the f1 progeny. in the highly inbred strain, developmental instability was only 2.6 times greater than in the f1 progeny. the greater developmental instability in the parthenogenetic strain may be accounted for by the immediate fixation of a large number of deleterious alleles. in the inbred strain, on the other hand, progressive inbreeding is likely to have purged the genome of some of its genetic load and its most deleterious variants. the greater developmental instability in the parthenogenetic and inbred strains implies a non-linear relationship between heritability (h(2)) and additive genetic variance (sigma(2)(a)) (which are both related to evolutionary potential), which is discussed in an evolutionary context. a linear relationship between the sigma(2)(a) of a trait and its h(2) is expected if developmental instability is constant and independent of the sigma(2)(a) of that trait. if the relationship between the sigma(2)(a) of a trait and its developmental instability is negative, an increased sigma(2)(a), which is in the numerator of the h equation, will imply a reduced phenotypic variability (sigma(2)(p)), which is in the denominator of the heritability equation. consequently, the concomitant increase in sigma(2)(s) and reduction in sigma(2)(s) both contribute to an increase in sigma(2)(p) and therefore an increase in evolutionary potential.",15,2006,8,8,1487,1498,,0,0,1,1"Christensen, MR; Graham, MD; Vinebrooke, RD; Findlay, DL; Paterson, MJ; Turner, MA",multiple anthropogenic stressors cause ecological surprises in boreal lakes,GLOBAL CHANGE BIOLOGY,Article,acidification; boreal lakes; climate warming; drought; global change; nonadditive effects; phytoplankton; zooplankton,"the number of combinations of anthropogenic stressors affecting global change is increasing; however, few studies have empirically tested for their interactive effects on ecosystems. most importantly, interactions among ecological stressors generate nonadditive effects that cannot be easily predicted based on single-stressor studies. here, we corroborate findings from an in situ mesocosm experiment with evidence from a whole-ecosystem manipulation to demonstrate for the first time that interactions between climate and acidification determine their cumulative impact on the food-web structure of coldwater lakes. interactions among warming, drought, and acidification, rather than the sum of their individual effects, best explained significant changes in planktonic consumer and producer biomass over a 23-year period. further, these stressors interactively exerted significant synergistic and antagonistic effects on consumers and producers, respectively. the observed prevalence of long- and short-term ecological surprises involving the cumulative impacts of multiple anthropogenic stressors highlights the high degree of uncertainty surrounding current forecasts of the consequences of global change.",77,2006,12,12,2316,2322,10.1111/j.1365-2486.2006.01257.x,1,1,1,3"Poyry, J; Luoto, M; Paukkunen, J; Pykala, J; Raatikainen, K; Kuussaari, M",different responses of plants and herbivore insects to a gradient of vegetation height: an indicator of the vertebrate grazing intensity and successional age,OIKOS,Article,,"empirical studies have suggested that species richness of grassland insects usually decreases under grazing management. by contrast, grazing has been shown to increase the species density and richness of vascular plants, especially on productive soils. in order to test the suggested differences in response to management between plants and insects, we simultaneously studied species richness of vascular plants and their insect herbivores, butterflies and moths, in 68 semi-natural grasslands with varying grazing intensity and frequency in sw finland. species richness of plants and insects was for the first time related to a quantitative measure of disturbance intensity and successional age, mean vegetation height, by using generalized additive models (gam). the effects of soil nutrients on vegetation height were accounted for by using phosphorus concentration as a productivity surrogate. the results showed that species richness of butterflies and moths peaked in taller vegetation compared with vascular plants, corresponding to a lower disturbance intensity and increasing time since abandonment. these patterns are discussed in the light of two hypotheses, the ""structural diversity hypothesis"" and ""dynamic equilibrium model"" of huston, both suggesting a weaker disturbance tolerance of insects compared with plants. butterflies and moths which are specialists in their larval host-plant use (monophagous and oligophagous species) preferred lower vegetation (higher disturbances) compared with generalists (polyphagous species), as predicted by huston's model. this difference indicates a stronger relationship with plant species richness for specialist than for generalist butterflies and moths. our results support the application of regionally and temporally varying grazing intensities in grassland conservation management.",50,2006,115,3,401,412,10.1111/j.2006.0030-1299.15126.x,0,0,1,1"Anderson, NJ; Bugmann, H; Dearing, JA; Gaillard, MJ",linking palaeoenvironmental data and models to understand the past and to predict the future,TRENDS IN ECOLOGY & EVOLUTION,Review,,"complex, process-based dynamic models are used to attempt to mimic the intrinsic variability of the natural environment, ecosystem functioning and, ultimately, to predict future change. palaeoecological data provide the means for understanding past ecosystem change and are the main source of information for validating long-term model behaviour. as global ecosystems become increasingly stressed by, for example, climate change, human activities and invasive species, there is an even greater need to learn from the past and to strengthen links between models and palaeoecological data. using examples from terrestrial and aquatic ecosystems, we suggest that better interactions between modellers and palaeoecologists can help understand the complexity of past changes. with increased synergy between the two approaches, there will be a better understanding of past and present environmental change and, hence, an improvement in our ability to predict future changes.",60,2006,21,12,696,704,10.1016/j.tree.2006.09.005,1,0,0,1"Seabrook, L; McAlpine, C; Fensham, R","cattle, crops and clearing: regional drivers of landscape change in the brigalow belt, queensland, australia, 1840-2004",LANDSCAPE AND URBAN PLANNING,Article,drivers; deforestation; land cover change; cultural landscapes; land use history,"landscape change occurs through the interaction of a multitude of natural and human driving forces at a range of organisational levels, with humans playing an increasingly dominant role in many regions of the world. building on the current knowledge of the underlying drivers of landscape change, a conceptual framework of regional landscape change was developed which integrated population, economic and cultural values, policy and science/technology. using the southern brigalow belt biogeographic region of queensland as a case study, the role of natural and human drivers in landscape change was investigated in four phases of settlement since 1840. the brigalow belt has experienced comparable rates of vegetation clearance over the past 50 years to areas of tropical deforestation. economic factors were important during all phases of development, but the five regional drivers often acted in synergy. environmental constraints played a significant role in slowing rates of change. temporal trends of deforestation followed a sigmoidal curve, with initial slow change accelerating though the middle phases then slowing in recent times. future landscape management needs to take account of the influence of all the components of the conceptual framework, at a range of organisational levels, if more ecologically sustainable outcomes are to be achieved. (c) 2006 elsevier b.v. all rights reserved.",44,2006,78,4,373,385,10.1016/j.landurbplan.2005.11.007,1,0,0,1"Lees, AC; Peres, CA",rapid avifaunal collapse along the amazonian deforestation frontier,BIOLOGICAL CONSERVATION,Article,birds; Brazil; habitat quality; remote sensing; rainforest; species-area relationships,"the combined effects of rapid habitat loss, fragmentation and disturbance on tropical forest avifaunas have not been examined to date. the southern amazonian 'arc of deforestation' marks the boundary of the most aggressive agricultural frontier in tropical forests worldwide. we sampled 21 disturbed and undisturbed primary forest patches, ranging in size from 1.2 to 14,476 ha, to elucidate the synergistic effects of both forest disturbance and fragmentation on bird community structure, and pinpoint which species were the ""winners"" and ""losers"" from this process. a number of forest patch metrics, derived from an independent remote sensing approach, explained much of the resulting presence/absence matrix. the bird community exhibited a highly nested structure, with small patches being most dissimilar from one another. bird species differed in their response to both forest patch size and forest canopy perforation according to their dependence on closed-canopy primary forest. forest patch geometry, which clearly modulated the shape of species-area relationships accounted for 83-96% of the variation in species richness, but forest habitat quality resulting from logging and surface-fire disturbance was also a significant predictor of species richness for the most forest-dependent taxa. (c) 2006 elsevier ltd. all rights reserved.",59,2006,133,2,198,211,10.1016/j.biocon.2006.06.005,1,0,0,1"Marr, AB; Arcese, P; Hochachka, WM; Reid, JM; Keller, LF",interactive effects of environmental stress and inbreeding on reproductive traits in a wild bird population,JOURNAL OF ANIMAL ECOLOGY,Article,Darwin's finches; environmental variability; inbreeding depression; population viability; stress by inbreeding interaction,"1. conservation biologists are concerned about the interactive effects of environmental stress and inbreeding because such interactions could affect the dynamics and extinction risk of small and isolated populations, but few studies have tested for these interactions in nature. 2. we used data from the long-term population study of song sparrows melospiza melodia on mandarte island to examine the joint effects of inbreeding and environmental stress on four fitness traits that are known to be affected by the inbreeding level of adult birds: hatching success, laying date, male mating success and fledgling survival. 3. we found that inbreeding depression interacted with environmental stress to reduce hatching success in the nests of inbred females during periods of rain. 4. for laying date, we found equivocal support for an interaction between parental inbreeding and environmental stress. in this case, however, inbred females experienced less inbreeding depression in more stressful, cooler years. 5. for two other traits, we found no evidence that the strength of inbreeding depression varied with environmental stress. first, mated males fathered fewer nests per season if inbred or if the ratio of males to females in the population was high, but inbreeding depression did not depend on sex ratio. second, fledglings survived poorly during rainy periods and if their father was inbred, but the effects of paternal inbreeding and rain did not interact. 6. thus, even for a single species, interactions between the inbreeding level and environmental stress may not occur in all traits affected by inbreeding depression, and interactions that do occur will not always act synergistically to further decrease fitness.",45,2006,75,6,1406,1415,10.1111/j.1365-2656.2006.01165.x,1,0,0,1"Santos, M; Brites, D; Laayouni, H","thermal evolution of pre-adult life history traits, geometric size and shape, and developmental stability in drosophila subobscura",JOURNAL OF EVOLUTIONARY BIOLOGY,Article,clinal variation; development; Drosophila subobscura; fluctuating asymmetry; geometric morphometrics; phenotypic plasticity; thermal selection; wing loading; wing shape; wing size,"replicated lines of drosophila subobscura originating from a large outbred stock collected at the estimated chilean epicentre (puerto montt) of the original new world invasion were allowed to evolve under controlled conditions of larval crowding for 3.5 years at three temperature levels (13, 18 and 22 degrees c). several pre-adult life history traits (development time, survival and competitive ability), adult life history related traits (wing size, wing shape and wing-aspect ratio), and wing size and shape asymmetries were measured at the three temperatures. cold-adapted (13 degrees c) populations evolved longer development times and showed lower survival at the highest developmental temperature. no divergence for wing size was detected following adaptation to temperature extremes (13 and 22 degrees c), in agreement with earlier observations, but wing shape changes were obvious as a result of both thermal adaptation and development at different temperatures. however, the evolutionary trends observed for the wing-aspect ratio were inconsistent with an adaptive hypothesis. there was some indication that wing shape asymmetry has evolutionarily increased in warm-adapted populations, which suggests that there is additive genetic variation for fluctuating asymmetry and that it can evolve under rapid environmental changes caused by thermal stress. overall, our results cast strong doubts on the hypothesis that body size itself is the target of selection, and suggest that pre-adult life history traits are more closely related to thermal adaptation.",21,2006,19,6,2006,2021,10.1111/j.1420-9101.2006.01139.x,0,0,1,1"Relyea, R; Hoverman, J",assessing the ecology in ecotoxicology: a review and synthesis in freshwater systems,ECOLOGY LETTERS,Review,biodiversity; density-mediated indirect effects; ecosystem function; fungicide; herbicide; insecticide; trait-mediated indirect effects,"the field of ecotoxicology is experiencing a surge in attention among ecologists as we gain a deeper appreciation for how contaminants can impact natural ecosystems. this interest is particularly strong in aquatic systems where many non-target organisms experience pesticides. in this article, we assess how pesticides affect freshwater systems by applying the conceptual framework of density- and trait-mediated indirect effects from the field of basic ecology. we demonstrate the utility of this framework for understanding the conditions under which pesticides affect species interactions, communities and ecosystems. through the integration of laboratory toxicity tests and this ecological framework, ecotoxicologists should be better able to identify the mechanisms through which pesticides affect communities and ecosystems. we also identify several areas of research that are in critical need of empirical attention including synergistic effects between pesticides and natural stressors, the importance of pesticides on community assembly via habitat preferences and oviposition effects, the timing and frequency of pesticide applications, pesticide effects on population dynamics, the evolution of pesticide resistance in non-target organisms and ecosystem recovery. with this knowledge, one can improve upon management decisions and help protect non-target species that are of conservation concern.",168,2006,9,10,1157,1171,10.1111/j.1461-0248.2006.00966.x,1,0,0,1"Jongejans, E; Sheppard, AW; Shea, K",what controls the population dynamics of the invasive thistle carduus nutans in its native range?,JOURNAL OF APPLIED ECOLOGY,Article,biological control; enemy release hypothesis; insect-plant interactions; invaded-native range comparison; matrix projection models; special herbivores; vital rate elasticity,"1. the invasive thistle carduus nutans causes major economic losses in the americas, australia and new zealand. for the first time, we have modelled its population dynamics in its native range, eurasia, where it rarely reaches problematic densities, in order to identify ways to improve management strategies for this weed in the invaded range. 2. in particular, we investigated whether specialist enemies in the thistle's native range suppress thistle populations, as predicted by the enemy-release hypothesis, and, if so, how this effect relates to other factors that may limit population growth. 3. we constructed population transition matrix models with data from three french populations. a vital rate elasticity analysis revealed that reproduction determines between 33% and 61% of the projected growth rate of the populations, and thus is a key driver of the population dynamics of this monocarpic short-lived perennial. 4. decreases in population size were predicted by the models for all three populations (lambda < 1). using limiting factor omission analyses, we showed that the suite of native insect herbivores causing seed losses had a larger impact than the joint effects of rosette damage by sheep and summer drought acting on seedling establishment. removal of insect herbivores increased the native population growth rate by 166% on average; removal of sheep damage and summer drought from the model increased population growth by 51%. specialist herbivores and drought interacted synergistically to affect reproduction. 5. synthesis and applications. we show that vital rate elasticity analysis provides more management information than elasticity analysis on the level of matrix elements, particularly when management options affect only certain vital rates. for example, it can be used to make predictions about the effectiveness of predispersal floral herbivores in control management. the model can also help identify ways in which biocontrol can be augmented using integrated weed management that reduces seedling establishment probabilities, for example by preventing overgrazing. this method illustrates how native range studies of invasive species can be used to generate insights into managing populations in the invaded range.",31,2006,43,5,877,886,10.1111/j.1365-2664.2006.01228.x,1,0,0,1"Benedick, S; Hill, JK; Mustaffa, N; Chey, VK; Maryati, M; Searle, JB; Schilthuizen, M; Hamer, KC","impacts of rain forest fragmentation on butterflies in northern borneo: species richness, turnover and the value of small fragments",JOURNAL OF APPLIED ECOLOGY,Article,beta-diversity; biodiversity; extinction risk; landscape ecology; larval host-plants; nested subsets; species-area relationships,"1. widespread and rapid losses of tropical rain forests have made understanding the responses of species to rain forest fragmentation an area of major concern. in this study we examined the impacts of habitat fragmentation on the species richness and faunal composition of butterflies in tropical rain forests in sabah, borneo. we analysed patterns of both alpha- and beta-diversity to assess the relative importance of differences in patch size, isolation and vegetation structure on the diversity and similarity of species assemblages. we used additive partitioning to assess the relative contributions of intact forest and forest remnants to overall species richness at a landscape scale and we examined which traits of species best predicted their responses to fragmentation. 2. species richness and diversity in rain forest remnants was significantly positively related to remnant size and significantly negatively related to isolation, in keeping with theories of island biogeography. species assemblages at different sites were significantly nested, with those species most adversely affected by forest fragmentation having a narrow range of larval host-plants and, to a lesser extent, being large-bodied. no species endemic to borneo was recorded in forest remnants smaller than 4000 ha, but even the smallest remnant (120 ha) supported species with geographical distributions confined within sundaland (west malaysia and the islands of the sunda shelf). 3. although assemblages were significantly nested, they departed substantially from perfect nestedness, with some species recorded only or predominantly in small, relatively depauperate remnants. as a result there was substantial beta-diversity among sites, which was related to variation in both fragment size and vegetation structure. at the landscape scale, diversity within sites was less than that between sites, and the majority of the diversity between sites was related to variation in fragment size. 4. synthesis and applications. substantial diversity was added to the assemblage of butterflies in bornean rain forests by virtue of species differences among fragments, which were related mainly to differences in patch size and vegetation structure. the data reported indicate that, despite having lower species richness, relatively small and isolated remnants of rain forest make a substantial contribution to regional diversity. small isolated forest remnants are generally accorded low conservation status and given little protection, with the result that they often disappear over time because of continued anthropogenic disturbance. the results of this study indicate that the conservation value of small remnants of forest, in particular their contribution to environmental heterogeneity, should not be overlooked.",53,2006,43,5,967,977,10.1111/j.1365-2664.2006.01209.x,0,0,1,1"Kinezaki, N; Kawasaki, K; Shigesada, N",spatial dynamics of invasion in sinusoidally varying environments,POPULATION ECOLOGY,Article; Proceedings Paper,biological invasions; traveling periodic wave; habitat fragmentation; periodic environment; irregular environment,"range expansions of invading species in homogeneous environments have been extensively studied since the pioneer works by fisher (ann eugen 7:255-369, 1937) and skellam (biometrika 38:196-218, 1951). however, environments for living organisms are often fragmented by natural or artificial habitat destruction. here we address how such environmental heterogeneity affects the range expansion of invading species. we consider a single-species invasion in heterogeneous environments whose habitat parameters vary in a sinusoidal or quasi-sinusoidal manner. accordingly, fisher's model is modified to make the intrinsic growth rate and diffusion coefficient spatially variable. by numerically solving the model, we examine the spatio-temporal pattern of propagating waves, and predict the speed as a function of the amplitude and the wave length of the diffusion coefficient and the intrinsic growth rate. firstly, the results demonstrate that in the sinusoidally varying environment, if the intrinsic growth rate solely oscillates, the speed increases with increases in the amplitude of oscillation. conversely, if the diffusion coefficient solely oscillates, the speed decreases with increases in the amplitude of oscillation. when both the intrinsic growth rate and diffusion coefficient oscillate, the speed is synergistically accelerated if the oscillations are in anti-phase, whereas it is decelerated if the oscillations are in same phase. secondly, the increase in the wave length in either the intrinsic growth rate or the diffusion coefficient leads to decreases in the speed. thirdly, in the irregularly varying environment, the irregularity in the amplitude of the intrinsic growth rate enhances the speed, while that of the diffusion coefficient attenuates the speed.",22,2006,48,4,263,270,10.1007/s10144-006-0263-2,1,0,0,1"Cumming, GS; Spiesman, BJ",regional problems need integrated solutions: pest management and conservation biology in agroecosystems,BIOLOGICAL CONSERVATION,Review,IPM; scale; adaptive management; hierarchy; ecosystem services; agriculture; landscape ecology; fragmentation; pesticide; biodiversity; ecosystem function,"ecosystems produce goods and services that are essential for the wellbeing of humans and other organisms. the earth's expanding human population is altering both pattern and process in ecosystems, and hence is impacting the provision of ecosystem goods and services at a variety of scales. food production and other ecosystem services, such as the many benefits provided by forests, are not exclusive of one another at a regional scale. although it is becoming obvious that uncoordinated local management is inadequate to address regional ecosystem changes in the face of regional drivers of change, few regional governments have addressed the need for holistic landscape management of regional ecosystem services. we compare and contrast two regional programs, the agricultural agenda of integrated pest management (ipm) and an as-yet hypothetical, fragmentation-oriented conservation agenda that we term 'regional fragmentation management' (rfm). ipm has a strong practical foundation but is weak on theory. rfm has a stronger theoretical base, but is weak on practice and has mainly focused on protected areas. both programs address only a small subset of the larger question of how to effectively maintain regional production of regional ecosystem services. some of the successes of ipm practitioners in building institutions and achieving societal acceptance for their program, particularly in relation to regionally coordinated ('areawide') pest management, suggest that regional ecosystem management is plausible. ipm offers some ingredients of an institutional role model for a broader, more ambitious program that seeks to manage regional ecosystem services and processes in a sustainable manner. as the looming crisis of global climate change brings a potential window of opportunity for the introduction of novel approaches for managing deforestation, closer synergies between conservation and agriculture at regional scales seem not only possible, but essential. (c) 2006 elsevier ltd. all rights reserved.",28,2006,131,4,533,543,10.1016/j.biocon.2006.02.025,1,0,0,1"Papaik, MJ; Canham, CD",species resistance and community response to wind disturbance regimes in northern temperate forests,JOURNAL OF ECOLOGY,Article,community dynamics; competition; disturbance; forerst ecology; local and long-distance seed dispersal; resistance to disturbance; seedling establishment; simulation model; succession; wind disturbance,"1 severe winds are the predominant cause of natural disturbance in temperate forests of north-eastern and north-central north america. conceptual models of the effects of wind disturbance have traditionally focused on the impacts of catastrophic disturbances and have painted a simple picture of how disturbance acts to maintain tree species diversity. these models ignore variation among species characteristics that could have important consequences for both resistance to and recovery from disturbance. 2 we integrated an empirically parameterized, mechanistic model of windstorm mortality (windstorm) and a seed-mass-based dispersal and recruitment model into a spatially explicit, individual tree model of forest dynamics (sortie) in order to create simulated long-term 'experiments' designed to explore the sensitivity of forest composition and structure to species-specific resistance to and recovery from disturbance. 3 we found that species-specific variation in resistance to wind mortality interacted strongly with: (i) shade tolerance characteristics, (ii) the medium-term history of disturbances, (iii) the long-term average severity of the disturbance regime and (iv) seedbed substrate dynamics to influence tree population dynamics and successional trajectories. 4 we also examined how local and long-distance dispersal affect response to wind disturbance. ignoring differences among local dispersal characteristics overestimates the importance of dispersal-limited species. our results show that long-distance immigration maintains species coexistence only if the immigration rate is very high relative to local dispersal. despite this, stand-scale models that ignore long-distance dispersal can underestimate population dynamics of dispersal-limited species. 5 our results indicate that landscape-scale heterogeneity in structure and species composition in these forests is facilitated by synergisms between the stochastic nature of wind disturbance and complex interactions between species traits that govern: (i) resistance to disturbance, (ii) local dispersal and seedling establishment and (iii) competitive (i.e. growth/survival) traits that do not adhere to strict tradeoffs. 6 we conclude that wind disturbance has much more complex and variable effects on long-term dynamics of forest structure and composition than suggested by previous models. in particular, non-catastrophic disturbances can generate important variation in forest dynamics that can either lead to dominance by a single or small number of species, or facilitate species coexistence.",41,2006,94,5,1011,1026,10.1111/j.1365-2745.2006.01153.x,1,0,0,1"Ashcroft, MB",a method for improving landscape scale temperature predictions and the implications for vegetation modelling,ECOLOGICAL MODELLING,Article,temperature; low pass filter; elevation; radiation; canopy; vegetation; model; GAM; Illawarra; Wollongong,"understanding how environmental factors influence the spatial distribution of vegetation allows environmental managers to plan for issues such as climate change, ecological restoration and intensified land use. elevation is often used as an indirect predictor of temperature, but this limits the applicability of environmental models to other study areas and introduces errors in mountainous terrain where variations in slope, aspect, and radiation can significantly alter the relationship between elevation and temperature. some studies have developed estimates for temperature that also consider factors such as radiation, but these usually estimate the temperature for each location without considering the surrounding environment. in this study, average summer maximum and minimum temperatures were recorded at various locations on the illawarra escarpment, near sydney, australia. it was hypothesised that wind and air movements would average out large differences in elevation and radiation in mountainous terrain and cause the temperatures to be more strongly correlated with local averages of elevation and radiation than they are with the actual elevation and radiation where the temperatures were recorded. the use of local averages improved the estimate of average summer maximum temperature from a regression r(2) of 0.185 using elevation alone, to an gamma(2) of 0.685 when using canopy cover, local average elevation and local average radiation. in contrast, average summer minimum temperatures were better predicted using the elevation of each location without averaging. the results were applied to vegetation modelling by comparing a generalised additive model using the predicted average temperatures with a model using elevation. the overall classification accuracy for vegetation communities in the study area was improved from 46.4% to 61.8%. therefore, improved temperature estimates also improved the explanatory performance of vegetation models. (c) 2006 elsevier b.v. all rights reserved.",13,2006,197,04-Mar,394,404,10.1016/j.ecolmodel.2006.03.014,0,0,1,1"Moore, TN; Fairweather, PG","decay of multiple species of seagrass detritus is dominated by species identity, with an important influence of mixing litters",OIKOS,Article,,"no studies of seagrass decay have examined effects of the number of species contained within the detrital pool. given the importance of decay for nutrient cycling and long-term productivity, we tested how three seagrass species affected decay in litterbags. experimental results clearly showed that species identity was the predominant driver of mass loss, with total loss not differing between bags containing one, two and three species. furthermore, we show there were also non-additive effects of mixing litter that were not predicted from single-species decay rates. the nature of the non-predictable mass loss varied both through time and with the number of species in the mixtures. this indicates that species richness indeed plays a role in this important ecosystem function but one that is of less importance than species identity. the concordance of these results with terrestrial studies suggests that mechanisms responsible for mixed-species decay rates may be broadly applicable across ecosystems.",30,2006,114,2,329,337,10.1111/j.2006.0030-1299.14576.x,0,0,1,1"Kahn, AE; Durako, MJ",thalassia testudinum seedling responses to changes in salinity and nitrogen levels,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,ammonium; osmolarity; photosynthesis; salinity; seedlings; Thalassia testudinum,"the dominant seagrass in florida bay, thalassia testudinum banks ex konig, is a stenohaline species with optimum growth around marine salinity (30-40psu). previous studies have examined the responses of mature short shoots of t testudinum to environmental stresses. our goal was to assess responses of seedlings to changes in water chemistry in florida bay that might occur as part of the comprehensive everglades restoration plan (cerp). specifically, we examined seedling survival, growth, photosynthesis, respiration and osmolality in response to hypo- and hyper-salinity conditions, as well as possible synergistic effects of depleted and elevated ammonium concentrations. the study was conducted in mesocosms on t testudinum seedlings collected during august 2003 near florida bay. hyper- and hypo-saline conditions were detrimental to the fitness of t testudinum seedlings. plants at 0 and 70psu exhibited 100% mortality and a significant decrease in survival was observed in the 10, 50 and 60psu treatments. increased levels of ammonium further decreased growth in the lower salinity treatments. seedlings in 30 and 40psu had the greatest growth. quantum yield and relative electron transport rate, measured using pam fluorometry, showed a decrease in photosynthetic performance on either side of the 30-40psu optimum. tissue osmolality decreased significantly with decreased salinity but tissue remained consistently hyperosinotic to the media across all salinity treatments. maintaining negative water potential and allocating more energy to osmoregulation may decrease the productivity of this species in salinity-stress conditions. our results suggest that the salinity-tolerance limits of this seagrass at the seedling stage are not as broad as those reported for mature plants. increased fresh water inflow, especially if co-occurring with an increase in water-column ammonium, could negatively affect successful recruitment of t. testudinum seedlings in northern regions of florida bay. (c) 2006 elsevier b.v. all rights reserved.",24,2006,335,1,1,12,10.1016/j.jembe.2006.02.011,1,0,0,1"Moreau, G; Eveleigh, ES; Lucarotti, CJ; Quiring, DT",ecosystem alteration modifies the relative strengths of bottom-up and top-down forces in a herbivore population,JOURNAL OF ANIMAL ECOLOGY,Article,additive mortality; compensatory mortality; disturbance; Neodiprion abietis; thinning,"1. ecosystem alterations can affect the abundance, distribution and diversity of plants and animals, and thus potentially change the relative strength of bottom-up (the plant resource) and top-down (natural enemies) trophic forces acting on herbivore populations. 2. the hypothesis that alterations of the forest ecosystem associated with precommercial thinning have contributed to the increased severity of outbreaks of neodiprion abietis (harris), a sawfly defoliator, through the reduction of trophic forces acting on n. abietis larvae, was tested using exclusion techniques. 3. the relative contributions to n. abietis larval mortality of bottom-up and top-down forces both increased with increasing levels of defoliation and were both reduced by thinning. the reduction of bottom-up and top-down forces caused a 58% mean increase in n. abietis larval survival in thinned compared with untreated stands, which is less than would be expected by the sum of the effects of thinning on each source of mortality. evidence indicates that the partly compensatory, partly additive nature of the mortality associated with trophic forces in the system under study is responsible for this discrepancy. 4. to our knowledge, this is the first study to show the impact of ecosystem alterations on the balance between bottom-up and top-down forces acting on an eruptive herbivore population along a gradient of host-plant defoliation, and how this can lead to increased outbreak severity. it is stressed that accurate estimates of the relative contributions of bottom-up and top-down forces to mortality cannot be obtained if the additive or compensatory nature of the mortality associated with these trophic forces is overlooked.",20,2006,75,4,853,861,10.1111/j.1365-2656.2006.01109.x,0,0,1,1"Karonen, M; Ossipov, V; Ossipova, S; Kapari, L; Loponen, J; Matsumura, H; Kohno, Y; Mikami, C; Sakai, Y; Izuta, T; Pihlaja, K","effects of elevated carbon dioxide and ozone on foliar proanthocyanidins in betula platyphylla, betula ermanii, and fagus crenata seedlings",JOURNAL OF CHEMICAL ECOLOGY,Article,beech; birch; butanol-HCl assay; carbon dioxide; HPLC; ozone; proanthocyanidins,"proanthocyanidins (pas) or condensed tannins are a major group of phenolic compounds in the leaves of birch trees and many other woody and herbaceous plants. these compounds constitute a significant allocation of carbon in leaves and are involved in plant responses to environmental stress factors, such as pathogens or herbivores. in some plants, pa concentrations are affected by atmospheric carbon dioxide (co(2)) and ozone (o(3)) levels that may influence, for example, species fitness, community structure, or ecosystem nutrient cycling. therefore, a study on the quantitative response of pas to elevated concentrations of carbon dioxide (co(2)) and ozone (o(3)) was undertaken in seedlings of betula platyphylla, betula ermanii, and fagus crenata. seedlings were exposed to ambient or elevated o(3) and co(2) levels during two growing seasons in the kanto district in japan. ten open-top chambers were used for five different treatments with two replicates: filtered air (fa), ambient air (ambient o(3), 43 ppb; ambient co(2), 377 ppm), elevated o(3) (1.5 x ambient o(3), 66 ppb), elevated co(2) (1.5 x ambient co(2), 544 ppm), and elevated o(3) and co(2) combined. in addition, seedlings growing in natural conditions outside of chambers were studied. leaf samples were analyzed for total pa concentrations by butanol-hcl assay and for polymeric pa concentrations by normal-phase high-performance liquid chromatography. total pa concentrations in leaves of all species were similarly affected by different treatments. they were significantly higher in seedlings treated with elevated co(2) and o(3) combined, and in seedlings growing outside chambers compared with the fa controls. f. crenata contained only traces of polymeric pas, but significant species x treatment interaction was observed in the polymeric pa concentrations in b. ermanii and b. platyphylla. in b. platyphylla, leaves treated with elevated co(2) + o(3) differed significantly from all other treatments. it was suggested that the strongest effect of elevated co(2) and o(3) combined on leaf pa contents resulted from the additive effect of these environmental factors on phenolic biosynthesis.",7,2006,32,7,1445,1458,10.1007/s10886-006-9061-8,0,0,1,1"Yergeau, E; Vujanovic, V; St-Arnaud, M",changes in communities of fusarium and arbuscular mycorrhizal fungi as related to different asparagus cultural factors,MICROBIAL ECOLOGY,Article,,"asparagus (asparagus officinalis) is a high-value perennial vegetable crop that has shown a marked decline in productivity after many years of continuous harvesting. this decline is caused by an increase in both abiotic (autotoxicity, harvesting pressure) and biotic stresses [fungal infections, mainly fusarium crown and root rot (fcrr)]. to gain insight into disease development and possible mitigation strategies, we studied the effects of harvesting, time in the growing season, and field age on fcrr development, fusarium species composition, and arbuscular mycorrhizal fungi (amf) communities in both a controlled field experiment and an ecological survey of commercial fields. in one experiment, a 3-year-old asparagus field was subdivided into plots that were harvested or not and sampled throughout the growing season to assess short-term dominant fusarium species shifts. in addition, diseased and healthy asparagus plants sampled from six commercial fields in the same geographical region were used to assess fusarium and amf communities in relation to different parameters. fusarium and amf communities were described by using a polymerase chain reaction (pcr)-denaturing gradient gel electrophoresis (dgge) approach, and results were analyzed by mainly correspondence analysis and canonical correspondence analysis. results showed that dominant fusarium taxa assemblages changed throughout the growing season. harvested plots had significantly more fcrr symptomatic plants at the end of the growing season, but this effect was not related with any trend in fusarium community structure. sampling site and plant age significantly influenced amf community structure, whereas only sampling site consistently influenced the fusarium community. diseased and healthy plants harbored similar fusarium and amf communities. shifts in fusarium community might not be responsible for different disease incidence because they are ubiquitous regardless of plant health status or harvesting regime. the different incidence noted might rather be related to plant physiology, antagonist microbial communities, or soil parameters.",13,2006,52,1,104,113,10.1007/s00248-006-9047-7,0,1,0,1"Lawes, MJ; Midgley, JJ; Boudreau, S; Griffiths, ME",lack of disturbance as an explanation for the additive basal area phenomenon in a stratified afrotemperate forest,AUSTRAL ECOLOGY,Article,competition; disturbance; emergent; longevity; temperate forest,"explanations for the additive basal area (ba) phenomenon in forests are frequently given in the context of stratification and the avoidance of competition for space or resources (e.g. light, nutrients, moisture). thus, large individuals avoid competition for light by emerging above the canopy and, in so doing, the ba of emergent individuals is often 'additive' to that of the rest of the individuals in a stand. the additive ba phenomenon was evident in a stratified afrotemperate forest and was not confined to the emergent stratum but occurred also within the canopy stratum where gymnosperm ba appeared to be additive. however, there was no evidence that stand ba was at carrying capacity (i.e. presumably neither space nor nutrient resources were limiting) and there was no statistical evidence of competitive effects. we argue that avoiding competition is an insufficient explanation for how biomass accumulates in stratified forests and suggest that local variation in disturbance regime and tree life-history provide a more plausible and general explanation for current forest stand structure and dynamics. we suggest that the additive effect is a result of long-lived individuals persisting in the prolonged absence of disturbance to canopy and emergent strata.",10,2006,31,4,471,477,10.1111/j.1442-9993.2006.01607.x,0,0,1,1"Ricklefs, RE",the unified neutral theory of biodiversity: do the numbers add up?,ECOLOGY,Article,community diversity; ecological drift; extinction; neutral theory; passerine birds; population size; regional diversity; speciation,"hubbell's unified neutral theory is a zero-sum ecological drift model in which population sizes change at random in a process resembling genetic drift, eventually leading to extinction. diversity is maintained within the community by speciation. hubbell's model makes predictions about the distribution of species abundances within communities and the turnover of species from place to place (beta diversity). however, ecological drift cannot be tested adequately against these predictions without independent estimates of speciation rates, population sizes, and dispersal distances. a more practical prediction from ecological drift is that time to extinction of a population of size n is approximately 2n generations. i test this prediction here using data for passerine birds (passeriformes). waiting times to speciation and extinction were estimated from genetic divergence between sister populations and a lineage-through-time plot for endemic south american suboscine passerines. population sizes were estimated from local counts of birds in two large forest plots extrapolated to the area of wet tropical forest in south america and from atlas data on european passerines. waiting times to extinction (ca. 2 ma) are much less than twice the product of average population size (4.0 and 14.4 x 10(6) individuals in south america and europe) and generation length (five and three years) for songbirds, that is, 40 and 86 ma, respectively. thus, drift is too slow to account for turnover in regional avifaunas. presumably, other processes, involving external drivers, such as climate and physiographic change, and internal drivers, such as evolutionary change in antagonistic interactions, predominate. hubbell's model is historical and geographic, and his perspective importantly links local and regional process and pattern. ecological reality can be added to the mix while retaining hubbell's concept of continuity of communities in space and time.",64,2006,87,6,1424,1431,10.1890/0012-9658(2006)87[1424:TUNTOB]2.0.CO;2,0,1,0,1"Hames, RS; Lowe, JD; Swarthout, SB; Rosenberg, KV",understanding the risk to neotropical migrant bird species of multiple human-caused stressors: elucidating processes behind the patterns.,ECOLOGY AND SOCIETY,Article,multiple scales; synergistic effects; citizen science; habitat fragmentation; acid rain; forests; anthropogenic change; soil; calcium; invertebrates,"ubiquitous human-caused changes to the environment act as multiple stressors for organisms in the wild, and the effects of these stressors may be synergistic, rather than merely additive, with unexpected results. however, understanding how focal organisms respond to these stressors is crucial for conservation planning for these species. we propose a paradigm that alternates extensive, broadscale data collection by volunteer collaborators to document patterns of response, with intensive fine-scale studies by professional researchers, to elucidate the processes underlying these patterns. we demonstrate this technique, building on our existing work linking patterns of population declines in the wood thrush (hylocichla mustelina) to synergistic effects of acid rain and habitat fragmentation. to better understand the processes behind these patterns, we use a simple protocol to explore linkages between acid rain, leaching of calcium from the soil, and declines in the abundance of calcium-rich invertebrate prey species, which may be necessary for successful breeding by this thrush. we sampled at 40 study sites across new york that were chosen based on estimated acid deposition and soil properties. our results show that the calcium content of the soils sampled is proportional to the soil ph, that the abundance of calcium-rich invertebrate prey tracks soil properties, and that the presence of a breeding wood thrush was correctly predicted in > 70% of study sites by the biomass of calcium-rich prey, and in particular, the biomass of myriapods (diplopoda). we show that a simple repeatable protocol, suitable for use by volunteers across broad geographic extents and ranges of habitat fragmentation, can help us understand the reactions of some forest birds to acid rain in combination with habitat fragmentation. we detail the development of this protocol for volunteers in the birds in forested landscapes project, and describe future plans.",10,2006,11,1,,,,1,0,1,2"Britton-Simmons, KH","functional group diversity, resource preemption and the genesis of invasion resistance in a community of marine algae",OIKOS,Article,,"although many studies have investigated how community characteristics such as diversity and disturbance relate to invasibility, the mechanisms underlying biotic resistance to introduced species are not well understood. i manipulated the functional group composition of native algal communities and invaded them with the introduced, japanese seaweed sargassum muticum to understand how individual functional groups contributed to overall invasion resistance. the results suggested that space preemption by crustose and turfy algae inhibited s. muticum recruitment and that light preemption by canopy and understory algae reduced s. muticum survivorship. however, other mechanisms i did not investigate could have contributed to these two results. in this marine community the sequential preemption of key resources by different functional groups in different stages of the invasion generated resistance to invasion by s. muticum. rather than acting collectively on a single resource the functional groups in this system were important for preempting either space or light, but not both resources. my experiment has important implications for diversity-invasibility studies, which typically look for an effect of diversity on individual resources. overall invasion resistance will be due to the additive effects of individual functional groups (or species) summed over an invader's life cycle. therefore, the cumulative effect of multiple functional groups (or species) acting on multiple resources is an alternative mechanism that could generate negative relationships between diversity and invasibility in a variety of biological systems.",54,2006,113,3,395,401,,0,0,1,1"Rodriguez-Estrella, R; Carmen, M; Moreno, B","rare, fragile species, small populations, and the dilemma of collections",BIODIVERSITY AND CONSERVATION,Article,collections; conservation; rare species; small populations,"considerable sums of money are aimed at biodiversity conservation programs at present, and although collection of specimens is necessary for the advancement of taxonomy and systematics, we detected a dilemma between conservation and collection of rare species with small populations. collecting may act synergistically with other factors to increase the risk of, or even drive species to extinction. we present some examples we believe show the conflict between collecting rare species with a small population and the conservation programs for those species. we also stress the need to review the minimum viable population size concept as it can be used as a justification for collecting small, rare, and declining population species.",5,2006,15,5,1621,1625,10.1007/s10531-004-4308-6,1,0,0,1"Kellermann, VM; van Heerwaarden, B; Hoffmann, AA; Sgro, CM",very low additive genetic variance and evolutionary potential in multiple populations of two rainforest drosophila species,EVOLUTION,Article,adaptation; animal model; desiccation resistance; evolutionary potential; heritability; quantitative traits; rainforest,"most quantitative traits are thought to exhibit high levels of genetic variance and evolutionary potential. however, this conclusion may be biased by a lack of studies on nonmodel organisms and may not generalize to restricted species. a recent study on a single, southern population of the rainforest-restricted drosophila birchii failed to find significant additive genetic variance for the desiccation resistance trait; however, it is unclear whether this pattern extends to other d. birchii populations or to other rainforest species. here we use an animal model design to show very low levels of additive genetic variance for desiccation resistance in multiple populations of two highly sensitive rainforest species of drosophila from tropical northeastern australia. in contrast, relatively high levels of genetic variance were found for morphological traits in all populations of the species tested. this indicates limited evolutionary potential for evolving increased desiccation resistance in these rainforest restricted species.",60,2006,60,5,1104,1108,10.1554/05-710.1,0,0,1,1"Rohlfs, M",genetic variation and the role of insect life history traits in the ability of drosophila larvae to develop in the presence of a competing filamentous fungus,EVOLUTIONARY ECOLOGY,Article,genetic variation; heritability differences; insect-mould interaction; inter-kingdom competition; life history; survival,"competitive interactions between organisms from distantly related phylogenetical branches have been suggested as being one of the most pervasive forms of interspecific competition. however, so-called inter-kingdom competition has rarely been the focus of ecological and evolutionary studies. thus, a relatively novel hypothesis has been proposed on the basis that saprophagous insects might intensively compete with filamentous fungi for ephemeral resources (e.g. decaying plant tissue). consideration that life history traits (e.g. developmental time) are adaptive in determining developmental success in the presence of con- or hetero-specifics competitors implies that these traits have been progressively established by natural selection. because a similar scenario may apply to antagonistic interactions between saprophagous insects and filamentous fungi, one can expect the existence of heritable variation in developmental success when insect larvae are forced to grow in the presence of noxious mould. therefore, this study aimed at discovering whether a local population of drosophila melanogaster indeed harbours genetic variation in developmental success in the presence of the mould aspergillus niger. by using the isofemale line technique, single larvae forced to feed on fungal infected or uninfected substrate were analysed for variation in survival probability to the adult stage, developmental time and body size of emerged adults. i found genetic variation in survival probability in fungal infected substrates but not in uninfected larval food sources. mean developmental time and body size varied significantly among isofemale lines in both types of larval environment. survival was negatively correlated with developmental time on fungal infected substrate, but variation in developmental time on fungal-free substrates was not correlated with survival on fungal infected food patches. within-trait correlation between fungal infected and uninfected substrates was surprisingly weak, and developmental time was not correlated with body size. the results of this study demonstrate (a) the existence of genetic variation for larval developmental success in the presence of a. niger in a drosophila population, and (b) heritability of important insect life history traits differed as a function of the larval environment (fungal infected or uninfected feeding substrate). i discuss models that might explain heritability differences and the evolutionary consequences of these results.",13,2006,20,3,271,289,10.1007/s10682-006-0002-3,0,1,0,1"Cardinale, BJ; Hillebrand, H; Charles, DF",geographic patterns of diversity in streams are predicted by a multivariate model of disturbance and productivity,JOURNAL OF ECOLOGY,Article,species diversity; disturbance; primary production; freshwater algae; periphyton; stream ecosystem functioning; flood; river,"univariate explanations of biodiversity have often failed to account for broad-scale patterns in species richness. as a result, increased attention has been paid to the development and testing of more synthetic multivariate hypotheses. one class of multivariate hypotheses, founded in successional diversity theory, predict that species richness is jointly influenced by periodic disturbances that create new niche opportunities in space or time, and the production of community biomass that speeds displacement of inferior by superior competitors. while the joint response of diversity to disturbance and productivity has gained support from theoretical and small-scale experimental studies, evidence that corresponding patterns of biodiversity occur broadly across natural systems is scarce. using a data set that employed standardized methods to sample 85 streams throughout the mid-atlantic united states of america, we show that biogeographical patterns of primary producer diversity in stream ecosystems are consistent with the predictions of a multivariate model that incorporates disturbance frequency and community biomass production as independent variables. periphyton species richness is a concave-down function of disturbance frequency (mean no. floods year(-1)) and of biomass production (mu g of biomass accrual cm(-2) day(-1)), and an increasing function of their interaction. changes in richness across the disturbance x productivity response surface can be related to several predicted life-history traits of the dominant species. our findings complement prior studies by showing that multivariate models which consider interactive effects of community production and ecosystem disturbance are, in fact, candidate explanations of much broader patterns of richness in natural systems. because multivariate models predict synergistic effects of ecological variables on species diversity, human activities - which are simultaneously altering both the disturbance regime and productivity of streams - could be influencing biodiversity more than previously anticipated.",45,2006,94,3,609,618,10.1111/j.1365-2745.2006.01107.x,1,0,0,1"McKinney, ML","correlated non-native species richness of birds, mammals, herptiles and plants: scale effects of area, human population and native plants",BIOLOGICAL INVASIONS,Article,exotic; homogenization; human population; introduced species,"several extrinsic factors (area, native species diversity, human population size and latitude) significantly influence the non-native species richness of plants, over several orders of magnitude. using several data sets, i examine the role of these factors in non-native species richness of several animal groups: birds, mammals and herptiles (amphibians, reptiles). i also examine if non-native species richness is correlated among these groups. i find, in agreement with sax [2001, journal of biogeography 28: 139-150], that latitude is inversely correlated with non-native species richness of many groups. once latitude is accounted for, area, human population size and native plant species richness are shown to be important extrinsic factors influencing non-native animal species. of these extrinsic factors, human population size and native plant species richness are the best predictors of non-native animal species richness. area, human population size and native plant species richness are highly intercorrelated, along with non-native species richness of all taxa. indeed a factor analysis shows that a single multivariate axis explains over half of the variation for all variables among the groups. one reason for this covariation is that humans tend to most densely occupy the most productive and diverse habitats where native plant species richness is very high. it is thus difficult to disentangle the effects of human population size and native species richness on non-native species richness. however, it seems likely that these two factors may combine to increase non-native species richness in a synergistic way: high native species richness reflects greater habitat variety available for non-native species, and dense human populations (that preferentially occupy areas rich in native species) increase non-native species importation and disturbance of local habitats.",21,2006,8,3,415,425,10.1007/s10530-005-6418-9,1,0,0,1"Noel, HL; Hopkin, SP; Hutchinson, TH; Williams, TD; Sibly, RM",population growth rate and carrying capacity for springtails folsomia candida exposed to ivermectin,ECOLOGICAL APPLICATIONS,Article,Collembola; density dependence; Folsomia candida; food availability; microarthropod; soil; soil invertebrate; springtail,"forecasting the effects of stressors on the dynamics of natural populations requires assessment of the joint effects of a stressor and population density on the population response. the effects can be depicted as a contour map in which the population response, here assessed by population growth rate, varies with stress and density in the same way that the height of land above sea level varies with latitude and longitude. we present the first complete map of this type using as our model folsomia candida exposed to five different concentrations of the widespread anthelmintic veterinary medicine ivermectin in replicated microcosm experiments lasting 49 days. the concentrations of ivermectin in yeast were 0.0, 6.8 28.83 66.4 and 210.0 mg/l wet weight. increasing density and chemical concentration both significantly reduced the population growth rate of folsomia candida, in part through effects on food consumption and fecundity. the interaction between density and ivermectin concentration was ""less-than-additive,"" implying that at high density populations were able to compensate for the effects of the chemical. this result demonstrates that regulatory protocols carried out at low density (as in most past experiments) may seriously overestimate effects in the field, where densities are locally high and populations are resource limited (e.g., in feces of livestock treated with ivermectin).",13,2006,16,2,656,665,10.1890/1051-0761(2006)016[0656:PGRACC]2.0.CO;2,0,0,1,1"Zanette, L; Clinchy, M; Smith, JNM",combined food and predator effects on songbird nest survival and annual reproductive success: results from a bi-factorial experiment,OECOLOGIA,Article,food supplementation; nest predation; predator pressure; song sparrows,"food and predators have traditionally been viewed as mutually exclusive alternatives when considering factors affecting animal populations. this has led to long controversies such as whether annual reproductive success in songbirds is primarily a function of food-restricted production or predator-induced loss. recent studies on both birds and mammals suggest many of these controversies may be resolved by considering the combined effects of food and predators. we conducted a 2x2 manipulative food addition plus natural predator reduction experiment on song sparrows (melospiza melodia) over three consecutive breeding seasons. food and predators together affected partial clutch or brood loss, nest survival (total clutch or brood loss) and annual reproductive success. when combined, our two treatments reduced partial losses by more than expected if the effects of food and predators were independent and additive. food and predators also interacted in their effects on nest survival since food addition significantly reduced the rate of nest predation. while annual reproductive success was highly correlated with nest predation (r(2)=0.71) the strength of this relationship was reinforced by the indirect effects of food addition on nest predation. a stepwise multiple regression showed that the residual variation in annual reproductive success was explained by food effects on the total number of eggs laid over the season and the combined effects of food and predators on partial losses noted above. we conclude that annual reproductive success in song sparrows is a function of both food-restricted production and predator-induced loss and indirect food and predator effects on both clutch and brood loss. we highlight the parallels between our results and those from a comparable bi-factorial experiment on mammals because we suspect combined food and predator effects are likely the norm in both birds and mammals.",36,2006,147,4,632,640,10.1007/s00442-005-0330-y,0,0,1,1"Morgan, TJ; Mackay, TFC",quantitative trait loci for thermotolerance phenotypes in drosophila melanogaster,HEREDITY,Article,chill-coma recovery; environmental stress; heat-stress resistance; temperature stress; QTL,"for insects, temperature is a major environmental variable that can influence an individual's behavioral activities and fitness. drosophila melanogaster is a cosmopolitan species that has had great success in adapting to and colonizing diverse thermal niches. this adaptation and colonization has resulted in complex patterns of genetic variation in thermotolerance phenotypes in nature. although extensive work has been conducted documenting patterns of genetic variation, substantially less is known about the genomic regions or genes that underlie this ecologically and evolutionarily important genetic variation. to begin to understand and identify the genes controlling thermotolerance phenotypes, we have used a mapping population of recombinant inbred (ri) lines to map quantitative trait loci (qtl) that affect variation in both heat- and cold-stress resistance. the mapping population was derived from a cross between two lines of d. melanogaster (oregon-r and 2b) that were not selected for thermotolerance phenotypes, but exhibit significant genetic divergence for both phenotypes. using a design in which each ri line was backcrossed to both parental lines, we mapped seven qtl affecting thermotolerance on the second and third chromosomes. three of the qtl influence cold-stress resistance and four affect heat- stress resistance. most of the qtl were trait or sex specific, suggesting that overlapping but generally unique genetic architectures underlie resistance to low- and high-temperature extremes. each qtl explained between 5 and 14% of the genetic variance among lines, and degrees of dominance ranged from completely additive to partial dominance. potential thermotolerance candidate loci contained within our qtl regions are identified and discussed.",92,2006,96,3,232,242,10.1038/sj.hdy.6800786,0,0,1,1"Wayne, AF; Cowling, A; Lindenmayer, DB; Ward, CG; Vellios, CV; Donnelly, CF; Calvey, MC",the abundance of a threatened arboreal marsupial in relation to anthropogenic disturbances at local and landscape scales in mediterranean-type forests in south-western australia,BIOLOGICAL CONSERVATION,Review,,"this study investigated associations between the relative abundance of the threatened ngwayir (western ringtail possum, pseudocheirus occidentalis) and anthropogenic disturbances at local and landscape scales within the publicly-managed jarrah (eucalyptus marginata) forests of south-western australia. logging, fire, fox (vulpes vulpes) control and forest fragmentation were investigated in relation to the relative abundance of ngwayir at 90 sites within an area of 285,000 ha east of manjimup; the location of the last remaining substantial population of ngwayir in jarrah forest. overall, ngwayir abundance was greatest in areas with limited anthropogenic disturbance. at the local-scale, ngwayir abundance was negatively associated with greater fire intensity. at the landscape-scale, it was positively associated with fox control and negatively associated with forest fragmentation and distance from non-remnant vegetation (i.e., agriculture and tree plantations). abundance was also greatest in predominantly unlogged landscapes and in forests that had been regrowing for an average of 40 years since the landscape was most recently logged, in other words, where logging was historically least intense. interactions between fox control efforts and forest fragmentation were also important. this study emphasises the importance of conducting research at appropriate spatial scales and to account for the synergistic effects of the causes of decline. an adaptive management approach to the mitigation of the agents of decline is recommended. indirect evidence indicates that high value habitat for ngwayir has in all likelihood been selectively cleared for agriculture, owing to its fertile and productive nature. habitat loss is, therefore, also likely to be a major cause of the modern decline of the species. while many jarrah forest areas that support remaining high abundances of the ngwayir have been incorporated into reserves, conservation of ngwayir habitat and populations outside reserves also will be essential for the recovery and long-term viability of the species. (c) 2005 elsevier ltd. all rights reserved.",12,2006,127,4,463,476,10.1016/j.biocon.2005.09.007,1,0,0,1"Ernoult, A; Tremauville, Y; Cellier, D; Margerie, P; Langlois, E; Alard, D",potential landscape drivers of biodiversity components in a flood plain: past or present patterns?,BIOLOGICAL CONSERVATION,Review,co-inertia analyses; GAM; landscape history; species diversity; surrogate,"changes in landscape pattern under the control of agriculture intensification are considered to be an important driver of biodiversity and often a threat for conservation. the response of species to landscape changes is complex, including possible time lags, and depends on the taxonomic group. the search for surrogate species or surrogate data for biodiversity is confronted with this complexity. this study was conducted on two taxonomic groups (birds and vascular plants) for 20 sites each of 1km(2) equally distributed in the seine valley floodplain. for plants, two habitats were studied: grasslands and hedges. we used a generalised additive model (gam) and co-inertia analyses to determine whether present or past landscape attributes can best explain the biodiversity components (structure and composition). this study confirms the major role of landscape pattern attributes for predicting some metrics of biodiversity, e.g. species richness. but this study shows that potential drivers of biodiversity come from both the past and present landscape patterns. the quality of surrogates for biodiversity is strongly dependent on understanding the importance of past conditions. this suggests the need for more functional surrogates, taking into account the situation of equilibrium or non-equilibrium between biodiversity and its drivers. (c) 2005 elsevier ltd. all rights reserved.",20,2006,127,1,1,17,10.1016/j.biocon.2005.07.008,0,0,1,1"Schiffer, M; Gilchrist, AS; Hoffmann, AA","the contrasting genetic architecture of wing size, viability, and development time in a rainforest species and its more widely distributed relative",EVOLUTION,Article,coadapted gene complexes; Drosophila birchii; Drosophila serrata; epistasis; line-cross analysis; local adaptation; Montium subgroup,"divergence among populations can occur via additive genetic effects and/or because of epistatic interactions among genes. here we use line-cross analysis to compare the importance of epistasis in divergence among two sympatric drosophila species from eastern australia, one (d. serrata) distributed continuously and the other (d. birchii) confined to rainforest habitats that are often disjunct. for d. serrata, crosses indicated that development time and wing size differences were due to additive genetic effects, while for viability there were digenic epistatic effects. crosses comparing geographically close populations as well as those involving the most geographically distant populations (including the southern species border) revealed epistatic interactions, whereas crosses at an intermediate distance showed no epistasis. in d. birchii, there was no evidence of epistasis for viability, although for development time and wing size there was epistasis in the cross between the most geographically diverged populations. strong epistasis has not developed among the d. birchii populations, and this habitat specialist does not show stronger epistasis than d. serrata. given that epistasis has been detected in crosses with other species from eastern australia, including the recently introduced d. melanogaster, the results point to epistasis not being directly linked to divergence times among populations.",11,2006,60,1,106,114,,0,0,1,1"Roelofs, D; Overhein, L; de Boer, ME; Janssens, TKS; van Straalen, NM",additive genetic variation of transcriptional regulation: metallothionein expression in the soil insect orchesella cincta,HEREDITY,Article,cadmium; croquemort; heritability; metallothionein; Orchesella cincta; transcriptional regulation,"field-selected metal tolerance in orchesella cincta is correlated with overexpression of the single copy cadmium (cd) inducible metallothionein (mt). previously, we have demonstrated large phenotypic variation in mt gene expression, and a higher frequency of high-expression phenotypes in a tolerant population. here, we describe midparent offspring regression analysis of mt gene expression in a laboratory culture originating from a noncontaminated natural population. families were either not exposed (n = 47) or exposed to 0.5 mu mol cd per gram dry food (n = 46). mean mt gene expressions normalized to 28s rrna and beta-actin rna were generated using real-time rt-pcr applied to parents and offspring rna and subjected to regression analysis. a significant heritability (h(2)) for mt gene expression was estimated between 0.36 (beta-actin normalized) and 0.46 (28s normalized) in cd exposed families. nontreated families did not yield a significant h(2) value. restriction fragment length polymorphism analysis of the metallothionein promoter sequence revealed eight promoter alleles that show structural variation. three alleles show increased frequencies in families with high mt expression. another gene, croquemort (isolated from a differential screening for 1 mu mole cd treatment) showed no h(2) of gene expression in response to 0.5 mmol cd. this gene codes for a receptor-protein involved in recognition of apoptotic cells and may participate in the general stress response. the present data suggest that evolution of metal tolerance in o. cincta can occur in the field by selection for high mt expression due to structural changes in mt cis-regulation.",32,2006,96,1,85,92,10.1038/sj.hdy.6800756,0,0,1,1"Hoffmann, A; Kellermann, V",revisiting heritable variation and limits to species distribution: recent developments,ISRAEL JOURNAL OF ECOLOGY & EVOLUTION,Article; Proceedings Paper,environmental variation; evolutionary limits; gene flow; heritability; species borders; transplant experiments,"there are several evolutionary reasons why species distributions are locally and geographically limited, and these mostly revolve around gene flow and levels of genetic variation in populations. while there has been progress in developing models assessing the impact of gene flow, empirical data on hypotheses about factors limiting distributions remain rare. a few recent plant studies have highlighted that levels of additive genetic variance are not limiting, suggesting a role for gene flow. however, some animal studies, mostly on drosophila species, have refocused attention on heritable variation as an evolutionary reason for distribution limits. there is a need for comparative studies that examine levels of heritable variation across related species groups with broad and narrow distributions, and also across a range of traits including those likely to be under selection at borders. these studies will help to lest specific predictions about the relative importance of genetic variance and gene flow in limiting current borders and also help in predicting the impact of future environmental changes on distribution shifts.",6,2006,52,04-Mar,247,261,10.1560/IJEE_52_3-4_247,0,0,1,1"Vermeulen, CJ; Bijlsma, R",changes in genetic architecture during relaxation in drosophila melanogaster selected on divergent virgin life span,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,aging; artificial selection; Drosophila melanogaster; genetic architecture; life history; life span; relaxation; reproduction; reversed selection; trade-off,"artificial selection experiments often confer important information on the genetic correlations constraining the evolution of life history. after artificial selection has ceased however, selection pressures in the culture environment can change the correlation matrix again. here, we reinvestigate direct and correlated responses in a set of lines of drosophila melanogaster that were selected on virgin life span and for which selection has been relaxed for 10 years. the decrease in progeny production in long-lived lines, a strong indication of antagonistic pleiotropy, had disappeared during relaxation. this was associated with a higher cost of reproduction to long-lived flies in mated, but not in virgin life span. these data strongly suggest that genetic mechanisms of mated and virgin life span determination are partly independent. furthermore, data on body weight, developmental time and viability indicated deleterious effects of longevity selection in either direction, giving rise to a nonlinear relationship with life span for these characters. in order to reclaim original patterns, we founded a new set of derived lines by resuming selection in mixed replicate lines of the original set. although selection was successful, most patterns in correlated characters remained, showing that these new patterns are resistant to new episodes of selection.",15,2006,19,1,216,227,10.1111/j.1420-9101.2005.00972.x,0,1,0,1"Rauser, CL; Tierney, JJ; Gunion, SM; Covarrubias, GM; Mueller, LD; Rose, MR",evolution of late-life fecundity in drosophila melanogaster,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,aging; antagonistic pleiotropy; fecundity; fecundity plateau; force of natural selection; late life; mortality; mortality-rate plateau; viability,"late-life fecundity has been shown to plateau at late ages in drosophila analogously to late-life mortality rates. in this study, we test an evolutionary theory of late life based on the declining force of natural selection that can explain the occurrence of these late-life plateaus in drosophila. we also examine the viability of eggs laid by late-age females and test a population genetic mechanism that may be involved in the evolution of late-life fecundity: antagonistic pleiotropy. together these experiments demonstrate that (i) fecundity plateaus at late ages, (ii) plateaus evolve according to the age at which the force of natural selection acting on fecundity reaches zero, (iii) eggs laid by females in late life are viable and (iv) antagonistic pleiotropy is involved in the evolution of late-life fecundity. this study further supports the evolutionary theory of late life based on the age-specific force of natural selection.",20,2006,19,1,289,301,10.1111/j.1420-9101.2005.00966.x,0,1,0,1"Rot-Nikcevic, I; Denver, RJ; Wassersug, RJ",the influence of visual and tactile stimulation on growth and metamorphosis in anuran larvae,FUNCTIONAL ECOLOGY,Article,corticosterone; development; mechanoreception; tadpoles; vision,"1. sensory modalities that allow tadpoles to assess their environment, and subsequently mediate their development, are not well understood. 2. by putting clay model tadpoles into the tanks with live tadpoles we have enhanced tactile and visual stimuli for tadpoles of three species (rana sylvatica, bufo americanus and xenopus laevis) in a controlled fashion. the goal was to determine whether visual and tactile cues in the absence of chemical signals influenced tadpole growth and development. 3. the response to enhanced visual and tactile stimuli was strong in rana, intermediate in xenopus, but absent in bufo tadpoles. rana tadpoles that experienced both stimuli enhanced developed the fastest and metamorphosed at the smallest body size. development was slower in the treatments with only one stimulus enhanced, and slowest in the controls. 4. our results suggest that tadpoles use both vision and mechanoreception for environment assessment, and that they are able to modify their growth and developmental rates in response to sensory enrichment. 5. tadpoles exposed to the combination of visual and tactile stimulation showed the highest whole-body content of the stress hormone corticosterone, suggesting that the enhanced stimuli were experienced as stressful. corticosterone is known to synergize with thyroid hormone to promote metamorphosis.",17,2005,19,6,1008,1016,10.1111/j.1365-2435.2005.01051.x,1,0,0,1"Havens, KE; Gawlik, DE",lake okeechobee conceptual ecological model,WETLANDS,Review,shallow lake; littoral zone; wetland; water level; nutrient loading; conceptual model,"with a surface area of nearly 1,800 square kilometers, lake okeechobee is a prominent central feature of the south florida aquatic ecosystem. the lake provides regional flood protection, supports a prized recreational fishery, provides habitat for migratory waterfowl and regional wading bird populations, and is a source of fresh water for irrigation, drinking, and restoration of downstream ecosystems. the main stressors on lake okeechobee are (1) large inputs of phosphorus from agricultural and other anthropogenic land uses in the watershed, (2) unnatural variation in water levels due to channelization of inflows and dike containment, and (3) rapid expansion of non-native plants. ecological effects are complicated due to three distinct in-lake zones with different water chemistry, physical properties, and biota. a central pelagic zone has turbid, nutrient-rich water and phytoplankton dominance; a shallow south and western near-shore zone has submerged plant or phytoplankton dominance (at low vs. high water levels, respectively); and a western littoral zone is dominated by emergent wetland plants. changes in water level influence the flow of nutrients between zones, thereby creating a synergistic effect between stressors. under high water conditions, there is considerable advective transport of nutrients from the pelagic zone into the littoral zone. under low water conditions, the littoral zone is cut off hydrologically and is a rainfall-driven oligotrophic wetland. low water also facilitates drying and wildfires in the littoral zone, which in turn has an influence on expansion of non-native plants and recovery of native plants from buried seed banks. all of these factors influence fish, wading birds, and other animals, which depend on littoral and near-shore plant communities for nesting and foraging habitat. this paper describes our current knowledge of these complex processes, the lake's expected responses to ongoing and planned restoration programs, and key areas of uncertainty requiring future research.",17,2005,25,4,908,925,10.1672/0277-5212(2005)025[0908:LOCEM]2.0.CO;2,1,0,0,1"Moe, SJ; Kristoffersen, AB; Smith, RH; Stenseth, NC",from patterns to processes and back: analysing density-dependent responses to an abiotic stressor by statistical and mechanistic modelling,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,non-parametric modelling; generalized additive modelling; time-series analysis; stage-specific density dependence; density toxicant interaction,"our knowledge about population-level effects of abiotic stressors is limited, largely due to lack of appropriate time-series data. to analyse interactions between an abiotic stressor and density-dependent processes, we used experimental time-series data for stage-structured populations (the blowfly lucilia sericata) exposed to the toxicant cadmium through 20 generations. resource limitation results in competition both in the larval and the adult stages. the toxicant has only negative effects at the organism level, but nevertheless, there were positive population-level effects. these are necessarily indirect, and indicate overcompensatory density-dependent responses. a non-parametric model (generalized additive model) was used to investigate the density-dependent structures of the demographic rates, without making assumptions about the functional forms. the estimated structures were used to develop a parametric model, with which we analysed effects of the toxicant on density-dependent and density-independent components of the stage-specific demographic rates. the parameter estimates identified both synergistic and antagonistic density-toxicant interactions. it is noteworthy that the synergistic interaction occurred together with a net positive effect of the toxicant. hence, the effects of such interactions should be considered together with the capacity for compensatory responses. the combination of the two modelling approaches provided new insight into mechanisms for compensatory responses to abiotic stressors.",9,2005,272,1577,2133,2142,10.1098/rspb.2005.3184,1,1,1,3"De Bello, F; Leps, J; Sebastia, MT",predictive value of plant traits to grazing along a climatic gradient in the mediterranean,JOURNAL OF APPLIED ECOLOGY,Article,CCA; disturbance; land-use change; plant functional group; phylogeny; regression tree; sheep,"1. in the face of large-scale environmental changes, predicting the consequences for species composition from species' traits can be a major step towards generalizing ecological patterns and management. few studies, however, have explored the applicability of this tool in relation to different climatic conditions. here, the changes in species composition along a gradient of sheep-grazing pressure (high, low, abandonment) were used to test whether a common set of plant functional traits (pft) would provide consistent predictions of species' responses to grazing in different biogeographical regions. 2. data were collected across an altitudinal and climatic gradient from mediterranean rangelands to subalpine grasslands in north-eastern spain. species' responses were calculated using partial constrained ordination to account only for the effect of grazing intensity. regression trees and general linear models were applied to identify traits that could predict species' responses. 3. results were mostly consistent with the ruderal vs. competitive strategy (sensu grime), in terms of life cycle, life form and plant height, and their expected responses to repeated disturbance. 4. however, the predictive capacity of the investigated traits changed with climatic conditions. traits generally related to grazing did not show a strong repeatability across the climatic gradient. convergent selection of climatic conditions and grazing indicated that plant features might reflect an adaptation to multiple selective forces. the climatic conditions acted as filters on the pool of pft available and shifted the relevance of plant traits as potential predictors. results were not substantially different after applying phylogenetically independent contrasts (pic). 5. synthesis and applications. at a local scale, plant functional traits are useful tools in predicting species' responses to grazing and, for conservation purposes, identifying species vulnerable to land-use changes. however, predictions cannot be extrapolated from one climatic region to another. the methodology proposed in this study to detect predicting traits can be applied more generally. regression trees, in particular, appear to be a useful tool because they account for non-additive effects and allow visualizations of trait combinations.",84,2005,42,5,824,833,10.1111/j.1365-2664.2005.01079.x,0,0,1,1"Joern, A; Mole, S","the plant stress hypothesis and variable responses by blue grama grass (bouteloua gracilis) to water, mineral nitrogen, and insect herbivory",JOURNAL OF CHEMICAL ECOLOGY,Article,chewing insects; environmental stress hypothesis; functional-convergence-to-plant-stress hypothesis; grasshopper; insect herbivory; total foliar nitrogen; total nonstructural carbohydrates,"acting simultaneously or sequentially, plants encounter multiple stresses from combined abiotic and biotic factors that result in decreased growth and internal reallocation of resources. the plant stress hypothesis predicts that environmental stresses on plants decrease plant resistance to insect herbivory by altering biochemical source-sink relationships and foliar chemistry, leading to more palatable food. such changes in the nutritional landscape for insects may facilitate insect population outbreaks during periods of moderate stress on host plants. we examined the plant stress hypothesis with field experiments in continental grassland (usa) using the c-4 grass bouteloua gracilis. water, nitrogen fertilizer, and herbivory from the grass-feeding grasshopper ageneotettix deorum were manipulated. combined stresses from water and mineral-n in the soil decreased plant growth and altered foliar percent total n (tn) and percent total nonstructural carbohydrate (tnc) concentrations in an additive fashion. grasshopper herbivory affected final biomass only in dry years; plants compensated for tissue loss when rainfall was abundant. foliar tn and tnc concentrations were dynamic with respect to variable climatic conditions and treatment combinations, showing significant interactions. grasshopper herbivory had its greatest impact on tn or tnc in dry years, interacting with other forms of stress. herbivory as a single factor had strong effects on tnc in years with normal precipitation, but not in a dry year. performance (developmental rate and survival) by the grasshoppers phoetaliotes nebrascensis and a. deorum were not greatly affected by plant stress in a manner consistent with the plant stress hypothesis.",22,2005,31,9,2069,2090,10.1007/s10886-005-6078-3,0,0,1,1"Miller, DL; Smeins, FE; Webb, JW; Yager, L","mid-texas, usa coastal marsh vegetation pattern and dynamics as influenced by environmental stress and snow goose herbivory",WETLANDS,Article,patch dynamics; coastal marsh ecotone; drought; snow goose herbivory; cyclic succession,"vegetation pattern and dynamics were characterized across a mid-texas, usa coastal marsh ecotone subjected to snow goose herbivory, drought, and salt-water pulses. for eight years following snow goose feeding, species cover was evaluated in heavy and light goose-use patches at increasing distances from tidal influence. just prior to and for two years after the feeding event, drought, and several salt-water pulses associated with tropical storms typified the hydrologic dynamics of the marsh. herbivory history was more important than distance from tidal influence, salinity, or flooding in explaining spatial and temporal vegetation pattern for three years. precipitation variation influenced vegetation dynamics in areas heavily used by geese. recovery to pre-herbivory composition and abundance required six years without further snow goose feeding. extremes of annual precipitation, salinities, and water levels impacted cover of spartina patens dominated patches little unless feeding snow geese uprooted vegetation. schoenoplectus americanus was more impacted by extremes of environmental dynamics than s. patens but even more impacted by synergistic effects of uprooting and environmental extremes. during this period, the ecotone could be characterized as patchy, with a gulfward waxing and waning of s. americanus.",9,2005,25,3,648,658,10.1672/0277-5212(2005)025[0648:MUCMVP]2.0.CO;2,1,0,0,1"Martorell, C; Peters, EM",the measurement of chronic disturbance and its effects on the threatened cactus mammillaria pectinifera,BIOLOGICAL CONSERVATION,Article,methods; overgrazing; land use; land degradation; density; multimetric indices,"measuring how anthropogenic disturbance affects biological systems is crucial for conservation and management. however, it is often difficult to quantify disturbance when it occurs in a slow, long-lasting - or chronic - fashion. because various human activities influence gradually an area, chronic disturbance must be measured on a continuous scale that accounts for different sources of disturbance. here we propose a method to develop multimetric indices for chronic disturbance. the approach is exemplified by considering the effects of disturbance on the threatened cactus mammillaria pectinifera. fourteen indicators of three agents of disturbance (human activities, livestock raising and land degradation) were measured in 10 populations of m. pectinifiera, and summarised through principal components analysis (pca). an index for each agent was also developed. m. pectinifera achieved maximum density at intermediate values of the first pca axis, which was related to disturbance intensity. assessing only both extremes of the disturbance gradient, where density is low, would erroneously suggest that disturbance has no effect on this plant. the different disturbance agents act synergistically on m. pectinifera, and their combined effects are detrimental. land degradation reduces plant density, while livestock enhances it. however, overgrazing promotes degradation, so maintaining appropriate livestock levels is critical for management. our method allowed us to identify which agents have more impact on threatened species, and sets the basis to manage disturbance agents in a way compatible with conservation. the method proposed here can be easily modified for its use in other environments and to account for different forms of anthropogenic disturbance. (c) 2005 elsevier ltd. all rights reserved.",35,2005,124,2,199,207,10.1016/j.biocon.2005.01.025,1,0,0,1"Moritz, MA; Odion, DC",examining the strength and possible causes of the relationship between fire history and sudden oak death,OECOLOGIA,Article,epidemiology; fire history; landscape pattern; plant disease ecology; Phytophthora ramorum; spatial analysis,"fire can be a dominant process in the ecology of forest vegetation and can also affect forest disease dynamics. little is known about the relationship between fire and an emerging disease epidemic called sudden oak death, which is caused by a new pathogen, phytophthora ramorum. this disease has spread across a large, fire-prone portion of california, killing great numbers of oaks and tanoaks and infecting most associated woody plants. suitable hosts cover a much broader geographic range, raising concern over where the disease may spread. to understand the strength and potential sensitivities of a fire-disease relationship, we examined geographic patterns of confirmed p. ramorum infections in relation to past fire history. we found these infections to be extremely rare within the perimeter of any area burned since 1950. this finding is not caused by spatial bias in sampling for the disease, and is robust to variation in host abundance scenarios and to aggregation of closely spaced sampling locations. we therefore investigated known fire-related factors that could result in significantly lower incidence of the disease in relatively recently burned landscapes. chemical trends in post-fire environments can influence the success of pathogens like p. ramorum, either by increasing plant nutrient stress or by reducing the occurrence of chemicals antagonistic to phytophthoras. succession in the absence of fire leads to greater abundance of host species, which will provide increased habitat for p. ramorum; this will also increase intraspecific competition where these trees are abundant, and other density-dependent effects (e.g. shading) can reduce resource allocation to defenses. despite these findings about a fire-disease relationship, a much deeper understanding is necessary before fire can be actively used as a tool in slowing the epidemic.",14,2005,144,1,106,114,10.1007/s00442-005-0028-1,0,1,0,1"Oksanen, E; Riikonen, J; Kaakinen, S; Holopainen, T; Vapaavuori, E",structural characteristics and chemical composition of birch (betula pendula) leaves are modified by increasing co2 and ozone,GLOBAL CHANGE BIOLOGY,Article,anatomy; Betula pendula; birch; cell wall chemistry; CO2; interaction; nutrient content; ozone; ultrastructure,"impacts of ozone and co2 enrichment, alone and in combination, on leaf anatomical and ultrastructural characteristics, nutrient status and cell wall chemistry in two european silver birch (betula pendula roth) clones were studied. the young soil-growing trees were exposed in open-top chambers over three growing seasons to 2 x ambient co2 and/or ozone concentrations in central finland. the trees were measured for changes in altogether 35 variables of leaf structure, nutrients and cell wall chemistry of green leaves, and 20 of the measured variables were affected by co2 and/or o-3. elevated co2 increased the size of chloroplasts and starch grains, number of mitochondria, p : n ratio, and contents of cell wall hemicellulose. elevated co2 decreased the total leaf thickness, specific leaf area, concentrations of n, k, cu, s and fe, and contents of cell wall α-cellulose, uronic acids, acid-soluble lignin and acetone-soluble extractives. elevated ozone led to thinner leaves, higher palisade to spongy ratio, increased number of peroxisomes and mitochondria, reduced content of mn, zn, cu, hemicellulose and uronic acids, and lower mn : n and zn : n ratios. in the combined exposure, interactions were antagonistic. ultrastructural changes became more evident towards the end of the exposure. young leaves were tolerant against ozone-caused oxidative stress, whereas oxidative h2o2 accumulation was found in older leaves. co2 enrichment improved ozone tolerance not only through increased photosynthesis rates, but also through changes in cell wall chemistry (hemicellulose, in particular). however, nutrient imbalances due to ozone and/or co2 may predispose the trees to other biotic and abiotic stresses. down-regulation and up-regulation of photosynthesis under elevated co2 through anatomical changes is discussed.",50,2005,11,5,732,748,10.1111/j.1365-2486.2005.00938.x,0,1,0,1"Duriez, O; Eraud, C; Barbraud, C; Ferrand, Y",factors affecting population dynamics of eurasian woodcocks wintering in france: assessing the efficiency of a hunting-free reserve,BIOLOGICAL CONSERVATION,Article,Eurasian woodcock; Scolopax rusticola; game species; survival; hunting effect; predation; population matrix model,"the eurasian woodcock scolopax rusticola is a migratory bird of major importance for hunting, which is susceptible to habitat loss and the stochastic effects of severe winter weather. conservation issues mostly concerned regulation of hunting, but the efficiency of hunting-free reserves has never been investigated. we studied causes of mortality and survival probabilities of 98 radio-tagged woodcocks in a reserve with no hunting and in an adjoining hunting area in brittany (france). predation, mostly by mammalian predators on fields at night, was similar among adults and yearlings, while hunting mortality was more important in yearlings. overall winter survival probabilities were 0.86 +/- se 0.07 in adults and 0.63 +/- se 0.07 in yearlings. survival probabilities of both age classes increased as birds spent more time in the reserve. equality of predation in both reserve and hunting areas suggests an additive mortality due to hunting over the winter. population matrix models predicted that such low survival probabilities cannot sustain long term viable populations. these results call for caution in the harvesting of woodcock populations wintering in western france and could be a forewarning of a decline. the regulation of hunting by setting bag limits or reducing the length of shooting seasons, or the creation of reserves might be appropriate tools for the sustainable management of woodcock populations. (c) 2004 elsevier ltd. all rights reserved.",19,2005,122,1,89,97,10.1016/j.biocon.2004.07.002,0,0,1,1"Osunkoya, OO; Othman, FE; Kahar, RS","growth and competition between seedlings of an invasive plantation tree, acacia mangium, and those of a native borneo heath-forest species, nelastoma beccarianum",ECOLOGICAL RESEARCH,Article,additive design; biological invasion; growth performance; heath (kerangas) forest; relative growth rate,"an introduced plantation tree species, acacia mangium willd., is becoming invasive in the brunei region of borneo. to examine its invasive potential, a greenhouse, additive series experiment (target-neighbour) involving seedlings of a. mangium and those of a common native heath-forest (kerangas), melastoma beccarianum cogn. was carried out under low and high light regimes in intra- and interspecific combinations over a 6-month period. significant variations in growth parameters (other than biomass allocation patterns) existed amongst seedlings from different treatments. a major part of this variation in growth could be attributed to the main factors of target species., neighbour species, and competition (seedling density). for the growth variables examined, the target-species response was not consistent across light regimes. under high light conditions, acacia was the better competitor; the lotka-volterra competition coefficient effect of melastoma on acacia was lower (alpha = 0.30) than the effect of acacia on melastoma (beta = 0.54). however, the reverse occurred under low light conditions with melastoma gaining the upper hand (alpha = 1.45 and beta = 0.44). these results show that light (and hence disturbance) can strongly influence the pattern and intensity of both intra- and interspecific competition between invasive and local flora species. relatively intact forest is unlikely to be invaded by acacia trees (as they are poor competitors under this scenario). on the other hand, the acacia trees can easily invade disturbed forests, especially those prone to recurring drought and fire, and over time convert the habitats to nearly monospecific stands, as is presently being observed in brunei.",25,2005,20,2,205,214,10.1007/s11284-004-0027-4,0,0,1,1"Polak, M; Starmer, WT",environmental origins of sexually selected variation and a critique of the fluctuating asymmetry-sexual selection hypothesis,EVOLUTION,Article,Drosophila bipectinata; environmental variation; fluctuating asymmetry; genetic variation; genotype by environment interaction; sex comb; sexual selection; thermal stress; Y chromosome,"identifying sources of phenotypic variability in secondary sexual traits is critical for understanding their signaling properties. role in sexual selection, and for predicting their evolutionary dynamics. the present study tests, for till effects of genotype, developmental temperature, and their interaction, on size and fluctuating asymmetry of the male sex comb. a secondary sexual character, in drosophila bipectinata duda. both the size and symmetry of elements of the sex comb have been shown previously to be under sexual selection in a natural population in northeastern australia. two independent reciprocal crosses were conducted at 25 degrees and 29 degrees c between genetic lines extracted from this population that differed in the size of the first (tc1) and third (tc3) comb segments. these temperatures are within the documented range experienced by the species in nature. additive and dominance genetic effects were detected for tc1. whereas additive genetic, and y-chromosomal effects were detected for tc3. tc2 and tc3 decreased sharply with increasing temperature, by 10% and 22%, respectively. in contrast, positional fluctuating asymmetry (pfa) significantly increased with temperature, by up to 38%. the results (1) document an important source of environmental variance in a sexual ornament expected to reduce trait heritability in field populations, and thus act to attenuate response to sexual selection, (2) suggest that variation in ornament size reflects differences in male condition; and (3) support the general hypothesis that asymmetry in a sexual ornament is indicative of developmental instability arising from environmental stress. the ""environmental heterogeneity'' (eh) hypothesis is proposed, and supportive evidence for it presented, to explain negative size-fa correlations in natural populations. data and theory challenge the use of negative size-fa correlations observed in nature to support the fa-sexual selection hypothesis, which posits that such correlations are driven by differences in genetic quality among individuals.",28,2005,59,3,577,585,,0,0,1,1"Przeslawski, R; Davis, AR; Benkendorff, K",synergistic effects associated with climate change and the development of rocky shore molluscs,GLOBAL CHANGE BIOLOGY,Article,egg mass; global climate change; intertidal; invertebrate development; mollusc; salinity; synergistic effects; temperature; UVR,"global climate change and ozone layer thinning will simultaneously expose organisms to increasingly stressful conditions. early life stages of marine organisms, particularly eggs and larvae, are considered most vulnerable to environmental extremes. here, we exposed encapsulated embryos of three common rocky shore gastropods to simultaneous combinations of ecologically realistic levels of ultraviolet radiation (uvr), water temperature stress and salinity stress to identify potential interactions and associated impacts of climate change. we detected synergistic effects with increases in mortality and retardation in development associated with the most physiologically stressful conditions. the effects of uvr were particularly marked, with mortality increasing up to 12-fold under stressful conditions. importantly, the complex outcomes observed on applying multiple stressors could not have been predicted from examining environmental variables in isolation. hence, we are probably dramatically underestimating the ecological impacts of climate change by failing to consider the complex interplay of combinations of environmental variables with organisms.",66,2005,11,3,515,522,10.1111/j.1365-2486.2005.00918.x,1,0,0,1"Leamy, LJ; Workman, MS; Routman, EJ; Cheverud, JM",an epistatic genetic basis for fluctuating asymmetry of tooth size and shape in mice,HEREDITY,Article,epistasis; molar size/shape; fitness; fluctuating asymmetry; mice; QTLs,"although there typically is little additive genetic variation for fluctuating asymmetry ( fa), or variation in nondirectional differences between left and right sides of bilateral characters, several investigators have hypothesized that fa may have an epistatic genetic basis. we tested this hypothesis by conducting a whole genome scan of fa of size and shape of the mandibular molars in house mice from an f-2 intercross population generated from crossing the large (lg/j) and small (sm/j) inbred strains. although no individual genes (qtls = quantitative trait loci) on any of the 19 autosomes significantly affected fa for centroid size, and only two affected shape fa, a number of pairwise combinations of qtls exhibited significant epistasis for fa in both molar size and shape. the qtls involved in these interactions differed for fa in molar size versus fa in molar shape, but their epistatic contributions to the total variance was nearly the same ( about 20%) for fa in both molar characters. it was noted that the genetic architecture of fa in the molar characters, consisting of little or no additive genetic variance but an abundance of epistatic genetic variance, is consistent with that of other typical fitness components such as litter size.",22,2005,94,3,316,325,10.1038/sj.hdy.6800637,0,0,1,1"Walton, JC; Martinez-Gonzalez, F; Worthington, R",desert vegetation and timing of solar radiation,JOURNAL OF ARID ENVIRONMENTS,Article,solar radiation; water stress; evapo-transpiration; Chihuahuan Desert,"timing and amount of solar radiation were examined as factors influencing the distribution of seven perennial plants on a small mountain located in the chihuahuan desert. average direct beam solar radiation fluxes at differing times throughout the day and year were estimated with computer calculations. principal components analysis was used to reduce the number of solar radiation parameters and include the maximum available information with a manageable number of variables. the remaining solar radiation parameters were compared to plant distributions using redundancy analysis and generalized additive models. unimodal, bimodal, and monotonic responses were all found depending upon the species and solar radiation parameter. niche separation at this location depends upon the timing as well as the amount of solar radiation. (c) 2004 elsevier ltd. all rights reserved.",5,2005,60,4,697,707,10.1016/j.jaridenv.2004.07.016,0,0,1,1"Natori, Y; Fukui, W; Hikasa, M",empowering nature conservation in japanese rural areas: a planning strategy integrating visual and biological landscape perspectives,LANDSCAPE AND URBAN PLANNING,Article; Proceedings Paper,landscape approach; local participation; rural environment; nature conservation planning; mapping,"there has been much discussion about the importance of nature conservation, but a concrete strategy has been lacking. most conservation measures are reactive to development projects that threaten the sites' conservation values. there is little synergy between nature conservation and other competing land-use policies. furthermore, conservation messages are not communicated well because there are few opportunities for those involved in research, policy formation and policy implementation to interact. we illustrate the methodological framework that can be used to address these issues in rural nature conservation by presenting our research conducted in the arai-keinan district of niigata, japan. the proposed methodological framework consists of integrating visual and biological landscape approaches to understand the area's natural environment and using participatory research to narrow the communication gaps among those involved. we stress the importance of expressing the research results and recommendations on a map as a strategy for effective nature conservation. the graphical presentation of a map not only allows for clearer delivery of messages from researchers to government officials and residents, but also facilitates coordination among competing land-use policies. the map is the central ammunition in reversing the reactive nature of conservation policies to that of a ""preemptive"" nature. future research directions to gain stronger political support are also discussed. (c) 2003 elsevier b.v. all rights reserved.",5,2005,70,04-Mar,315,324,10.1016/j.landurbplan.2003.10.025,1,0,0,1"Asquith, NM; Mejia-Chang, M","mammals, edge effects, and the loss of tropical forest diversity",ECOLOGY,Article,"agouti; Burro Colorado Island, Panama; Dasyprocta spp.; edge effects; irrigation experiments; island biogeography; Proechimys semispinosus; Protium panamense; seed dispersal; seedling herbivory; spiny rat; tropical forest diversity","relative to the surrounding mainland forests, a subset of tree species dominates wind-exposed, forested islands in gatun lake, panama. we explored how tree diversity in these fragments has been affected by (1) impoverishment of the mammal community and (2) changes in abiotic conditions following island formation ca. 90 years ago. to test effects of changes in the mammal community, we assessed seed and seedling survival for nine tree species in five forests: small islands with no mammals; small islands with spiny rats but no larger mammals; medium islands (intermediate mammal community); barro colorado island (intermittently present puma and jaguar); and mainland forests (intact mammal community). to test effects of abiotic stress, we chose experimental sites at wind-exposed, wind-protected, and interior forest sites. we predicted that fragments with less diverse mammal communities would be characterized by (1) fewer seeds dispersed and cached, (2) lower long-term seed survival, and (3) higher rates of seedling herbivory by mammals. where alteration of the environment has caused greater exposure to dry-season winds, we predicted that (4) germination and seedling establishment and (5) dry-season seedling survival would be low. further, we expected that (6) dry-season seedling survival would increase if soil moisture levels were raised, but that (7) wet-season seedling survival is independent of wind exposure. in the larger forests, seed and seedling survival were low, and differences in mammal community composition had little effect. small islands that supported only rats had the same low seed survival as larger forests. elimination of all mammals resulted in much higher seed survival, and slightly higher seedling survival. germination and seedling survival were lower at wind-exposed than at protected sites, but irrigation had no effect on dry-season seedling survival. it appears that the dominant species on gatun lake fragments have passed through a series of filters: seeds must first avoid being eaten by spiny rats, survive the first dry season, and then avoid seedling herbivory by rats. biotic and abiotic factors determine seedling survival in tropical forests; synergistic changes in these factors can thus lead to dramatic losses of diversity.",28,2005,86,2,379,390,10.1890/03-0575,1,0,0,1"Vandvik, V; Heegaard, E; Maren, IE; Aarrestad, PA",managing heterogeneity: the importance of grazing and environmental variation on post-fire succession in heathlands,JOURNAL OF APPLIED ECOLOGY,Article,Calluna vulgaris; conservation management; disturbance regimes; diversity; generalized linear models; interactive effects; principal response curves; spatial variation,"1. semi-natural habitats have been shaped by human disturbance regimes for centuries. spatially and temporally heterogeneous land-use practices, such as cutting, burning, grazing and turf-cutting, have resulted in complex mosaic landscapes that are of high priority for conservation in europe. contemporary conservation subjects these systems to management regimes that are generally less diverse, in terms of disturbances and fine-scale temporal and spatial variability, than traditional land use, but the ecological consequences of these simplifications are unclear. 2. we investigated the interactive effects of fire and grazing on plant species composition and diversity along local environmental (moisture) gradients in coastal heathlands. a replicated series of post-fire successions (n = 12) was initiated in three heathland habitats and the areas subjected to two grazing regimes. floristic and environmental data were recorded in permanent plots over a 5-year period. community data were analysed using multivariate ordination techniques (principal components analysis, partial redundancy analyses, and principal response curves) and generalized linear models. 3. fire induced strong successional trends in the species composition of the heathlands. these trends differed among heathland habitats, and with grazing. strong interactions between fire, habitat and grazing implied that the effect of grazing on the successional dynamics differed among habitats. species diversity decreased in the first year after fire but increased beyond the pre-fire levels during succession. this trend was not affected by local environment or grazing, although there were main effect differences in diversity between environments and grazing regimes. 4. synthesis and applications. our results demonstrate that the two management practices do not have simple additive effects within the semi-natural system studied, as grazing created ecological opportunities for additional sets of species, increased variability among habitats, and added complexity to the post-fire successional dynamics. in order to preserve diversity, conservation management should thus aim to preserve the level of complexity of the traditional management regimes, both in terms of the actual disturbances (e.g. fire and grazing) as well as the spatial scales at which they are applied. further, the considerable change in these effects along the local environmental gradient brings into question the efficiency of general management prescriptions, and indicates that local environmental variability should be taken into account in the conservation of semi-natural habitats.",64,2005,42,1,139,149,10.1111/j.1365-2664.2005.00982.x,0,0,1,1"Leamy, LJ; Klingenberg, CP",the genetics and evolution of fluctuating asymmetry,ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS,Review; Book Chapter,developmental instability; dominance; epistasis; heritability,"variation in the subtle differences between right and left sides of bilateral characters, or fluctuating asymmetry (fa), has long been considered to be primarily environmental in origin, and this has promoted its use as a measure of developmental instability (di) in populations. there is little evidence for specific genes that govern fa per se. numerous studies show that fa levels in various characters are influenced by dominance and especially epistatic interactions among genes. an epistatic genetic basis for fa may complicate its primary use in comparisons of di levels in outbred or wild populations subjected or not subjected to various environmental stressors. although the heritability of fa typically is very low or zero, epistasis can generate additive genetic variation for fa that may allow it to evolve especially in populations subjected to bottlenecks, hybridizations, or periods of rapid environmental changes caused by various stresses.",126,2005,36,,1,21,10.1146/annurev.ecolsys.36.102003.152640,0,0,1,1"Dmitriev, A; Guscha, N; Krizanovska, M",synergism of low dose chronic radiation and biotic stress for plants,Equidosimetry - Ecological Standardization and Equidosimetry for Radioecology and Environmental Ecology,Proceedings Paper,,,0,2005,2,,231,236,10.1007/1-4020-3650-7_26,1,0,0,1"Efimov, VM; Kovaleva, VY; Markel, AL",a new approach to the study of genetic variability of complex characters,HEREDITY,Article,heritability; selection; craniometry; behaviour; multivariate analysis,"a new approach to multivariate genetic analysis of complex organismal traits is developed. it is based on examination of the distribution of parental strains and the f-1 and f-2 hybrids in a multidimensional space, and the determination of the directions corresponding to heterozygosity, epistatic and additive gene effects. the effect of heterozygosity includes variability produced by interaction between and within heterozygous loci. the additive gene effects and the remaining epistatic interactions between the homozygous loci can be visualized separately from the effects of heterozygosity by an appropriate projection of the points in multidimensional space. in all, 20 morphological, physiological and behavioural characters and 21 craniometric measures were studied in crosses between two laboratory rat strains. linear combinations of craniometric and of morphophysiological characters with a high narrow-sense heritability could be identified. these combinations characterized the organismal stress response, which had been selected for in one of the strains. the prospects for the practical application of the new approach and also for the evaluation of the contribution of the genetic diversity to phenotypic variability in animals in natural populations are discussed.",7,2005,94,1,101,107,10.1038/sj.hdy.6800580,0,0,1,1"Sargian, P; Mostajir, B; Chatila, K; Ferreyra, GA; Pelletier, E; Demers, S",non-synergistic effects of water-soluble crude oil and enhanced ultraviolet-b radiation on a natural plankton assemblage,MARINE ECOLOGY PROGRESS SERIES,Article,ultraviolet radiation; dissolved hydrocarbons; non-synergistic effect; phytoplankton; bacteria,"the present study demonstrates the effects of the water-soluble fraction (wsf) of a crude oil, enhanced ultraviolet-b radiation (uvbr: 280 to 320 nm), and the combination of wsf and enhanced uvbr on a natural plankton assemblage (< 150 mu m) isolated from the lower st. lawrence estuary. to study the separate and dual effects of wsf and uvbr, 12 microcosms (9 1) were immersed in the water column of larger mesocosms (polyethylene bags; 1800 1), providing 4 treatments, each in triplicate: (1) nuvbr + wsf (natural uvbr with wsf), (2) huvbr + wsf (enhanced uvbr with wsf), (3) nuvbr (natural uvbr without wsf), and (4) huvbr (enhanced uvbr without wsf). during 5 d we monitored the incident radiation, wsf and nutrient concentrations, abundance and production of heterotrophic bacteria and phytoplankton. strong deleterious effects of wsf and lower effects of uvbr were observed on the phytoplankton assemblage, with d decrease in growth rates accompanied by an increase in mean cell size which reflected a perturbation of the cell division cycle. using the nuvbr treatement as reference conditions, the above effects resulted in d reduction of 84, 79 and 60% of total abundance of the phytoplankton fraction < 20 mu m in the huvbr + wsf, nuvbr + wsf and huvbr treatments, respectively. significant higher values of bacterial abundances were observed in the wsf-added treatments compared to nuvbr without wsf. however, bacterial thymidine incorporation exhibited diel variations, suggesting cumulative uvbr-induced dna and/or pah-induced dna damages, and possible repair mechanisms with the co-occurrence of more available growth substrates from stressed phytoplankton. the absence of significant differences between both wsf-added treatments under the 2 different uvbr conditions suggests that there is no additive interaction between wsf and uvbr. this study provides therefore the first evidence of a non-synergistic interaction between both stresses, and suggests that uvbr-induced effects on marine microorganisms can be completely masked by the strong deleterious effects of soluble petroleum hydrocarbons.",22,2005,294,,63,77,10.3354/meps294063,1,0,1,2"Connell, SD",assembly and maintenance of subtidal habitat heterogeneity: synergistic effects of light penetration and sedimentation,MARINE ECOLOGY PROGRESS SERIES,Article,algae; human; impact; positive effect; understorey,"i experimentally separated the positive and negative effects of light penetration and sedimentation on the assembly and maintenance of 3 subtidal habitats whose heterogeneity characterizes much of the world's temperate coastline; encrusting (non-geniculate) coralline algae, articulated (geniculate) coralline algae and filamentous, turf-forming algae. the ability of encrusting corallines to monopolize and retain space without overgrowth depended on the presence of shade (positive effect) if sediment deposition was below that observed on coast characterized by high rates of sedimentation (negative effect). in contrast, the growth and persistence of articulated corallines depended on the absence of shade (negative effect) and high levels of sediment accumulation observed on human-dominated coast (positive effect). the recruitment of filamentous-turfs was facilitated by full light, but was not strongly affected by sedimentation. instead, filamentous - turfs tolerated heavy sediment accumulation, a factor thought to explain the concomitant increase in spatial dominance of algal-turfs and loss of canopy-forming algae on reefs with heavy sedimentation. importantly, different habitats will assemble or be maintained to match the environmental conditions in which they are most extensive, demonstrating the key role of physical factors associated with habitat-formers (kelp forests) and human-dominated coast (heavy sedimentation). these results also demonstrate that an appreciation of the integrated roles of physical processes may assist the development of predictive models about the assembly and maintenance of heterogeneity of natural communities, and their potential disruption by humans.",61,2005,289,,53,61,10.3354/meps289053,1,0,0,1"Walls, RL; Wardrop, DH; Brooks, RP",the impact of experimental sedimentation and flooding on the growth and germination of floodplain trees,PLANT ECOLOGY,Article,Acer rubrum; Fraxinus pennsylvanica; Quercus palustris; sediment; wetlands; floodplains; adventitious roots,"land-use changes in a forested floodplain's watershed can lead to incremental changes in the hydrology and sedimentation rates of the floodplain. the impacts of these changes can be difficult to measure due to the slow response time of mature trees. seedlings and saplings, on the other hand, may show an immediate response. responses during these early life history stages can have major consequences for regeneration of floodplain forests and ultimately result in community alteration. this study tested the importance of changes in hydrology and sedimentation on the germination and growth rates of three common floodplain tree species: acer rubrum, fraxinus pennsylvanica and quercus palustris. two-year-old saplings were grown in a greenhouse under two hydrologic regimes, with or without the addition of sediment. neither periodic flooding with or without sediment nor static flooding on its own affected the growth of the seedlings. with the addition of sediment, static flooding for two weeks lead to a significant decrease in sapling growth. there was a significant species x treatment interaction, suggesting that each species responded differently to the application of flooding and sediment. the timing of germination and the total percent germination for f pennsylvanica and q. palustris seeds were tested under the same conditions. flooding and sediment acted in an additive manner to delay the germination of both e pennsylvanica and q. palustris and to reduce the total germination rate of q. palustris. there was no difference in the total germination rate of f pennsylvanica seeds under any treatment. during the growth trials, adventitious roots sprouted on saplings grown under sedimentation. adventitious roots growing into sediment rather than floodwater should be able to utilize the sediment's nutrients and may compensate for some of the stress of flooding. the results of this study suggest that sediment tolerances will vary among species, but will not necessarily correlate with flood tolerances, and that sedimentation may be as important as flooding in determining floodplain plant community composition.",25,2005,176,2,203,213,10.1007/s11258-004-0089-y,0,0,1,1"Clinchy, M; Zanette, L; Boonstra, R; Wingfield, JC; Smith, JNM",balancing food and predator pressure induces chronic stress in songbirds,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,chronic stress; food supplementation; predator pressure; synergistic effects; Melospiza melodia,"the never-ending tension between finding food and avoiding predators may be the most universal natural stressor wild animals experience. the 'chronic stress' hypothesis predicts: (i) an animal's stress profile will be a simultaneous function of food and predator pressures given the aforesaid tension; and (ii) these inseparable effects on physiology will produce inseparable effects on demography because of the resulting adverse health effects. this hypothesis was originally proposed to explain synergistic (inseparable) food and predator effects on demography in snowshoe hares (lepus americanus). we conducted a 2 x 2, manipulative food addition plus natural predator reduction experiment on song sparrows (melospiza melodia) that was, to our knowledge, the first to demonstrate comparable synergistic effects in a bird: added food and lower predator pressure in combination produced an increase in annual reproductive success almost double that expected from an additive model. here we report the predicted simultaneous food and predator effects on measures of chronic stress in the context of the same experiment: birds at unfed, high predator pressure (hpp) sites had the highest stress levels; those at either unfed or hpp sites showed intermediate levels;- and fed birds at low predator pressure sites had the lowest stress levels.",126,2004,271,1556,2473,2479,10.1098/rspb.2004.2913,1,0,1,2"Lydy, M; Belden, J; Wheelock, C; Hammock, B; Denton, D",challenges in regulating pesticide mixtures,ECOLOGY AND SOCIETY,Article,,"this paper introduces the field of mixture toxicity and the challenges in regulating pesticide mixtures. even though pesticides are unique chemical stressors designed to have biological activity that can affect a number of nontarget species, they are intentionally placed into the environment in large quantities. currently, methods and terminology for evaluating mixture toxicity are poorly established. the most common approach used is the assumption of additive concentration, with the concentrations adjusted for potency to a reference toxicant. using this approach, the joint action of pesticides that have similar chemical structures and modes of toxic action can be predicted. however, this approach and other modeling techniques often provide little insight into the observed toxicity produced by mixtures of pesticides from different classes. particularly difficult to model are mixtures that involve a secondary toxicant that changes the toxicokinetics of a primary toxicant. this may result in increased activation or a change in the persistence of the primary toxicant within the organism and may be responsible for a several-fold increase or decrease in toxicity. at present, the ecological effects caused by mixtures of pesticides are given little consideration in the regulatory process. however, mixtures are being considered in relation to human health in the pesticide registration process, setting a precedent that could be followed for ecological protection. additionally, pesticide mixtures may be regulated through toxicity testing of surface water under the clean water act. the limits of our basic knowledge of how mixtures interact are compromising both these avenues for regulating mixtures. we face many challenges to adequately protecting the environment from mixture toxicity; these challenges include understanding the interactions of toxicants within an organism, identifying the mixtures that most commonly occur and cause adverse effects, and developing a regulatory structure capable of minimizing environmental impacts.",61,2004,9,6,,,,0,0,1,1"Stephenson, AG; Leyshon, B; Travers, SE; Hayes, CN; Winsor, JA","interrelationships among inbreeding, herbivory, and disease on reproduction in a wild gourd",ECOLOGY,Article,Cricurbita; disease ecology; herbivory; inbreeding depression; male function; pathogen infection; reproductive output; resistance; tolerance; viral disease,"because inbreeding, herbivory, and disease are common in plants and their separate impacts on fitness are well documented, investigators have begun to examine the consequences of inbreeding on plant-herbivore and plant-pathogen interactions. in this study, we examined the interrelationships among inbreeding, herbivory, and disease on reproductive output through both male (pollen production and pollen performance) and female (fruit and seed production and seed germination) functions. inbred (selfed) and outbred plants from five families of a wild gourd (cucurbita pepo ssp. texana) were grown in five 0.2-ha randomized blocks in an experimental garden. half of the inbred and half of the outbred plants were sprayed weekly with a contact pesticide to control herbivores. the other half of the plants served as the controls (no-spray treatment). the spray treatment significantly reduced damage by cucumber beetles and aphid infestation levels, the two primary herbivores of the wild gourd. moreover, because these herbivores are the sole vectors for the five most common viral diseases of cucurbits (watermelon mosaic-2, cucumber mosaic, zucchini yellow mosaic, papaya ringspot, and squash mosaic), the spray treatment also significantly reduced the amount and severity of the symptoms of viral diseases. our analyses reveal that (1) there is variation for resistance to herbivores and pathogens among the five families used in the study, indicating that there is broad-sense heritability for resistance; (2) inbred plants suffer greater herbivore damage and have more symptoms of viral infection than outbred plants, i.e., there is inbreeding depression for herbivore/pathogen resistance; (3) the impacts of insecticide applications and inbreeding on reproduction are mostly additive; (4) both male and female functions are significantly affected by the spray treatment and inbreeding; and (5) the adverse effects of both inbreeding and the increased exposure to herbivores/pathogens in the no-spray treatment are greater for female function than for male function, indicating that the impact of genetic and environmental stress can differentially affect the two sexual functions. together, these findings have important implications for the evolution of selfing, the conservation of small populations, and the establishment and transmission of diseases within populations.",53,2004,85,11,3023,3034,10.1890/04-0005,0,0,1,1"van Oers, K; Drent, PJ; de Jong, G; van Noordwijk, AJ",additive and nonadditive genetic variation in avian personality traits,HEREDITY,Article,Parus major; personalities; exploration; boldness; sex-dependent expression; maternal effects,"individuals of all vertebrate species differ consistently in their reactions to mildly stressful challenges. these typical reactions, described as personalities or coping strategies, have a clear genetic basis, but the structure of their inheritance in natural populations is almost unknown. we carried out a quantitative genetic analysis of two personality traits (exploration and boldness) and the combination of these two traits (early exploratory behaviour). this study was carried out on the lines resulting from a two-directional artificial selection experiment on early exploratory behaviour (eeb) of great tits (parus major) originating from a wild population. in analyses using the original lines, reciprocal f-1 and reciprocal first backcross generations, additive, dominance, maternal effects ands sex-dependent expression of exploration, boldness and eeb were estimated. both additive and dominant genetic effects were important determinants of phenotypic variation in exploratory behaviour and boldness. however, no sex-dependent expression was observed in either of these personality traits. these results are discussed with respect to the maintenance of genetic variation in personality traits, and the expected genetic structure of other behavioural and life history traits in general.",63,2004,93,5,496,503,10.1038/sj.hdy.6800530,0,0,1,1"Norry, FM; Dahlgaard, J; Loeschcke, V",quantitative trait loci affecting knockdown resistance to high temperature in drosophila melanogaster,MOLECULAR ECOLOGY,Article,dominance; Drosophila; heat-knockdown resistance; heat-shock proteins; heat-stress resistance; QTL; thermal adaptation,"knockdown resistance to high temperature is an ecologically important trait in small insects. a composite interval mapping was performed on the two major autosomes of drosophila melanogaster to search for quantitative trait loci (qtl) affecting knockdown resistance to high temperature (krht). two dramatically divergent lines from geographically different thermal environments were artificially selected on krht. these lines were crossed to produce two backcross (bc) populations. each bc was analysed for 200 males with 18 marker loci on chromosomes 2 and 3. three x-linked markers were used to test for x-linked qtl in an exploratory way. the largest estimate of autosome additive effects was found in the pericentromeric region of chromosome 2, accounting for 19.26% (bc to the low line) and 29.15% (bc to the high line) of the phenotypic variance in bc populations, but it could represent multiple closely linked qtl. complete dominance was apparent for three qtl on chromosome 3, where heat-shock genes are concentrated. exploratory analysis of chromosome x indicated a substantial contribution of this chromosome to krht. the results show that a large-effect qtl with dominant gene action maps on the right arm of chromosome 3. further, the results confirm that qtl for heat resistance are not limited to chromosome 3.",38,2004,13,11,3585,3594,10.1111/j.1365-294X.2004.02323.x,0,0,1,1"Ross, KA; Taylor, JE; Fox, MD; Fox, BJ",interaction of multiple disturbances: importance of disturbance interval in the effects of fire on rehabilitating mined areas,AUSTRAL ECOLOGY,Article,fire; interval; mining; multiple disturbance; restoration,"multiple disturbance regimes are increasingly common as novel anthropogenic disturbances are added to existing natural disturbances. however, it is generally unknown whether simultaneous or sequential effects of different forms of disturbance are predictable from the independent effects of each disturbance. this study examines the short-term effects of sequential disturbance by mineral sand-mining followed by fire in a forest community in south-eastern australia. four combinations of disturbance were sampled: unburned mined, burned mined, unburned forest (unmined) and burned forest (unmined, with between-fire interval matching the disturbance interval between mining and fire of the burned mined treatment). all combinations were sampled approximately 12 months following fire on the burned sites. the impact of fire after mining depended on disturbance interval. sites burned 0.5-2.4 years since mining had fewer native vascular plant species than unburned mined sites of the same mined age, whereas sites with 10-16 years or 20-26 years between mining and fire had greater native species richness than unburned mined sites of the same age. burning 20-26 years after mining brought native species richness within the range of burned forest. for both unmined and mined sites native seedling densities increased with burning, and with longer disturbance intervals. weed species richness and weed seedling densities were greater on mined sites than in forest, and burning mined sites elevated weed seedling densities further, particularly for short intervals. both disturbance interval and fire intensity are likely to have contributed to these results, as intensity on mined areas increased with interval, and at 20-26 years post-mining was equivalent to unmined forest. these results suggest that fire could be used to promote rehabilitation of these mined areas after at least 10 years, but should be excluded from earlier stages of post-mining regeneration. however, other sources of spatial and temporal variability should be considered in addition to interval and intensity, as variation among mined areas was correlated with post-fire weather conditions and available weed sources. finally, the combined effects of mining and fire could not be predicted from knowledge of the disturbances operating separately, indicating that effects of multiple disturbance may be synergistic rather than additive.",19,2004,29,5,508,529,10.1111/j.1442-9993.2004.01405.x,1,0,1,2"Kasurinen, A; Kokko-Gonzales, P; Riikonen, J; Vapaavuori, E; Holopainen, T",soil co2 efflux of two silver birch clones exposed to elevated co2 and o-3 levels during three growing seasons,GLOBAL CHANGE BIOLOGY,Article,clone; elevated CO2; elevated O-3; open-top chambers; silver birch (Betula pendula Roth); soil CO2 efflux,"in the present open-top chamber experiment, two silver birch clones (betula pendula roth, clone 4 and clone 80) were exposed to elevated levels of carbon dioxide (co2) and ozone (o-3), singly and in combination, and soil co2 efflux was measured 14 times during three consecutive growing seasons (1999-2001). in the beginning of the experiment, all experimental trees were 7 years old and during the experiment the trees were growing in sandy field soil and fertilized regularly. in general, elevated o-3 caused soil co2 efflux stimulation during most measurement days and this stimulation enhanced towards the end of the experiment. the overall soil respiration response to co2 was dependent on the genotype, as the soil co2 efflux below clone 80 trees was enhanced and below clone 4 trees was decreased under elevated co2 treatments. like the o-3 impact, this clonal difference in soil respiration response to co2 increased as the experiment progressed. although the o-3 impact did not differ significantly between clones, a significant time x clone x co(2)x o-3 interaction revealed that the o-3-induced stimulation of soil respiration was counteracted by elevated co2 in clone 4 on most measurement days, whereas in clone 80, the effect of elevated co2 and o-3 in combination was almost constantly additive during the 3-year experiment. altogether, the root or above-ground biomass results were only partly parallel with the observed soil co2 efflux responses. in conclusion, our data show that o-3 impacts may appear first in the below-ground processes and that relatively long-term o-3 exposure had a cumulative effect on soil co2 efflux. although the soil respiration response to elevated co2 depended on the tree genotype as a result of which the o-3 stress response might vary considerably within a single tree species under elevated co2, the present experiment nonetheless indicates that o-3 stress is a significant factor affecting the carbon cycling in northern forest ecosystems.",18,2004,10,10,1654,1665,10.1111/j.1365-2486.2004.00841.x,0,0,1,1"Asbjornsen, H; Ashton, MS; Vogt, DJ; Palacios, S","effects of habitat fragmentation on the buffering capacity of edge environments in a seasonally dry tropical oak forest ecosystem in oaxaca, mexico",AGRICULTURE ECOSYSTEMS & ENVIRONMENT,Article,habitat fragmentation; dry tropical highlands; edge effects; Mexico; drought; soil moisture; buffering capacity; oak forests,"the composition, structure, and disturbance dynamics of the native oak forests in seasonally dry tropical highland regions throughout the world have been drastically altered due to human land use. edge environments are a dominant feature in these highly fragmented landscapes, and may directly influence the capacity of the vegetation to ameliorate microclimate conditions and support the successful regeneration of disturbed habitat. in this study, microclimate variables (surface soil moisture, photosynthetically active radiation and ground, surface and air temperatures) were assessed across edge gradients occurring between forest remnants and openings of different sizes (<0.1 and >1 ha) in both a highly fragmented landscape and a relatively undisturbed adjacent landscape over a 2-year period. surface soil moistures increased progressively from the open areas (10.8-40.1 g m(-3)) into the forest understory (16.8-54.7 g m(-3)). the steepness of the edge gradient was less pronounced in the highly fragmented landscape (23.02 g m(-3)) compared to the reference landscape (29.34 g m(-3)). these results suggest that microsite variability across edges was reduced in this landscape in response to fragmentation. further, the occurrence of an extreme drought event during the second year diminished differences between the fragmented and reference landscapes, thereby leading to greater homogeneity of the microclimate across the edge environments. structural differences in forest patches within the fragmented landscape were also found to interact synergistically with habitat fragmentation to influence patterns in microclimate across edge environments. the capacity of oak forests to ameliorate the availability and flux of surface soil moisture in seasonally dry tropical ecosystems through their effect on evaporative moisture loss, and the reduction of this buffering capacity in response to habitat fragmentation documented in this study, suggests that fragmentation has significantly altered the temporal and spatial heterogeneity of microclimate conditions in these landscapes. (c) 2003 elsevier b.v. all rights reserved.",17,2004,103,3,481,495,10.1016/j.agee.2003.11.008,1,0,0,1"Agrawal, AA","resistance and susceptibility of milkweed: competition, root herbivory, and plant genetic variation",ECOLOGY,Article,Asclepias syriaca; associational susceptibility; cardenolides; competitive release; diffuse coevolution; induced plant resistance; latex; leaf miner Liriomyza asclepiadis; plant-insect interactions; Tetraopes tetraophthalmus; trait-mediated indirect effect; trichomes,"beetles in the genus tetraopes share a long evolutionary history with milkweeds (asclepias spp.), feeding on roots as larvae and leaves as adults. despite their extreme specialization on milkweed, tetraopes require drying grass stems as oviposition sites, even though they do not consume grass. the natural history of the interaction suggests that herbivory may be likely only when milkweeds are in close proximity to grasses. theory also predicts that two stresses on plants, competition and herbivory, may have non-additive negative impacts on correlates of fitness. in field experiments conducted over two years, i followed the consequences of grass competition and beetle attack for herbivory, growth, and reproduction of milkweed, and reciprocal effects of milkweed on grass in common gardens. to assess the effect of milkweed traits on beetles, i conducted a quantitative genetic experiment using full-sibling families of milkweed and measured the effects of putative resistance traits on the abundance of tetraopes adults. milkweeds growing next to grass were initially unaffected in growth but suffered 10% greater leaf herbivory by adult tetraopes than did milkweeds growing alone. this effect was caused by direct attraction of beetles to grass, not by a competitive modification of milkweed's phenotype. in late summer of the first growing season, when tetraopes naturally oviposits, i experimentally added larvae to milkweed roots with and without grass competition. within a month, i detected an interaction between competition and herbivory: neither had an individual impact, but jointly they reduced milkweed growth. in spring of the second growing season, when tetraopes had completed development, i again found strong evidence for a non-additive effect of competition and herbivory together, severely reducing plant growth compared to their individual effects. root herbivory induced a plant response that reduced the abundance of leaf-mining flies by 40%, but only for milkweeds with grass competition. neither competition nor herbivory affected the production of defensive latex, cardenolides, or carbon, but they interacted to affect leaf nitrogen content. thus, although trait-mediated indirect interactions were implicated in the effect of competition and root herbivory on leaf miner abundance, i did not uncover the mechanism. in the final harvest, beetle herbivory reduced reproductive characters (fruit production, fruit mass, aboveground biomass) by 20-30%, whereas competition had negligible effects. the net interaction effect for grass was competitive, with a 23% reduction in grass biomass caused by milkweed in the absence of herbivory. however, the presence of beetle herbivory on milkweed roots completely alleviated the competitive effect of milkweed on grass. thus, the associational effect of grass on milkweed resulted in milkweed suffering the non-additive effects of competition and herbivory, whereas grass enjoyed competitive release by facilitating its neighbor's herbivore. many traits of milkweed (e.g., growth, reproduction, and several resistance traits) showed variation among 23 full-sibling families, indicating that competitive ability and resistance may be subject to natural selection. a multiple regression analysis on family means revealed that leaf trichome density and nitrogen content were negatively genetically correlated with abundance of tetraopes adults, but probability of flowering and plant height were positively associated. leaf miners were most strongly negatively affected by latex and trichomes. thus, complex interactions among competition, root herbivory, and plant genetic variation affect the herbivore and plant community and may result in diffuse co-evolution between milkweed and its herbivores. i present a general model that predicts the conditions in which plant-plant interactions result in net competition or facilitation.",80,2004,85,8,2118,2133,10.1890/03-4084,0,0,1,1"Seal, AN; Haig, T; Pratley, JE",evaluation of putative allelochemicals in rice root exudates for their role in the suppression of arrowhead root growth,JOURNAL OF CHEMICAL ECOLOGY,Article,abietic acid; decarboxylation; dose-response curves; GC/MS/MS; hydroxystyrenes; phenolic acids; rice allelopathy; Sagittaria montevidensis; tandem mass spectrometry; weed suppression,"in previous studies, 15 putative allelopathic compounds detected in rice root exudates were quantified by gc/ms/ms. in this study, multiple regression analysis on these compounds determined that five selected phenolics, namely caffeic, p-hydroxybenzoic, vanillic, syringic, and p-coumaric acids, from rice exudates were best correlated with the observed allelopathic effect on arrowhead (sagittaria montevidensis) root growth. despite this positive association, determination of the phenolic acid dose-response curve established that the amount quantified in the exudates was much lower than the required threshold concentration for arrowhead inhibition. a similar dose-response curve resulted from a combination of all 15 quantified compounds. significant differences between the amounts of trans-ferulic acid, abietic acid, and an indole also existed between allelopathic and non-allelopathic rice cultivars. the potential roles of these three compounds in rice allelopathy were examined by chemoassay. overall, neither the addition of trans-ferulic acid nor 5-hydroxyindole-3-acetic acid to the phenolic mix significantly contributed to phytotoxicity, although at higher concentrations, trans-ferulic acid appeared to act antagonistically to the phytotoxic effects of the phenolic mix. the addition of abietic acid also decreased the inhibitory effect of the phenolic mix. these studies indicate that the compounds quantified are not directly responsible for the observed allelopathic response. it is possible that the amount of phenolic acids may be indirectly related to the chemicals finally responsible for the observed allelopathic effect.",45,2004,30,8,1663,1678,10.1023/B:JOEC.0000042075.96379.71,0,1,0,1"Lawrence, RK; Demarais, S; Relyea, RA; Haskell, SP; Ballard, WB; Clark, TL",desert mule deer survival in southwest texas,JOURNAL OF WILDLIFE MANAGEMENT,Article,desert mule deer; drought; harvest; mortality; natural stressors; Odocoileus hemionus eremicus; predation; predator control; pregnancy; survival; Texas,"we studied population structure and limiting factors within a desert mule deer (odocoileus hemionus eremicus) population in brewster county of the trans-pecos region in texas, usa. we estimated and compared annual survival and pregnancy rates from march 1990-february 1993 for 121 adult (>33 months old) male and female, 61 subadult (21-33 months old), and 77 young (8-20 months old) deer. variation in weather patterns (i.e., drought) was associated with-if not causative of-annual variation in survival patterns. adult female and young survival had the strongest correlation with drought. pregnancy status of young (less than or equal to1.5 yr) and old (greater than or equal to6.5 yr) deer appeared most affected by drought. seasonal periods of natural stress differed for adult sex classes, with most female mortalities occurring during months associated with parturition and lactation, and most male natural stress losses occurring during late winter and early spring. the major mortality sources were hunting and natural stressors for adult males, natural stressors and predation for adult females, and predation and natural stressors for young. subadult mortalities were too few to identify significant mortality agents. the significance of natural stress-related survival and fecundity impacting herd productivity and stability warrants further consideration of poorly understood causative mechanisms. ideally, replicated treatment areas would be used to address compensatory and additive mortality issues relative to predator abundance, harvest, and natural-stress losses.",19,2004,68,3,561,569,10.2193/0022-541X(2004)068[0561:DMDSIS]2.0.CO;2,0,0,1,1"Lehtonen, M","the environmental - social interface of sustainable development capabilities, social capital, institutions",ECOLOGICAL ECONOMICS,Article; Proceedings Paper,environmental-social interface; sustainable development; social capital; capabilities; environmental policy evaluation,"the social dimension has commonly been recognised as the weakest 'pillar' of sustainable development, notably when it comes to its analytical and theoretical underpinnings. while increasing attention has lately been paid to social sustainability, the interaction between the 'environmental' and the 'social' still remains a largely uncharted terrain. nevertheless, one can argue that the key challenges of sustainable development reside at the interfaces-synergies and trade-offs-between its various dimensions. this paper looks for preliminary ideas on frameworks for analysing the environmental-social interface. it first discusses the concept of sustainable development and the relations of the three dimensions of sustainability on the basis of the fundamental premises of neoinstitutional and ecological economics, and briefly presents the 'bioeconomy model'. based on this conceptualisation of sustainable development, it then goes on to analyse two popular ways of addressing the social dimension of sustainability, namely, the 'capability approach' of amartya sen, and the concept of social capital, and discusses the potential of these as bases for the analysis of the environment-social interaction. the organisation for economic cooperation and development (oecd) environmental performance review (epr) programme is presented as an example of attempts to analyse the environmental-social interface in practice. the paper concludes by noting that a single framework for studying environmental-social interface is neither feasible nor desirable. it questions the usefulness of analysing only two dimensions of sustainability at a time; and emphasises the need to situate the analysis in its context. in particular, it stresses the need to involve the potential users, as well as to take into account the planned use of the analysis and the interactions between different levels of analysis and decision-making. capabilities and social capital can both be useful in structuring thoughts, but are not as such directly applicable as suitable analytical frameworks. in particular, they do not provide adequate tools for examining the social preconditions for institutional change needed for environmentally sustainable development. (c) 2004 elsevier b.v. all rights reserved.",88,2004,49,2,199,214,10.1016/j.ecolecon.2004.03.019,1,0,0,1"Lenssen, JPM; van de Steeg, HM; de Kroon, H",does disturbance favour weak competitors? mechanisms of changing plant abundance after flooding,JOURNAL OF VEGETATION SCIENCE,Article,clonal growth; competitive ability-tolerance tradeoff; competitive hierarchy; competitive release; flood tolerance; trade-off; zonation,"question: does disturbance reduce competition intensity and thus favour weak competitors that are presumably less affected by disturbance than strong competitors? methods: we used a single flooding event with increasing duration to simulate disturbance with increasing intensity. six flood-plain grass species, typical of different flood regimes were grown in monocultures and in an additive species mixture. flooding took place early in the first growing season and changes were monitored until the end of the second growing season. results: longer flooding durations initially decreased competition, but only a single species (agrostis) increased its abundance in mixtures after flooding. the two weakest competitors in our selection (poa trivialis and elytrigia repens) failed to benefit from flooding because direct losses from flooding exceeded gains from reduced competition. accordingly, we found no trade-off between flooding tolerance and competitive ability indicating that floods affect strong and weak competitors equally, although some species tolerated floods better than others. conclusions: since competition is only temporarily weakened after disturbance, increased competitive ability relative to other species may provide a more effective strategy for persistence in flood-disturbed sites. above-ground runners seem an important prerequisite for enhanced competitive ability of clonal species in flood-disturbed sites.",39,2004,15,3,305,314,10.1658/1100-9233(2004)015[0305:DDFWCM]2.0.CO;2,0,0,1,1"Sih, A; Bell, AM; Kerby, JL",two stressors are far deadlier than one,TRENDS IN ECOLOGY & EVOLUTION,Article,,"natural organisms often face a barrage of stressors, both natural and human induced. two known stressors that impact amphibian populations are pesticides and predators. recent work by relyea and by mills and relyea reveals strikingly strong, synergistic negative effects of these two factors on amphibian larvae. adding predation risk on top of supposedly sublethal concentrations of a common pesticide caused a massive increase in larval mortality. interestingly, the increased mortality did not require exposure to actual predation . that is, simply the 'smell of danger' (predator chemical cues) caused 80-90% of larvae that were held in otherwise 'safe' levels of the pesticide to die. notably, this effect occurred in some species, but not in others. these new studies highlight the need for further interdisciplinary work on the conditions under which combinations of stressors have particularly strong negative effects on natural organisms.",88,2004,19,6,274,276,10.1016/j.tree.2004.02.010,1,0,0,1"Perez-Rostro, CI; Racotta, IS; Ibarra, AM",decreased genetic variation in metabolic variables of litopenaeus vannamei shrimp after exposure to acute hypoxia,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,hypoxia; normoxia; genetic variance; lactate; proteins; carbohydrates,"concentration of proteins, carbohydrates, lactate, total lipids, acylglycerides, and carotenoids in shrimp were evaluated for their changes under acute hypoxia, and for their genetic variation under normoxic and hypoxic conditions. proteins and lactate concentrations in muscle and hepatopancreas were significantly higher and carbohydrates in hepatopancreas were decreased in the hypoxic group. family variances were significantly different only for proteins and carbohydrates in hepatopancreas in the normoxic group, indicating the existence of genetic variation for these traits. when family variances for each biochemical component were compared between normoxic and hypoxic groups, it was seen that most decreased. however, total variance was not significantly changed in response to hypoxia except for lactate (increased) and carotenoids (decreased) in hepatopancreas. the decrease in genetic variance without an increase in phenotypic variances in an acute response to hypoxia might be related to the known suppression of metabolic pathways that either use or produce atp, which could result in a decreased expression of additive genes. (c) 2003 elsevier b.v. all rights reserved.",10,2004,302,2,189,200,10.1016/j.jembe.2003.10.010,0,0,1,1"McPeek, MA",the growth/predation risk trade-off: so what is the mechanism?,AMERICAN NATURALIST,Review,activity; damselfly; digestion; growth; physiological response to predators; trade-off,"among damselflies in natural lakes, ischnura species grow faster than coexisting enallagma species, but enallagma species have higher survival under predation than ischnura species. this growth/predation risk trade-off apparently allows these taxa to coexist in ponds and lakes across the holarctic. however, laboratory studies presented here show that the mechanism assumed by most theoretical and empirical studies to mediate this trade-off, namely activity simultaneously modulating foraging returns and predation risk, does not operate in this system. ischnura verticalis larvae were more active than larvae of enallagma species in a short-term behavioral experiment, which explains why ischnura experiences greater mortality from predation. however, this greater activity did not translate into higher feeding rates. ischnura verticalis and enallagma species ate comparable amounts of food in both the short-term behavioral experiment and a longer feeding and digestion experiment. in spite of no difference in the amount of food ingested or assimilated, i. verticalis larvae grew faster than enallagma larvae because they were better able to physiologically convert assimilated food into their own biomass in the presence of mortality threats. from these studies we understand the phenotypic mechanisms determining the antagonistic patterns of relative growth and survival between these two genera, but why these patterns exist remains unclear.",71,2004,163,5,E88,E111,10.1086/382755,0,1,0,1"Ochoa-Gaona, S; Gonzalez-Espinosa, M; Meave, JA; Bon, VSD","effect of forest fragmentation on the woody flora of the highlands of chiapas, mexico",BIODIVERSITY AND CONSERVATION,Article,disturbance; floristic change; floristic diversity; forest structure; fragmentation indices; landscape ecology,"this study was conducted in the chiapas highlands, a tropical mountain region where traditional agricultural practices have resulted in a mosaic landscape of forest fragments embedded in a matrix of secondary vegetation and crop fields. the question addressed was how may woody species richness be affected by forest fragment attributes derived from traditional land-use patterns. species inventories of total woody species, canopy and understorey trees, and shrubs were obtained in 22 forest fragments ( greater than or equal to5 ha). multiple regression analyses were applied to examine the effects of size, matrix, isolation and shape of the forest fragments on richness of these species guilds. fragment size was correlated with shape (r = 0.75) and isolation ( r = - 0.69), and isolation was correlated with shape ( r = - 0.75). total species richness, and number of shrubs and understorey trees in fragments were related to isolation; moreover, additive effects of fragment shape were found for shrubs. the number of canopy species was not related to any fragment variable. matrix did not help to explain species richness, possibly due to the landscape structure created by the traditional land-use patterns. in addition to size and isolation, we point out the need of considering shape and matrix as additional fragmentation attributes, along with social and economic factors, if we are ever going to be successful in our management and conservation actions.",24,2004,13,5,867,884,10.1023/B:BIOC.0000014457.57151.17,0,0,1,1"Opdam, P; Wascher, D",climate change meets habitat fragmentation: linking landscape and biogeographical scale levels in research and conservation,BIOLOGICAL CONSERVATION,Article,climate change; habitat fragmentation; metapopulation dynamics; geographical range; habitat network,"climate change and habitat fragmentation are considered key pressures on biodiversity. in this paper we explore the potential synergetic effects between these factors. we argue that processes at two levels of spatial scale interact: the metapopulation level and the species range level. current concepts of spatially dynamic metapopulations and species ranges are consistent, and integration improves our understanding of the interaction of landscape level and geographical range level processes. in landscape zones in which the degree of habitat fragmentation allows persistence, the shifting of ranges is inhibited, but not blocked. in areas where the spatial cohesion of the habitat is below the critical level of metapopulation persistence, the expansion of ranges will be blocked. an increased frequency of large-scale disturbances caused by extreme weather events will cause increasing gaps and an overall contraction of the distribution range, particularly in areas with relatively low levels of spatial cohesion. taking into account the effects of climate change on metapopulations, habitat distribution and land use changes, future biodiversity research and conservation strategies are facing the challenge to re-orient their focus and scope by integrating spatially and conceptually more dynamic aspects at the landscape level. (c) 2003 elsevier ltd. all rights reserved.",285,2004,117,3,285,297,10.1016/j.biocon.2003.12.008,1,0,0,1"Bukovinszky, T; Trefas, H; van Lenteren, JC; Vet, LEM; Fremont, J",plant competition in pest-suppressive intercropping systems complicates evaluation of herbivore responses,AGRICULTURE ECOSYSTEMS & ENVIRONMENT,Article,"intercropping; interspecific competition; ""Host plant quality hypothesis""; Brevicoryne brassicae; Plutella xylostella; Pieris brassicae","in the light of current theories on the effects of intercropping on pest reduction, population responses of the diamondback moth (plutella xylostella), the cabbage aphid (brevicoryne brassicae) and the life history traits of the large white butterfly (pieris brassicae) were studied in a brussels sprout (brassica oleracea gemmifera)/malting barley (hordeum vulgare) additive row intercrop and a brussels sprout monoculture. more p. xylostella adults were caught in the monoculture than in the intercrop. numbers of r xylostella larvae and pupae per sprout plant were lower in intercropped plots than in monocultures. however, more larvae and pupae were found per m(2) leaf area in the inter- than in the monocrop. both the densities per plant and per m(2) leaf area of b. brassicae populations were lower in the inter- than in the monocrop. after the barley withered and competition with brussels sprout abated, aphid densities became higher in the inter- than in the monocrop. these findings may be explained by interspecific plant competition resulting in stressed sprout plants with a smaller size and delayed phenology relative to monocropped plants. effects of differences in plant nutritional quality on herbivore performance were studied by offering leaves of inter- and monocropped sprout plants to larval r brassicae. performance and food utilisation were significantly better on leaves from the intercrop, (lower dry weight consumption, higher growth rates) than from the monocrop. defoliation rate was also higher on leaves of intercropped plants than on monocropped ones. the studies indicate that plant stress and consequent changes in developmental rate and nutritional quality of plants are playing a role in herbivore population responses to intercropping. it is argued that such confounding effects of plant competition in intercropping designs can hamper the evaluation of herbivore responses in pest-suppressive agro-ecosystems. (c) 2003 elsevier b.v. all rights reserved.",28,2004,102,2,185,196,10.1016/j.agee.2003.08.008,0,0,1,1"Pelabon, C; Hansen, TF; Carlson, ML; Armbruster, WS",variational and genetic properties of developmental stability in dalechampia scandens,EVOLUTION,Article,Dalechampia scandens; developmental stability; evolvability; fluctuating asymmetry; genetic variation; heritability; homozygosity,"because low developmental stability may compromise the precision with which adaptations can be reached, the variability and genetic basis of developmental stability are important evolutionary parameters. developmental stability is also an important clue to understanding how traits are regulated to achieve their phenotypic target value. however, developmental stability must be studied indirectly through proxy variables, such as fluctuating asymmetry, that are suggested to have noisy and often nonlinear relationships to the underlying variable of interest. in this paper we first show that mean-standardized measures of variance and covariance in fluctuating asymmetry, unlike heritabilities, repeatabilities, and correlations, are linearly related to corresponding measures of variation in underlying developmental stability. we then examine the variational properties of developmental stability in a population of the neotropical vine, dalechampia scandens (euphorbiaceae). by studying fluctuating asymmetry in a large number of floral characters in both selfed and outcrossed individuals in a diallel design, we assemble strong evidence that both additive genetic and individual variation and covariation in developmental stability are virtually absent in this population.",25,2004,58,3,504,514,10.1111/j.0014-3820.2004.tb01674.x,0,0,1,1"Thuiller, W; Araujo, MB; Lavorel, S",do we need land-cover data to model species distributions in europe?,JOURNAL OF BIOGEOGRAPHY,Article,bioclimatic models; climate gradients; land-use effects; large-scale patterns; species distributions,"aim to assess the influence of land cover and climate on species distributions across europe. to quantify the importance of land cover to describe and predict species distributions after using climate as the main driver. location the study area is europe. methods (1) a multivariate analysis was applied to describe land-cover distribution across europe and assess if the land cover is determined by climate at large spatial scales. (2) to evaluate the importance of land cover to predict species distributions, we implemented a spatially explicit iterative procedure to predict species distributions of plants (2603 species), mammals (186 species), breeding birds (440 species), amphibian and reptiles (143 species). first, we ran bioclimatic models using stepwise generalized additive models using bioclimatic variables. secondly, we carried out a regression of land cover (lc) variables against residuals from the bioclimatic models to select the most relevant lc variables. finally, we produced mixed models including climatic variables and those lc variables selected as decreasing the residual of bioclimatic models. then we compared the explanatory and predictive power of the pure bioclimatic against the mixed model. results (1) at the european coarse resolution, land cover is mainly driven by climate. two bioclimatic axes representing a gradient of temperature and a gradient of precipitation explained most variation of land-cover distribution. (2) the inclusion of land cover improved significantly the explanatory power of bioclimatic models and the most relevant variables across groups were those not explained or poorly explained by climate. however, the predictive power of bioclimatic model was not improved by the inclusion of lc variables in the iterative model selection process. main conclusion climate is the major driver of both species and land-cover distributions over europe. yet, lc variables that are not explained or weakly associated with climate (inland water, sea or arable land) are interesting to describe particular mammal, bird and tree distributions. however, the addition of lc variables to pure bioclimatic models does not improve their predictive accuracy.",189,2004,31,3,353,361,,0,0,1,1"Giller, PS; Hillebrand, H; Berninger, UG; Gessner, MO; Hawkins, S; Inchausti, P; Inglis, C; Leslie, H; Malmqvist, B; Monaghan, MT; Morin, PJ; O'Mullan, G",biodiversity effects on ecosystem functioning: emerging issues and their experimental test in aquatic environments,OIKOS,Article,,"recent experiments, mainly in terrestrial environments, have provided evidence of the functional importance of biodiversity to ecosystem processes and properties. compared to terrestrial systems, aquatic ecosystems are characterised by greater propagule and material exchange, often steeper physical and chemical gradients, more rapid biological processes and, in marine systems, higher metazoan phylogenetic diversity. these characteristics limit the potential to transfer conclusions derived from terrestrial experiments to aquatic ecosystems whilst at the same time provide opportunities for testing the general validity of hypotheses about effects of biodiversity on ecosystem functioning. here, we focus on a number of unique features of aquatic experimental systems, propose an expansion to the scope of diversity facets to be considered when assessing the functional consequences of changes in biodiversity and outline a hierarchical classification scheme of ecosystem functions and their corresponding response variables. we then briefly highlight some recent controversial and newly emerging issues relating to biodiversity-ecosystem functioning relationships. based on lessons learnt from previous experimental and theoretical work, we finally present four novel experimental designs to address largely unresolved questions about biodiversity-ecosystem functioning relationships. these include (1) investigating the effects of non-random species loss through the manipulation of the order and magnitude of such loss using dilution experiments; (2) combining factorial manipulation of diversity in interconnected habitat patches to test the additivity of ecosystem functioning between habitats; (3) disentangling the impact of local processes from the effect of ecosystem openness via factorial manipulation of the rate of recruitment and biodiversity within patches and within an available propagule pool; and (4) addressing how non-random species extinction following sequential exposure to different stressors may affect ecosystem functioning. implementing these kinds of experimental designs in a variety of systems will, we believe, shift the focus of investigations from a species richness-centred approach to a broader consideration of the multifarious aspects of biodiversity that may well be critical to understanding effects of biodiversity changes on overall ecosystem functioning and to identifying some of the potential underlying mechanisms involved.",165,2004,104,3,423,436,,0,0,1,1"Vinebrooke, RD; Cottingham, KL; Norberg, J; Scheffer, M; Dodson, SI; Maberly, SC; Sommer, U",impacts of multiple stressors on biodiversity and ecosystem functioning: the role of species co-tolerance,OIKOS,Article,,"ecosystem resistance to a single stressor relies on tolerant species that can compensate for sensitive competitors and maintain ecosystem processes, such as primary production. we hypothesize that resistance to additional stressors depends increasingly on species tolerances being positively correlated (i.e. positive species co-tolerance). initial exposure to a stressor combined with positive species co-tolerance should reduce the impacts of other stressors, which we term stress-induced community tolerance. in contrast, negative species co-tolerance is expected to result in additional stressors having pronounced additive or synergistic impacts on biologically impoverished functional groups, which we term stress-induced community sensitivity. therefore, the sign and strength of the correlation between species sensitivities to multiple stressors must be considered when predicting the impacts of global change on ecosystem functioning as mediated by changes in biodiversity.",204,2004,104,3,451,457,,1,0,1,2"Hendry, AP; Morbey, YE; Berg, OK; Wenburg, JK",adaptive variation in senescence: reproductive lifespan in a wild salmon population,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,ageing; aging; reproductive trade-offs; energy allocation; adaptation-by-time; sockeye salmon,"the antagonistic pleiotropy theory of senescence postulates genes or traits that have opposite effects on early-life and late-life performances. because selection is generally weaker late in life, genes or traits that improve early-life performance but impair late-life performance should come to predominate. variation in the strength of age-specific selection should then generate adaptive variation in senescence. we demonstrate this mechanism by comparing early and late breeders within a population of semelparous capital-breeding sockeye salmon (oncorhynchus nerka). we show that early breeders (but not late breeders) are under strong selection for a long reproductive lifespan (rls), which facilitates defence of their nests against disturbance by later females. accordingly, early females invest less energy in egg production while reserving more for nest defence. variation along this reproductive trade-off causes delayed or slower senescence in early females (average rls of 26 days) than in late females (reproductive lifespan of 12 days). we use microsatellites to confirm that gene flow is sufficiently limited between early and late breeders to allow adaptive divergence in response to selection. because reproductive trade-offs should be almost universal and selection acting on them should typically vary in time and space, the mechanism described herein may explain much of the natural variation in senescence.",51,2004,271,1536,259,266,10.1098/rspb.2003.2600,0,1,0,1"Kercher, SM; Zedler, JB",multiple disturbances accelerate invasion of reed canary grass (phalaris arundinacea l.) in a mesocosm study,OECOLOGIA,Article,eutrophication; flooding; fluctuating resource hypothesis; invasibility; invasive species,"disturbances that intensify with agriculture and/or urban development are thought to promote the spread of invasive plants, such as the clonal perennial reed canary grass ( phalaris arundinacea l). to test this relationship and interactions among disturbances, we subjected wet prairie assemblages within 1.1 m(2) mesocosms to invasion by phalaris and addition of nutrients, sediments, and flooding. species richness decreased with the application of sediments and/or flooding of 4 consecutive weeks or longer. losses of up to six dominant and subdominant species in these treatments increased light transmission through the plant canopy by as much as 400% over the control. light availability in july and september was a strong predictor of end-of-season aboveground biomass of phalaris. phalaris was also 35% and 195% more productive when nutrients were added at low and high levels, respectively. multiple factors in combination were usually additive in their effects on invasion, but sediments and nutrients interacted with flood regime to synergistically increase invasion in some cases. a separate experiment likewise revealed a synergistic interaction between added nutrients and simulated grazing. we suggest that multiple factors be mitigated simultaneously to reduce invasion of phalaris.",83,2004,138,3,455,464,10.1007/s00442-003-1453-7,1,0,1,2"Folke, C; Carpenter, S; Walker, B; Scheffer, M; Elmqvist, T; Gunderson, L; Holling, CS","regime shifts, resilience, and biodiversity in ecosystem management",ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS,Review,alternate states; regime shifts; response diversity; complex adaptive systems; ecosystem services,"we review the evidence of regime shifts in terrestrial and aquatic environments in relation to resilience of complex adaptive ecosystems and the functional roles of biological diversity in this context. the evidence reveals that the likelihood of regime shifts may increase when humans reduce resilience by such actions as removing response diversity, removing whole functional groups of species, or removing whole trophic levels; impacting on ecosystems via emissions of waste and pollutants and climate change; and altering the magnitude, frequency, and duration of disturbance regimes. the combined and often synergistic effects of those pressures can make ecosystems more vulnerable to changes that previously could be absorbed. as a consequence, ecosystems may suddenly shift from desired to less desired states in their capacity to generate ecosystem services. active adaptive management and governance of resilience will be required to sustain desired ecosystem states and transform degraded ecosystems into fundamentally new and more desirable configurations.",925,2004,35,,557,581,10.1146/annurev.ecolsys.35.021103.105711,1,0,0,1"Hager, HA",differential effects of typha litter and plants on invasive lythrum salicaria seedling survival and growth,BIOLOGICAL INVASIONS,Article,disturbance; plant and litter effects; plant invasion; seedling transplant experiment; wetlands,"invasive species are a problem because of their detrimental ecological and economic effects. increased disturbance caused by human impacts is hypothesized as a primary factor promoting the spread of invaders. plants and plant litter can have important effects on plant colonization and community composition by affecting seedling survival and growth. i examined the hypothesis that invasion of non-native lythrum salicaria in typha-dominated marshes is disturbance-dependent. if so, the removal of typha plants or litter would increase the survival and growth of l. salicaria seedlings. additionally, the removal of both plants and litter could result in an additive or synergistic effect on the establishment of l. salicaria. alternatively, l. salicaria may be a successful invader because it has a high capacity to establish and grow regardless of neighbours. in this case, l. salicaria would be expected to perform well even in plants and litter. strategies for managing l. salicaria will depend on which factors promote invasion. i measured the differential effects of plants and litter, alone and in combination. on the survival and growth of l. salicaria seedlings transplanted into marshes. the presence of plants and litter did not affect seedling survival in relatively dry wetland sites, indicating that l. salicaria seedlings have the capacity to persist in the presence of neighbouring typha spp. competitors. however, removal of both plants and litter allowed increased growth of l. salicaria seedlings in drier wetlands. therefore, growth was facilitated by disturbance that removed all vegetation. small disturbances (0.6 m(2)) decreased competitive suppression by native typha spp. neighbours and resulted in significant increases in growth. disturbance of wetlands at risk of invasion by l. salicaria should be avoided.",11,2004,6,4,433,444,10.1023/B:BINV.0000041558.22300.3a,1,0,1,2"Thaler, JS; Bostock, RM",interactions between abscisic-acid-mediated responses and plant resistance to pathogens and insects,ECOLOGY,Article,abscisic acid; induced responses; jasmonic acid; phytohormonal ecology; salicylic acid; tomato,"one goal of phytohormonal ecology is to study the interactions between biotic and abiotic stress at hierarchical levels of biological organization. from an ecological perspective, exposure to one stress may alter the plant's probability of being exposed to another stress. from a mechanistic perspective, hormonal and biochemical signaling interactions between responses to each stress may influence the severity or ability to adaptively respond to the subsequent stress. in this article, we consider the relationship between plant water and salt stress and attack by pathogens and herbivores. empirical data suggest that water stress and the probability of attack by pathogens and herbivores are correlated between habitats. biochemical interactions between plant responses to water and salt stress and insect. and pathogen attack are also interrelated. initial biochemical models indicated that abscisic acid (aba), an important hormone in responses to water and salt stress, had a synergistic positive role with jasmonate-induced defenses against herbivores and an,antagonistic role with salicylate-based resistance to some pathogens. based on this background, we developed predictions about how water and salt stress would alter plant resistance to insects and pathogens and tested the predictions using tomato plants as a model system. we: used polyphenol oxidase activity as a marker of the jasmonate response and, pathogenesis-related protein p4 as a marker of the salicylate response. first, we examined levels of chemical defense in wild-type and aba-deficient plants and the ability of these plants to resist insect and pathogen attack. in the second experiment, we exposed plants to short-term salinity stress and tested their subsequent resistance to a chewing. insect spodoptera exigua and the bacterial speck pathogen pseudomonas syringae pv. tomato. we have two key findings. first, aba-deficient plants had higher levels of salicylate-mediated responses and were more resistant to bacterial speck disease, consistent with the proposed role of salicylate in defense against pathogens. this suggests linkage between water availability to the plant and salicylate action in pathogenesis through aba signaling. aba-deficient plants had reduced resistance to the insect spodoptera exigua, suggesting a positive correlation between responses to water stress and herbivory. the lack of difference in chemical expression of the jasmonate (ja) response (polyphenol oxidase activity) between wild-type and aba-deficient plants did not support the proposed mechanism of synergism with the jasmonate response. second, salt stress reduced the chemical induction, (e.g., pathogenesis-related protein p4) of the salicylate response, but this did not affect resistance to the pathogen. salt stress did not alter resistance to the herbivore trichoplusia ni, but did alter the negative signal interaction between the jasmonate and salicylate responses. under control conditions, the jasmonate and salicylate responses are antagonistic to one another, with induction of one response reducing the inducibility of the other. under salt stress conditions, the negative effect of salicylate on the jasmonate response was reduced. thus, complex interactions occur between. aba, ja, and sa, hormones that are important regulators of abiotic and biotic stress responses. phytohormonal ecology is attempting to link ecological and hormonal interactions to develop a predictive framework for how and why plants coordinate responses to the environment.",107,2004,85,1,48,58,10.1890/02-0710,1,1,0,2"Jankovsky, L; Cudlin, P; Cermak, P; Moravec, I",the prediction of development of secondary norway spruce stands under the impact of climatic change in the drahany highlands (the czech republic),EKOLOGIA-BRATISLAVA,Article,climatic change; Norway spruce; temperature; precipitation; growth; risk,"the aim of the study was to define the rate of stress load of existing norway spruce stands of nutrient-rich sites of the drahany highlands (the czech republic) and to predict its further development with respect to risks of the activation of fungal pathogens and insect pests. in the past, stands under conditions of the 3(rd) and 4(th) forest vegetation zones of the drahany highlands were relatively slightly up to moderately loaded by synergistic effects of natural and anthropogenic stress factors on assimilatory organs. in the majority of stands, the inner tolerance of trees to the stressors has been already exceeded. however, the adaptation potential of stands to multiple stress impact has not been used up yet. changed climatic conditions predicted by the climatic change scenarios will result in the destabilization of existing spruce stands. the stand disintegration will be accompanied with the acceleration of armillaria sp. and cambioxylophagous insect as mortality stressors. it is possible to expect that growing spruce in the present 1(st) to 3(rd) forest vegetation zones will not be possible. similarly, in the most distributed management group 45 nutrient-rich sites of medium altitudes, it is possible to expect destabilization and disintegration of existing stands.",0,2004,23,,101,112,,1,0,0,1"Hooper, HL; Sibly, RM; Maund, SJ; Hutchinson, TH",the joint effects of larval density and c-14-cypermethrin on the life history and population growth rate of the midge chironomus riparius,JOURNAL OF APPLIED ECOLOGY,Article,carrying capacity; density dependence; life tables; pyrethroids; resource limitation,"1. chemical effects on organisms are typically assessed using individual-level endpoints or sometimes population growth rate (pgr), but such measurements are generally made at low population densities. in contrast most natural populations are subject to density dependence and fluctuate around the environmental carrying capacity as a result of individual competition for resources. as ecotoxicology aims to make reliable population projections of chemical impacts in the field, an understanding of how high-density or resource-limited populations respond to environmental chemicals is essential. 2. our objective was to determine the joint effects of population density and chemical stress on the life history and pgr of an important ecotoxicological indicator species, chironomus riparius, under controlled laboratory conditions. populations were fed the same ration but initiated at different densities and exposed to a solvent control and three concentrations of c-14-cypermethrin in a sediment-water test system for 67 days at 20 +/- 1 degreesc. 3. density had a negative effect on all the measured life-history traits, and pgr declined with increasing density in the controls. exposure to c-14-cypermethrin had a direct negative effect on juvenile survival, presumably within the first 24 h because the chemical rapidly dissipated from the water column. reductions in the initial larval densities resulted in an increase in the available resources for the survivors. subsequently, exposed populations emerged sooner and started producing offspring earlier than the controls. c-14-cypermethrin had no effect on estimated fecundity and adult body weight but interacted with density to reduce the time to first emergence and first reproduction. as a result, pgr increased with cypermethrin concentration when populations were initiated at high densities. 4. synthesis and applications. the results showed that the effects of c-14-cypermethrin were buffered at high density, so that the joint effects of density and chemical stress on pgr were less than additive. low levels of chemical stressors may increase carrying capacity by reducing juvenile competition for resources. more and perhaps fitter adults may be produced, similar to the effects of predators and culling; however, toxicant exposure may result in survivors that are less tolerant to changing conditions. if less than additive effects are typical in the field, standard regulatory tests carried out at low density may overestimate the effects of environmental chemicals. further studies over a wide range of chemical stressors and organisms with contrasting life histories are needed to make general recommendations.",21,2003,40,6,1049,1059,10.1111/j.1365-2664.2003.00858.x,0,0,1,1"Ervin, DE; Welsh, R; Batie, SS; Carpentier, CL",towards an ecological systems approach in public research for environmental regulation of transgenic crops,AGRICULTURE ECOSYSTEMS & ENVIRONMENT,Article; Proceedings Paper,transgenic; environmental; ecological; systems; research,"a review of current research shows insufficient monitoring and testing have been conducted to reliably assess the degree of environmental risks posed by transgenic crops. the major risks include increased resistance to particular pesticides, gene flow into related plant species, and negative effects on non-target organisms. significant gaps in knowledge, often stemming from missing markets for ecological services, warrant a cautious environmental regulatory approach for transgenic crops. the objective of this paper is to identify the types of ecological systems public research to implement effective biosafety controls. us biosafety regulatory processes tend to focus on controlling type i error, i.e. restricting the release of the crops when significant environmental risks do not exist, because the economic losses from denying commercialization can be estimated. however, the precautionary principle, which focuses on controlling type ii errors, i.e. releasing the crops when serious ecosystem damage will occur, adds a necessary criterion given the current deficit in ecological science. the key challenge facing regulators is to find the appropriate balance of controlling type i versus type ii errors. the research program should embed the lessons of evolutionary biology and ecological sciences. viewing the plant as a production machine that can be ""brute-force"" reengineered for more efficiency is a poor analogy. unanticipated and unintended results, positive and negative, will emerge from such engineering because plants are complex systems embedded in poorly understood, complex, and interacting ecosystems. an ideal public research program should capture the interconnectedness of ecological systems, the essential roles of ecosystem services, nonlinear and threshold responses to accumulating stresses, and global expansion of the technology. basic elements of such a program include long-term studies of cumulative and synergistic pesticide resistance effects, potential gene flow problems for those transgenic crop trait-weed complexes with high probabilities of outcrossing and ecological disruption, and scientific protocols for assessing deleterious effects on non-target organisms. for all three effects, expanded ecosystem monitoring of the commercialized crops in varied settings is needed for improved type ii error definitions and estimates. the development of improved risk analysis methodologies and protocols should also be a priority. finally, scientific effort to stimulate precautionary research, such as the development of transgenic crops that mimic ecological systems functioning, could avert many risks. creating information to avoid significant ecological damages and foster precautionary research and development for transgenic crops are neglected roles of public biotechnology research. (c) 2003 elsevier science b.v. all rights reserved.",26,2003,99,03-Jan,1,14,10.1016/S0167-8809(03)00145-2,1,0,0,1"Fujita, KI; Kubo, I",synergism of polygodial and trans-cinnamic acid on inhibition of root elongation in lettuce seedling growth bioassays,JOURNAL OF CHEMICAL ECOLOGY,Article,allelopathy; synergism; polygodial; trans-cinnamic acid; seedling growth; Polygonum hydropiper; lettuce; Lactuca sativa; plasma membrane H+-ATPase,"a bicyclic sesquiterpene dialdehyde, polygodial did not inhibit root elongation up to a concentration of 12.5 mug/ml in a lettuce seedling assay: trans-cinnamic acid inhibited the elongation by 50% at 1.2 mug/ml (8.1 mum). the inhibitory activity of trans-cinnamic acid was enhanced 17-fold when used in combination with 6.25 mug/ml (26.5 mum) of polygodial. a decrease in the ph of the medium was observed during normal seedling growth, indicating transport of protons from the cells by a plasma membrane h+-atpase. the inhibitory effect of trans-cinnamic acid on the elongation was reduced to some extent in 2 mm phosphate buffer (ph 7.0) during seedling growth. although polygodial did not inhibit the activity of h+-atpase in the plasma membrane fraction of roots in normally growing seedlings, a decrease in activity was found in the fraction obtained from seedlings incubated with 20 mug/ml of polygodial. these results suggest that polygodial functions synergistically with trans-cinnamic acid in the inhibition of root elongation via restriction of proton transport from the cytoplasm of germinated cells.",16,2003,29,10,2253,2262,10.1023/A:1026270329989,1,0,0,1"Jones, JI; Li, W; Maberly, SC","area, altitude and aquatic plant diversity",ECOGRAPHY,Article,,"several explanations have been given for the decline in species richness with altitude. however, separating the influences of altitude, area, and isolation is difficult because of the conical shape of mountains. we used species lists of aquatic plants from > 300 lakes in a small geographical area to investigate the influence of altitude on species richness. altitude and/or surface area were better predictors of species richness than any measure of water chemistry. the surface area and depth of individual lakes were not related to altitude, neither was the degree of isolation from other waterbodies. although species range size increased with altitude, range sizes of all but the rarer species (in the data set) encompassed the lowest altitudes, indicating species loss rather than turnover and no influence of the rapoport rescue effect. nevertheless we found a decline in species richness with altitude, additive to the effect of area. species were ascribed to attribute groups according to an a priori classification based on morphological and life-history traits. the number of attribute groups and number of species within each group increased with area, suggesting both increased diversity and coexistence within niches. with altitude, the number of attribute groups declined, but the number of species per group increased, consistent with a loss of richness and reduced competition. the species remaining at high altitudes were characterised by stress tolerant traits, associated with sites of low productivity. our results suggest an absolute effect of altitude on species richness, irrespective of other influences and consistent with a decline in productivity.",50,2003,26,4,411,420,10.1034/j.1600-0587.2003.03554.x,0,0,1,1"McCune, B; Berryman, SD; Cissel, JH; Gitelman, AI",use of a smoother to forecast occurrence of epiphytic lichens under alternative forest management plans,ECOLOGICAL APPLICATIONS,Article,ecological neighborhood model; epiphytes; forest planning; habitat model; lichens; Lobaria oregana; nonparametric smoothing; Northwest Forest Plan; Pacific Northwest (USA); riparian forests,"we used habitat models to forecast the frequency of occurrence of epiphytic lichen species in a forested landscape under two alternative plans: a literal application of standard prescriptions in the northwest forest plan and a plan patterned in part after natural disturbance regimes. the plans were evaluated for the blue riverwatershed in the cascade range of oregon, usa. we used two model types: logistic regression and an ecological neighborhood model using a form of nonparametric regression (spocc; species occurrence modeler). both logistic regression and spocc successfully estimated the occurrence of the lichen lobaria oregana in the current landscape, based on elevation and structural classes of forests. structural classes were defined by combinations of (1) overstory retention of remnant trees, (2) young cohort age, and (3) stream position (upland vs. riparian). lobaria oregana rapidly diminished in frequency in the landscape at elevations above 900-1000 in. young, even-aged stands had little or no lobaria oregana. most of the other structural classes, however, were very similar in frequency of lobaria. the differences in lichens between retention levels and between mature and old growth stands were very small compared to the differences with respect to elevation and clearcutting. similar results, with varying importances of elevation and forest structure, were, obtained for most of the 20 species with the strongest models. many of these species were associated with old growth, and many were forecasted to be more frequent under either management plan than in the current landscape. this is a likely response to the reduction of even-aged management in this, landscape. we recommend using spocc for flexible nonparametric fitting of,species relationships to a multivariate habitat. spocc avoids the need to specify response functions and, because it is multiplicative rather than additive, automatically models responses to interactions among predictors.",22,2003,13,4,1110,1123,10.1890/1051-0761(2003)13[1110:UOASTF]2.0.CO;2,0,0,1,1"Roman-Cuesta, RM; Gracia, M; Retana, J",environmental and human factors influencing fire trends in enso and non-enso years in tropical mexico,ECOLOGICAL APPLICATIONS,Article,causal relations; Chiapas; Mexico; El Nino; fire distribution; fire incidence; human-related variables; tropical rainforest,"tropical and subtropical areas present the vast majority of contemporary global fires. despite the human origin of most of these fires, little is,known of how environmental and socioeconomic variables contribute to the spatial patterns of fire incidence and burned areas. the tropical mexican state of chiapas represents a good case study to analyze these interactions, due to the availability of official data, and its similarities to other tropical countries, in terms of environmental and socioeconomic characteristics. this study evaluates the relative importance of human-related and environmental variables in determining the distribution of the number of fires and area burned in the tropical state of chiapas in years, of normal and extreme climatic conditions (non-el nino vs. el nino). we have searched for causal relationships among fire, environmental, and socioeconomic variables in chiapas using path analysis. results of this study show a major, importance of environmental variables in non-el nino years, suggesting that the status of the vegetation was the main cause determining fire ignition and fire spread in these years. contrarily, the observed trends in the el nino period indicate that fire trends were mainly determined by the presence of ignition agents. in these el nino years, vegetation is so severely water stressed that, when fire starts, all vegetation types burn, regardless of their flammability properties. the main vegetation types affected by fire in non-el nino years were the most flammable ones, such as pine-oak communities, while rainforests burned the most in el nino years. altitude, pine-oak communities, and poverty levels played major roles in the arboreal fire incidence in non-el nino years, whereas the distribution of pastures appeared as an important, variable determining arboreal fire incidence in el nino years. when all fires were considered (affecting any vegetation layer), almost identical trends were observed, with the incorporation of a new variable influencing the area burned: density of infrastructure. the results of this study strengthen the importance of el nino years in the conservation of rainforest ecosystems and suggest the existence of synergistic effects involving fires, fragmentation, and certain elements of the landscape, such as cattle pastures, in tropical areas.",40,2003,13,4,1177,1192,10.1890/1051-0761(2003)13[1177:EAHFIF]2.0.CO;2,1,0,0,1"Houlton, BZ; Driscoll, CT; Fahey, TJ; Likens, GE; Groffman, PM; Bernhardt, ES; Buso, DC",nitrogen dynamics in ice storm-damaged forest ecosystems: implications for nitrogen limitation theory,ECOSYSTEMS,Article,ice storm; nitrogen; nitrogen loss; nitrogcn cycling; nutrient limitation; nitrification; nitrogen mineralization; nitrogen saturation; forest ecosystem; biogeochemistry; Hubbard Brook Experimental Forest; watershed,"despite the widely recognized importance of disturbance in accelerating the loss of elements from land, there have been few empirical studies of the effects of natural disturbances on nitrogen (n) dynamics in forest ecosystems. we were provided the unusual opportunity for such study, partly because the intensively monitored watersheds at the hubbard brook fxperimental forest (hbef), new hampshire, experienced severe canopy damage following an ice storm. here we report the effects of this disturbance on internal n cycling and loss for watershed 1 (w1) and watershed 6 (w6) at the hbef and patterns of n loss from nine other severely damaged watersheds across the southern white mountains. this approach allowed us to test one component of n limitation theory, which suggests that n losses accompanying natural disturbances can lead to the maintenance of n limitation in temperate zone forest ecosystems. prior to the ice storm, fluxes of nitrate (no3-) at the base of w1 and w6 were similar and were much lower than n inputs in atmospheric deposition. following the ice storm, drainage water no3- concentrations increased to levels that were seven to ten times greater than predisturbance values. we observed no significant differences in n mineralization, nitrification, or denitrification between damaged and undamaged areas in the hbef watersheds, however. this result suggests that elevated no3- concentrations were not necessarily due to accelerated rates of n cycling by soil microbes but likely resulted from decreased plant uptake of no3-. at the regional scale, we observed high variability in the magnitude of no3- losses: while six of the surveyed watersheds showed accelerated rates of no3- loss, three did not. moreover, in contrast to the strong linear relationship between no3- loss and crown damage within hbef watersheds [r(2): (w1 = 0.91, w6 = 0.85)], streant water no3- concentrations were weakly related to crown damage (r(2) = 0.17) across our regional sites. the efflux of no3- associated with the ice storm was slightly higher than values reported for soil freezing and insect defoliation episodes, but was approximately two to ten times lower than no3- fluxes associated with forest harvesting. because over one half of the entire year's worth of n deposition was lost following the ice storm, we conclude that catastrophic disturbances contribute synergistically to the maintenance of n limitation and widely observed delays of n saturation in northern, temperate zone forest ecosystems.",57,2003,6,5,431,443,10.1007/s10021-002-0198-1,1,0,0,1"Sgro, CM; Blows, MW",evolution of additive and nonadditive genetic variance in development time along a cline in drosophila serrata,EVOLUTION,Article,additive genetic variance; clines; evolution; life history; nonadditive genetic variance,"latitudinal clines provide natural systems that may allow the effect of natural selection on the genetic variance to be determined. ten clinal populations of drosophila serrata collected from the eastern coast of australia were used to examine clinal patterns in the trait mean and genetic variance of the life-history trait egg-to-adult development time. development time significantly lengthened from tropical areas to temperate areas. the additive genetic variance for development time in each population was not associated with latitude but was associated with the population mean development time. additive genetic variance tended to be larger in populations with more extreme development times and appeared to be consistent with allele frequency change. in contrast, the nonadditive genetic variance was not associated with the population mean but was associated with latitude. levels of nonadditive genetic variance were greatest in the region of the cline where the gradient in the change in mean was greatest, consistent with barton's (1999) conjecture that the generation of linkage disequilibrium may become an important component of the genetic variance in systems with a spatially varying optimum.",21,2003,57,8,1846,1851,,0,0,1,1"Pakkasmaa, S; Merila, J; O'Hara, RB",genetic and maternal effect influences on viability of common frog tadpoles under different environmental conditions,HEREDITY,Article,Bayesian models; environmental stress; heritability; maternal effects; pH; Rana temporaria,"the influence of environmental stress on the expression of genetic and maternal effects on the viability traits has seldom been assessed in wild vertebrates. we have estimated genetic and maternal effects on the viability (viz probability of survival, probability of being deformed, and body size and shape) of common frog, rana temporaria, tadpoles under stressful (low ph) and nonstressful (neutral ph) environmental conditions. a bayesian analysis using generalized linear mixed models was applied to data from a factorial laboratory experiment. the expression of additive genetic variance was independent of ph treatments, and all traits were significantly heritable (survival: h(2) approximate to 0.08; deformities: h(2) approximate to 0.26; body size: h(2) approximate to 0.12; body shape: h(2) approximate to 0.14). likewise, nonadditive genetic contributions to variation in all traits were significant, independent of ph treatments and typically of magnitude similar to the additive genetic effects. maternal effects were large for all traits, especially for viability itself, and their expression was partly dependent on the environment. in the case of body size, the maternal effects were mediated largely through egg size. in general, the results give little evidence for the conjecture that environmental stress created by low ph would impact strongly on the genetic architecture of fitness-related traits in frogs, and hamper adaptation to stress caused by acidification. the low heritabilities and high dominance contributions conform to the pattern typical for traits subject to relatively strong directional selection.",47,2003,91,2,117,124,10.1038/sj.hdy.6800289,0,0,1,1"Norris, WR; Hemesath, LM; Debinski, DM; Farrar, DR","does bird community composition vary along a disturbance gradient in northeast iowa, usa, forests?",NATURAL AREAS JOURNAL,Article,birds; disturbance; forest; habitat relationships; northeast Iowa,"most previous studies of bird-habitat relationships in midwestern u.s. forests have excluded recently disturbed habitats from consideration. we investigated whether the composition of a forest avifauna varies along a disturbance gradient ranging from mature, infrequently disturbed forests to successional. frequently disturbed forests impacted by logging and pasturing practices. we evaluated the degree of disturbance of 44 forests in northeast iowa, usa (including mature and recently disturbed forests), using an additive. multicriteria index ranging in value from 20 (mature: infrequently disturbed) to 0 (successional: highly disturbed). we conducted forest bird censuses at these study sites using point counts in 1995 and 1996. then, we used stepwise regression analyses to test for relationships between the abundance (mean number of birds detected per census point at each site) and species richness (mean number of bird species detected per census point at each site) of birds and the index. for these analyses, birds were divided into subsets by migratory status, nest substrate, and conservation categories. the disturbance index predicted the abundance of 2 out of 10 bird groups: permanent residents were more abundant in frequently disturbed forests, and area-sensitive bird species were more abundant in infrequently disturbed forests. the index predicted the species richness of 7 out of 10 bird groups. short-distance migrants, permanent residents, and ground nesters were more diverse in frequently disturbed, successional forests, while neotropical migrants, tree nesters, species of high management concern, and area-sensitive birds had higher species richness in mature, infrequently disturbed forests. these results suggest that mature forest vegetation is important habitat for uncommon and rare bird species in northeast iowa.",4,2003,23,3,262,273,,0,0,1,1"Pizzari, T; Snook, RR",perspective: sexual conflict and sexual selection: chasing away paradigm shifts,EVOLUTION,Article,fitness; promiscuity; reproduction; sexual antagonism; sexual coevolution; sexual mutualism,"traditional models of sexual selection propose that partner choice increases both average male and average female fitness in a population. recent theoretical and empirical work, however, has stressed that sexual conflict may be a potent broker of sexual selection. when the fitness interests of males and females diverge, a reproductive strategy that increases the fitness of one sex may decrease the fitness of the other sex. the chase-away hypothesis proposes that sexual conflict promotes sexually antagonistic, rather than mutualistic, coevolution, whereby manipulative reproductive strategies in one sex are counteracted by the evolution of resistance to such strategies in the other sex. in this paper, we consider the criteria necessary to demonstrate the chase-away hypothesis. specifically, we review sexual conflict with particular emphasis on the chase-away hypothesis; discuss the problems associated with testing the predictions of the chase-away hypothesis and the extent to which these predictions and the predictions of traditional models of sexual selection are mutually exclusive; discuss misconceptions and mismeasures of sexual conflict; and suggest an alternative approach to demonstrate sexual conflict, measure the intensity of sexually antagonistic selection in a population, and elucidate the coevolutionary trajectories of the sexes.",109,2003,57,6,1223,1236,10.1111/j.0014-3820.2003.tb00331.x,0,1,0,1"Yuan, LL; Norton, SB",comparing responses of macroinvertebrate metrics to increasing stress,JOURNAL OF THE NORTH AMERICAN BENTHOLOGICAL SOCIETY,Article,stressor-response; habitat; nutrients; conductivity; metals; macroinvertebrates,"metrics characterizing the benthic macroinvertebrate assemblages in wadeable streams in the mid-atlantic region of the united states were analyzed to explore the relative responses of the metrics to different types of anthropogenic stress. the data used in our study were collected by the us environmental protection agency environmental monitoring and assessment program from 1993 to 1996. regression models were developed relating metric values at reference sites to natural sources of variability. these models were then used to predict reference values at test sites. test site metric observations were scaled by subtracting the predicted reference value and dividing by the standard deviation of residuals at reference sites. stressor-response relationships for each scaled metric were then estimated using generalized additive models. metric responses to 4 groups of stressors (nutrient enrichment, habitat degradation, elevated metals concentrations, and elevated ion concentrations) were different. the proportional abundance of tolerant taxa was the most sensitive indicator of nutrient enrichment and habitat degradation, whereas ephemeroptera richness was the most sensitive indicator of elevated metals or ion concentrations.",40,2003,22,2,308,322,10.2307/1468000,0,0,1,1"Wirth, T; Bernatchez, L",decline of north atlantic eels: a fatal synergy?,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,conservation; Atlantic eels; Bayesian inference; microsatellites; demographic history; climatic changes,"panmictic species pose particular problems for conservation because their welfare can be addressed effectively only on a global scale. we recently documented by means of microsatellite analysis that the european eel (anguilla anguilla) is not panmictic but instead shows genetic isolation by distance. in this study, we extended the analysis to the american eel (a. rostrata) by applying identical analytical procedures and statistical power. results obtained for the american eel were in sharp contrast with those obtained for the european eel: the null hypothesis of panmixia could not be rejected, and no isolation by distance was detected. this implies that the species must be managed as a single population. using bayesian statistics, we also found that the effective population sizes for both species were surprisingly low and that the populations had undergone severe contractions, most probably during the wisconsinan glaciation. the apparent sensitivity of eels to climatic changes affecting the strength and position of the gulf stream 20 000 years ago is particularly worrying, given the effects of the ongoing global warming on the north atlantic climate. moreover, additional short-term stresses such as surging glass eel prizes, overfishing and lethal parasitic infections negatively affect eel population size. the fascinating transatlantic migration and life cycle of atlantic eels is also their achilles' heel as these negative short- and long-term effects will probably culminate in a fatal synergy if drastic conservation measures are not implemented to protect these international biological resources.",99,2003,270,1516,681,688,10.1098/rspb.2002.2301,1,0,0,1"Hirst, RA; Pywell, RF; Marrs, RH; Putwain, PD",the resistance of a chalk grassland to disturbance,JOURNAL OF APPLIED ECOLOGY,Article,calcareous grassland; CCA; DCA; habitat disturbance; military training; Salisbury Plain Training Area; succession; tracked vehicles,"1. concepts of ecosystem stability, resilience and resistance have been discussed theoretically for nearly three decades. understanding the effects of habitat disturbance and mechanisms of recovery in practice are vital for successful conservation management and restoration, particularly of subseral communities with high conservation interest and sites subject to unavoidable disturbances. chalk grasslands are one such habitat, with high european conservation importance, and the greatest remaining extent in north-west europe lies within the salisbury plain training area (spta), the largest uk military training area. in order to understand the resistance and recovery of this habitat type, we undertook an experimental approach using imposed disturbance treatments. 2. an experiment was designed to compare the disturbance effects of a land rover, a truck and a challenger ii tank on a tall bromopsis erecta -dominated chalk grassland community on the spta. permanent quadrats were established on a site experimentally disturbed by single and multiple passes of the three vehicles and a tank turn (slew). post-disturbance changes were recorded in the vegetation and soils in permanent quadrats. 3. one year after the disturbance, all the treatments still had significant soil compaction effects and all treatments except the single land rover pass resulted in a significant reduction in sward height. the grassland community sampled was significantly less resistant to disturbance by tracked vehicles than wheeled vehicle disturbance, with tracked vehicles creating the greatest recorded soil compaction and exposure of bare soil and longer-term changes in sward composition. 4. ordination techniques were used to characterize post-disturbance successional trajectories. these suggest that chalk grassland is significantly less resistant to disturbance caused by multiple passes of tracked vehicles and tracked vehicle turns. chalk grassland recovery from these types of disturbance is less predictable. 5. identifying vegetation community resistance assists understanding of the ecosystem response to long-term and cumulative stress and facilitates strategic management of habitats where disturbance events are commonplace, especially in areas of high nature conservation interest. these data demonstrate that small-scale but acute disturbance events can have significant effects on plant community composition, and can have wider reaching impacts on other aspects of site management. there are important implications for the management of off-road vehicles in recreational and agricultural contexts, and for the formulation of a strategic sustainable management plan for the spta that incorporates both military and conservation objectives. 6. synthesis and applications. resistance to disturbance is not necessarily an additive function. managers of chalk grasslands should limit activities that create high intensity disturbance events because the succession trajectory following such events may be less direct and with less predictable outcomes than that following lower intensity disturbances. increased predictability of succession trajectories following medium to low disturbance events means these types of disturbance might be used deliberately to create short-term and small-scale heterogeneity in both species composition and sward structure. site managers should be aware that certain activities not previously considered to be potentially damaging might be creating significant habitat disturbance effects, as changes to soil structure, functioning and fauna can occur in the absence of changes in plant community composition.",22,2003,40,2,368,379,10.1046/j.1365-2664.2003.00800.x,0,0,1,1"Bonneaud, C; Mazuc, J; Gonzalez, G; Haussy, C; Chastel, O; Faivre, B; Sorci, G",assessing the cost of mounting an immune response,AMERICAN NATURALIST,Article,life-history traits; LPS; parasite resistance; parental effort; reproductive success; trade-off,"the evolution of parasite resistance has often been assumed to be governed by antagonistic selection pressures. defense against pathogens, by mounting an immune response, confers evident benefits but may also incur costs, so that the optimal level of defense is expected to depend on the balance between benefits and costs. although the benefits of immune surveillance are well known, estimates of costs are still equivocal. here we studied the behavioral and physiological modifications associated with exposure to a non-replicating antigen (lipopolysaccharide [lps] of escherichia coli) in a passerine species, the house sparrow (passer domesticus). we further investigated whether the behavioral and physiological changes provoked by lps induced measurable repercussions on life-history traits, such as the breeding effort and reproductive success. finally, we tested whether the trade-off between immune activation and breeding effort was modulated by the workload required to feed the brood. exposure to lps reduced activity and increased body mass loss of captive individuals; similarly, lps injection induced a dramatic drop in feeding rate and reproductive success of breeding females. however, this reduction depended on brood size, suggesting that the strength of the trade-off between immune activation and reproduction was affected by the workload required to feed the brood. overall, this study stresses the magnitude of costs associated with mounting immune responses and the ecological and evolutionary consequences for natural populations.",252,2003,161,3,367,379,10.1086/346134,0,1,0,1"Phelan, JP; Archer, MA; Beckman, KA; Chippindale, AK; Nusbaum, TJ; Rose, MR",breakdown in correlations during laboratory evolution. i. comparative analyses of drosophila populations,EVOLUTION,Article,antagonistic pleiotropy; correlations; fitness characters; laboratory evolution; longevity; stress resistance; selection,"we provide evidence from comparisons of populations of drosophila that evolutionary correlations between longevity and stress resistance break down over the course of laboratory evolution. using 15 distinct evolutionary regimes, we created 75 populations that were differentiated for early fecundity, longevity, starvation resistance, desiccation resistance, and developmental time. in earlier experiments, selection for postponed aging produced increases in stress resistance, whereas selection for increased stress resistance produced increases in longevity. direct estimates of correlations also indicated an antagonistic relationship between early fecundity on one hand and longevity or stress resistance on the other. laboratory evolution of extreme values of stress resistance, however, led to a breakdown in these evolutionary relationships. there was no evidence that these significant changes in correlation resulted from genotype-by-environment interactions or inbreeding. these findings suggest that correlations between functional characters are not necessarily durable features of a species, and that short-term evolutionary responses cannot be extrapolated reliably to longer-term evolutionary patterns.",43,2003,57,3,527,535,,0,1,0,1"Steinger, T; Roy, BA; Stanton, ML",evolution in stressful environments ii: adaptive value and costs of plasticity in response to low light in sinapis arvensis,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,adaptation; genetic variation; life-history; phenotypic plasticity; plasticity cost; selection; specific leaf area; stress,"plants possess a remarkable capacity to alter their phenotype in response to the highly heterogeneous light conditions they commonly encounter in natural environments. in the present study with the weedy annual plant sinapis arvensis, we (a) tested for the adaptive value of phenotypic plasticity in morphological and life history traits in response to low light and (b) explored possible fitness costs of plasticity. replicates of 31 half-sib families were grown individually in the greenhouse under full light and under low light (40% of ambient) imposed by neutral shade cloth. low light resulted in a large increase in hypocotyl length and specific leaf area (sla), a reduction in juvenile biomass and a delayed onset of flowering. phenotypic selection analysis within each light environment revealed that selection favoured large sla under low light, but not under high light, suggesting that the observed increase in sla was adaptive. in contrast, plasticity in the other traits measured was maladaptive (i.e. in the opposite direction to that favoured by selection in the low light environment). we detected significant additive genetic variance in plasticity in most phenotypic traits and in fitness (number of seeds). using genotypic selection gradient analysis, we found that families with high plasticity in sla had a lower fitness than families with low plasticity, when the effect of sla on fitness was statistically kept constant. this indicates that plasticity in sla incurred a direct fitness cost. however, a cost of plasticity was only expressed under low light, but not under high light. thus, models on the evolution of phenotypic plasticity will need to incorporate plasticity costs that vary in magnitude depending on environmental conditions.",71,2003,16,2,313,323,10.1046/j.1420-9101.2003.00518.x,0,0,1,1"Rasanen, K; Laurila, A; Merila, J","geographic variation in acid stress tolerance of the moor frog, rana arvalis. ii. adaptive maternal effects",EVOLUTION,Article,acid tolerance; amphibians; environmental stress; genetic adaptation; maternal effects,"the knowledge about the relative contributions of additive genetic and maternal effects, as well as the proximate determinants of maternal effects variation, on population differentiation remains elusive. likewise, although embryonic performance is often an important component of fitness, it has been relatively little explored in respect to population differentiation. by conducting reciprocal crosses between an acid and a neutral origin population of moor frogs (rana arvalis), we investigated the relative importance of additive genetic versus maternal effects in local adaptation to acidity in embryonic traits. furthermore, by performing removal experiments of gelatinous egg capsules (jelly), we evaluated the possibility that differences in the extraembryonic membranes might explain the interpopulation variation in embryonic acid tolerance found in this and earlier studies. embryos were raised from fertilization to hatching at three different ph levels (ph 4.0, 4.25, and 7.5) in the laboratory, and acid stress tolerance was measured in terms of embryonic survival, growth and development (i.e., size and age at hatching). the results show that the higher acid tolerance of acid population embryos (in terms of survival) was maternally determined, indicating adaptive maternal effects. the jelly removal experiment revealed that adaptation to acidity in embryonic survival may arise through variation related to structure/composition of the egg capsules. there was no evidence for a genetic basis in acid tolerance in sublethal effects, but additive and nonadditive genetic effects were found in embryonic growth and development, independently of treatment. the results indicate a role for maternal effects in local adaptation to acidity in amphibians, and genetically based differences in early life-histories among the populations.",39,2003,57,2,363,371,10.1554/0014-3820(2003)057[0363:GVIAST]2.0.CO;2,0,0,1,1"Zalewski, M; Lapinska, M; Bayley, PB",fish relationships with wood in large rivers,ECOLOGY AND MANAGEMENT OF WOOD IN WORLD RIVERS,Proceedings Paper,,"the importance of wood for fish as individuals, populations, and communities and its role in the formation of habitats in large rivers is reviewed. small-scale effects of wood on fish dominate the literature, but effects on populations and communities at the basin scale are not additive because increasing development of wood-influenced habitats modifies the transport of water, nutrients, and sediments. this, in turn, creates and maintains habitat resulting in increased spatial and temporal diversity and system resilience, which subsequently affect different life cycles of riverine fishes. such effects depend on location; the relative influence of instream wood on fish and physical processes tends to decrease downstream in large basins, but the converse may be true in floodplains as their influence increases downstream. because climatic factors control hydrology and temperature throughout the basin, and fish responses to management depend on large-scale, longer term processes as well as smaller ones, the research results reviewed here are assessed in the context of a basin-scale framework, the ecohydrology concept (ehc). a restoration strategy based on a basin-scale framework fosters a natural disturbance regime, increases the ability of the system to absorb impacts, and utilizes natural processes in the development of management tools. reintroduction of wood in large rivers is an essential strategic component but will not, on its own, achieve significant benefits for fish and other biota without at least partial restoration of hydrological cycles, riparian vegetation, selected floodplains, and the associated natural disturbance regime.",28,2003,37,,195,211,,0,0,1,1"Smithwick, EAH; Harmon, ME; Domingo, JB",modeling multiscale effects of light limitations and edge-induced mortality on carbon stores in forest landscapes,LANDSCAPE ECOLOGY,Article,additive model; carbon; disturbance; emergent behaviors; forest edges; horizontal interactions; light; models; scale; spatial pattern; wind,"analyses of carbon ( c ) dynamics at broad scales usually do not consider spatial interactions. the assumption is that c dynamics can be modeled within homogenous ( i. e., even- aged ) patches and then summed to predict broad- scale dynamics ( an additive approach ). the goal of this paper is to elucidate the scales over which this additive approach is sufficient to explain observed c dynamics at broad scales. we define emergent "" behaviors"" ( vs. emergent "" properties"" ) as those behaviors that cannot be predicted solely from the additive properties of units at a finer scale. we used a forest process model to check for possible emergent behaviors due to pattern-process interactions at multiple levels, from the patch to the landscape. specifically, using artificial forest landscapes with various spatial structures, we estimated the relative effects of edge- induced, tree mortality ( mainly due to wind ) and light limitations on c dynamics. emergent behaviors were observed at all levels examined, indicating that emergent behaviors did not cease as one proceeded from the patch to the landscape level, as we had expected. however, the magnitude of the emergent behaviors depended on the level of spatial interaction considered as well as the type and intensity of the processes included. in all simulations, interactions of light and wind processes resulted in significant emergent behaviors only when parameters controlling wind mortality were set to the highest levels observed in the literature. in one simulation, the magnitude of emergent behaviors differed among the landscapes, indicating that interactions among patches may not be accounted for by an additive correction for edge effects unless spatial interactions are addressed. the implication is that some c dynamics in fragmented landscapes may not be captured at broad- scales using an additive approach, whereas in other cases spatial interactions are small enough to be ignored.",15,2003,18,7,701,721,10.1023/B:LAND.0000004254.94982.67,0,0,1,1"Little, EE; Bridges, CM; Linder, G; Boone, M",establishing causality in the decline and deformity of amphibians: the amphibian research and monitoring initiative model,MULTIPLE STRESSOR EFFECTS IN RELATION TO DECLINING AMPHIBIAN POPULATIONS,Proceedings Paper,chemical; physical; biotic variables; environmental stress; amphibians; risk assessment; causality; deformity and decline,"research to date has indicated that a range of environmental variables such as disease, parasitism, predation, competition, environmental contamination, solar ultraviolet radiation, climate change, or habitat alteration may be responsible for declining amphibian populations and the appearance of deformed organisms, yet in many cases no definitive environmental variable stands out as a causal factor. multiple stressors are often present in the habitat, and interactions among these can magnify injury to biota. this raises the possibility that the additive or synergistic impact of these stressors may be the underlying cause of amphibian declines. effective management for the restoration of amphibian populations requires the identification of causal factors contributing to their declines. a systematic approach to determine causality is especially important because initial impressions may be misleading or ambiguous. in addition, the evaluation of amphibian populations requires consideration of a broader spatial scale than commonly used in regulatory monitoring. we describe a systematic three-tiered approach to determine causality in amphibian declines and deformities. tier i includes an evaluation of historic databases and extant data and would involve a desktop synopsis of the status of various stressors as well as site visits. tier 2 studies are iterative, hypothesis driven studies beginning with general tests and continuing with analyses of increasing complexity as certain stressors are identified for further investigation. tier 3 applies information developed in tier 2 as predictive indicators of habitats and species at risk over broad landscape scales and provides decision support for the adaptive management of amphibian recovery. this comprehensive, tiered program could provide a mechanistic approach to identifying and addressing specific stressors responsible for amphibian declines across various landscapes.",3,2003,1443,,263,277,10.1520/STP11187S,1,0,1,2"Kochubey, SM; Pardalos, PM; Yatsenko, VA",method and the device for remote sensing of vegetation,"REMOTE SENSING FOR AGRICULTURE, ECOSYSTEMS, AND HYDROLOGY IV",Proceedings Paper,remote sensing; vegetation; reflectance spectrum; chlorophyll; spectroscopy; estimation; optimization; optical sensors,in this paper we consider the problem of estimating chlorophyll content in vegetation using an experimental optical method from noisy spectral data. it is shown that the quantitative analysis of the spectral curves for the reflection of plant leaves may be the basis for development of new methods for interpretation of the data obtained by the remote measurement of plants. a mathematical model of vegetation reflectance is proposed to estimate the chlorophyll concentration from spectral data. estimates are defined as minimizers of penalized cost functionals with sequential quadratic programming (sqp) methods. an estimation tool is related to the local scoring procedure for a generalized additive model. experimental and simulation results are shown for different agricultural plants using a functional parametric fitting of spectral curves.,0,2003,4879,,243,251,10.1117/12.462461,0,0,1,1"McClanahan, T; Polunin, N; Done, T",ecological states and the resilience of coral reefs,CONSERVATION ECOLOGY,Review,,"we review the evidence for multiple ecological states and the factors that create ecological resilience in coral reef ecosystems. there are natural differences among benthic communities along gradients of water temperature, light, nutrients, and organic matter associated with upwelling-downwelling and onshore-offshore systems. along gradients from oligotrophy to eutrophy, plant-animal symbioses tend to decrease, and the abundance of algae and heterotrophic suspension feeders and the ratio of organic to inorganic carbon production tend to increase. human influences such as fishing, increased organic matter and nutrients, sediments, warm water, and transportation of xenobiotics and diseases are common causes of a large number of recently reported ecological shifts. it is often the interaction of persistent and multiple synergistic disturbances that causes permanent ecological transitions, rather than the succession of individual short-term disturbances. for example, fishing can remove top-level predators, resulting in the ecological release of prey such as sea urchins and coral-eating invertebrates. when sea urchins are not common because of unsuitable habitat, recruitment limitations, and diseases, and when overfishing removes herbivorous fish, frondose brown algae can dominate. terrigenous sediments carried onto reefs as a result of increased soil erosion largely promote the dominance of turf or articulated green algae. elevated nutrients and organic matter can increase internal eroders of reef substratum and a mixture of filamentous algae. local conservation actions that attempt to reduce fishing and terrestrial influences promote the high production of inorganic carbon that is necessary for reef growth. however, global climate change threatens to undermine such actions because of increased bleaching and mortality caused by warm-water anomalies, weakened coral skeletons caused by reduced aragonite availability in reef waters, and increased incidence of diseases in coral reef species. consequently, many coral reefs, including those that are heavily managed, have experienced net losses in accumulated inorganic carbon in recent decades and appear likely to continue this trend in coming decades. reefs urgently need to be managed with a view to strengthening their resilience to the increased frequency and intensity of these pressures. ecological targets must include the restoration or maintenance of species diversity, keystone species, spatial heterogeneity, refugia, and connectivity. achieving these goals will require unprecedented cooperative synergy between human organizations at all political levels, from intergovernmental to local.",84,2002,6,2,,,,1,0,0,1"Gergel, SE",assessing cumulative impacts of levees and dams on floodplain ponds: a neutral-terrain model approach,ECOLOGICAL APPLICATIONS,Article,dams; flood magnitude; floodplain; levees; neutral-terrain model; temporary pond; wetlands; Wisconsin River,"nearly all large rivers and their floodplains in the northern hemisphere are subject to multiple disturbances such as levees, impoundments, channelization, dams, and chances in land use. isolating the relative impact of different disturbances is difficult when the combined effects are nonadditive. i developed a ""neutral-terrain model"" to examine the cumulative impacts of levees and dams on the hydroperiod of ponds and wetlands that form throughout floodplains after flood events. using simulated floods of different magnitude, i address two major questions: (1) what is the relative influence of levees vs. dams on the duration and abundance of temporary ponds and wetlands? (2) are the cumulative effects of levees and dams additive, synergistic, or antagonistic? levees decreased the area occupied by temporary ponds (as compared to the natural scenario), until the levee was breached by large-magnitude events. when the levee was breached, no differences were found between the natural- and levee-floodplain scenarios. a simulated upstream dam decreased, increased, or had no effect on the area occupied by temporary ponds, depending on flood magnitude. synergistic interactions between levees and dams were apparent for larger floods, where the reduction in flood stage caused by an upstream dam prevented levee breaching. lastly, i introduce a qualitative framework for understanding the impacts of levees and dams on the duration of floodplain ponds. i also discuss the applications of this new three-dimensional simulation modeling technique, neutral-terrain modeling, as a tool for addressing spatial aspects of watershed and floodplain questions.",15,2002,12,6,1740,1754,10.2307/3099935,1,1,1,3"Oksanen, J; Minchin, PR",continuum theory revisited: what shape are species responses along ecological gradients?,ECOLOGICAL MODELLING,Article,gradient analysis; Beta response function; Gaussian response function,"the shape of species' responses along ecological gradients has important implications for both continuum theory and community analysis. most current theories and analytical models in community ecology assume that responses are unimodal and symmetric. however, interactions between species and extreme environmental stress may cause skewed or non-unimodal responses. to date, statistical tools for evaluating response shapes have been either inappropriate, inefficient or biased. using a data set on vascular plant distributions along an elevation gradient, we show that huisman-olff-fresco (hof) models are an effective method for this purpose, allowing models of various forms (skewed, symmetric, plateau, monotonic) to be tested for adequacy. hof modeling was compared with alternative methods for response fitting, including gaussian responses as generalized linear model (glms), generalized additive models (gam) and beta functions with fixed or estimated endpoints. in our data set, skewed and plateau responses are less common than symmetric ones. less than half of the species have skewed or plateau responses that can not be adequately modeled by gaussian models. we show that beta function models with fixed endpoints are biased, confounding skewness and the location of the mode and should not be used to test response shapes. beta models with estimated endpoints are fairly consistent with other models. gam's cannot provide clear tests of skewness or kurtosis of response curves, though we show that gam's, in general, confirmed the shapes chosen by hof modeling. we provide free software for fitting hof models and encourage further applications to community data collected along different types of ecological gradients. (c) 2002 elsevier science b.v. all rights reserved.",174,2002,157,03-Feb,119,129,10.1016/S0304-3800(02)00190-4,0,0,1,1"Agrawal, AF",genetic loads under fitness-dependent mutation rates,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,genetic load; mutation rate; sexual reproduction,"although much theory depends on the genome-wide rate of deleterious mutations, good estimates of the mutation rate are scarce and remain controversial. furthermore, mutation rate may not be constant, and a recent study suggests that mutation rates are higher in mildly stressful environments. if mutation rate is a function of condition, then individuals carrying more mutations will tend to be in worse condition and therefore produce more mutations. here i examine the mean fitnesses of sexual and asexual populations evolving under such condition-dependent mutation rates. the equilibrium mean fitness of a sexual population depends on the shape of the curve relating fitness to mutation rate. if mutation rate declines synergistically with increasing condition the mean fitness will be much lower than if mutation rate declines at a diminishing rate. in contrast, asexual populations are less affected by condition-dependent mutation rates. the equilibrium mean fitness of an asexual population only depends on the mutation rate of the individuals in the least loaded class. because such individuals have high fitness and therefore a low mutation rate, asexual populations experience less genetic load than sexual populations, thus increasing the twofold cost of sex.",19,2002,15,6,1004,1010,10.1046/j.1420-9101.2002.00464.x,1,0,0,1"Verschoor, BC; Pronk, TE; de Goede, RGM; Brussaard, L",could plant-feeding nematodes affect the competition between grass species during succession in grasslands under restoration management?,JOURNAL OF ECOLOGY,Article,fertility; herbivory; nutrients; stress; synergism,"1 we examined the effects of plant-feeding nematodes on competition between holcus lanatus and anthoxanthum odoratum . in the drentse a nature reserve, the netherlands, a relatively productive grassland, represented by h. lanatus , has gradually been replaced by a less-productive community, represented by a. odoratum , after the application of fertiliser was stopped. stressed plants are generally considered to be more sensitive to herbivory. 2 we hypothesized that plant-feeding nematodes would exacerbate the competitive disadvantage of h. lanatus resulting from nutrient limitation. we compared performance in an adjusted de wit replacement series with monocultures, grown in soil that was either treated or untreated with nematicides at both low and high nutrient supply. 3 the biomass production of both plant species was negatively affected by intra- and interspecific competition. although h. lanatus was a stronger competitor than a. odoratum in mixed cultures, it was more sensitive to plant-feeding nematodes and nutrient limitation. nematodes and nutrient stress therefore reduced the competitive suppression of a. odoratum by h. lanatus . low nutrient availability did not enhance the effect of plant-feeding nematodes on plant growth and competition, indicating additive rather than synergistic effects on plant performance. 4 we conclude that plant-feeding nematodes may contribute to species replacements in grasslands after fertilization has been stopped, albeit to a lesser extent than reduced nutrient availability. plant species-specific differences in tolerance to plant-feeding nematodes in general, rather than host specificity of nematodes, are responsible for any effects.",26,2002,90,5,753,761,10.1046/j.1365-2745.2002.00710.x,1,0,1,2"Kulakowski, D; Veblen, TT",influences of fire history and topography on the pattern of a severe wind blowdown in a colorado subalpine forest,JOURNAL OF ECOLOGY,Article,dendrochronology; disturbance; interactions; legacies; Rocky Mountain forests,"1 in 1997, a major windstorm blew down over 10 000 hectares of subalpine forest in routt national forest in north-western colorado. we tested whether fire history and topographic variation, across the landscape, determined subsequent susceptibility to damage from this windstorm. 2 we combined dendrochronological techniques with a geographical information system (gis) to examine the relationship between the effects of the blowdown and the spatial heterogeneity of the vegetation. we reconstructed the spatial fire history in a c. 4400 ha area by first identifying distinct patches in the landscape on aerial photographs, and then in the field by determining the disturbance history of each patch by dating fire scars, ages of post-fire cohorts and releases of remnant trees. 3 both topographic position and fire history contribute to susceptibility to wind damage. stands at higher elevations, on easterly slopes and closer to ridges were most affected. younger stands (i.e. more recently affected by stand-initiating fires) were less affected particularly in areas affected by low-moderate severity blowdown (< 80% damage). the ecological effects of the very severe 1997 windstorm were mediated by the legacies of fires which occurred several centuries ago. interactions between natural disturbances, such as fire and blowdown, lead to synergistic effects on forest dynamics, even when disturbance is infrequent.",54,2002,90,5,806,819,10.1046/j.1365-2745.2002.00722.x,1,0,0,1"Fowler, NL","the joint effects of grazing, competition, and topographic position on six savanna grasses",ECOLOGY,Article,Bothriochloa ischaemum; Bouteloua spp.; Buchloe dactyloides; community composition; competition; defoliation; grassland; herbivory; savanna; Schizachyrium scoparium; Texas; topography,"i investigated the separate and joint effects of herbivory (grazing) and competition on six grass species and on their distributions across the landscape. in a factorial field experiment, cattle were excluded from half the subplots, and neighboring plants were removed from half the subplots. transplants of each of the species were planted in plots on hillsides and in flat areas, and the entire experiment was replicated in two pastures. the effects of grazing were negative and were proportional to the ungrazed height of each species. in the absence of grazing and competition, the flat plots were more favorable than the hillside plots. grazing reversed the relative favorableness of flat and hillside plots, most likely because grazing was more intense in the flat plots due to cattle preference for flatter ground. the removal of neighboring plants always had a positive effect, indicating competition from neighboring plants. the relative impact of competition from pre-existing plants was generally greater in the flat plots than in the hillside plots. the relative impacts of grazing were generally greater in the absence of competing plants, and the relative impacts of competition were generally greater in the absence of grazing. the most likely explanation for this antagonistic interaction between the effects of herbivory and competition is an indirect positive effect of grazing that arose from a reduction in competition experienced by a target plant due to the defoliation of its neighbors. the results of this study, when combined with the known distributions of the six grass species in this region, indicate that herbivory, rather than competition or the physical environment, controls the distribution of at least five of the six species across the landscape. for example, schizachyrium scoparium grew well in ungrazed flat subplots but very poorly in grazed flat subplots; grazing, got the physical environment or competition, accounts for the absence of s. scoparium from most flat sites in this region. competition modulates the effects of herbivory and edaphic factors on landscape distributions but does not control the distribution of any, of the six species.",25,2002,83,9,2477,2488,10.2307/3071808,0,1,0,1"Pahkala, M; Rasanen, K; Laurila, A; Johanson, U; Bjorn, LO; Merila, J",lethal and sublethal effects of uv-b/ph synergism on common frog embryos,CONSERVATION BIOLOGY,Article,,"although the negative effects of ultraviolet-b (uv-b) radiation on the development of many amphibian species have been demonstrated, some species-such as the common frog (rana temporaria)-seem to be tolerant of uv-b radiation. the amount of uv-b radiation received is likely to vary among populations of the same species, but little is known about geographic variation in uv-b tolerance. similarly, although uv-b radiation can have synergistic effects with other stressors, no studies have focused on geographic variation of these effects on amphibians. we investigated the synergistic effects of uv-b radiation and low ph on hatchability and early development of r. temporaria embryos in a factorial laboratory experiment with animals originating from southern and northern sweden. newly fertilized eggs were exposed to three different uv-b treatments (no uv-b [control], 1.254 k/j/m(2) [normal] and 1.584 k/j/m(2) [26% enhanced]) and two ph treatments (4.5 [low] and 7.6 [neutral]). ultraviolet-b radiation in combination with low ph lead to markedly (approximately 50%) reduced survival rates and increased (approximately 30%) frequency of developmental anomalies in the northern but not in the southern population. the uv-b- exposed embryos hatched at smaller size in the southern population, whereas low ph reduced hatchling size in both populations. in both populations and ph treatments, embryos in the normal uv-b treatment developed significantly faster than embryos in the enhanced or control uv-b treatments. no interaction between ph and uv-b on developmental rates or hatchling size was detected. the results demonstrate-contrary to earlier belief-that r. temporaria embryos are not insensitive to increased levels of uv-b radiation. the lethal effects of uv-b radiation may, however, become manifested only in combination with other stressors, such as low ph, and the effects of this synergism may differ among different populations of the same species.",30,2002,16,4,1063,1073,10.1046/j.1523-1739.2002.00527.x,1,0,0,1"Hansen, LJ; Whitehead, JA; Anderson, SL",solar uv radiation enhances the toxicity of arsenic in ceriodaphnia dubia,ECOTOXICOLOGY,Article,arsenic; C. dubia; synergy; ultraviolet radiation,"extensive research exists regarding the toxicity of metals (including arsenic) to aquatic invertebrates. however, there has been little consideration of potential synergies between metals and ultraviolet (uv) radiation-despite considerable debate on this topic in human health research. ultraviolet radiation is nearly ubiquitous in the natural environment, but it is generally overlooked as a confounding variable in toxicological assessments. we evaluate synergies between arsenic and solar uv radiation using the crustacean, ceriodaphnia dubia. both laboratory (with simulated solar radiation) and outdoor (with natural solar radiation) factorial experiments were performed with two intensities of uv (low and high) and four arsenic concentrations (0, 1, 1.25 and 1.5mg/l). the laboratory experiment was multigenerational, examining survival and fecundity effects. the combination of high uv+1.5mg/l as adversely impacted survival; whereas, high uv+0mg/l as and low uv+1.5mg/l as treatments did not. these results suggest synergism. this pattern was consistent for all three generations. fecundity effects were not consistent across generations, and arsenic was demonstrated to have a greater impact than uv. outdoor experiments were limited to assessing survival. exposures in september 1999 resulted in a pattern similar to that in the laboratory exposure. high uv+1.5mg/l as treatment elicited diminished survival as compared to high uv+0mg/l as and low uv+1.5mg/l as. these results indicate that a synergistic effect between arsenic and uv exposure is possible under ambient conditions and within a relatively narrow dose range. the mechanism of this effect is unknown but could include synergistic genotoxic or oxidative stress. these findings point to the importance of using realistic uv exposures when determining criteria for protection of aquatic life.",12,2002,11,4,279,287,10.1023/A:1016304422221,1,0,0,1"Bubliy, OA; Loeschcke, V",effect of low stressful temperature on genetic variation of five quantitative traits in drosophila melanogaster,HEREDITY,Article,Drosophila melanogaster; environmental stress; genetic variation; heritability; low temperature,"a half-sib analysis was used to investigate genetic variation for three morphological traits (thorax length, wing length and sternopleural bristle number) and two life-history traits (developmental time and larva-to-adult viability) in drosophila melanogaster reared at a standard (25degreesc) and a low stressful (13degreesc) temperature. both phenotypic and environmental variation showed a significant increase under stressful conditions in all traits. for estimates of genetic variation, no statistically significant differences were found between the two environments. narrow heritabilities tended to be higher at 13degreesc for sternopleural bristle number and viability and at 25degreesc for wing length and developmental time, whereas thorax length did not show any trend. however, the pattern of genetic variances and evolvability indices (coefficient of genetic variation and evolvability), considered in the context of literature evidence, indicated the possibility of an increase in additive genetic variation for the morphological traits and viability and in nonadditive genetic variation for developmental time. the data suggest that the effect of stressful temperature may be trait-specific and this warns against generalizations about the behaviour of genetic variation under extreme conditions.",25,2002,89,,70,75,10.1038/sj.hdy.6800104,0,0,1,1"Cuppen, JGM; Crum, SJH; Van den Heuvel, HH; Smidt, RA; Van den Brink, PJ",effects of a mixture of two insecticides in freshwater microcosms: i. fate of chlorpyrifos and lindane and responses of macroinvertebrates,ECOTOXICOLOGY,Article,ecological risk assessment; invertebrates; multi-stress; pesticides; semi-field,"effects of chronic application of a mixture of the insecticides chlorpyrifos and lindane were studied in indoor freshwater microcosms. the exposure concentrations (based on 0, 0.005, 0.01, 0.05, 0.1 and 0.5 times the lc50 of the most sensitive standard test organism for each compound) were kept at a constant level for four weeks. the calculated mean concentrations for chlorpyrifos were found to be almost at their corresponding nominal level during the treatment period. the mean calculated lindane concentrations, however, were found to be 15-40% higher than intended. in the post treatment period both insecticides dissipated fast (t(1)/2: chlorpyrifos 9 days, lindane 22 days) from the water phase. the concentrations of the mixture at the highest treatment level corresponded to 0.53 toxic units (tu) for daphnia magna and 0.61 tu for the most sensitive fish. the decomposition of populus leaves in litter bags was significantly lower at the three highest insecticide concentrations. the macroinvertebrate community was seriously affected at the three highest treatment levels, with crustacea and the chironomidae corynoneura proving to be the most sensitive groups. gastropoda and oligochaeta were relatively insensitive and some taxa (e.g. valvata piscinalis, juvenile physa fontinalis, nemertea and stylaria lacustris) increased in numbers. the observed effects could be explained from the individual toxicity of the insecticides to the invertebrates, and did not indicate synergistic effects. a second paper (van den brink et al., 2002) addresses the effects on other endpoints, as well as the overall risk assessment of the insecticide mixture.",23,2002,11,3,165,180,10.1023/A:1015470731330,1,0,0,1"Barata, C; Baird, DJ; Soares, AMVM",demographic responses of a tropical cladoceran to cadmium: effects of food supply and density,ECOLOGICAL APPLICATIONS,Article,cadmium; Daphnia; density-dependent effects; food availability; life table response experiments (LTRE); Moinodaphnia macleayi; population growth rate,"life table response experiments (ltre) were per formed to investigate effects of food supply on density-dependent effect,, on life history and population responses of the tropical cladoceran moinodaphnia macleayi to cadmium. its short life cycle and relatively constant age-specific birth and mortality rate, allowed population growth rates (x) to be accurately estimated from short life table experiments and by using a simplified two-stage demographic model. decomposition and regression analyses of x showed that density-dependent effects on population responses to cadmium were modified by food availability through density-dependent effects on mortality and reproductive rate. at moderate food levels (1.8 mug c/ml of chorella vulgaris) and low densities (<125 animals/l), the effects of cadmium on lambda decreased with increasing population density, due to antagonistic effects between the contributions of age at first reproduction and daily reproduction on x. at high densities (> 125 animals[l), the negative effects or cadmium on daily reproduction rates increased with density hence density promoted the negative effects of cadmium on x. at low, food levels (0.4 mug c/ml of chorella vulgaris), increasing population density reduced juvenile survival, increasing food per head. thus adverse effects of cadmium on reproduction, which had the greatest contribution to lambda, were buffered by increasing population density. regression analysis performed on population responses across increasing population density levels and cadmium concentrations showed that at high densities and low food levels ecological compensation will prevent populations at the steady-state equilibrium size from being driven to extinction by toxicity effects at the individual level. alternatively, at low densities, when food availability is not limiting, exposure to toxic substances can increase extinction probability. these results indicate that risk assessment procedures based on demographic analysis performed at low densities and high food levels may overestimate the ecological risk posed by toxic substances.",34,2002,12,2,552,564,10.2307/3060962,0,1,0,1"Casagrandi, R; Gatto, M","habitat destruction, environmental catastrophes, and metapopulation extinction",THEORETICAL POPULATION BIOLOGY,Article,threshold; moment closure; bifurcation analysis; habitat loss; patch erosion; environmental disasters,"the extinction process of fragmented populations, characterized by a small number of conspecifics inhabiting each patch, is heavily affected by natural and human disturbance. to evaluate the risk of extinction we consider a network of identical patches connected by passive or active dispersal and hosting a finite, discrete number of individuals. we discuss three types of disturbance affecting the metapopulation: permanent loss of habitat patches, erosion of existing patches, and random catastrophes that wipe out the entire population of a patch. starting from an infinite-dimensional markov model that fully accounts for demographic stochasticity, we reduce it to finite dimension via moment closure with negative-binomial approximation. the compact models obtained in this way account for the dynamics of the fraction of empty patches, the average number of individuals in occupied patches, and the variance of their distribution. after comparing the performance of these compact models with that of the infinite-dimensional model in the case of no disturbances, we then proceed to computing persistence-extinction boundaries as bifurcation lines of the compact models in the space of demographic and disturbance parameters. we consider bifurcations with respect to demographic and environmental parameters and contrast our results with those of previous theories. we find out that environmental catastrophes increase the risk of extinction for both frequent and infrequent dispersers, while the random loss of patches has a much larger influence on frequent dispersers. this influence can be counterbalanced by active dispersal. local erosion of habitat fragments has a larger influence on infrequent than on frequent dispersers. we finally discuss the important synergistic effects of disturbances acting simultaneously. (c) 2002 elsevier science (usa).",36,2002,61,2,127,140,10.1006/tpbi.2001.1559,1,0,0,1"Hartig, EK; Gornitz, V; Kolker, A; Mushacke, F; Fallon, D","anthropogenic and climate-change impacts on salt marshes of jamaica bay, new york city",WETLANDS,Article,salt marsh; Spartina alterniflora; climate change; global warming; sea-level rise; global climate models; erosion,"field studies and aerial photograph interpretation suggest that large sections of jamaica bay salt marshes in new york city near john f. kennedy international airport are deteriorating rapidly. the relatively recent salt marsh losses may be caused by a variety of factors, potentially interacting synergistically. possible factors include reduced sediment input, dredging for navigation channels, boat traffic, and regional sea-level rise. field work included aboveground biomass measurements of spartina alterniflora, mapping plant community distribution, and documenting biogeomorphological indicators of marsh loss. current productivity (standing crop biomass), which ranged from approximately 700 to 1500 g m(-2), was typical of healthy marshes in this region, in spite of other indicators of marsh degradation. historical aerial photographs of several islands showed that sampled marshes have diminished in size by similar to 12% since 1959. overall island low marsh vegetation losses since 1974 averaged 38%, with smaller islands losing up to 78% of their vegetation cover. ground observations indicate that major mechanisms of marsh loss include increased ponding within marsh interiors, slumping along marsh edges, and widening of tidal inlets. projections of future sea-level rise, using outputs from several global climate models and data from local tide gauges, in conjunction with a range of plausible accretion rates, suggest that under current stresses, jamaica bay salt marshes are unlikely to keep pace with accelerated rates of sea-level rise in the future.",71,2002,22,1,71,89,10.1672/0277-5212(2002)022[0071:AACCIO]2.0.CO;2,1,0,0,1"Nilsson, T; Fricke, C; Arnqvist, G",patterns of divergence in the effects of mating on female reproductive performance in flour beetles,EVOLUTION,Article,cost of reproduction; cryptic female choice; male accessory substances; sperm competition; Tenebrionidae,"sexual selection can lead to rapid divergence in reproductive characters. recent studies have indicated that postmating events, such as sperm precedence, may play a key role in speciation. here, we stress that other components of postmating sexual selection may be involved in the evolution of reproductive isolation. one of these is the reproductive investment made by females after mating (i.e., differential allocation). we performed an experiment designed to assess genetic divergence in the effects of mating on female reproductive performance in flour beetles, tribolium castaneum. females were mated to mates of three different wild-type genotypes at two different frequencies, in all possible reciprocal combinations. male genotype affected all aspects of female reproduction. through its effects on female longevity. total offspring production, reproductive rate. mating rate. and fertility. moreover, male and female genotype interacted in their effects on offspring production and reproductive rate. we use the pattern of these interactions to discuss the evolutionary process of divergence and suggest that the pattern is most consistent with that expected if divergence was driven by sexually antagonistic coevolution. in particular, the fact that females exhibited a relatively weak response to males with which they were coevolved suggests that females have evolved resistance to male gonadotropic signals/stimuli.",48,2002,56,1,111,120,,0,1,0,1"Jennings, S; Nicholson, MD; Dinmore, TA; Lancaster, JE",effects of chronic trawling disturbance on the production of infaunal communities,MARINE ECOLOGY PROGRESS SERIES,Article,fishing effects; size spectra; production; infauna; disturbance; power analysis,"trawling. causes widespread physical disturbance in shallow shelf seas. while the impacts of trawling on the biomass and community structure of benthic fauna are well known, no existing studies have quantified the effects of trawling disturbance on the absolute production of small benthic infauna. we investigated the effects of beam trawling disturbance on the production of small benthic infauna (afdm > 0.78 to 62.5 mg) at 9 sites that were subject to a 17.5-fold range in annual trawling disturbance, using a size-based approach that could be applied to other soft-bottom systems. we developed a generalised additive model to test for relationships between trawling disturbance and infaunal production and size structure, after accounting for differences in sediment characteristics and depth. the statistical power of our analyses to detect linear and non-linear relationships between production and disturbance, including increased production at intermediate levels of disturbance, was high (>90% probability of detecting a 50% change in production across the range of disturbance). the analyses showed that trawling frequencies of 0.35 to 6.14 times yr(-1) did not have a significant effect on the production of small infauna or polychaetes. this result contrasts with order of magnitude decreases in the production of large infauna, and shows that small polychaetes with fast life histories are less vulnerable to trawling disturbance. since small infaunal polychaetes are a key source of food for flatfishes, we conclude that beam trawling disturbance does not have a positive or negative effect on their food supply.",48,2002,243,,251,260,10.3354/meps243251,0,0,1,1"Cochrane, MA",synergistic interactions between habitat fragmentation and fire in evergreen tropical forests,CONSERVATION BIOLOGY,Article,,"the growing prevalence of fragmentation and fire in tropical forests makes it imperative to quant fy changes in these disturbances and to understand the ways in which they interact across the landscape. i used a multitemporal series of landsat images to study the incidence and coincidence of fire and fragmentation in two areas of para state in the eastern brazilian amazon,, tailandia and paragominase. in both areas, deforestation and forest fires were quantified for time series of 6-10years. the tailandia study area typifies a landscape with the herringbone pattern of government-settled colonists, and the paragominas area is dominated by large cattle ranches. in both areas, over 90% of the forests affected by fire were associated with form est edges. although most burned forest occurred within 500 m of forest edges, some fires occurred in deep forest, several kilometers from any edge. the obvious synergism between forest fragmentation and fire poses serious risks to tropical ecosystems and has important implications for land management.",101,2001,15,6,1515,1521,10.1046/j.1523-1739.2001.01091.x,1,0,0,1"Harris, JA; Hobbs, RJ",clinical practice for ecosystem health: the role of ecological restoration,ECOSYSTEM HEALTH,Article,,"in this paper, we discuss the need for synergy between the emerging fields of ecosystem health and ecological restoration and examine whether anyone engaged in ecological restoration has attempted this yet, explicitly or implicitly. we provide definitions of terms used in ecosystem health and examples of ecological restoration practices in each of the major ecosystem health categories. we point to the need for effective and measurable indicators of ecosystem health. if we view the concept of ecosystem health as the diagnostic toolbox and ecological restoration as the treatment toolbox for the management of damaged ecosystems, there is clearly the potential for useful synergy. the challenge is to blend a level of generality that allows comparison among different systems with the ability to be specific enough to be helpful in particular cases.",9,2001,7,4,195,202,10.1046/j.1526-0992.2001.01041.x,1,0,0,1"Schaberg, PG; DeHayes, DH; Hawley, GJ",anthropogenic calcium depletion: a unique threat to forest ecosystem health?,ECOSYSTEM HEALTH,Article,,"numerous anthropogenic factors can deplete calcium (ca) from forest ecosystems. because an adequate supply of ca is needed to support fundamental biological functions, including cell membrane stability and stress response, the potential for ca deficiency following the individual, cumulative, or potentially synergistic, influences of anthropogenic factors raises important questions concerning organism and ecosystem health. past work has shown that one ca-depleting factor (foliar acid mist exposure) reduces concentrations of biologically important membrane-associated ca (mca) from red spruce foliar cells, destabilizes these cells, and results in their increased susceptibility to the freezing injury responsible for red spruce decline in northeastern u.s. montane ecosystems. data presented here indicate that these same disruptions can occur for other tree species and that soil-based ca manipulation can also alter critical mca pools. considering the unique role ca plays in the physiological response of cells to environmental change and stress, we hypothesize that depletion of biologically available ca (e.g., mca) could result in a scenario similar to recognized immune deficiency syndromes in animals. a hypothetical pathway through which anthropogenically induced ca deficiencies could predispose plants, and possibly animals, to exaggerated injury following exposure to environmental stress is presented, and the potential implications of this scenario to ecosystem health are discussed.",58,2001,7,4,214,228,10.1046/j.1526-0992.2001.01046.x,1,0,0,1"Foley, PA; Luckinbill, LS",the effects of selection for larval behavior on adult life-history features in drosophila melanogaster,EVOLUTION,Article,aging; dietary restriction; Drosophila; fecundity; fruit fly; life history; longevity,"selection for late-life fecundity and longevity in adult drosophila melanogaster is well known to modify numerous characteristics of life history and physiology. we report experiments here in which selection applied to behavior affects features in an identical fashion. selection for feeding rate of larval d. melanogaster modifies caloric intake, as measured by the uptake and incorporation of labeled glucose. selection for slow larval feeding produced lines of d. melanogaster in which larvae synthesized significantly less lipid prior to pupation and eclosed to have low early-life fecundity and a long life as adults. they also had greater lifetime fecundity, but lower viability of egg to hatched adult. alternatively, fast-feeding larvae incorporated more lipid before pupation and eclosed with high early-fecundity that declined rapidly throughout their short adult life. slow-feeding populations also had a significantly enhanced expression of the stress-resistance genes cuzn-sod, catalase, and hsp70. selection on larval feeding behavior reproduced the antagonistic evolutionary trade-off found under selection for adult life span and mimicked the physiological response in life span as seen in many species when dietary restriction is imposed on adults, thus, nutrient acquisition during development appears to share a common evolutionary and genetic basis with the allocation processes that determine adult life-history traits and the related phenotypic dietary restriction phenomena.",25,2001,55,12,2493,2502,,0,1,0,1"Koch, MS; Erskine, JM","sulfide as a phytotoxin to the tropical seagrass thalassia testudinum: interactions with light, salinity and temperature",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,die-back; Florida Bay; stress,"over the last several decades, sulfides have been identified as a potent phytotoxin. however, little is known about the effects of sulfide on thalassia testudinum, a dominant tropical seagrass, or other seagrass species. it has been hypothesized that high sulfide exposure is a major contributor to t. testudinum ""die-back"" in the large subtropical lagoon of south florida, florida bay. three experiments were conducted to pursue the mechanism by which t. testudinum was resilient to sulfide exposure in our previous experiment and to investigate the levels of sulfide that cause t. testudinum mortality. two low-light (similar to 150 mu mol par m(-2) s(-1)) experiments were conducted to evaluate the role of light and photosynthesis on sulfide toxicity. secondly, we tested the effects of high salinity (hs) and high temperature (ht) on sulfide tolerance to determine if these interactions could synergistically create a ""die-back"" response. leaf elongation rates were not significantly affected by below-ground sulfide exposure in the range of 1-10 mm when incubated at subsaturating light and ambient sediment ph (7.0). leaf o-2 production rates were also unaffected by sulfide exposure. in fact, all plants post-treatment possessed rhizome-extractable o-2 concentrations greater than 30%. when sulfide treatments (6 mm) were combined with hs and ht treatments, however, we observed our first ""die-back"" response. shoots exposed to 6.0 mm sulfide under hs and ht had 50% and 33% mortality rates, and those in the ht + hs treatment had 100% mortality. interestingly, no mortality was seen in the hs or ht treatments without sulfides added. the first two experiments in this study and our previous experiment clearly suggest that t. testudinum may be tolerant to short-term ( < 28 days) below-ground tissue exposure to high sulfide concentrations. an important caveat appears to be, however, when sulfide exposure is combined with other stressors common in florida bay and other tropical/subtropical lagoons and estuaries. these results point to the importance of examining multiple interactive stressors when elucidating the factors causing ""die-back"" in seagrasses. (c) 2001 elsevier science b.v. all rights reserved.",70,2001,266,1,81,95,10.1016/S0022-0981(01)00339-2,1,0,0,1"Chamberlain, K; Guerrieri, E; Pennacchio, F; Pettersson, J; Pickett, JA; Poppy, GM; Powell, W; Wadhams, LJ; Woodcock, CM",can aphid-induced plant signals be transmitted aerially and through the rhizosphere?,BIOCHEMICAL SYSTEMATICS AND ECOLOGY,Article,induced defence; aphids; signals; rhizosphere; phytopheromones,"aphids, through their close association with plants, cause systemic release of semiochemicals. these may have negative effects on subsequent aphid colonisation and can also have positive roles with insects that are antagonistic to aphid development, for example parasitoids. one of the semiochemicals involved in host selection by aphids is methyl salicylate. and since this compound was shown to have a role as a plant stress signal, the hypothesis that aphids might facilitate identification of new plant signals was examined. confirmation was obtained during an investigation of avoidance of unsuitable hosts by the lettuce aphid, nasonovia ribis-nigri. (z)-jasmone was identified as a plant-derived semiochemical acting negatively for a number of aphid species, and positively for insect antagonists such as parasitoids and predators. however, when the compound was employed at 0.1 ppm in air above intact plants, these plants then attracted aphid parasitoids long after the (z)-jasmone itself was no longer detectable, a specific interaction was proposed. since the (z)-jasmone appeared to be selectively taken up by the plants. aerial interactions between intact barley plants from different cultivars, which may be differentially releasing stress associated signals, can also influence acceptability to aphids. furthermore, it has been shown that exudates from the roots of aphid-infested plants, grown hydroponically or in soil, cause intact plants to become more attractive to parasitoids. (c) 2001 published by elsevier science ltd.",58,2001,29,10,1063,1074,10.1016/S0305-1978(01)00050-3,0,1,0,1"Fedorenko, SI",tolerance of birch stands of the northern transural forest steppe to abiotic and biotic stress factors,RUSSIAN JOURNAL OF ECOLOGY,Article,birch stands; tolerance; meteorological parameters; defoliation; radial growth,"it is shown that both diffuse and complete drying of birch stands is due to the additive effects of meteorological factors (hydrothermal parameters of the first and second halves of the growing period) and tree defoliation by phyllophagous insects, with the former being of primary importance.",0,2001,32,6,432,436,10.1023/A:1012590319005,0,0,1,1"Kennington, WJ; Gilchrist, AS; Goldstein, DB; Partridge, L",the genetic bases of divergence in desiccation and starvation resistance among tropical and temperate populations of drosophila melanogaster,HEREDITY,Article,adaptive landscapes; epistasis; quantitative genetics; shifting-balance theory; stress-resistance,"desiccation and starvation resistance are two stress-related traits which vary geographically with climate in drosophila melanogaster. to investigate the contribution of epistasis to population divergence for these traits, we crossed tropical and temperate populations from two different geographical regions to produce f(1), f(2) and first backcross generations. line-cross analysis of generation means revealed that genetic bases of divergence for both traits were complex and remarkably similar in a number of respects. strong additive and dominance effects were present in most of the models, whereas epistatic and maternal effects were less common. the presence of epistatic effects in approximately half of the models presented in this study is consistent with line-cross studies of diverged traits in other animals, and does not support the view that epistasis is the predominant means by which populations diverge. in addition, evidence of maternal effects in both traits adds to a growing body of recent evidence that suggests maternal contributions to population differentiation are more widespread than previously thought. this finding undermines the accuracy of studies inferring epistasis directly from the magnitude of f(2) breakdown. more line-cross analysis studies of naturally diverged populations that take into account maternal effects will shed further light on the true incidence of epistasis and its importance in the evolutionary process.",18,2001,87,,363,372,10.1046/j.1365-2540.2001.00925.x,0,0,1,1"Muldavin, EH; Neville, P; Harper, G",indices of grassland biodiversity in the chihuahuan desert ecoregion derived from remote sensing,CONSERVATION BIOLOGY,Article,,"we used a relatively simple and direct remote-sensing approach to determine biodiversity values in arid ecosystems and thus identify potential conservation sites. we developed indices based on regression models between, grass, shrub, litter, exposed-soil groundcover components and landsat thematic mapper satellite imagery reflectance values over a reference site in the northern chihuahuan desert in new mexico. this site supports low-disturbance grasslands that have been under a continuous grazing regime for over 100 years. greater richness and abundance of noninvasive and nonruderal plant species were associated with the low-disturbance grasslands that had lower shrub abundance, increased litter and grass cover, and lower exposed soil. using the thematic mapper indices, we computed an additive grassland biodiversity index such that, as exposed soil and shrub values go down, litter and grass values go up, as does the biodiversity index. when the biodiversity index was applied to the reference-site landscape, grasslands previously identified for their high conservation value were detected. as a further test, we applied the indices to a site in chihuahua, mexico, that supports similar grasslands but for which there are few other data on condition and conservation values. the soil, grass, and shrub indices were moderately effective in describing the range of variation at the mexico site, but the litter equation was not. still, higher biodiversity value in terms of nonruderal plant diversity tended to correspond to higher grass cover and lower soil exposure and a higher overall biodiversity index. some localized calibration with geologic substrate may be required along with an assessment of the temporal constraints, but generally the index shows promise for quickly and efficiently detecting desert grasslands of high biodiversity conservation value.",32,2001,15,4,844,855,10.1046/j.1523-1739.2001.015004844.x,0,0,1,1"Forbes, VE; Sibly, RM; Calow, P","toxicant impacts on density-limited populations: a critical review of theory, practice, and results",ECOLOGICAL APPLICATIONS,Review,compensation; density dependence; ecotoxicology; experimental design; food limitation; population dynamics,"most natural populations experience some density dependence, and longterm average rates of population growth are likely to be close to zero (i.e., steady state). an essential question, therefore, is how and to what extent do density-dependent effects influence the responses of populations to toxicant impacts? here we consider three general types of interaction between density dependence and toxicant effects: additive, less than additive, and more than additive. if we know enough about the life-history dynamics of an organism and how its life-history traits are affected by density and toxicant exposure, we should be able to use life-history models to predict responses of populations living under density-dependent control to chemical exposure. however, because the number of factors influencing the outcome is large, we demonstrate that simple, general, a priori predictions are not feasible. a review of the literature confirms that a variety of interactions has been observed in experimental systems. it is essential that experiments are designed so that the interactions of interest can be determined. we review these critically. experimental designs that are appropriate for exploring density-toxicant interactions on individual physiological performance may be unable to detect potential compensatory interactions at the population level. designs most likely to simulate the dynamics of field populations will be unable to determine the mechanistic bases underlying population- level impacts. to facilitate an ecologically correct interpretation of density-toxicant interactions, it is therefore essential that the limitations of the chosen experimental designs be recognized and made explicit.",58,2001,11,4,1249,1257,10.2307/3061025,0,0,1,1"Pahkala, M; Laurila, A; Bjorn, LO; Merila, J",effects of ultraviolet-b radiation and ph on early development of the moor frog rana arvalis,JOURNAL OF APPLIED ECOLOGY,Article,acidification; amphibians; growth; synergism; UV-B,"1. although the potential negative effects of increased ultraviolet-b (uv-b) radiation on early life stages of aquatic organisms are widely recognized, possible synergistic effects with other stressors have seldom been studied outside the laboratory. we investigated the effects of uv-b radiation and ph on hatchability and early development of moor frog rana arvalis eggs in the field and in laboratory experiments conducted during april 1998 and april 2000 in central sweden. 2. in the field experiments, no evidence was found for reduced hatchability or increased frequency of developmental anomalies of embryos exposed to ambient levels of uv-b compared with embryos shielded from uv-b radiation. 3. hatchlings shielded from ambient uv-b radiation did not grow larger than their exposed full-sibs, giving no support to the hypotheses that (i) the repair of cellular uv-b damage might be energetically costly nor (ii) that uv-b-induced photoproducts directly reduce growth. 4. although low ph (5.0) reduced hatchability, increased frequency of developmental anomalies and reduced early embryonic growth in r. arvalis, there was no evidence for synergistic effects of ph and uv-b on any of these traits. 5. the lack of uv-b radiation effects on the development of r. arvalis embryos cannot be ascribed to relatively low effective daily doses of radiation (c. 0.43 kj m(-2)) during the field experiments, as in the laboratory even higher doses at uv-b 1.25 kj m(-2) and 1.58 kj m(-2) (all dna weighed) had no negative effects. 6. these results suggest that current levels of uv-b radiation in northern europe are not likely to reduce fitness in natural populations of the moor frog, even in areas already stressed by acidity.",18,2001,38,3,628,636,10.1046/j.1365-2664.2001.00623.x,1,0,0,1"Morgan, IJ; McDonald, DG; Wood, CM","the cost of living for freshwater fish in a warmer, more polluted world",GLOBAL CHANGE BIOLOGY,Review,acidity; ammonia; fish; global warming; growth; temperature,"little of the vast literature on the temperature physiology of freshwater fish is useful in predicting the effects of global warming. in the present review a series of laboratory experiments is reviewed in which rainbow trout (oncouhynchus mykiss) were exposed to simulated global warming, a 2 degreesc increment superimposed upon the natural thermal regime, in the presence and absence of two common freshwater pollutants, ammonia and acidity (low ph). simulated global warming had little effect on the growth and physiology of trout fed to satiation over much of the summer. however, in late summer, when ambient water temperature was at its highest, the addition of 2 degreesc caused a marked inhibition of appetite and growth, although this impact was not exacerbated by a reduction in food availability. in winter, +2 degreesc stimulated metabolism, appetite and growth by approximately 30-60%. exposure of satiation-fed trout to low levels of pollutants produced unexpected results. ammonia (nh3 + nh4+ = 70 mum) stimulated summer growth and energy conversion efficiency, whilst acidification (ph 5.2) increased appetite and growth but caused no disturbance of electrolyte balance. these pollutant effects were additive upon, but not synergistic with, the effects of +2 degreesc. the ability of the fish to acclimate to the experimental conditions was tested with acute lethal temperature and/or toxicant challenges. fish exposed to +2 degreesc had a slightly (0.2-1.0 degreesc) but significantly higher lethal temperature than those exposed to ambient temperature when fed to satiation. however, there was no evidence of acclimation to either ammonia or low ph. it is concluded that the impact of global warming on freshwater fish will vary seasonally. the additional temperature may provide growth benefits in winter, but may threaten fish populations living towards the upper end of their thermal tolerance zone in (late) summer.",44,2001,7,4,345,355,10.1046/j.1365-2486.2001.00424.x,1,0,1,2"Hojer, R; Bayley, M; Damgaard, CF; Holmstrup, M",stress synergy between drought and a common environmental contaminant: studies with the collembolan folsomia candida,GLOBAL CHANGE BIOLOGY,Article,climate change; collembola; combined effects; drought; ecotoxicology; synergy,"the term global change is used predominantly in connection with the global temperature increase and associated changes in weather patterns over the next century. in a broader sense it also covers other anthropogenic impacts on the environment such as habitat fragmentation and pollution. the individual effects of each of these stress types have been extensively studied in the biota. however, organisms will frequently encounter these stress types in combination rather than alone and there is little information available on the effects of stress combinations. here an examination is made of the interaction between realistic levels of summer drought and a common contaminant of agricultural soil (4-nonylphenol, np), on a widespread soil invertebrate, the collembolan folsomia candida. these stress factors were tested individually and in combination using a full factorial design. this approach revealed the existence of highly significant bliss type synergistic interaction between the two stress types. thus, exposure to np significantly reduced the drought tolerance of this organism and, reciprocally, the toxicity of np (lc(50)) during realistic summer drought was more than doubled in comparison to the value obtained under optimal soil moisture conditions. furthermore, it is shown that np has a detrimental effect on the physiological mechanisms underlying this animal's drought tolerance, thus providing some explanation for the mechanisms involved in the synergy. it is argued that this type of synergy is unlikely to be confined to this particular combination of stresses and thus there is a need to study the interactions between dominant natural stresses and pollution. the most important implication of these results is that some of the effects of global climate changes can be predicted to be most severe in polluted areas.",34,2001,7,4,485,494,10.1046/j.1365-2486.2001.00417.x,1,0,0,1"Cronin, JT; Abrahamson, WG",goldenrod stem galler preference and performance: effects of multiple herbivores and plant genotypes,OECOLOGIA,Article,Eurosta solidaginis; gall insect; herbivore assemblage; host choice; preference-performance relationship,"few studies have examined how the preference-performance relationship of an herbivore for different genotypes of its host plant is affected by the presence and/or feeding activity of other members of the herbivore assemblage. in an outdoor garden, we manipulated the abundance of three common herbivores, the meadow spittlebug, a leaf beetle, and an aphid, on replicate 1-m(2) plots of 16 different genotypes of tall goldenrod, solidago altissima. adults of the goldenrod stem galler, eurosta solidaginis, were subsequently released into the garden to oviposit among the host plants. oviposition preference was strongly influenced by plant genotype and the presence of two of the herbivores, spittlebugs and leaf beetles. the effects of the herbivores were additive: the presence of leaf beetles reduced preference by 6%, spittlebugs by 18%, and both herbivores combined by 25%. plant genotype-herbivore species interaction effects on stem-galler preference, which would indicate the presence of genetic variation among goldenrod genotypes in their norms of reaction for their acceptability as a host to the stem galler, were absent in this study. the performance of the stem galler was also significantly affected by goldenrod genotype, but in general was not affected by the presence of herbivores early in the season (the exception was a positive correlation between the proportion of ramets infested by all herbivores and gall size). overall, we could find no correlation between preference and performance. this is in accord with results from previous studies on this system that were performed in the absence of herbivores, suggesting that the presence of herbivores in this study did not qualitatively alter the preference-performance relationship. we suggest that the lack of a positive correlation between host-plant preference and larval performance may reflect a constraint on the discriminatory ability of female stem gallers preventing them from selecting the best hosts among plants that differ in genotype and level of environmental stress (e.g., presence of interspecific herbivores).",32,2001,127,1,87,96,,0,0,1,1"Semere, T; Froud-Williams, RJ",the effect of pea cultivar and water stress on root and shoot competition between vegetative plants of maize and pea,JOURNAL OF APPLIED ECOLOGY,Article,competitive ability; intercropping; mode of competition; relative yield total; resource complementarity,"1. improvements in intercrop yields may be achieved through an understanding of yield advantages due to above-ground or below-ground interactions. 2. forage maize and two morphologically contrasting cultivars of pea (leafy cv. bohatyr and semi-leafless cv. grafila) were grown alone and in additive mixtures, under two contrasting levels of soil moisture (+/- water stress). 3. the mechanism of competition between maize and pea was studied by separating the effects of root competition and shoot competition, using soil and aerial partitions. plants were grown in rectangular tanks in a glasshouse. 4. leafy pea cv. bohatyr was as competitive as maize, both below-ground and above-ground, whereas semi-leafless pea cv. grafila was less competitive than maize or pea cv. bohatyr. the greater competitive ability of the leafy pea, both above- and below-ground, was probably due to its greater growth rate, associated with its greater leaf area. 5. the competitive ability of maize, relative to peas, was considerably reduced by water stress. both the root and shoot competitive abilities of pea were greater under water stress, compared with those of maize. 6. relative yield total (ryt) values were significantly greater when maize and pea were subjected to shoot competition only (ryt = 1.76) than when subjected to root competition (ryt = 1.17) or when subjected to both shoot and root competition (ryt = 1.13). this reflects the fact that the effects of root competition were greater than those of shoot competition. 7. root competition decreased the shoot dry weights, plant height and leaf area of both maize and pea, whereas shoot competition had no significant effect on these attributes, indicating that soil resources, i.e. mineral nutrients and water, were more limiting than light.",36,2001,38,1,137,145,10.1046/j.1365-2664.2001.00570.x,0,0,1,1"Palatova, E; Mauer, O","mutual relations of mountain ash, beech and spruce root systems in the mixed mountain forest",EKOLOGIA-BRATISLAVA,Article,mountain ash; European beech; Norway spruce; root system architecture; mutual relations of root systems,"the paper presents an analysis of the root system distribution and mutual relations of root systems within the soil space of transitional mountain forest. the analysis included the trees of european mountain ash, european beech and norway spruce at the age of twenty to sixty years and made use of non-destructive methods (soil georadar) and a destructive archacological study. it follows from the results that the studied tree species share the soil space although the condition leads to thr: asymmetric spatial distribution of roots. the relations between mountain ash and beech are antagonistic. reasons are discussed,md some recommendations are proposed to minimize stress;it managing the tree species in question.",2,2001,20,,79,91,,0,1,0,1"Cudlin, P; Novotny, R; Moravec, I; Chmelikova, E",retrospective evaluation of the response of montane forest ecosystems to multiple stress,EKOLOGIA-BRATISLAVA,Article,,"montane forests have been under long-term synergistic chronic effects of natural and anthropogenic stress impacts, and imposed from time to time to acute climatic and pollution stress events. crown structure transformation (formation of secondary shoots of different orders in successive series on damaged and/or defoliated branches) is a very sensitive indicator of longterm tree damage processes (30-40 years back), and of the subsequent regenerative processes. tree crowns on six permanent research plots in the krkonose mts were visually investigated and classified into several stages of crown structure transformation. one or more trees from the most frequent stages were selected for investigation of the branch structure transformation. set of indicators, enabling to estimate stress response history of trees at branch, tree, and stand levels, was proposed. rate of secondary shoot formation, which compensates a defoliation of primary shoots, indicates overcharging of ""stress exceedance starting level"". ""significant harmful effect time"" can be detected by estimation of the time of termination of annual wood production of primary shoots, in addition, trends of probable subsequent development of trees investigated were estimated at branch, tree, and stand levels. the proposed approach outlined in this paper could be used for the investigation of structural and functional changes of various ecosystems under multiple stress impacts.",22,2001,20,1,108,124,,1,0,0,1"Silbermann, R; Tatar, M",reproductive costs of heat shock protein in transgenic drosophila melanogaster,EVOLUTION,Article,antagonistic pleiotropy; molecular chaperone; reproduction; senescence; trade-off; transgene,"senescence may evolve when genes have antagonistic effects between early reproduction and later age-specific mortality. although widely consistent with data of quantitative genetics, this model has yet to be validated with the identification of a specific locus presenting such trade-offs. the molecular chaperone hsp70 may be a candidate for such a gene. heat induced expression of the hsp70 protein in adults decreases rates of age-specific mortality during normal aging, while maternally experienced heat shock depresses the production of mature progeny. here we show that maternal heat shock reduces the proportion of egg hatch but not the viability of successfully hatched offspring. to assess whether heat induced maternal expression of hsp70 causes reduced egg hatch, we measured the proportion of eggs that hatch from females engineered to overexpress hsp70 transgenes. we used the same transgenic strains that extend longevity upon hsp70 expression and found that hsp70 is sufficient to suppress egg hatch. the proportion of egg hatch as a function of hsp70 expression was not reduced in the first eggs laid after maternal heat shock, but appears in later laid eggs, which were at preoogenic and early vitellogenic stages during the maternal expression of hsp70. the contervailing effects of hsp70 upon fecundity and subsequent age-specific mortality exemplify antagonistic pleiotropy, and this trade-off could contribute to the evolution of drosophila senescence.",86,2000,54,6,2038,2045,,0,1,0,1"Larsen, JK; Madsen, J",effects of wind turbines and other physical elements on field utilization by pink-footed geese (anser brachyrhynchus): a landscape perspective,LANDSCAPE ECOLOGY,Article,avoidance distance; GIS; habitat loss; landscape; physical elements; pink-footed geese; waterbirds; windbreaks; wind turbines,"the effects of wind turbines and other physical landscape elements on field utilization by wintering pink-footed geese (anser brachyrhynchus) were studied in a danish farmland landscape. within the study area geese were feeding on pastures, which together with cereals were the main crop types. apart from wind turbines a variety of potentially disturbing landscape elements was present, e.g., high-power lines, windbreaks, roads and settlements. patterns of field use were assessed by measuring goose dropping densities along transects perpendicular to wind farms (with turbines in clusters and in lines) and other landscape elements. local effects were expressed in terms of 'avoidance distance', i.e., the distance from a given landscape element to the point at which 50% of maximal dropping density was reached. the spatial distribution of landscape elements within an eight km radius from the goose roost was determined from aerial photographs. the area occupied by various elements, together with the adjacent zones which were not available to geese due to their associated avoidance distances, were quantified using geographic information system (gis). the avoidance distance of wind farms with turbines in lines and in clusters were ca 100 m and ca 200 m, respectively. geese did not enter the area between turbines within the cluster. at the landscape level, the combined effect of physical elements other than wind turbines caused an effective loss of 68% of the total field area (40 km(2)). wind turbines caused an additional loss of 4% of the field area. however, of the remaining area available to geese (13 km(2)), wind turbines caused a loss of 13% of the total area. the habitat loss per turbine was higher for the wind farm with turbines arranged in a large cluster than for wind farms with turbines in small clusters or lines. this difference was mainly due to the fact that wind farms in small clusters or with a linear layout were generally placed close to roads or other elements with existing associated avoidance zones, whereas the large cluster was placed in the open farmland area. the avoidance zones associated with physical elements in the landscape do not take into account possible synergistic effects and, hence, actual field areas affected are likely to be minimum estimates. implications of these findings for planning of wind farms in areas of conservation interest to geese are discussed.",37,2000,15,8,755,764,10.1023/A:1008127702944,1,0,0,1"Nystrom, M; Folke, C; Moberg, F",coral reef disturbance and resilience in a human-dominated environment,TRENDS IN ECOLOGY & EVOLUTION,Review,,"facing a human-dominated world, ecologists are now reconsidering the role of disturbance for coral reef ecosystem dynamics. human activities alter the natural disturbance regimes of coral reefs by transforming pulse events into persistent disturbance or even chronic stress, by introducing new disturbance, or by suppressing or removing disturbance. adding these alterations to natural disturbance regimes will probably result in unknown synergistic effects. simultaneously. humans are altering the capacity of reefs to cope with disturbance (e.g. by habitat fragmentation and reduction of functional diversity), which further exacerbates the effects of altered disturbance regimes. a disturbance that previously triggered the renewal and development of reefs might, under such circumstances, become an obstacle to development. the implications of these changes for reef-associated human activities, such as fishing and tourism, can be substantial.",298,2000,15,10,413,417,10.1016/S0169-5347(00)01948-0,1,0,0,1"Ives, AR; Klug, JL; Gross, K",stability and species richness in complex communities,ECOLOGY LETTERS,Article,biodiversity; community structure; disturbances; environmental fluctuations; population dynamics; resilience,"using both numerical simulations and analytical methods, we investigate how the stability of ecological communities depends on the number of species they contain. to investigate complex communities, we construct communities from modular ""subcommunities"" that can have arbitrary community structure; e.g. subcommunities could consist of pairs of predator and prey species, trios of prey, specialist predator and generalist predator, or any collection of interacting species. by building entire communities from subcommunities, we can change the number of species in the community without changing community structure. we further suppose that species sharing the same ecological role in different subcommunities act additively on the per capita population growth rates of other species. under these assumptions, the interactions between species from different subcommunities have no effect on community-level stability, measured by the variability in the combined densities of species sharing the same ecological role in different subcommunities. furthermore, increasing species richness (i.e. the number of subcommunities comprising the community) increases community-level stability only when it introduces species that respond differently to environmental fluctuations. therefore, our results support the ""insurance hypothesis"" that species richness increases community-level stability by insuring that some species in a community are tolerant of different environmental fluctuations.",97,2000,3,5,399,411,10.1046/j.1461-0248.2000.00144.x,0,0,1,1"Dahlgaard, J; Hoffmann, AA",stress resistance and environmental dependency of inbreeding depression in drosophila melanogaster,CONSERVATION BIOLOGY,Article,,"both inbreeding and environmental stress can have adverse effects on fitness that affect the conservation of endangered species. two important issues are whether stress and inbreeding effects are independent as opposed to synergistic, and whether inbreeding effects are general across stresses as opposed to stress-specific. we found that inbreeding reduced resistance to acetone and desiccation in adult drosophila melanogaster, whereas resistance to knockdown heat stress was not affected. inbred flies, however, experienced a greater proportional decrease in productivity than outbreds following heat stress. correlations using line means indicated that all resistance traits were uncorrelated in the inbred as well as in the outbred flies. recessive, deleterious alleles therefore did not appear to have any general deleterious effects on stress resistance. inbreeding within a specific environment and selection for resistant genotypes may therefore purge a population of deleterious genes specific to only one environmental stress.",59,2000,14,4,1187,1192,10.1046/j.1523-1739.2000.99206.x,1,0,0,1"Pringle, CM",threats to us public lands from cumulative hydrologic alterations outside of their boundaries,ECOLOGICAL APPLICATIONS,Article,dams; freshwater management; groundwater; hydrologic connections; national forests; national parks; national wildlife refuges; surface water; US public lands; water diversions,"u.s. public lands are increasingly threatened by human alteration of hydrologic connections outside their boundaries. cumulative effects of dams, impoundments, regulated flows, wetlands drainage, and groundwater extraction outside of public land boundaries can play a key role in controlling the hydrology and biology within these managed areas. expanding human populations require more water, and they often look to public lands to meet their demands. immediate challenges facing water resource managers are increased pressure to dam rivers and pump aquifers near public lands, as a result of water shortages exacerbated by droughts coupled with increased demands from municipal and agricultural growth. as pollutants become more concentrated in less water, water quality often becomes a major related issue. while these problems are particularly acute in rapidly growing regions of the arid west where water is severely limited, they are also emerging in the east. data on cumulative effects of hydrologic alterations on the biological integrity of public lands have not been systematically assessed at a national level. however, emerging trends can be used to gauge the magnitude of outside pressures and to place water resource challenges into context. the u.s. national park service is participating in water rights adjudications in over 50 different park service units. the u.s. forest service currently has over 500 legal claims concerning water rights for national forests located in 55 basins of 11 western states. similar conflicts exist for national wildlife refuges which are particularly vulnerable to water quality and quantity problems because of their small size; in 1994, 150 out of 224 western wildlife refuges reported conflicts with other water users, and only 98 reported that their existing water rights assured delivery of adequate water in an average year. as human demands for water continue to expand, financially strapped federal land management agencies have a greater need for strengthened institutional, legal, and scientific tools to manage hydrologic connections. two case studies from different biogeographic extremes (stillwater national wildlife refuge in the arid nevada desert and the caribbean national forest in the wet tropics of puerto rico) illustrate the synergism that can occur between field managers and scientists in implementing localized solutions. moreover, they highlight the critical need to address cumulative long-term effects of hydrologic alterations outside of public land boundaries. recommendations include: establishment of more stream gaging stations and monitoring programs within and adjacent to public lands; development of new and innovative partnerships between federal land management agencies and both federal and academic scientists; and interdisciplinary research and development of science-based tools to predict cumulative and interactive effects of hydrologic alterations.",32,2000,10,4,971,989,10.2307/2641012,1,0,0,1"Anderson, JJ",a vitality-based model relating stressors and environmental properties to organism survival,ECOLOGICAL MONOGRAPHS,Article,"allometry; dose-response studies; environmental properties; mortality rates, age dependent and age independent; organism vitality as basis of survival model; selection; stochastic equation; survival; vitality; xenobiotic stresses","a survivorship curve is shaped by the differential survivability of the organisms within the population, and a change in a survivorship curve with a stressor reflects the differential response of the organisms to the stressor. quantifying this linkage in a simple, rigorous way is valuable for characterizing the response of populations to stressors and ultimately for understanding the evolutionary selection of individuals exposed to stressors. to quantify this stressor-individual-population linkage with as few parameters as possible. i present a simple mechanistic model describing organism survival in terms of age-dependent and age-independent mortality rates. the age-independent rate is represented by a poisson process. for the age-dependent rate, a concept of vitality is defined, and mortality occurs when an organism's vitality is exhausted. the loss of vitality over age is represented by a continuous brownian-motion process, the weiner process; vitality-related mortality occurs when the random process reaches the boundary of zero vitality. the age at which vitality-related mortality occurs is represented by the weiner-process probability distribution for first-arrival time. the basic model has three rate parameters: the rate of accidental mortality, the mean rate of vitality loss, and the variability in the rate of vitality loss. these rates are related to body mass, environmental conditions, and xenobiotic stressors, resulting in a model that characterizes intrinsic and extrinsic factors that control a population's survival and the distribution of vitality of its individuals. the model assumes that these factors contribute to the rate parameters additively and linearly. the model is evaluated with case studies across a range of species exposed to natural and xenobiotic stressors. the mean rate of vitality loss generally is the dominant factor in determining the shape of survival curves under optimal conditions. xenobiotic stressors add to the mean rate in proportion to the strength of the stressor. the base, or intrinsic, vitality loss rate is proportional to the - 1/3 power of adult body mass across a range of iteroparous species. the increase in vitality loss rate with a xenobiotic stressor can be a function of body mass according to the allometric relationship of the organism structures affected by the stressor. the model's applicability to dose-response studies is illustrated with case studies including natural stressors (temperature, feeding interval, and population density) and xenobiotic stressors (organic and inorganic toxicants). the model provides a way to extrapolate the impact of stressors measured in one environment to another environment; by characterizing how stressors alter the vitality probability distribution, it can quantify the degree to which a stressor differentiates members of a population.",34,2000,70,3,445,470,10.1890/0012-9615(2000)070[0445:AVBMRS]2.0.CO;2,0,0,1,1"Bubliy, OA; Loeschcke, V; Imasheva, AG",effect of stressful and nonstressful growth temperatures on variation of sternopleural bristle number in drosophila melanogaster,EVOLUTION,Article,Drosophila melanogaster; fluctuating asymmetry; heritability; selection; sternopleural bristle number; temperature stress; variation,"the effect of stressful (31 degrees c) and nonstressful (25 degrees c) growth temperatures on quantitative variation and developmental stability (fluctuating asymmetry) of drosophila melanogaster was examined in a short-term selection experiment on sternopleural bristle number. realized heritabilities based on 10 generations of selection in an upward direction did nor differ between the two temperature regimes, which indicated that additive genetic variation was not affected by a high, stressful temperature. phenotypic variability and fluctuating asymmetry of sternopleural bristles were significantly higher under stressful conditions when averaged over generations, although most pairwise comparisons in separate generations showed nonsignificant differences between temperatures.",29,2000,54,4,1444,1449,10.1554/0014-3820(2000)054[1444:EOSANG]2.0.CO;2,0,0,1,1"Beck, JB; Toft, S",artificial selection for aphid tolerance in the polyphagous predator lepthyphantes tenuis,JOURNAL OF APPLIED ECOLOGY,Article,diet quality; heredity; natural control; natural stress factor; prey defence,"1. insight into the capacity of natural enemies to control pests may lead to wiser pest management, including a reduction in the use of pesticides. the presence of polyphagous predators may contribute to the control of aphid populations and thereby prevent outbreaks. many arthropod generalist predators have a limited tolerance to the consumption of aphids. however, differences exist between and within species in the ability to cope with an aphid diet; some within-species variation could be due to genetic differences between individuals. 2. in order to demonstrate additive genetic variation in aphid tolerance, a breeding programme was carried out where offspring of field-collected females of the linyphiid spider lepthyphantes tenuis were selected for survival on a pure diet of the aphid rhopalosiphum padi through the first juvenile instar. aphid tolerance was estimated as the survival in proportion to survival of a control line, fed mixed collembola. development and reproduction were recorded in order to detect possible selection effects. 3. after only one generation of selection, survival to the first moult on an aphid diet was significantly improved. the aphid tolerance of the first instar spiderlings increased by 63% and a high heritability for the trait was found. an f-2 control group derived from selected parents had significantly reduced survival compared with an f-2 control group derived from control parents. 4. developmental rate and reproduction were lower in the selected group than in the control line, demonstrating a cost of tolerance to aphids. 5. the background of the genetic variation and its possible implications for the natural limitation of aphid populations in agricultural systems is discussed. consideration of the control potential of polyphagous predators must include their genetic variation in aphid tolerance. management practices aimed at augmenting specialist aphid predators, e.g. by erecting banks or cover crops containing non-pest aphids, may provide selection pressure for increased aphid tolerance in polyphagous predators.",17,2000,37,4,547,556,10.1046/j.1365-2664.2000.00514.x,0,0,1,1"Duarte, CM",marine biodiversity and ecosystem services: an elusive link,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,seagrass; marine ecosystems; ecosystem services,"efforts to test the hypothesised positive link between ecosystem services and functions and biodiversity are increasing in order to forecast the consequences of the present erosion of biodiversity on ecosystem functions and to provide an additional basis for the conservation of biodiversity. these efforts have been, however, modest in marine ecosystems. an examination of seagrass communities, which are simple assemblages with a limited membership of about 50 species worldwide and < 12 species in any one community, provides, however, strong evidence for the existence of such positive link between species richness and ecosystem functions. ecosystem functions are, however, dependent on the particular membership of the community, rather that its number, for the functions are species-specific properties. yet evidence, is provided, that an increasing species richness should be, on average, linked to an increase in the functional repertoire present in the community, will lead to a more efficient use of resources and a greater capacity to ensure the sustainability of ecosystem functions under disturbance or ecosystem change. closer examination indicates that the functional variability of mixed-species seagrass assemblages is correlated to the variability in species size, whereas species of similar size tend to show similar functional capacities and, therefore, a greater degree of functional redundancy. in addition, the demonstration of positive interactions in seagrass communities, which are also dependent on the presence of engineering species in the community that facilitate the growth of other species, provides increasing grounds to expect an enhanced functional performance of mixed communities over that expected from a simple additive contribution of the community members. multispecific communities also hold, within the functional repertoire they contain, many unrealised functional potentials that may prove instrumental to ensure the sustainability of ecosystem functions in the presence of disturbance or a changing environment. the arguments offered, illustrated for the comparatively simple seagrass communities, provide strong reasons to expect a strong - if difficult to test experimentally - positive relationship between species diversity and the functions of marine ecosystems and, thereby, the services they yield to humanity. (c) 2000 elsevier science bn. all rights reserved.",103,2000,250,02-Jan,117,131,10.1016/S0022-0981(00)00194-5,0,0,1,1"Cadee, N",genetic and environmental effects on morphology and fluctuating asymmetry in nestling barn swallows,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,brood size manipulation; cross-fostering; developmental instability; environmental stress; fluctuating asymmetry; heritability,"a barn swallow hirundo rustica partial cross-fostering experiment with simultaneous brood size manipulation was conducted in two years with contrasting weather conditions, to estimate heritable variation in tarsus, tail and wing size and fluctuating asymmetry. environmental stress had contrasting effects depending on trait type. significant heritabilities for tarsus, tail and wing size were found only in enlarged broods irrespective of year effects, while tarsus asymmetry was significantly heritable in the year with benign weather conditions irrespective of brood size manipulation effects. tail, wing and composite (multicharacter) asymmetry were never significantly heritable. the environment with the higher heritability generally had higher additive genetic variance and lower environmental variance, irrespective of trait type. heritability was larger for trait size than for trait asymmetry. patterns of genetic variation in nestlings do not necessarily translate to the juvenile or adult stage, as indicated by lack of correlation between nestling and fledgling traits.",20,2000,13,3,359,370,,0,0,1,1"Bijlsma, R; Bundgaard, J; Boerema, AC",does inbreeding affect the extinction risk of small populations? predictions from drosophila,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,conservation biology; Drosophila melanogaster; environmental stress; extinction probability; genotype-environment interaction; inbreeding depression; inbreeding; population persistence,"a fundamental assumption underlying the importance of genetic risks within conservation biology is that inbreeding increases the extinction probability of populations. although inbreeding has been shown to have a detrimental impact on individual fitness, its contribution to extinction is still poorly understood. we have studied the consequences of different levels of prior inbreeding for the persistence of small populations using drosophila melanogaster as a model organism. to this end, we determined the extinction rate of small vial populations differing in the level of inbreeding under both optimal and stress conditions, i.e. high temperature stress and ethanol stress. we show that inbred populations have a significantly higher short-term probability of extinction than non-inbred populations, even for low levels of inbreeding, and that the extinction probability increases with increasing inbreeding levels. in addition, we observed that the effects of inbreeding become greatly enhanced under stressful environmental conditions. more importantly, our results show that the impact of environmental stress becomes significantly greater for higher inbreeding levels, demonstrating explicitly that inbreeding and environmental stress are not independent but can act synergistically. these effects seem long lasting as the impact of prior inbreeding was still qualitatively the same after the inbred populations had been expanded to appreciable numbers and maintained as such for approximately 50 generations. our observations have significant consequences for conservation biology.",176,2000,13,3,502,514,,1,0,0,1"Gadallah, MAA","effects of indole-3-acetic acid and zinc on the growth, osmotic potential and soluble carbon and nitrogen components of soybean plants growing under water deficit",JOURNAL OF ARID ENVIRONMENTS,Article,glycine max; indole-3-acetic acid; osmotic adjustment; soybean; water stress; zinc,"three-week old soybean (glycine max) plants were subjected to a factorial combination of four regimes of soil matric water potential (psi(m) = - 0. 03, - 0.5, - 1.0 and - 1.5 mpa), two levels of supplementary zn (o and 20 mgl(-1)) and two levels of foliar iaa application (o and 10 mgl(-1)). under control conditions (no zn, no iaa), increasing soil drying progressively retarded shoot and root growth (length and dry mass production), reduced leaf relative water content (rwc) and decreased the contents of chlorophyll (chl) and shoot soluble sugars (ss), but increased soluble sugar content of roots and lowered osmotic water potential of shoots and roots (osmotic adjustment). total free amino acid (taa) content increased in shoots but decreased in roots whereas contents of soluble proteins (sp) decreased in shoots and roots. the effect of water stress was statistically significant (p < 0.05) and had a major effect las indicated by eta(2) values) on leaf rwc, shoot and root dry masses and osmo tic potential. supplementary zn improved root growth at all levels of stress and shoot growth under severe stress. improvement of growth was positively correlated with the internal tissue zn concentrations (r - 0.91 and 0.86 for shoot and 0.94 and 0.82 for root length and dry mass respectively). exogenous iaa raised (p < 0.05) rwc, chi, dm (slightly), root ss, and sp, whereas shoot taa was lowered. effects on root taa and shoot ss were more complex: they were lowered at zero stress and raised under severe stress. iaa and zn in combination had additive effects on chi, growth and osmotic potential, but their combined effects on sp and taa were more complex. it is concluded that the treatment of soybean plants grown under conditions of low soil water potentials and zn deficiency with zn and iaa solutions counteracted the deleterious effects of stress, especially at high stress levels, and helped stressed plants to grow successfully under these adverse unfavourable conditions. (c) 2000 academic press.",36,2000,44,4,451,467,10.1006/jare.1999.0610,0,0,1,1"Dawson, A",mechanisms of endocrine disruption with particular reference to occurrence in avian wildlife: a review,ECOTOXICOLOGY,Article; Proceedings Paper,endocrine disruption; birds; steroid hormones; P450; thyroid,"this review examines the evidence for endocrine disruption in birds. it reviews in vitro and in vivo laboratory based evidence for endocrine disruption by (1) agonism or antagonism of gonadal steroid hormones, (2) altering the activity of cytochrome p450 enzymes, (3) altering thyroid hormone function, (4) affecting intrinsic neuroendocrine control mechanisms and (5) activation of the stress response. it also discusses the evidence for the existence of such effects in free-living birds. in vitro studies demonstrate that mechanisms for potential endocrine disruption exist, but in vivo studies suggest that such mechanisms are insufficient to overwhelm endogenous homeostatic control. there are only two phenomena in wild birds where endocrine disruption has been cited as a possible cause: eggshell thinning and supernormal clutches. evidence suggests that neither of these is caused by endocrine disruption. despite three decades of concern, there is no evidence that avian wildlife has suffered endocrine disruption.",40,2000,9,02-Jan,59,69,10.1023/A:1008964128501,0,1,0,1"Vetaas, OR","the effect of environmental factors on the regeneration of quercus semecarpifolia sm. in central himalaya, nepal",PLANT ECOLOGY,Article,canopy disturbance; Himalaya; lopping; regeneration niche; size-class distribution,"poor regeneration of oak forest has been observed in north america and eurasia. in the himalaya it has mainly been explained by anthropogenic pressures. this study analyses the regeneration of two quercus semecarpifolia sm. forests (2-3000 m a.s.l.), where one forest has almost nil disturbance and the other has different degrees of canopy disturbance. the relationships between biotic and abiotic environmental variables and the number of quercus semecarpifolia seedlings and saplings (i.e., recruits < 10 cm diameter at breast height (dbh)) were analysed by means of generalized additive models (gam). the two forests were compared with respect to size-class distributions of mature trees (i.e., > 10 cm dbh), and the number of recruits. the size-class distributions indicate that regeneration is most reliable in the nearly undisturbed forest. most recruits were found under high canopy cover and high potential radiation. canopy disturbance has a negative effect on the number of seedlings. seedlings seem to prefer a ph of around 6, loss-on-ignition between 20 and 30 %, and total nitrogen between 2 and 3 %. in general, there were very few plots with saplings, and there was not a clear relationship between the number of saplings and the soil variables. the size-class diagrams indicate a lack of young trees in the disturbed forest, and it is hypothesized that fire may inhibit recruits reaching the canopy phase.",16,2000,146,2,137,144,10.1023/A:1009860227886,0,0,1,1"Sera, B; Falta, V; Cudlin, P; Chmelikova, E",contribution to knowledge of natural growth and development of mountain norway spruce seedlings,EKOLOGIA-BRATISLAVA,Article,climax; natural regeneration; Krkonose Mts; Picea abies; seedlings,"influence of the climatic and pollution stress, soil substrates, mosses and dominant herb species on the norway spruce (picea abies l. k a r s t.) seedling development and their cohort growth was investigated in six permanent research plots in the krkonosc mts from 1995 to 1997. the results showed dependence of seedling development on the synergic influence of the multiple stress. the highest number of seedling cohorts was observed in the least damaged plots (the modry dul and the sluncene udoli plots), where climatic conditions are not so severe, the canopy cover is high and consequently litter coverage is high, too. on the contrary, no seedlings were found in the heavily damaged mumlavska hora plot and only a few seedlings were observed in the alzbetinka plot (the north exposition and also relatively high polluted plot). one of the important secondary stress factors is an expansive growth of some dominant plants species. the majority of seedlings was germinating and growing in patches covered by litter. the seedling development in other substrates (as mosses and some herb layer communities) was much less frequent.",6,2000,19,4,420,434,,1,0,0,1"Lesser, MP",depth-dependent photoacclimatization to solar ultraviolet radiation in the caribbean coral montastraea faveolata,MARINE ECOLOGY PROGRESS SERIES,Article,corals; ozone depletion; UVR; action spectra; photosynthesis,"the importance of solar ultraviolet radiation (uvr, 290 to 400 nm), and uvb (290 to 320 nm) in particular, as an environmental factor affecting the biology and ecology of coral reefs has taken on renewed interest since the demonstration of global stratospheric ozone loss through human activities. the hermatypic coral montastraea faveolata occurs over a wide bathymetric range in the florida keys reef tract. the bathymetric range of m, faveolata and its role in reef community structure make it an important species for which to assess the effects of present day uvr irradiances. both uvr irradiances and uvr-absorbing mycosporine-like amino acids (maas) decreased significantly with increasing depth in m, faveolata. we irradiances were measured to a depth of 30 m during this study and maximum rates of productivity in m, faveolata were significantly affected by the presence of uvr. action spectra (= biological weighting function) for the photoinhibition of photosynthesis by wr were measured for samples of m, faveolata at 3, 10, 18, 23, and 30 m. using these action spectra, radiation amplification factors (rafs) were calculated for corals at the same depths. rafs for m, faveolata suggest that corals at depths greater than 3 m will be more sensitive to increases in we irradiance, such as might be caused by ozone depletion, than their shallow-water counterparts. despite this increase in sensitivity to uvb, calculations incorporating continued ozone depletion suggest that at the present rate of stratospheric ozone depletion corals deeper than 5 m in the florida keys will be affected very little, if at all, by increases in uvr. these results, however, do not incorporate the interacting and synergistic effects of uvr with other physical parameters (e.g. temperature) that will be essential to understanding and predicting the fate of coral reefs under conditions of global change.",57,2000,192,,137,151,10.3354/meps192137,1,0,0,1"Harris, LC; Khan, MA; Zou, J; Smith, BN; Hansen, LD",effects of salinity and temperature on respiratory metabolism of salicornia utahensis from a great basin playa,SHRUBLAND ECOSYSTEM GENETICS AND BIODIVERSITY: PROCEEDINGS,Proceedings Paper,,"plants that live in the desert playas of the great basin must simultaneously tolerate very high concentrations of salt and high temperature. this study characterizes the respiratory metabolism of one species growing in this environment. an isothermal calorimetric method was used to measure the dark metabolic heat rate (q) and co2 production rate (r-co2) of stem tissue from salicornia utahensis grown in the greenhouse or in constant temperature growth chambers at six different concentrations of nacl solutions ranging from 0 to 1.0 m. metabolic rates were measured at eight temperatures from 5 to 40degreesc. temperature and salt dependencies of q and r-co2 were used to model response of both growth and substrate carbon conversion efficiency. salt and temperature stresses are not additive, but rather oppose one another, in other words, the higher the salt, the higher the temperature the plants will tolerate and vice versa. the maximum temperature tolerated is an approximately linear function of salt concentration, being about 20 degreesc at 0 m salt and about 32 degreesc at 1 m.. concentration of the endogenous osmoticant glycinebetaine increased with salt and temperature but only to about 20 c and 900 mm nacl.",1,2000,NA,21,265,270,,0,0,1,1"Agee, JK",wilderness fire science: a state-of-knowledge review,"WILDERNESS SCIENCE IN A TIME OF CHANGE CONFERENCE, VOL 5: WILDERNESS ECOSYSTEMS, THREATS, AND MANAGEMENT",Proceedings Paper,,"wilderness fire science has progressed since the last major review of the topic, but it was significantly affected by the large fire events of 1988. strides have been made in both fire behavior and fire effects, and in the issues of scaling, yet much of the progress has not been specifically tied to wilderness areas or funding. although the management of fire in wilderness has been slow to recover from the fires of 1988, science has progressed most significantly in its ability to deal with fire at a landscape level. major challenges include better understanding of the regional context and function of wilderness areas, as well as understanding and incorporating fire patchiness, variability and synergistic disturbance factors into predictive models. if more precise models are to be applied accurately in wilderness, better weather databases are essential.",2,2000,5,15,5,22,,1,0,0,1"O'Neill, RV; Riitters, KH; Wickham, JD; Jones, KB",landscape pattern metrics and regional assessment,ECOSYSTEM HEALTH,Article,,"the combination of remote imagery data, geographic information systems software, and landscape ecology theory provides a unique basis for monitoring and assessing large-scale ecological systems. the unique feature of the work has been the need to develop and interpret quantitative measures of spatial pattern-the landscape indices. this article reviews what is known about the statistical properties of these pattern metrics and suggests some additional metrics based on island biogeography, percolation theory, hierarchy theory, and economic geography. assessment applications of this approach have required interpreting the pattern metrics in terms of specific environmental endpoints, such as wildlife and water quality, and research into how to represent synergystic effects of many overlapping sources of stress.",70,1999,5,4,225,233,10.1046/j.1526-0992.1999.09942.x,1,0,0,1"Boughton, DA; Smith, ER; O'Neill, RV",regional vulnerability: a conceptual framework,ECOSYSTEM HEALTH,Editorial Material,,"regional vulnerability assessment, or reva, is an approach to place-based ecological risk assessment that is currently under development by the off ice of research and development of the u.s. environmental protection agency (epa). the assessment is done at the scale of epa regions and builds on data collected for the environmental monitoring and assessment program (emap) of the epa. the pilot reva is being developed for the u.s, mid-atlantic region to identify those ecosystems, together with the ecological goods and services they provide, that are most vulnerable to being lost in the next 20 years. the project is currently exploring different conceptual approaches to integrated assessment. in this article, we give an operational approach to estimating ecosystem vulnerability and discuss important issues arising from it. the first issue is estimating vulnerability at the regional scale as opposed to the more familiar local scale. the second issue is integrating information about different sorts of risks in order to prioritize them at the regional scale. the challenge of integration is considerable because of the possibility of synergistic (mutually reinforcing) interactions between different environmental stresses. synergistic effects are often too poorly known to include, yet potentially too important to ignore. vulnerability at the regional scale may provide a pragmatic, middle-road approach to this problem by highlighting and characterizing geographic areas that are expected to change the most in the future. the goal is not exact predictions, but a first-cut early warning system to identify and prioritize the risks of undesirable environmental changes over the next few decades.",25,1999,5,4,312,322,10.1046/j.1526-0992.1999.09949.x,1,0,0,1"Takahashi, K; Kohyama, T",size-structure dynamics of two conifers in relation to understorey dwarf bamboo: a simulation study,JOURNAL OF VEGETATION SCIENCE,Article,Abies sachalinensis; co-existence; competition; coniferous forest; Picea glehnii; recruitment; Sasa,"size-structure dynamics and co-existence of the conifers abies sachalinensis and picea glehnii in subalpine forests in japan, in relation to the understorey dwarf bamboo sasa, were examined using a simulation model. this model explicitly incorporated recruitment rate, size growth rate and mortality. recruitment and growth rates were assumed to be suppressed by the cumulative basal area of taller trees and the density of sasa. as for the one-sided crowding effect, two types of model were examined. the total basal area of the two species suppresses the growth and recruitment rates in an additive model, while the basal area of each species has a separate effect included in a specific model. two types of recruitment process were examined, i.e. open and closed systems; recruitment rates of open and closed systems are independent of, and proportional to, the basal area of the same species within the plot, respectively. parameters were estimated from data of plot censuses for four years. the parameters of the specific model showed that recruitment and size growth rates were more suppressed by the same species than the other species. recruitment of a. sachalinensis was mon sensitive to suppression by sasa compared with p. glehnii. the stationary size structure of the two species, generated from both the models with the open system, fitted well to the observed size structures across various sasa densities. a. sachalinensis and p. glehnii dominated at lower and higher densities of sasa, respectively. however, the closed-system simulation showed that the stable co-existence of the two species with a good fit to the observed size structure occurred only in the specific model. these results suggest that within-species interference, which is more severe than between-species interference, is important for the co-existence of the two species and that the relative dominance of the two species readily explained the differential responses to sasa abundance.",19,1999,10,6,833,842,10.2307/3237308,0,0,1,1"Chatila, K; Demers, S; Mostajir, B; Gosselin, M; Chanut, JP; Monfort, P",bacterivory of a natural heterotrophic protozoan community exposed to different intensities of ultraviolet-b radiation,AQUATIC MICROBIAL ECOLOGY,Review,ultraviolet-B; protozoa; bacterivory; bacterioplankton; clearance rate; ingestion rate; St. Lawrence Estuary,"the effects of ultraviolet-b radiation (uvbr) on the bacterivory of a natural marine protozoan community were examined as part of a 7 d experiment designed to study the effects of different uvbr intensities on the summer planktonic assemblage of the lower st. lawrence estuary, quebec, canada. the experiment was conducted in large containers (mesocosms) subjected to 1 of the following uvbr regimes: excluded uvbr (wuvb), natural uvbr (nuvb), and natural uvbr enhanced with either 2 lamps (luvb) or 3 lamps (huvb). incubations with fluorescently labeled bacteria were conducted daily as a tool to understand the interaction between the potential bacterivores (heterotrophic ciliates and nanoflagellates) and bacteria within the studied system. uvbr intensities had no significant effects on the estimated clearance and ingestion rates (cr and ir, respectively) until day 5 of the experiment. during the following 2 d, characterized by low nutrient concentration, both cr and ir decreased with the increase of the daily uvbr (at 305 and 320 nm) doses received. the maximum difference between treatments was observed on day 7, where both clearance and ingestion rate values in the nuvb, luvb and huvb treatments were significantly lower than the wuvb treatment. our data suggest that over a 1 d period and under conditions of high nutrient concentrations, protozoan bacterivory is not affected by uvbr increases. when nutrient concentrations become low, bacterivores become more susceptible to damaging uvbr effects. we think that the deterioration of food quality, itself resulting from the synergistic action of nutrients and uvbr stresses, is responsible for the increased sensitivity of bacterivores to uvbr. uvbr-induced decreases in bacterivory would represent a considerable loss to the higher tropic levels that feed upon bacterivores.",13,1999,20,1,59,74,10.3354/ame020059,1,0,0,1"Howe, HF; Brown, JS",effects of birds and rodents on synthetic tallgrass communities,ECOLOGY,Article,"birds, seed predation by; diversity; experimental restoration; field experiment; foraging theory; granivory; herbivory; rodent browsing; tallgrass community, revegetation; tallgrass plantings, small vertebrate effects on; tallgrass prairie, composition and diversity; vole herbivory","we used a bird and mammal exclosure design on plowed ground to rest for the effects of granivory and herbivory by small vertebrates on early stages of tallgrass prairie succession. seed predation by birds and browsing by rodents had major and additive impacts. in high- and low-density plantings, respectively, seed-eating birds reduced plant densities by 20% and 23% and grass biomass by 24% and 34%. meadow voles did not affect plant numbers but reduced forb biomass by 35% in high- and 57% in low-density plantings. in high- and low-density plots, respectively, birds reduced species richness by 3% and 17% without influencing diversity; selective browsing by voles on two legumes and one coneflower left species number unaffected but reduced diversity by 4% and 25% by accentuating dominance of already-prominent species. bird effects were more pronounced in high-density plantings, while vole effects were most pronounced in low-density plantings. results suggest that opportunistic finches and doves that seek out high seed concentrations depress tallgrass plant densities on open ground, while voles, which selectively forage on emerging vegetation, alter community structure, especially when their home ranges include low-density plant assemblages. both results are likely to be relevant to native prairies after burns or other disturbance, and ro ecological restoration.",68,1999,80,5,1776,1781,10.1890/0012-9658(1999)080[1776:EOBARO]2.0.CO;2,0,0,1,1"Peters, AD",the effects of pathogen infection and mutation on life history characteristics in arabidopsis thaliana,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,Arabidopsis thaliana; mutation; parasitism; synergism; sexual reproduction,"the nature of the interaction among deleterious mutations is important to models in many areas:of evolutionary biology. in addition, interactions between genetic and environmental factors may affect the predictions of such models. individuals of unknown genotypes of arabidopsis thaliana, ecotype marburg, were-exposed to five levels of chemical (ems) mutagenesis and three levels of pseudomonas syringae infection. survival, growth and flowering characteristics of each individual were measured. the logarithm of fitness is expected to be a linear function of mutation number if mutations act independently. furthermore, the expected number of mutations should be approximately a linear function of time of exposure to mutagen. therefore, nonlinear effects of mutagen exposure on the logarithm of fitness characters would suggest epistasis between mutations. similarly, if pathogen infection and mutation act independently of each other, their effects should be additive on a log scale. statistical interactions between these factors would suggest they do not act independently; particularly, if highly mutated individuals suffer more when infected than do less mutated individuals, this, suggests that pathogens and mutations act synergistically. pseudomonas-infected individuals were shown to have an increased probability of flowering under-conditions of short day length, but to ultimately produce fewer flowers than uninfected individuals. this suggests a plastic response to stress and, despite that response, an ultimately deleterious effect of infection on fitness. leaf rosette growth was negatively and linearly related to the expected number of mutations, and the effects of mutation on different life-cycle stages appeared to be uncorrelated. no significant interactions between pathogen and mutation main effects were found. these results suggest that mutations act multiplicatively with each other and with pathogen infection in determining individual fitness.",15,1999,12,3,460,470,,1,0,1,2"Mitchell, RJ; Zutter, BR; Gjerstad, DH; Glover, GR; Wood, CW",competition among secondary-successional pine communities: a field study of effects and responses,ECOLOGY,Article,Andropogon virginicus; competitive effect; competitive response; Liquidambar styraciflua; mechanisms of competition; multiple resource limitation; Pinus taeda; plant competition; temporal resource heterogeneity,"three common associates on secondary-successional pine sites (andropogon virginicus, liquidambar styraciflua, and pinus taeda) were established in a field study in which a wide array of plant densities and species proportions were established using an additive series design. to mimic a specific competitive scenario (i.e., a managed early successional pinus stand), andropogon and liquidambar were established a year prior to the establishment of pinus. competitive effect (the attenuation of resources) and competitive response (the growth of each species as a function of resource availability) were determined. effect on soil water varied among species, depth of soil, and time. in the surface soil, soil water was largely influenced through non-uptake effects, while uptake effects were predominant in deeper portions of the solum. when competitor abundance was expressed on an aboveground biomass basis, rather than a density basis, species differences in effects on soil water were eliminated. differences among the species in effects on soil water per unit leaf area or leaf biomass appear to be largely explained by differences in stomatal conductance. predawn leaf-water potential was integrated over the season using a water-stress integral. analysis of the water-stress integral suggested that liquidambar and andropogon both affected water available to pious; however, only liquidambar affected andropogon, and only andropogon affected seasonal water available to liquidambar. light was most strongly influenced by liquidambar density; however, as andropogon density increased, the effects of liquidambar were reduced. andropogon response was correlated with light but not with water stress or leaf nitrogen. this reflects high light requirements and high water use efficiency of c-4 plants. liquidambar response was related to water stress and leaf nitrogen, perhaps reflecting the greater nitrogen requirements of hardwoods. pinus response was significantly related to all three resources individually, i.e., water stress, light, and leaf nitrogen. pinus response was better explained by a regression model that included light and water stress than by water stress or light alone. pinus growth as a function of water stress and light indicated that communities dominated by liquidambar largely reduced pinus growth through reduction in light, while communities dominated by andropogon reduced pinus growth primarily by increasing water stress. in mixed communities of liquidambar and andropogon, pine growth was constrained more equally by light and water stress.",39,1999,80,3,857,872,10.1890/0012-9658(1999)080[0857:CASSPC]2.0.CO;2,0,0,1,1"Whitham, TG; Martinsen, GD; Floate, KD; Dungey, HS; Potts, BM; Keim, P",plant hybrid zones affect biodiversity: tools for a genetic-based understanding of community structure,ECOLOGY,Article,biodiversity; conservation and endangered species; genetic basis of community structure; genetic diversity; indirect effects; keystone species; plant hybrid zones; specialists and generalists,"plant hybrid zones are dynamic centers of ecological and evolutionary processes for plants and their associated communities. studies in the wild and in gardens with synthetic crosses showed that hybrid eucalypts supported the greatest species richness and abundances of insect and fungal taxa. in an updated review of 152 case studies of taxa associated with diverse hybridizing systems, there were 43 (28%) cases of hybrids being more susceptible than their parent species, 7 (5%) resistant, 35 (23%) additive, 35 (23%) dominant, and 32 (21%) showed no response to hybridization. thus, most taxa respond to hybrids in ways that result in equal or greater abundance, and hybrids tend to accumulate the taxa of their parent species. these studies suggest that genetic-based plant traits affect the distribution of many species and that the variation in hybrids can be used as tools to examine the genetic components of community structure and biodiversity. several patterns have emerged thus far. (1) genetic variation between classes of hybrids (e.g., f(1)'s vs. backcrosses) may equal or even exceed that found between species. (2) as a reflection of this genetic variation, herbivores are more likely to differentiate between hybrid classes than they are to differentiate between pure plant species. (3) the communities associated with different hybrid classes can differ from one another as well as from their parental species. (4) generalist and specialist herbivores predictably vary in their responses to hybrids. (5) plant hybrid zones may represent essential habitat for some arthropod species. (6) even nesting birds respond to hybridizing plants. (7) including multiple trophic levels and taxa from microbes to vertebrates, susceptible hybrid genotypes support greater biodiversity than resistant genotypes. (8) the effects of hybridization on common or keystone species can either positively or negatively affect biodiversity. the indirect impacts of hybridization on biodiversity may exceed the direct impacts and may result in ""apparent"" herbivore resistance or susceptibility at the community level. (9) although hybrids are often maligned, exotic or problem hybrids generally result from human disturbances, whereas native hybrids are part of natural ecosystems and should be conserved. three predictions are made: (1) intermediate genetic differences between the parental species will result in the greatest genetic variation in the hybrid zone, which in turn will have a positive effect on biodiversity. (2) bidirectional introgression enhances species richness on hybrids, whereas f(1) sterility and unidirectional introgression limit the accumulation of species on hybrids. (3) although susceptible hybrids are likely to support the greatest biodiversity, the impacts of hybridization on keystone species will be crucial in determining the overall effect.",139,1999,80,2,416,428,,0,0,1,1"Reusch, TBH; Williams, SL",macrophyte canopy structure and the success of an invasive marine bivalve,OIKOS,Article,,"in both terrestrial and aquatic environments introductions of non-indigenous species are continuing and represent one important component of global change. negative biotic interactions by resident species may prevent successful invaders from becoming pests. few experimental data are available on the presence and significance of such biotic resistance other than predation or competition. this study addresses the role of habitat structure provided by a native eelgrass (zostera marina) canopy on growth and survival of the non-indigenous mussel musculista senhousia, a habitat-modifying gregarious suspension feeder with strong effects on native infauna and eelgrass. in 2 southern california bays, a series of transplantation experiments using tagged mussels revealed that inside an eelgrass canopy, musculista growth rates were reduced by more than half in 3 of 4 experiments compared to adjacent unvegetated areas. musculista survival also decreased inside the vegetation in a 4-mo experiment. as one element of habitat structure, we tested the effects of eelgrass parch size, using natural (1 site) and planted (1 site) eelgrass patches of defined sizes. growth rates of musculista were highest outside the veneration and decreased as eelgrass patch size increased. as a potential mechanism for the canopy effects, we suggest that musculista receives less food inside the vegetation. in the experimental plots, the presence and spatial extent of the macrophyte canopy strongly affected near bottom (10 cm) horizontal water flow assessed with a direct dye tracking method. reduced mussel growth rates were linearly associated with lower water flow, and presumably, food flux. over a period of 7 mo, food resources (particulate chlorophyll a) were consistently lower 1 and 5 cm above the sea floor inside eelgrass patches compared to the sand aat. the reduction in food availability matched the growth reduction of musculista. also, mussel condition (dry flesh mass/shell mass) was worse in individuals growing in eelgrass than in the sand aat. previous experiments revealed that dense beds of musculista impede the rhizome growth and vegetative propagation of eelgrass, yet mussels attain abundances sufficient for interference only if eelgrass beds are patchy. thus, anthropogenic disturbances on eelgrass beds, which often result in meadow fragmentation, and the proliferation of musculista may have synergistic negative effects on the persistence of eelgrass beds.",49,1999,84,3,398,416,10.2307/3546420,1,0,0,1"Cockell, CS",crises and extinction in the fossil record - a role for ultraviolet radiation?,PALEOBIOLOGY,Review,,"a number of natural events can cause ozone depletion, including asteroid and comet impacts, large-scale volcanism involving the stratospheric injection of chlorine, and close cosmic events such as supernovae. these events have previously been postulated to have been sole or contributory causes of mass extinctions. following such events, uv-b radiation would have been elevated at the surface of the earth. the possibilities for detecting elevated uv-b as a kill mechanism in the fossil record are discussed. in the case of impact events and large-scale volcanism, the taxa affected by increases in uv-b radiation are likely to be similar to those affected by cooling and by the initial drop in irradiance caused by stratospheric dust injection. thus uv-b may synergistically exacerbate the effects of these other environmental changes and contribute to stress in the biosphere, although uv-b alone is unlikely to cause a mass extinction. by the same token, however, this similarity in affected taxa is likely to make delineating the involvement of uv-b radiation in the fossil record more difficult. cosmic events such as supernovae may produce smaller extinction events, but ones that are ""cleaner"" uv catastrophes without the involvement of other environmental changes.",20,1999,25,2,212,225,,1,0,0,1"Rachich, J; Reader, R",interactive effects of herbivory and competition on blue vervain (verbena hastata l.: verbenaceae),WETLANDS,Article,herbivore exclusion; inflorescence mass; neighbor removal; plant survival; substitutive interaction; synergistic interaction,"we conducted an herbivore-exclusion plus neighbor-removal experiment to determine whether herbivory and competition had independent or interactive effects on a wetland plant, blue vervain (verbena hastata). eight-week-old plants were added to 1.5 m(2) experimental plots with neighboring reed canary grass (phalaris arundinacea) either left intact or removed and herbivores either not excluded or excluded. neighbors were removed with herbicide and hand-weeding while herbivores were excluded by surrounding a plant with 6-mm wire mesh and spraying the plant weekly with a systemic insecticide. treatment effects were determined by monitoring plant survival over two growing seasons and by measuring inflorescence mass in the second season. the two treatments had a synergistic, interactive effect on plant survival (g = 25.7, p < 0.001). four of the five plants per treatment survived when exposed to herbivory alone or to competition alone, but no plants survived when exposed to both herbivory and competition. the two treatments had a substitutive, interactive effect on inflorescence mass (f = 11.26, p < 0.0005). mean infloresccnce mass was only 0-1 g plant(-1) when plants were exposed to herbivory alone or to competition alone or to both herbivory and competition. plants not exposed to either herbivory or competition had a mean inflorescence mass of 60 g plant(-1). since effects of herbivory and competition were interactive rather than independent, future studies measuring either herbivory or competition effects on wetland plants should include both herbivore-exclusion and neighbor-removal treatments.",9,1999,19,1,156,161,,1,0,0,1"Imasheva, AG; Bosenko, DV; Bubli, OA",variation in morphological traits of drosophila melanogaster (fruit fly) under nutritional stress,HEREDITY,Article,Drosophila melanogaster; evolvability; fluctuating asymmetry; genetic variation; morphological traits; stress,"the effect of nutritional stress on phenotypical and genetic variation was examined for five morphological traits (thorax length, wing length, sternopleural chaeta number, abdominal chaeta number and arista branch number) in 30 isofemale lines of drosophila melanogaster. phenotypical variation of all traits except sternopleural chaeta number and fluctuating asymmetry of all bilateral traits were significantly higher in flies reared under poor feeding conditions. estimates of isofemale line heritability (coefficients of intraclass correlation) did not show a consistent pattern among traits. however, additive genetic variance was generally higher in poor feeding conditions in all traits except sternopleural chaeta number, although these differences were not statistically significant. similarly, estimates of evolvability were higher under nutritional stress for all traits except sternopleural chaeta number. these results suggest that nutritional stress increases the expression of genetic variation for some morphological traits in drosophila and, in this respect, is similar to the effects of temperature stress studied previously.",61,1999,82,,187,192,10.1038/sj.hdy.6884660,0,0,1,1"Andre, M; Chagvardieff, P",synergies between plant research conducted for terrestrial and for space purposes,LIFE SCIENCES: ARTIFICIAL ECOSYSTEMS,Article; Proceedings Paper,,"during the past 10 years, the main part of celss studies has concerned the exploration of limits of plant productivity. very high yields were obtained in continuous and high lighting, without reaching any limit. concepts of mineral nutrition were renewed. celss activities now induce a development in the techniques of image processing applied to plants in order to follow the growth, to detect stresses or diseases or to pilot harvesting robots. notable efforts concern the development of sensors, the study of trace contaminants and the micro-organisms monitoring. in parallel, several instruments for plant culture in closed systems were developed. the advantages of closure are emphasised in comparison with open flow systems. the concept of artificial ecosystems developed for space research is more and more taken into account by the scientific community. it is considered as a new tool to study basic and applied problems related to ecology and not especially concerned with space research. (c) 1999 cospar. published by elsevier science ltd.",1,1999,24,3,265,269,10.1016/S0273-1177(99)00313-0,1,0,0,1"Linke-Gamenick, I; Forbes, VE; Sibly, RM",density-dependent effects of a toxicant on life-history traits and population dynamics of a capitellid polychaete,MARINE ECOLOGY PROGRESS SERIES,Article,fluoranthene; Capitella sp M; population density; organic pollution; population growth rate,"the toxic effects of the widespread polycyclic aromatic hydrocarbon (pah), fluoranthene (flu), on life-history traits of capitella sp. m as a function of population density were investigated in a life-table-response-experiment (ltre) lasting 134 d. animals from laboratory cultures were exposed to 6 different flu concentrations (range 0 to 80 mu g flu [g dry wt sed](-1), ppm) at 3 population densities (range 529 to 36 842 worms m(-2)), and survivorship, growth rate until maturity and reproductive parameters were recorded. fluoranthene exposure significantly reduced juvenile survivorship in a concentration-dependent manner, whereas population density had no effect on this trait. in contrast, increasing density (= food limitation) was associated with significant decreases in body size at maturity and increased time to maturity, while flu had. no effect on these traits. effects of flu on time to first reproduction, % reproducing females, larvae per brood, broods per female and population growth rate (lambda) varied in response to the intensity of density dependence. in general, interactions between flu and density were compensatory (antagonistic) at low toxicant exposures, but synergistic at the highest. population effects are summarised by effects on population growth rate. our main result is that at low concentrations of flu (0 to 40 ppm), increasing density alleviated flu's effects on lambda. thus increasing flu decreased lambda at low density but had no effect at high density. at the highest concentrations of flu, however, the reverse was the case ('synergistic effects'). here, the effect of increasing density is to exacerbate the effects of flu. this result is particularly important because it demonstrates that ltres carried out at low density (non-food limited), as most have been in the past, may seriously underestimate effects in the field, where densities are generally high and likely to produce food limitation, as here. our results suggest that when food availability is limiting, the impact of low levels of toxicant stress on population dynamics may be marginal. by contrast at higher toxicant exposures, food limitation exacerbates toxicant effects and may increase the likelihood of extinction.",46,1999,184,,139,148,10.3354/meps184139,1,1,0,2"Cook, CJ",smarter baits: the effects of stress on bait aversion and options to avoid the development of bait aversions,NEW ZEALAND JOURNAL OF ECOLOGY,Article; Proceedings Paper,toxins; aversion; sublethal effects,"in poisoning operations, sublethal consumption of the toxin, can produce bait aversion. this decreases the effect of the poisoning and may create problems due to the presence of uneaten toxin in the environment. the use of new bait additives may prevent aversion development. here i report the effects of two bait additives, corticosterone and mifepristone, in altering bait aversion development in rats exposed to the widely used poison, monofluoroacetate (1080). corticosterone is a glucocorticoid hormone, released in response to stress. mifepristone (ru 38486), inhibits the actions of this hormone. imposed stress as well as administration of corticosterone, decreased consumption. concurrent administration of mifepristone prevented these decreases. mifepristone in low doses increased aversion in stressed, but not unstressed rats. at high doses, mifepristone both increased consumption and decreased aversion in all rats following exposure to 1080. administration of corticosterone also produced dose-dependent effects on aversion. at low doses in unstressed rats corticosterone, alone, increased aversion, while at high doses in all rats it decreased aversion. stress, and the hormonal outcome of this state, may thus contribute to aversion by influencing both consumption and aversion development.",1,1999,23,2,275,279,,0,0,1,1"Forbes, BC",land use and climate change on the yamal peninsula of north-west siberia: some ecological and socio-economic implications,POLAR RESEARCH,Article; Proceedings Paper,,"compared to climate, land use change is expected to comprise a more important component of global change in the coming decades. however, climate is anticipated to surpass land use as a factor later in the next century, particularly in the arctic. discussed here are the implications of land use and climate change on the yamal peninsula of north-west siberia, homeland of the yamal nenets. since the discovery of super-giant natural gas fields in the 1960s, extensive exploration has resulted in the direct withdrawal of large areas for infrastructure development and associated disturbance regimes have led to cumulative impacts on thousands of additional hectares of land. the land withdrawals have pushed a relatively consistent or increasing number of reindeer onto progressively smaller parcels of pasture. this has led to excessive grazing and trampling of lichens, bryophytes and shrubs and, in many areas, erosion of sandy soils via deflation. the low arctic tundra lies entirely within the continuous permafrost zone and ice-rich substrates are widespread. one implication of this is that both anthropogenic and zoogenic disturbance regimes may easily initiate thermokarst and aeolian erosion, leading to significant further losses of pastures. even without industrial disturbance, a slight change of the climate would result in massive thermokarst erosion. this would have negative consequences equal to or greater than the mechanical disturbances described above. the synergistic effects of land use coupled with climate change therefore have profound implications for the ecosystems of yamal, as well as the future of the nenets culture, society and economy.",13,1999,18,2,367,373,10.1111/j.1751-8369.1999.tb00316.x,1,0,0,1"Carey, AB; Kershner, J; Biswell, B; de Toledo, LD","ecological scale and forest development: squirrels, dietary fungi, and vascular plants in managed and unmanaged forests",WILDLIFE MONOGRAPHS,Review,ecological scale; forest development; Glaucomys sabrinus; habitat; northern flying squirrel; Oregon; Tamias townsendii; Townsend's chipmunk,"understanding ecological processes and their spatial scales is key to managing ecosystems for biodiversity, especially for species associated with late-seral forest. we focused on 2 species of squirrel (sciuridae: northern flying squirrel, glaucomys sabrinus, and townsend's chipmunk, tamias townsendii) in a cross-sectional survey of managed and natural stands in southwestern oregon during 1985-59. we measured vegetation and abundances of squirrels at >2,000 points in 19 stands in 3 seral stages. we described the diets of die squirrels in the stands. we analyzed data at point, stand, and stage scales to identify key processes contributing to biodiversity and scales at which emergent properties (synergistic effects) appeared. four factors (crown-class differentiation, decadence, canopy stratification, and understory development) accounted for 63% of variance in vegetation structure. decadence contributed to variation mostly in late-seral forest. within stands, most habitat variables were poorly correlated. across stands many variables were highly correlated, suggesting forests developed emergent properties above the point level but at or below stand level (16 ha). plant species composition was summarized by 21 vegetation site types. stands had 7-19 site types arrayed in fine scale (point and soups of points 40 m apart). site types were used to measure habitat habitat breadth (within-stand heterogeneity resulting from disturbance and forest development). vegetation structure varied on a 0.5-ha scale. stand-level characteristics were more influential than nominal seral stage for a variety of organisms. late-seral forests were more moist and complex with greater habitat breadth than 40-70-year managed stands. structural factors, moisture-temperature gradient values (mgv), and habitat breadth were used to describe the habitat space potentially available to squirrels. correlations between squirrels and habitat variables within stands were low linear regressions explained <20% of the within-stand variance in squirrel captures, but logistic regressions correctly classified 74 and 88% of the points according to usage (used, not used) by flying squirrels and chipmunks, respectively. compared to available habitat space, the realized habitat of flying squirrels had high decadence and complex canopies. the realized habitat of chipmunks had complex canopies and large, dominant trees. overall, chipmunks were less selective than flying squirrels and used 83% of the habitat space compared to 59% by flying squirrels. among stands, variance in carrying capacity of eying squirrels mas lest explained (70%) by decadence, habitat breadth, and mgv. for chipmunks, decadence and canopy stratification provided the lest model (72% of variance explained). both squirrels had mycologically diverse diets; richness was correlated with decadence and canopy stratification. major dietary fungi were associated with woody debris. flying squirrels had higher carrying capacities and overlap among foraging patches of individuals, but smaller foraging patches, in late seral forest than in managed stands. squirrels were more abundant in late seral forest than in managed forests. abundance in some stands deviated markedly from the stage mean-stand character was more influential than nominal seral stage. the 4 structural factors each represented all important ecological process; decadence and canopy stratification apparently had profound influences on other life forms. carefully timed variable-density thinnings could accelerate crown-class differentiation, canopy stratification, and understory development and increase habitat breadth. management of decadence is more problematic and may require various interventions, in eluding inducing decay in live trees, conserving biological legacies from previous stands, and ensuring recruitment of coarse woody debris.",7,1999,NA,142,5,71,,1,0,0,1"Paine, RT; Tegner, MJ; Johnson, EA",compounded perturbations yield ecological surprises,ECOSYSTEMS,Article,altered community states; dispersal; multiple disturbances; recovery intervals; scaling disturbances,"all species have evolved in the presence of disturbance, and thus are in a sense matched to the recurrence pattern of the perturbations. consequently, disturbances within the typical range, even at the extreme of that range as defined by large, infrequent disturbances (lids), usually result in little long-term change to the system's fundamental character. we argue that more serious ecological consequences result from compounded perturbations within the normative recovery time of the community in question. we consider both physically based disturbance (for example, storm, volcanic eruption, and forest fire) and biologically based disturbance of populations, such as overharvesting, invasion, and disease, and their interactions. dispersal capability and measures of generation time or age to first reproduction of the species of interest seem to be the important metrics for scaling the size and frequency of disturbances among different types of ecosystems. we develop six scenarios that describe communities that have been subjected to multiple perturbations, either simultaneously or at a rate faster than the rate of recovery, and appear to have entered new domains or ""ecological surprises."" in some cases, three or more disturbances seem to have been required to initiate the changed state. we argue that in a world of ever-more-pervasive anthropogenic impacts on natural communities coupled with the increasing certainty of global change, compounded perturbations and ecological surprises will become more common. understanding these ecological synergisms will be basic to environmental management decisions of the 21st century.",377,1998,1,6,535,545,10.1007/s100219900049,1,0,0,1"Chippindale, AK; Gibbs, AG; Sheik, M; Yee, KJ; Djawdan, M; Bradley, TJ; Rose, MR",resource acquisition and the evolution of stress resistance in drosophila melanogaster,EVOLUTION,Article,desiccation; developmental time; Drosophila melanogaster; growth rate; life-history evolution; physiology; starvation; stress resistance; trade-offs,"resistance to environmental stress is one of the most important forces molding the distribution and abundance dance of species. we investigated the evolution of desiccation stress resistance using 20 outbred drosophila melanogaster populations directly selected in the laboratory for adult desiccation resistance (d), postponed senescence (o), and their respective controls (c and b). both aging and desiccation selection increased desiccation resistance relative to their controls, creating a spectrum of desiccation resistance levels across selection treatments. we employed integrative approach, merging data on the life histories of these populations with a detailed physiology of water balance. the physiological basis of desiccation resistance may be mechanisms enhancing either resource conservation or resource acquisition and allocation. desiccation-resistant populations had increased water and carbohydrate stores, and showed age-specific patterns of desiccation resistance consistent with the resource accumulation mechanism. a significant proportion of the resources relevant to resistance of the stress were accumulated in the larval stage. males and females of desiccation-selected lines exhibited distinctly different patterns of desiccation resistance and resource acquisition, in a manner suggesting intersexual antagonism in the evolution of stress resistance. preadult viability of stress-selected populations was lower than that of controls, and development was slowed. our results suggest that there is a cost to preadult resource acquisition, pointing out a complex trade-off architecture involving characters distributed across distinct life-cycle stages.",100,1998,52,5,1342,1352,10.2307/2411304,0,1,0,1"Lively, CM; Lyons, EJ; Peters, AD; Jokela, J",environmental stress and the maintenance of sex in a freshwater snail,EVOLUTION,Article,competition; environmental stress; geographic parthenogenesis; mutational deterministic hypothesis; Potamopyrgus antipodarum; sexual reproduction,"synergism among mutations can lead to an advantage to sexual reproduction, provided mutation rates are high enough (the mutational deterministic hypothesis). here we tested the idea that competition for food can increase the advantage to sexual reproduction, perhaps by increasing the synergism among mutations in asexual individuals. we compared the survivorship of sexual and asexual snails (potamopyrgus antipodarum) under two treatments: starved and fed. we predicted higher mortality for asexual snails when starved, but found that sexual and asexual individuals survived at the same rate, independent of treatment. these results suggest that the distribution of sex in this snail may not be explained by variation in competition among populations.",25,1998,52,5,1482,1486,10.2307/2411317,1,0,0,1"Hoffmann, AA; Schiffer, M",changes in the heritability of five morphological traits under combined environmental stresses in drosophila melanogaster,EVOLUTION,Article,Drosophila; environmental stress; evolvability; heritability; variation,"heritabilities and evolvabilities for morphological traits were compared between two environments in drosophila melanogaster using parent-offspring comparisons. one of the environments was favorable. the other stressful environment involved a combination of repeated cold shocks, poor nutrition, and ethanol added to the medium, which markedly decreased viability. for wing traits, heritabilities were relatively lower in the stressful environment, while heritabilities for bristle traits were not influenced by conditions. heritability changes were largely due to an increase in the environmental variance under stress, whereas levels of additive genetic variance were relatively constant. evolvabilities were similar between environments except for crossvein length.",38,1998,52,4,1207,1212,10.2307/2411250,0,0,1,1"Leathwick, JR; Burns, BR; Clarkson, BD",environmental correlates of tree alpha-diversity in new zealand primary forests,ECOGRAPHY,Article,,"correlations between environment and tree alpha-diversity in new zealand's primary forests were examined using an extensive quantitative dataset (14 540 plots). generalised additive models were used to examine relationships between species richness and temperature, solar radiation, root-zone moisture deficit, relative humidity, lithology, drainage, and plot size for all trees (112 species), and separately for broadleaved trees (88 species), conifers (17), and the genus nothofagus (4). diversity both for all tree species and for broadleaved trees was predicted to be highest on sites with high temperatures, high solar radiation, and high soil and atmospheric moisture, and on sedimentary and basaltic substrates. highest conifer diversity was predicted on sites with intermediate temperatures, low solar radiation; high root-zone and atmospheric moisture, and rhyolitic and quaternary substrates, particularly where drainage was impeded. highest nothofagus diversity was predicted for sites combining low temperatures, high solar radiation, high root-zone moisture but low atmospheric moisture, and on granitic substrates. differences in diversity between the species groups on different lithologies are interpreted as reflecting both the effects of variation in large-scale disturbance histories, and the effects of confounding environmental factors associated with particular substrates. there were also significant interactions between species groups: both broadleaved tree and conifer richness were predicted to be lower on sites where one or more nothofagus spp. - all of which have marked patchiness in their distribution - are present. although these results are consistent with the hypothesis that tree diversity is highest on sites conducive to high productivity, history is also indicated as an important determinant of tree diversity in new zealand.",58,1998,21,3,235,246,10.1111/j.1600-0587.1998.tb00561.x,0,0,1,1"Puigdefabregas, J; Mendizabal, T",perspectives on desertification: western mediterranean,JOURNAL OF ARID ENVIRONMENTS,Article; Proceedings Paper,,"in the western mediterranean desertification is triggered by climatic variability and demographic disequilibrium, both of which directly and indirectly affect water budgets and land degradation through associated changes in land use patterns. this paper gives a historical perspective by reviewing major findings in climate and land use changes in the area, including information from tree ring, palynological, sedimentological, archaeological and archive analysis, with special emphasis on the past 500 years. this paper discusses the synergies between these changes and their implications to the most vulnerable ecosystems, such as mountain and semiarid ecosystems, and compares current desertification processes in the area's north and south. in both cases rangelands and irrigated zones are the most affected land use systems. in the maghreb (algeria, morocco and tunisia), rangelands are being destroyed by overgrazing and agricultural encroachment. in northern countries rangelands are increasing at the expense of marginal agriculture. this paper discusses some controversial implications of rangeland vegetation recovery on fire and water regimes and reviews information on the steppes of stipa tenacissima, paying attention to changes and degradation patterns, irreversible thresholds and implications of their spatial structure. finally, this paper discusses western mediterranean irrigated lands as hot spots of desertification; their vulnerability to rainfall variability; the difficulties of relieving them from overexploitation of water resources; and their terminal symptoms, such as soil salinization, exhaustion and deterioration of aquifers, and damage to downstream fluvial and wetland systems. (c)1998 academic press limited.",125,1998,39,2,209,224,10.1006/jare.1998.0401,1,0,0,1"Brewer, JS; Rand, T; Levine, JM; Bertness, MD","biomass allocation, clonal dispersal, and competitive success in three salt marsh plants",OIKOS,Article,,"although a trade-off between colonization and competitive ability is widely recognized to promote species co-existence. this trade-off is rarely tested. biomass allocation patterns, clonal dispersal, and competitive success of three salt marsh plant species grown in pots or trays were examined in the greenhouse. the competitive ranking was determined by a pairwise additive-series competition experiment in pots under low nutrient conditions. competitive ability and patterns of biomass allocation differed significantly among species. the competitive dominant, juncus gerardi, exhibited higher root:shoot and root:rhizome ratios than its competitive subordinates, spartina patens and distichlis spicata. contrary to what was previously observed in the field, spartina patens was only slightly competitively superior to distichlis spicata in the greenhouse (i.e., the difference was not statistically significant). distichlis spicata and spartina parens exhibited very similar patterns of biomass allocation, including similar patterns of allocation to roots and rhizomes. although the ranking of the three species with respect to clonal dispersal rates in trays (i.e., distichlis spicata > spartina patens > juncus gerardi) was inversely correlated with their competitive abilities in the field, differences in dispersal rates were small and not statistically significant. thus, a hypothesized trade-off between competitive ability and colonization ability in these three species does not appear to be strongly correlated with interspecific differences in rates of clonal dispersal in trays in the greenhouse. it is hypothesized that the superior colonization ability of distichlis spicata observed in the field depends greatly on its ability to tolerate harsh edaphic conditions within gaps.",22,1998,82,2,347,353,10.2307/3546975,0,0,1,1"Prato, FS; Kavaliers, M; Thomas, AW; Ossenkopp, KP",modulatory actions of light on the behavioural responses to magnetic fields by land snails probably occur at the magnetic field detection stage,PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,Article,opioid; analgaesia; ELF bioeffects; land snails,"the attenuation of opioid peptide-mediated antinociception or analgaesia is a well-established effect of extremely low frequency (elf) magnetic fields. results of prior studies indicated a modulatory role for light such that when the elf exposures were carried out in the absence of light, the inhibitory effect on analgaesia was reduced. here, we investigated whether this modulatory effect of light occurs at either the magnetic field detection stage or is associated with a post-detection mechanism. we compared the effects of the presence and absence of light on the attenuation of opioid-induced analgaesia in the land snail, cepaea nemoralis, by (i) an elf magnetic field (15 min, 60 hz, 141 mu t peak), and (ii) the prototypic opiate antagonist, naloxone. determinations were performed during the subjective 'day' and 'night' in the presence (1.9 w m(-2) and 1.0 mw m(-2), respectively) and absence of light (less than 10(-6) w m(-2)). the inhibitory effects of the elf magnetic fields and naloxone on opioid-induced analgaesia were similar in the presence of light; whereas in the absence of light the inhibitory effects of the elf magnetic fields as a percentage of sham were markedly reduced, while those of naloxone were unaffected. this indicates that the modulatory effects of light on the actions of the elf magnetic fields probably affect the detection mechanism prior to its coupling to the opioid system.",14,1998,265,1394,367,373,,0,1,0,1"Tremblay, R; Myrand, B; Sevigny, JM; Blier, P; Guderley, H","bioenergetic and genetic parameters in relation to susceptibility of blue mussels, mytilus edulis (l.) to summer mortality",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,cytochrome C oxinase; heterozygosity; Mytilus edulis; scope for growth; summer mortality; oxygen consumption,"our study examined whether the differences in susceptibility to summer mass mortality of two stocks of mussels from the magdalen islands (quebec, canada) are related to bioenergetic and/or genetic factors. the relative importance of maintenance and maximal metabolic rates, scope for growth (sfg) and the o:n ratio were followed over time to assess whether the increased incidence of mortality in late summer reflects a decrease in bioenergetic status at this period. the stock of mussels which was more susceptible to summer mortality had higher values of v-o2. furthermore this stock had a more negative scope for growth and lower o/n ratio in early august. these parameters are likely to reflect unfavourable environmental conditions, which led the mussels to rely upon protein catabolism. we also observed a negative correlation between multiple-locus heterozygosity and standard v-o2. the more susceptible stock of mussels had a lower degree of multiple-locus heterozygosity. thus, we suggest that the periodic, but irregular, outbreaks of summer mortality are the result of a synergistic interaction involving dietary deficiencies, temperature, a possible post-spawning, stress and the genetic characteristics of the stock. the higher metabolic demand associated with a reduced degree of heterozygosity will impose a supplementary stress and render such stocks more vulnerable to summer mortality. the results are in agreement with the hypothesis that high levels of heterozygosity are related with lower costs of maintenance. (c) 1998 elsevier science b.v.",55,1998,221,1,27,58,10.1016/S0022-0981(97)00114-7,1,0,0,1"Sgro, CM; Hoffmann, AA",heritable variation for fecundity in field-collected drosophila melanogaster and their offspring reared under different environmental temperatures,EVOLUTION,Article,Drosophila; evolvability; fecundity; heritability; nature; temperature,"heritable variation for fitness components is normally measured under favorable laboratory conditions, but organisms in the held experience variable conditions that are often stressful and may affect the expression of heritable variation. we examined heritable variation for early fecundity in three samples of drosophila melanogaster from the field. flies were obtained from a rotting fruit pile in summer, autumn, and spring, and progeny were reared under laboratory conditions. field parents were tested for fecundity at 14 degrees c or 28 degrees c depending on ambient temperatures. wing/thorax length ratios measured on flies from the spring collection suggested that flies had developed at around 20 degrees c. progeny were reared and tested at 14 degrees c, 25 degrees c, and 28 degrees c. in the summer collection, parent-offspring regression coefficients were high and significant, compared to nonsignificant values obtained in two of three autumn comparisons. in the spring collection, parent-offspring regressions were negative regardless of testing temperature, suggesting that field females with a high fecundity produced offspring with low scores. comparisons of f(1) and f(2) laboratory generations indicated intermediate heritabilities for fecundity in the laboratory. the lower bound heritability estimate for fecundity in field individuals was 37% in summer and 59% in autumn. estimates of field heritability and evolvability for wing length measured in the spring collection were lower than in the laboratory. the results indicate that heritabilities and additive genetic variances for fecundity can be high in field-reared flies, but that results may vary between field collections.",27,1998,52,1,134,143,10.2307/2410928,0,0,1,1"Kohno, Y; Matsumura, H; Kobayashi, T",differential sensitivity of trees to simulated acid rain or ozone in combination with sulfur dioxide,ACID DEPOSITION AND ECOSYSTEM SENSITIVITY IN EAST ASIA,Review,,"declines of several tree species and forests in the different areas of japan are noted, as european forests are suffering. however, they may be linked with different causes: forest succession dynamics, diseases and pests, meteorological extreme conditions, air pollutants, acidic deposition, and so on. exposure experiments have been conducted to assess cause-effects relationships with acidic deposition and forest decline. simulated acid rain or ozone in combination with sulfur dioxide was exposed to sixteen potted-tree species for 3 growing seasons. rain acidity below ph 4.0 could induce deleterious effects on some broad-leaved trees, however, coniferous trees did not show any significant growth reduction. sulfur dioxide and/or ozone induced complicated differential growth responses than the wet deposition did. some indicated additive harmful effects of sulfur dioxide. others showed synergistic adverse effects of ozone and sulfur dioxide. experimental results suggest that ambient level of ozone may take an important role to reduce tree vitality, since ozone induced chronic changes in carbon allocation will be accelerated by increased nitrogen input. assuming that fossil fuel energy consumption will continue at the current rate in the china, sulfur emission will be double at the year of 2010. without any countermeasures for reduction of sulfur dioxide emission, it may induce possible adverse direct effects on the natural vegetation due to increasing concentration of sulfur dioxide rather than due to increasing wet deposition of sulfate. exposure experiments suggest that differential sensitivity of plants to primary gaseous pollutants and its critical level will be a more important factor to explain forest decline rather than the soil acidification stress associated with wet acid deposition.",2,1998,NA,,143,188,,1,0,1,2"Saikkonen, K; Faeth, SH; Helander, M; Sullivan, TJ",fungal endophytes: a continuum of interactions with host plants,ANNUAL REVIEW OF ECOLOGY AND SYSTEMATICS,Review,mutualism; antagonism; grasses; woody plants,"endophytic fungi living asymptomatically within plant tissues have been found in virtually all plant species. endophytes are considered plant mutualists: they receive nutrition and protection from the host plant while the host plant may benefit from enhanced competitive abilities and increased resistance to herbivores, pathogens, and various abiotic stresses. limited evidence also indicates that endophytes may influence population dynamics, plant community diversity, and ecosystem function. however, most of the empirical evidence for this mutualism and its ecological consequences has been based on a few agronomic grass endophytes. more recent studies suggest that endophyte-host plant interactions are variable and range from antagonistic to mutualistic. a more comprehensive view of the ecology and evolution of endophytes and host plants is needed. this article discusses how life history traits-such as fungal reproduction and pattern of infections and genotypic variation and ecological factors-influence the direction and strength of the endophyte-host plant interaction.",413,1998,29,,319,343,10.1146/annurev.ecolsys.29.1.319,0,1,0,1"Leuven, RSEW; Haans, JLM; Hendriks, AJ; Lock, RAC; Bonga, SEW",assessing cumulative impacts of multiple stressors on river systems,NEW CONCEPTS FOR SUSTAINABLE MANAGEMENT OF RIVER BASINS,Proceedings Paper,,"the cumulative impacts of multiple stressors on water systems are of rapidly growing concern within the field of environmental sciences and management, most studies have focused on mixture toxicity and have dealt with responses of biota at either organismal or population level. few studies have addressed responses of organisms exposed to combinations of chemical and physical stressors. although antagonistic, additive and synergistic effects have been described for exposure of biota to combinations of chemical stressors, it seems to be agreed that concentration addition proves to be a reasonable worst case estimation. therefore, aggregation of physico-chemical parameters in water quality indices and supplementary specifications of environmental quality objectives to account for mixture toxicity are generally based on concentration addition. in spite of a growing interest in multiple stressors, basic data are often lacking or inadequate to allow precise predictions of the cumulative impacts of multiple stressors at the ecosystem level. even in the long term, investigation of all probable ecotoxicological responses to exposure to all possible combinations of stressors does not seem practically or economically feasible. monitoring of a sophisticated combination of physico-chemical, and biological parameters improves detection and ecotoxicological risk assessment of multiple stressors. application of quantitative structure-activity relationships, algorithms for mixture toxicity of known substances, (bio)chemical group parameters and response-oriented sum parameters may reduce uncertainties of cumulative impact assessment and can improve water quality management.",3,1998,NA,,241,259,,1,1,1,3"Rose, AB; Basher, LR; Wiser, SK; Platt, KH; Lynn, IH","factors predisposing short-tussock grasslands to hieracium invasion in marlborough, new zealand",NEW ZEALAND JOURNAL OF ECOLOGY,Article,multivariate analysis; generalised additive models; plant invasion; determinants of invasion; invasibility; grazing; degradation,"the effects of environment and management on the composition of short-tussock grasslands and the abundance of the invasive weed hieracium pilosella were investigated in two small catchments. species composition and site factors were recorded on a total of 182 plots and the management history of each catchment was reviewed. h. pilosella was present on >80% of all plots, but was at an early stage of invasion in one catchment (<5% cover) and dominant in the other (25% cover). classification and ordination revealed strong between-catchment differences in community composition that reflected differences in environment (soil fertility and rainfall), disturbance history (animal populations and burning), and the stage of invasion by h. pilosella. in both catchments h. pilosella tended to be least abundant on the wettest, driest, and most fertile soils. however, such relationships were weak. generalised additive models and regression showed that in the earlier stage of invasion individual site factors explained less than 20% of the variation in h. pilosella cover. topographic position and slope (both indicative of soil moisture) were the most significant combined predictors, but together explained only 32% of the variation. in the later stage of invasion individual factors explained up to 33% of the variation. topsoil sulphur, slope, and topsoil calcium were the most significant combined predictors, but together explained only 53% of the variation. between-catchment comparisons highlighted the inter-related roles of environment, disturbance history, geographic location, availability of h. pilosella propagules, and stage of invasion in more fully explaining the abundance of h. pilosella. of five models that have been proposed for hieracium invasion, the: ""grassland decline"" model best incorporated the inter-related factors that influence spatial and temporal variation in h. pilosella abundance in the study area. this model concentrates on identifying predisposing and trigger factors that increase the likelihood of invasion and accounts for multiple causes and interactions by specifying five key factors that influence the ability of a plant species to invade existing vegetation: environment, disturbance, vegetation structure and composition, life history attributes of the invader, and the availability of invading propagules. the model potentially provides a comprehensive framework for evaluating the causes of hieracium invasion, targeting research effort, and developing sustainable management strategies.",33,1998,22,2,121,140,,0,0,1,1"Lewis, J",evaluating the impacts of logging activities on erosion and suspended sediment transport in the caspar creek watersheds,PROCEEDINGS OF THE CONFERENCE ON COASTAL WATERSHEDS: THE CASPAR CREEK STORY,Proceedings Paper,,"suspended sediment has been sampled at both the north and south fork weirs of caspar creek in northwestern california since 1963, and at 13 tributary locations in the north fork since 1986. the north fork gaging station (nfc) was used as a control to evaluate the effects of logging in the south fork, in the 1970's, on annual sediment loads. in the most conservative treatment of the data, suspended loans increased by 212 percent over the total predicted for a 6-yr period commencing with the onset of logging. when the roles of the watersheds were preserved and the same analysis repeated to evaluate harvesting in the north fork under california forest practice rules in the 1990's, no significant increase was found at nfc in either annual suspended or bed load with the am,ent of automatic pumping samplers, we were able to sample sediment concentration much more frequently in the 1980's. this allowed storm event loads from control watersheds in the north fork to be used in a new regression analysis for nfc. according to this more sensitive analysis, for the 7-yr period commencing with the onset of logging, the sum of the suspended storm loads at nfc was 89 percent higher than that predicted for the undisturbed condition. the much greater increase after logging in the south fork is too great to be explained by differences in sampling methods and in water years, and appears to be the result of differences in roan alignment, yarding methods, and stream protection zones. similar analyses of storm event loads for each of the treated subwatersheds in the north fork suggested increased suspended loans in all but one of the tributaries, but effects were relatively small or absent at the main stern locations. of watersheds with less than 50 percent cut, only one showed a highly significant increase. the greater increase in sediment at nfc, compared to other main-stem stations, is largely explained by a 3,600-m(3) landslide that occurred in 1995 in a subwatershed that drains into the main stem just above nfc. differences among tributary responses can be explained in terms of channel conditions. analysis of an aggregated model simultaneously fit to all of the data shows that sediment load increases are correlated with flow increases after lagging. field evidence suggests that the increased flows, accompanied by soil disruption and intense burning, accelerated erosion of unbuffered stream banks and channel headward expansion. windthrow along buffered streams also appears to be important as a source of both woody debris and sediment. all roads in the north fork are located on upper slopes and do not appear to be a significant source of sediment reaching the channels. the aggregated model permitted evaluation of certain types of cumulative effects. effects of multiple disturbances on suspended loans were approximately additive and, with one exception, downstream changes were no greater than would hare been expected from the proportion of area disturbed. a tendency for main-stem channels to yield higher unit-area suspended loads was also detected but after logging this was no longer the case in the north fork of caspar creek.",16,1998,NA,,55,69,,0,0,1,1"Chesson, P; Huntly, N",the roles of harsh and fluctuating conditions in the dynamics of ecological communities,AMERICAN NATURALIST,Article,,"harsh conditions (e.g., mortality and stress) reduce population growth rates directly; secondarily, they may reduce the intensity of interactions between organisms. near-exclusive focus on the secondary effect of these forms of harshness has led ecologists to believe that they reduce the importance of ecological interactions, such as competition, and favor coexistence of even ecologically very similar species. by examining both the costs and the benefits, we show that harshness alone does not lessen the importance of species interactions or limit their role in community structure. species coexistence requires niche differences, and harshness does not in itself make coexistence more likely. fluctuations in environmental conditions (e.g., disturbance, seasonal change, and weather variation) also have been regarded as decreasing species interactions and favoring coexistence, but we argue that coexistence can only be favored when fluctuations create spatial or temporal niche opportunities. we argue that important diversity-promoting roles for harsh and fluctuating conditions depend on deviations from the assumptions of additive effects and linear dependencies most commonly found in ecological models. such considerations imply strong roles for species interactions in the diversity of a community.",389,1997,150,5,519,553,10.1086/286080,0,0,1,1"Kohler, HR; Eckwert, H",the induction of stress proteins (hsp) in oniscus asellus (isopoda) as a molecular marker of multiple heavy metal exposure .2. joint toxicity and transfer to field situations,ECOTOXICOLOGY,Article,isobologram; isopods; joint toxicity; hsp70; stress proteins; toxic unit,"in laboratory toxicity tests, woodlice (oniscus asellus) exposed to a variety of different combinations of the metals cadmium, lead and zinc exhibited a broad range in intensity of the induction of the 70 kda stress protein (hsp70, stress-70). using two-dimensional isobolograms and the 'toxic unit' concept, it could be shown that cadmium and lead as well as cadmium and zinc or lead and zinc act as synergists and cause superadditive effects on the stress response of these animals. using a three-dimensional isobologram based on the stress-70 level in response to numerous combinations of all three tested metals, transfer to the field could be achieved: data obtained from o. asellus populations abundant at field sites, the soils of which are influenced mainly by different concentrations of these heavy metals, were found to fit this laboratory test-based model.",20,1997,6,5,263,274,10.1023/A:1018635012910,1,0,1,2"Knick, ST; Rotenberry, JT",landscape characteristics of disturbed shrubsteppe habitats in southwestern idaho (usa),LANDSCAPE ECOLOGY,Article,agriculture; Artemisia tridentata; Bromus tectorum; disturbance regime; exotic annual grassland; habitat fragmentation; landscape characteristics; military training; shrubsteppe; wildfire,"we compared 5 zones in shrubsteppe habitats of southwestern idaho to determine the effect of differing disturbance combinations on landscapes that once shared historically similar disturbance regimes. the primary consequence of agriculture, wildfires, and extensive fires ignited by the military during training activities was loss of native shrubs from the landscape. agriculture created large square blocks on the landscape, and the landscape contained fewer small patches and more large shrub patches than non-agricultural areas. in contrast, fires left a more fragmented landscape. repeated fires did not change the distribution of patch sizes, but decreased the total area of remaining shrublands and increased the distance between remaining shrub patches that provide seed sources. military training with tracked vehicles was associated with a landscape characterized by small, closely spaced, shrub patches. our results support the general model hypothesized for conversion of shrublands to annual grasslands by disturbance. larger shrub patches in our region, historically resistant to fire spread and large-scale fires because of a perennial bunchgrass understory, were more fragmented than small patches. presence of cheatgrass (bromus tectorum), an exotic annual, was positively related to landscape patchiness and negatively related to number of shrub cells. thus, cheatgrass dominance can contribute to further fragmentation and loss of the shrub patch by facilitating spread of subsequent fires, carried by continuous fuels, through the patch. the synergistic processes of fragmentation of shrub patches by disturbance, invasion and subsequent dominance by exotic annuals, and fire are converting shrubsteppe in southwestern idaho to a new state dominated by exotic annual grasslands and high fire frequencies.",55,1997,12,5,287,297,10.1023/A:1007915408590,1,0,0,1"Lessard, S",fisher's fundamental theorem of natural selection revisited,THEORETICAL POPULATION BIOLOGY,Article,,"w. j. ewens, following g. r. price, has stressed that fisher's fundamental theorem of natural selection about the increase in mean fitness is of general validity without any restrictive assumptions on the mating system, the fitness parameters, or the numbers of loci and alleles involved, but that it concerns only a partial change in mean fitness, this partial change is obtained by replacing the actual genotypic fitnesses by the corresponding additive genetic values and by keeping these values fixed in the change of the mean with respect to changes in genotype frequencies. we propose an alternate interpretation for this partial change which uses partial changes in genotype frequencies directly consequent on changes in gene frequencies, the fitness parameters being kept constant. we argue that this interpretation agrees more closely with fisher's own explanations. moreover, this approach leads to a decomposition for the total change in mean fitness which explains, unifies, and extends previous decompositions, we consider a wide range of models, from discrete-time selection models with nonoverlapping generations to continuous-time models with overlapping generations and age effects on viability and fecundity, which is the original framework for fisher's fundamental theorem. (c) 1997 academic press.",38,1997,52,2,119,136,10.1006/tpbi.1997.1324,0,0,1,1"Tanaka, Y",extinction of populations due to inbreeding depression with demographic disturbances,RESEARCHES ON POPULATION ECOLOGY,Article,extinction; inbreeding depression; deleterious mutation; genetic load; conservation biology,"the process of population extinction due to inbreeding depression with constant demographic disturbances every generation is analysed using a population genetic and demographic model. the demographic disturbances introduced into the model represent loss of population size that is induced by any kind of human activities, e.g. through hunting and destruction of habitats. the genetic heterozygosity among recessive deleterious genes and the population size are assumed to be in equilibrium before the demographic disturbances start. the effects of deleterious mutations are represented by decreases in the growth rate and carrying capacity of a population. numerical simulations indicate rapid extinction due to synergistic interaction between inbreeding depression and declining population size for realistic ranges of per-locus mutation rate, equilibrium population size, intrinsic rate of population growth, and strength of demographic disturbances. large populations at equilibrium are more liable to extinction when disturbed due to inbreeding depression than small populations. this is a consequence of the fact that large populations maintain more recessive deleterious mutations than small populations. the rapid extinction predicted in the present study indicates the importance of the demographic history of a population in relation to extinction due to inbreeding depression.",14,1997,39,1,57,66,10.1007/BF02765250,1,0,0,1"Beach, KS; Smith, CM",ecophysiology of a tropical rhodophyte .3. recovery from emersion stresses in ahnfeltiopsis concinna (j ag) silva et decew,JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,desiccation; intertidal zonation; irradiance; macroalgae; microclimate; photosynthesis; respiration; stress physiology; temperature,"the capacity to recover photosynthetic activity from emersion stresses varied between tissues from microsites separated by < 10 cm in the tropical turf forming alga ahnfeltiopsis concinna (j. ag.) silva et decew. tissues from canopy microsites which are regularly exposed to a greater range of irradiance, temperature and osmotic stresses than tissues from understory microsites had greater capacity to recover from these stresses alone or in combination compared to tissues from understory microsites. this, the first multifactorial analysis of physiological recovery from emersion stresses for any macroalgae, revealed the synergistic effects of high irradiance and temperature stresses while suggesting that enhanced temperature tolerance upon desiccation is not a universal feature of macroalgae at high tidal elevations. net photosynthesis was enhanced by 20% water loss or exposure to 2150 mosm.kg(-1) media compared to values for tissues that were in a fully immersed state. osmolarities in the range 200-3500 mosm.kg(-1) had a minimal negative impact on net photosynthesis. the temperature optimum for net photosynthesis was 33 degrees c while the upper performance threshold was 40 degrees c. highly responsive stress acclimation capacity coupled with microclimate benefits of a turf form may substantially contribute to the ecological success of this species as an ecological dominant at high tidal elevations in the hawaiian archipelago. additionally, this diminutive physiological gradient emphasizes the differences in environmental pressures between high tidal amplitude, low-irradiance temperate regions and low tidal amplitude, high-irradiance tropical regions. in general, these pressures result in similar conspicuous photoacclimative and stress tolerance adaptations but over vastly different spatial scales. (c) 1997 elsevier science b.v.",15,1997,211,2,151,167,10.1016/S0022-0981(96)02721-9,1,0,0,1"Boonstra, R; Hochachka, WM",maternal effects and additive genetic inheritance in the collared lemming dicrostonyx groenlandicus,EVOLUTIONARY ECOLOGY,Article,aggression; behaviour; Canadian Arctic; collared lemming; cycles; Dicrostonyx groenlandicus; dispersal; heritability; maternal effects; size,"we examined patterns of inheritance of size, growth and behavioural traits of collared lemmings (dicrostonyx groenlandicus). work was conducted on field-caught parents from the canadian arctic and their lab-born progeny. we partitioned inherited variance in traits into additive genetic and maternal effects components by using a half-sib breeding experiment in which each sire was mated to two dams. we found no evidence of statistically significant amounts of additive genetic variance in any of the traits measured. however, significant maternal effects were detected for several size- and growth-related traits. three behavioural traits involving aggression, dispersal and activity showed no statistically significant inheritance of any kind. the presence of maternal effects may have consequences for population dynamics by causing 'lags' resulting in inappropriate phenotypes being produced under regimes of fluctuating selection pressure. we recommend that maternal effects should be investigated as a potential general cause of population cycles in small mammals.",46,1997,11,2,169,182,10.1023/A:1018447815825,0,0,1,1"Chaves, N; Escudero, JC; GutierrezMerino, C",role of ecological variables in the seasonal variation of flavonoid content of cistus ladanifer exudate,JOURNAL OF CHEMICAL ECOLOGY,Article,Cistus ladanifer; flavonoids; exudate; seasonal variation; environmental stress; UV irradiation; hydric stress; hot climate,"the leaves and photosynthetic stems of cistus ladanifer, a plant that colonizes arid lands, secrete an exudate that shows a large seasonal variation in its flavonoid content. the maximum secretion of flavonoids in the exudate is produced during summer, increasing approximately three-to fourfold with respect to the secretion measured in spring. summer is the season in which the plant suffers the greatest stress from environmental physical variables such as uv irradiation, high temperatures, and hydric stress. studies were conducted in plants from several locations, which were selected considering daily uv irradiation (open or shaded areas), annual precipitation, and annual average maximum and minimum temperatures. additional studies to control uv irradiation, drought, and temperature separately were performed with c. ladanifer plants growing in a glasshouse and in a culture room. the uv irradiation was found to be the major inducer of the enhanced flavonoid secretion during summer, because no significant increase of flavonoid secretion during summer was observed when the c. ladanifer plants in the field were covered with a plexiglas box (total uv absorption below 380 nm). these results support an ecophysiological role of the flavonoids in the exudate to protect the plant against the damaging effects of uv irradiation. the culture room experiments confirmed this point and also showed that the induction of flavonoid secretion by uv irradiation is synergistically augmented by drought. the glasshouse and culture room experiments showed drought and high temperatures (between 30 degrees and 45 degrees c) to correlate with the summer increase of the more methylated flavonoids (kaempferols and 7-methylated apigenins) in the exudate. because these more methylated flavonoids have higher hydropathy than the less methylated, these results suggest that the secretion of more methylated flavonoids is part of the defense mechanism of the plant against the hydric stress of summer.",42,1997,23,3,579,603,10.1023/B:JOEC.0000006398.79306.09,1,0,0,1"Eeva, T; Lehikoinen, E; Sunell, C",the quality of pied flycatcher (ficedula hypoleuca) and great tit (parus major) females in an air pollution gradient,ANNALES ZOOLOGICI FENNICI,Article,,"we studied whether pied flycatcher (ficedula hypoleuca) and great tit (parus major) females differed in quality between polluted and unpolluted habitats. comparing female condition between incubation and nestling periods, we aimed at testing whether biometric differences in f. hypoleuca females were caused by assortative settlement (i.e. intraspecific competition) or as a consequence of breeding in environments exposed to different levels of pollution stress. body mass, wing length, fat reserves, age distribution, timing of breeding and breeding density of females were measured along an air pollution gradient from a copper smelter in sw finland in 1991-1994. we found few differences in female quality which could be explained by assortative settling. females were of the same size in all areas. at nestling time p. major females were heaviest in a moderately polluted area. however, females in the most polluted area were not lighter than those in background areas. female fat reserves in both species were smaller in the polluted area in one cold breeding season. this suggests that natural (weather) and human induced (pollution) stress factors affected female condition additively. the proportion of young f. hypoleuca females was slightly higher in the polluted area than elsewhere. p. major females started laying earlier near the factory complex than farther away. f. hypoleuca females laid later in the polluted area in early breeding seasons but in late seasons laying started simultaneously everywhere. especially f. hypoleuca bred more sparsely in the polluted area. observed differences in the condition of f. hypoleuca females along the pollution gradient emerged mainly in the course of breeding.",19,1997,34,1,61,71,,0,0,1,1"Hrnciarova, T; Ruzicka, M",classification of the ecological stability of the territory,EKOLOGIA-BRATISLAVA,Article,,"the evaluation of the ecological stability of the territory in slovakia went through a certain development, that led to an obligatory methodology for the evaluation of district in the measures of 1:50 000, that was ratified by the government. the main sources of the methodology of the territorial system of ecological stability (tses), are the maps of contemporary landscape structure, of the spatial synthesis of the positive and negative factors, the classification of ecological stability of the territory the proposed map of tses. part of the tses is a spatial classification of the ecological stability of the territory (est) in which the presence, the present state and influence of the positive and negative factors and characteristics on the landscape are evaluated. the result of this method is the selection of areas with nearly the same degree of ecological stability. based on this classification it is possible to give the hierarchy of needs for protection and for the utilization of the landscape. there are three bases belonging to the classification of est: - ecostabilizing elements of the landscape with complementary function of the est, these are the characteristics of the landscape that support the est, they are the existing elements of the present landscape structure and the biotopes with ecostabilizing characteristics and propositions - elements of nature and natural sources protection with protecting and developing function of the est, these are the factors of the landscape which result from the needs of the present and proposed nature and natural sources protection, they contribute to the preserving of the development of est - stress factors of the landscape with lowering or disturbing function of the est, these are the factors which represent the anthropic load of the environment created by the negative stress factors. the result from the material and non material elements of the present landscape structure and form their synergetic influence. this methodology was verified on the example of the territory of east slovakia (the district of humenne, michalovce, trebisov and vranov nad topl'ou) in the measure of 1.50 000.",2,1997,16,1,81,98,,1,0,0,1"Vitousek, PM; DAntonio, CM; Loope, LL; Rejmanek, M; Westbrooks, R",introduced species: a significant component of human-caused global change,NEW ZEALAND JOURNAL OF ECOLOGY,Review,biological invasion; invasions into parks and preserves; invasion and biological diversity; invasion and ecosystems; land-use change; introduced pests and pathogens,"biological invasions are a widespread and significant component of human-caused global environmental change. the extent of invasions of oceanic islands, and their consequences for native biological diversity, have long been recognized. however, invasions of continental regions also are substantial. for example, more than 2,000 species of alien plants are established in the continental united states. these invasions represent a human-caused breakdown of the regional distinctiveness of earth's flora and fauna - a substantial global change in and of itself. moreover, there are well-documented examples of invading species that degrade human health and wealth, alter the structure and functioning of otherwise undisturbed ecosystems, and/or threaten native biological diversity. invasions also interact synergistically with other components of global change. notably land use change. people and institutions working to understand, prevent, and control invasions are carrying out some of the most important - and potentially most effective - work on global environmental change.",870,1997,21,1,1,16,,1,0,0,1"Wilkinson, CR","global change and coral reefs: impacts on reefs, economies and human cultures",GLOBAL CHANGE BIOLOGY,Article,coral reefs; economies; fisheries; global change; pollution; tourism,"coral reefs have reconstituted themselves after previous large sea-level variations, and climate changes. for the past 6000 years of unusually stable sea-level, reefs have grown without serious interruptions. during recent decades, however, new stresses threaten localized devastation of many reefs. a new period of global climate change is occurring, stimulated by anthropogenic increases in greenhouse gases. coral reefs will cope well with predicted sea-level rises of 4.5 cm per decade, but reef islands will not. higher sea levels will provide corals with greater room for growth across reef flats, but there are no foreseeable mechanisms for reef island growth to keep pace with sea-level rise, therefore many low islands may ultimately become uninhabitable. climate change will introduce localized variations in weather patterns, but changes to individual reefs cannot be predicted. reefs on average should cope well with regional climate change, as they have coped with similar previous fluctuations. air temperature increases of 0.2-0.3 degrees c/decade will induce slower increases in sea-surface temperatures, which may cause localized, or regional increases in coral bleaching. changes in rainfall will impact on reefs near land masses. likewise, increased storms and variations in el nino southern oscillation (enso) may stress some reefs, but not others. the greatest impact of climate change will be a synergistic enhancement of direct anthropogenic stresses (excessive sediment and pollution from the land; over-fishing, especially via destructive methods; mining of coral rock and sand; and engineering modifications), which currently cause most damage to coral reefs. many of the world's reefs have been degraded and more will be damaged as anthropogenic impacts increase under the 'demophoric' increases in population (demos) and economic (phoric) activity. this biotic and habitat loss will result in severe economic and social losses. reefs, however, have considerable recovery powers and losses can be minimized by effective management of direct human impacts and reducing indirect threats of global climate change.",45,1996,2,6,547,558,10.1111/j.1365-2486.1996.tb00066.x,1,0,0,1"Folke, C; Holling, CS; Perrings, C","biological diversity, ecosystems, and the human scale",ECOLOGICAL APPLICATIONS,Article,"biodiversity; biological diversity, conservation of; critical ecosystem processes; disturbance, capacity to buffer; ecological services, maintenance of; ecosystem function and resilience; functional diversity; market externalities; multiple equilibria; nature reserves; transboundary effects","this paper considers the significance of biological diversity in relation to large-scale processes in complex and dynamic ecological-economic systems. it focuses on functional diversity, and its relation to production and maintenance of ecological services that underpin human societies. within functional groups of organisms two important categories of species are identified: keystone process species and those essential for ecosystem resilience. the latter group represents ''natural insurance capital.'' in addition to basic research on the interplay among biological diversity, functional performance, and resilience in complex self-organizing systems, we suggest that a functional approach has two main implications for a strategy for biodiversity conservation: (1) biodiversity conservation to assure the resilience of ecosystems is required for all systems, no matter how heavily impacted they are. it should not be limited to protected areas. (2) the social, cultural, and economic driving forces in society that cause biodiversity loss need to be addressed directly. specifically, (a) differences between the value of biological diversity to the private individual and its fundamental value to society as a whole need to be removed; (b) social and economic policies that encourage biodiversity loss should be reformed, especially where there is a risk of irreversible damage to ecosystems and diversity; and (c) institutions that are adaptive and work in synergy with ecosystem processes and functions are critical and should be created at all levels.",162,1996,6,4,1018,1024,10.2307/2269584,1,0,0,1"Power, M",characterizing cumulative impacts using a brook trout population dynamics model,ECOLOGICAL MODELLING,Article,cumulative impacts; population dynamics; risk assessment,"an individuals-based modelling framework is used to characterize the nature of exploitation and toxaphene stressors acting simultaneously on a population of brook trout (salvelinus fontinalis) in terms of age 0+ and adult abundance, survivorship and population size-structure. a no-stressor control case was estimated against which exploitation-only, toxaphene-only and cumulative exploitation and toxaphene stressor cases were compared to determine the extent and significance of impacts. single stressor case results were used to predict cumulative impacts by assuming additivity and predictions compared to modelled cumulative stressor results. comparisons indicated the inadequacy of assuming additivity in predicting cumulative impacts. a factorial experimental design was used to estimate the size and significance of interactive effects. effects are substantial and underscore the necessity of interpreting probable impacts of increases in a single stressor in conjunction with knowledge of other stressors acting on a population. a positive functional relationship between variability in population abundance and stress was estimated and is suggested as a potentially useful means of characterizing risks posed to populations by increases in, or additions to, population stressors. multiple stressors were also demonstrated to effectively eliminate the significance of density-dependent mortality processes in determining age 0+ and adult abundance. taken together, results indicate the inappropriateness of attempting to predict additional perturbation impacts without considering the sum of population stressors and their associated interactions.",5,1996,90,3,257,270,10.1016/0304-3800(95)00153-0,0,0,1,1"Tanaka, Y",density-dependent selection on continuous characters: a quantitative genetic model,EVOLUTION,Article,density-dependent selection; life history; quantitative genetics; reaction norm; selection gradient,"a quantitative genetic model of density-dependent selection is presented and analysed with parameter values obtained from laboratory selection experiments conducted by mueller and his coworkers. the ecological concept of r- and k-selection is formulated in terms of selection gradients on underlying phenotypic characters that influence the density-dependent measure of fitness. hence the selection gradients on traits are decomposed into two components, one that changes in the direction to increase r, and one that changes in the direction to increase k. the relative importance of the two components is determined by temporal fluctuations in population density. the evolutionary rate of r and k (per-generation changes in r and k due to the genetic responses of the underlying traits) is also formulated. numerical simulation has shown that with moderate genetic variances of the underlying characters, r and k can evolve rapidly and the evolutionary rate is influenced by synergistic interaction between characters that contribute to r and k. but strong r-selection can occur only with severe and continuous disturbances of populations so that the population density is kept low enough to prevent k-selection.",6,1996,50,5,1775,1785,10.2307/2410735,1,0,0,1"Slovik, S",early needle senescence and thinning of the crown structure of picea abies as induced by chronic so2 pollution .1. model deduction and analysis,GLOBAL CHANGE BIOLOGY,Article,"air pollution; canopy thinning; damage symptoms; forest decline; modelling; Norway spruce (Picea abies, Pinaceae); resistance (tolerance); sulphur dioxide (SO2); tree nutrition (nutrient cycling)","regarding time ranges of years, a rationale has been developed which is capable of explaining observed 'spruce decline' symptoms observed when spruce is exposed to air containing ambient levels of so2. it integrates and interrelates (i) ecophysiological data (tree morphology, assimilate partitioning, canopy turnover, senescence physiology, stomatal conductance, canopy throughfall, sulphur metabolism, tonoplast symport), (ii) pedological data (soil leaching, cation recycling, litter decomposition, forest nutrition), and (iii) meteorological data (site elevation, length of the annual trunk growth period, so2-pollution). furthermore, it can explain field observations at numerous sites of spruce decline in central europe where so2 is implicated as a factor of forest decline: (i) thinning of the canopy structure; (ii) early needle senescence; (iii) cation deficiency; (iv) low so2 tolerance at sites with depleted soils in the mountains; (v) synergism of so2 pollution and acidic precipitation; (vi) recovery after liming, fertilization and after decreasing so2 pollution; and (vii) higher so2 tolerances of deciduous angiosperms. different so2 tolerance strategies are identified that are employed by more so2-tolerant tree species. ecophysiological so2 tolerance factors interact in a complex synergistic or antagonistic manner. it is concluded that chronic so2 pollution at ambient concentrations predisposes mainly evergreen gymnosperms to suffer under synergistic environmental stresses (frost, drought, pathogens, etc.). thinning of the crown structure is massive at extreme sites, where several stresses act simultaneously on the trees (depleted soils, high so2 pollution, acidic rain, etc.). mathematical formulations allow precise definitions of terms such as cooperativity, synergism, antagonism, vitality, predisposition, latency, etc. this universal rationale, which is applicable to all tree species, is exemplified here for norway spruce (picea abies [l.] karst.). integration of parameters yields an ordinary differential equation, which can be solved analytically. it predicts reversible dynamics of crown structures and gives an ecophysiological background to 'damage'.",5,1996,2,5,443,458,10.1111/j.1365-2486.1996.tb00094.x,1,1,0,2"Samways, MJ",insects on the brink of a major discontinuity,BIODIVERSITY AND CONSERVATION,Article,insects; populations; landscapes; conservation; discontinuity,"population surges and local extinctions are not uncommon among insects. in response to climatic changes in the past, insects have often shifted their ranges. this long-term range shifting and the vagaries of short-term weather makes reserve selection unrealistically rigid for many species. although some insect species are surviving in reserves, others have disappeared from such small areas because of adverse weather. in contrast, many other insects depend on localized disturbance for survival. in response to anthropogenic disturbance, some native insects have become more abundant and widespread, such as orthoptera in response to grazing and burning, and some odonata in response to aquatic weeds and water impoundment. the effect of some exotic invasive insects on some native ecosystems is of major concern. human-induced insect population crashes and species extinctions are becoming more common and widespread, and exacerbated by the synergistic effect of the various local impacts with global changes. a major insect population and species extinction discontinuity is beginning to take place. yet, there is also an increase in range and abundance of some other insects. the world is becoming increasingly species-poorer and more homogenous in its insect fauna.",15,1996,5,9,1047,1058,10.1007/BF00052715,1,0,0,1"Pimm, SL",lessons from a kill,BIODIVERSITY AND CONSERVATION,Article,extinction; Hawaii; synergisms,"during their colonization by polynesians and later by europeans, the hawaiian islands suffered a massive loss of species. all the extinctions are indirectly attributable to human impact. nonetheless, it has proved extremely difficult to specify which of several possible mechanisms caused each particular extinction. this seems to admit defeat in the battle to understand past extinctions. such understanding could guide our efforts to protect species that are now threatened with extinction. will it be easier to understand the causes of future extinctions? surveys of future extinctions stress habitat destruction as the simple and dominant mechanism. this contrasts to its secondary (and generally confused) role in past extinctions. i argue that this contrast between the complexity of the past and the apparent simplicity of the future arises because extinction mechanisms are inherently synergistic. once extensive species losses begin, it may be impossible to separate the mechanisms and thus manage an individual species as if its decline had a single cause.",26,1996,5,9,1059,1067,10.1007/BF00052716,1,0,0,1"Ray, GC",coastal-marine discontinuities and synergisms: implications for biodiversity conservation,BIODIVERSITY AND CONSERVATION,Article,biodiversity; discontinuity; coastal-marine ecology; marine conservation,"coastal-marine biodiversity conservation must focus increasingly at the level of the land- and seascape. five cases illustrate discontinuities and synergisms and how system changes may take place. for caribbean coral reefs, the result of overfishing and disease has been a 'shrinkage' in the entire system, the effects of which may cascade through the coastal seascape. for beringia, patterns of benthic diversity are best understood in a manner that matches the multiscale, integrated dynamics of weather, ice, marine mammal feeding, and community structure. in the case of us east coast estuaries, oyster reefs may be keystone elements, with important effects on functional diversity. large-scale coastal systems depend upon the connectivity of fresh and marine waters in the coastal zone, having implications for the apparent stochasticity of coastal fisheries. and, for a coastal barrier-lagoon site, a state change may be described in terms of a combination of succession, the attainment of a quasi-equilibrium state, and disturbance. a profound problem for conservation is that there is very little information about the relationship between species diversity and ecological function. coastal-marine biodiversity conservation is best addressed at the level of the land- and seascape.",18,1996,5,9,1095,1108,,1,0,0,1"Messina, FJ; Richards, JH; McArthur, ED",variable responses of insects to hybrid versus parental sagebrush in common gardens,OECOLOGIA,Article,Artemisia tridentata; hybrid susceptibility; common garden; herbivory; population crosses,"both ecological and genetic mechanisms have been proposed to explain patterns of herbivore attack on interspecific plant hybrids, but distinguishing among them can be difficult in natural hybrid zones. we per formed a common-garden experiment to evaluate four genetic hypotheses: dominance, additivity, elevated hybrid susceptibility, and elevated hybrid resistance. censuses and cage experiments were used to compare insect responses to basin big sagebrush (artemisia tridentata spp. tridentata), mountain big sagebrush (a. t. vaseyana), and their f-2 progeny. after two growing seasons, hybrid shrubs resembled mountain big sagenbrush in size, but were more similar to basin big sagebrush in flower production. censuses of naturally colonizing insects (the gall midge rhopalomyia obovata, the bagworm moth apterona helix, and the aphid obtusciauda coweni) tended to support the dominance hypothesis: if the insect clearly discriminated between the two parents, its frequency on hybrids closely resembled that on one of the parents. moreover, colonization of hybrids in all three cases suggested a dominance deviation toward the susceptible parent rather than toward the resistant parent. in contrast to the censuses, cage experiments involving two insects supported the hybrid-susceptibility hypothesis; both survival and growth of the grasshopper melanoplus sanguinipes and growth of the leaf beetle trirhabda pilosa were higher on hybrid shrubs than on either parent. because many secondary compounds have been determined to occur at intermediate concentrations in f-2 shrubs, dominance for susceptibility may indicate that insects respond to plant traits (e.g., oviposition stimulants and deterrents) in a threshold manner. mechanisms underlying increased hybrid susceptibility are less clear, but our experimental design makes environmental explanations (e.g., the plant-stress hypothesis) unlikely. although we eliminated several confounding factors, our results agree with the conclusion from natural hybrid zones that insect responses to hybrid plants are likely to be idiosyncratic; even congeneric species did not respond similarly to hybrid and parental plants.",37,1996,107,4,513,521,10.1007/BF00333943,0,0,1,1"Lancaster, J",scaling the effects of predation and disturbance in a patchy environment,OECOLOGIA,Article,disturbance; flow refugia; harsh-benign hypothesis; heterogeneity; predation,"the effects of hydraulic disturbances on the impact of two predatory benthic invertebrates on their prey were examined in a stream at two distinct spatial scales. at the scale of small habitat patches (0.0625 m(2)), hydraulic patch type was an important determinant of the microdistribution of prey and predators. prey abundances were similar across all patch types at baseflow, but local densities were higher in patches identified as low-flow refugia after periods of high and fluctuating flow. the microdistribution pattern of predatory larvae of a caddisfly, plectrocnemia conspersa, was similar to that of its prey, whereas predatory larvae of an alderfly, sialis fuliginosa, did not shift their microdistribution significantly with discharge and were always most abundant in low-flow refugia. there was little evidence of an aggregative response of predators with prey, even though both predators and prey are mobile. both predator species showed similar patch-specific patterns of per capita consumption rates: uniform consumption-rates across hydraulic patch types at low and moderate flows, but highest in flow refugia during high flows. species-specific patterns, however, were apparent in the magnitude and direction of differences between consumption rates during disturbance events, and in comparable patches at base flow: at high flow, consumption rates for p. conspersa were exaggerated (3.9 times higher) in flow refugia but ''at par'' in other patches; for s. fuliginosa they were ''at par'' in flow refugia but reduced in other patches (up to 3.3. times lower). these differences may be related to species-specific foraging behaviours (search vs ambush predators) and the influence of prey movements on feeding success. using the patch-scale results only, it is difficult to predict the effects of physical disturbance on predation intensity at the larger scales of whole habitats, populations or communities. at the large scale (>200 m(2)), net predator impacts were estimated over the stream reach, using a spatially explicit model that accounts, in an additive way, for habitat heterogeneity and patch-specific responses of predators and prey. the relationship between predator impact over the whole reach and hydraulic disturbance differed for the two predators. the predator impact of s. fuliginosa decreased with increasing hydraulic disturbance, as predicted by the harsh-benign hypothesis. there was no directional trend for p. conspersa, however, and maximum predator impact may occur at intermediate disturbance levels. for the prey community in this stream, predation pressure from s. fuliginosa appears to fluctuate directly with the discharge hydrograph, whereas predation from p. conspersa may be more persistent. flow refugia may play a dual role in the sructure of stream communities by preventing catastrophic mortality of animals (predators and prey) from physical forces during disturbances, and by maintaining (or perhaps increasing) predation pressure. summing the effects of species interactions in small habitat patches to the larger scale of a whole stream reach indicates that the scale of approach influences the observed patterns and their implied underlying process.",55,1996,107,3,321,331,10.1007/BF00328448,0,0,1,1"Hoft, M; Verpoorte, R; Beck, E","growth and alkaloid contents in leaves of tabernaemontana pachysiphon stapf (apocynaceae) as influenced by light intensity, water and nutrient supply",OECOLOGIA,Article,monoterpene indole alkaloids; tropical trees; abiotic factors; growth; C/N balance,"the growth of tabernaemontana pachysiphon (apocynaceae) plants and the alkaloid content of leaves were investigated in the greenhouse at three levels of nutrient supply under two contrasting water and light regimes. we determined height increment, above-ground biomass production, leaf size, specific leaf weight and the content of the alkaloids apparicine, a2, isovoacangine, tubotaiwine and tubotaiwine-n-oxide. the effects of major controlling factors such as light, water and nutrient supply could be directly correlated with growth and were largely independent of each other. in contrast, leaf-alkaloid contents were influenced by interdependencies among the main factors and individually affected in a synergistic or antagonistic manner which deviated from the effects on growth. the following general trends could be identified with respect to the quantitatively predominant alkaloids apparicine, tubotaiwine and isovoacangine. increasing nutrient supply had a positive effect on both growth and alkaloid content. drought increased alkaloid content, but retarded growth. high light intensity lowered alkaloid content but promoted growth. we investigated the relationship between primary production and the production of secondary metabolites with respect to relative and total alkaloid content as well as in relation to the leaves' nitrogen status. our results showed that under conditions of low nutrient supply, higher proportions of leaf nitrogen were allocated to alkaloids than at moderate or high nutrient supply. under conditions of drought and low light, all plants allocated almost equal proportions of leaf nitrogen to alkaloids, regardless of fertiliser. total alkaloid content per plant, however, increased with fertilisation. with respect to the n-allocation strategy, we found no indication of a trade-off between primary production and the production of secondary metabolites in this species. rather, our results are in accordance with the carbon nutrient balance hypothesis.",35,1996,107,2,160,169,10.1007/BF00327899,1,1,0,2"Fox, BJ; Fox, MD; Taylor, JE; Jackson, GP; Simpson, J; Higgs, P; Rebec, L; Avery, R","comparison of regeneration following burning, clearing or mineral sand mining at tomago, nsw .1. structure and growth of the vegetation",AUSTRALIAN JOURNAL OF ECOLOGY,Article,Australia; burning; clearing; mining; forest; succession; vegetation structure,"we have begun a long-term ecological research project to address questions about the impact of multiple disturbances on the species richness of communities and whether multiple disturbances are additive or interactive. a protected water catchment area was chosen, which is subjected to fires, sand mining and clearing, and for which detailed records are available. the study area, at tomago (32 degrees 52's, 151 degrees 45'e), has forest, woodland, shrubland and swamp on a sand substrate, with the vegetated dunes forming part of a coastal embayment. forty-four sites were located in forested areas that had undergone disturbance by either fire, sand mining or clearing. sites of each disturbance type were grouped into four age classes: less than 1 year since disturbance, nominally 1991; 5 years, nominally 1986; 11 years, nominally 1980; and 17 years, nominally 1974. a set of burned sites, with the time of the last fire matched to the times of the other disturbances, was used as the control response. in this paper we describe the study area and sites, then examine the effects of each single disturbance on vegetation structure. canopy cover increased with time and type of disturbance, with 17 year old cleared or mined sites similar to the cover of 11 year old burned sites. in the first two years after disturbance, burned sites had significantly more understorey vegetation than cleared or mined sites, but by 5 years all three were similar. the data presented here show that regeneration of mined sites at tomago is substantially slower than regeneration following disturbance by fire, with the regeneration of cleared sites intermediate but, closer to mining than fire. after 17 years regeneration, cleared and sand mined sites had not returned to the vegetation structure of the pre-disturbance state. understorey height and the amount of vegetation on cleared or mined sites have not achieved the levels in the original forest, although canopy cover did seem to have reached pre-disturbance levels. current rehabilitation techniques are more sophisticated than those used 17 years ago and continued monitoring of sites currently being rehabilitated may show a faster return to pre-disturbance states. having established the hierarchy and nature of the response to each single disturbance here, we are now in a position to investigate the impact of multiple disturbances.",31,1996,21,2,184,199,10.1111/j.1442-9993.1996.tb00599.x,0,0,1,1"Bennington, CC; McGraw, JB",environment-dependence of quantitative genetic parameters in impatiens pallida,EVOLUTION,Article,environmental stress; genotype-by-environment interaction; heritability; Impatiens pallida; life-history characters,"population response to selection depends on the presence of additive genetic variance for traits under selection. when a population enters an alien environment, environment-induced changes in the expression of genetic variance may occur. these could have large effects on the response to selection. to investigate the environment-dependence of genetic variance, we conducted a reciprocal transplant experiment between two ecotypically differentiated populations of impatiens pallida using the progeny of a standard mating design. the floodplain site was characterized by high water availability, moderate temperatures, and continuous dense stands of impatiens. the hillside site was drier, with larger temperature extremes and supported only scattered patches of impatiens with significantly lower seed production and earlier mortality. estimates of heritability were low for each of the 13 trails measured in each population and site (range from 0-28%). additive genetic variance for life-history traits tended to be larger than for morphological traits, but genetic variance in fitness was estimated to be not significantly different from zero in all cases. significant heritability was detected in both populations for one trait (date of first cleistogamous flower) known to be closely related to fitness on the hillside. in general, heritability was reduced for populations when grown in the hillside site relative to the floodplain site, suggesting that stress acts to reduce the expression of genetic variance and the potential to respond to selection there. consistent reductions in heritability associated with more stressful environments suggest that populations invading such sites may undergo little adaptive differentiation and be more prone to local extinction.",43,1996,50,3,1083,1097,10.2307/2410649,0,0,1,1"Leathwick, JR; Rogers, GM","modelling relationships between environment and canopy composition in secondary vegetation in central north island, new zealand",NEW ZEALAND JOURNAL OF ECOLOGY,Article,secondary succession; disturbance; environmental factors; classification; plant community analysis; Generalised Additive Models,"relationships between composition of secondary vegetation and environment were studied in central north island, new zealand. a classification procedure was used to identify broad compositional groups which included forest, broadleaved scrub, shrub-fernland, sclerophyllous scrub and shrubland, and tussock-shrubland. generalised additive models (gams) were used to examine relationships between species' distributions and mean annual temperature and rainfall, stand age, distance from intact forest, slope, topography, and drainage. there were marked differences in the environmental relationships of individual species. we conclude that temperature and rainfall have a dominant role in determining succession after disturbance at a regional scale, but distance from intact forest, topography, slope and solar radiation, become important at local scales. variation unaccounted for by these environmental factors is most likely linked to historical factors such as variation in disturbance and/or grazing and browsing regimes. intervention by managers will probably be required in the future if the current diversity of secondary vegetation in central north island is to be maintained.",13,1996,20,2,147,161,,0,0,1,1"Barker, JSF; Krebs, RA",genetic variation and plasticity of thorax length and wing length in drosophila aldrichi and d-buzzatii,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,body size; developmental temperature; phenotypic plasticity; reaction norm,"reaction norms across three temperatures of development were measured for thorax length, wing length and wing length/thorax length ratio for ten isofemale lines from each of two populations of drosophila aldrichi and d. buzzatii. means for thorax and wing length in both species were larger at 24 degrees c than at either 18 degrees c or 31 degrees c, with the reduction in size at 18 degrees c most likely due to a nutritional constraint. although females were larger than males, the sexes were not different for wing length/thorax length ratio. the plasticity of the traits differed between species and between populations of each species, with genetic variation in plasticity similar for the two species from one locality, but much higher for d. aldrichi from the other. estimates of heritabilities for d. aldrichi generally were higher at 18 degrees c and 24 degrees c than at 31 degrees c, but for d. buzzatii they were highest at 31 degrees c, although heritabilities were not significantly different between species at any temperature. additive genetic variances for d. aldrichi showed trends similar to that for heritability, being highest at 18 degrees c and decreasing as temperature increased. for d. buzzatii, however, additive genetic variances were lowest at 24 degrees c. these results are suggestive that genetic variation for body size characters is increased in more stressful environments. thorax and wing lengths showed significant genetic correlations that were not different between the species, but the genetic correlations between each of these traits and their ratio were significantly different. for d. aldrichi, genetic variation in the wing length/thorax length ratio was due primarily to variation in thorax length, while for d. buzzatii, it was due primarily to variation in wing length. the wing length/thorax length ratio, which is the inverse of wing loading, decreased linearly as temperature increased, and it is suggested that this ratio may be of greater adaptive significance than either of its components.",57,1995,8,6,689,709,10.1046/j.1420-9101.1995.8060689.x,0,0,1,1"BONSDORFF, E; NORKKO, A; SANDBERG, E","structuring zoobenthos - the importance of predation, siphon cropping and physical disturbance",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,CRANGON CRANGON; DISTURBANCE; MACOMA; PREDATION; SADURIA; SIPHON CROPPING; ZOOBENTHOS,"in a set of field and laboratory experiments, the relative importance of (1) direct predation (measured as mortality in the prey populations), (2) physical disturbance of the sediment (sand and mud), and the combined effects of disturbance and predation, and (3) sublethal siphon cropping, were tested on an infaunal food web in the low-saline northern baltic sea. the predators used (saduria entomon and crangon crangon) are the major epibenthic crustacean predators of the northern baltic coastal waters. and the prey organism in the experiments (the bivalve macoma balthica) is, by frequency of occurrence and by biomass, the dominant infaunal organism among the zoobenthos. in the field the predatory effect of saduria was tested on the entire infaunal community. the field experiment on direct predation by saduria on the entire infaunal assemblage significantly reduced the density of the polychaete manayunkia aestuarina. aquarium experiments show that although direct predation by saduria or physical sediment disturbance alone had little effects on juvenile (< 3 mm) macoma, the combined effects of these factors were significant, and more important than the sum of the two single factors, demonstrating synergistic negative effects. experiments with saduria and crangon in relation to adult (7-17 mm) macoma showed sublethal effects on length-weight relationships and on a general index of condition in the mussels. the experiments illustrate that intricate combinations of biotic and physical (environmental) mechanisms may play important roles in the organization of zoobenthic communities.",54,1995,192,1,125,144,10.1016/0022-0981(95)00067-2,1,0,0,1"LEATHWICK, JR",climatic relationships of some new-zealand forest tree species,JOURNAL OF VEGETATION SCIENCE,Article,CONIFER; GENERAL ADDITIVE MODEL; MOISTURE AVAILABILITY; NOTHOFAGUS; SOLAR RADIATIONS; SPECIES DISTRIBUTION,"a dataset of some 10 000 plots was used to describe the climatic relationships of 33 widespread new zealand tree species. estimates of mean annual temperature, temperature seasonality, mean annual solar radiation, and moisture balance were derived from mathematical surfaces fitted to climate station data. plots were also categorized into five lithological classes and three drainage classes. generalized additive models were used to examine species/environment relationships. mean annual temperature and mean annual solar radiation are most strongly correlated with current tree distributions, followed by moisture balance, temperature seasonality, lithology, and drainage. most broad-leaved tree species other than nothofagus spp. reach their greatest levels of occurrence in warm, moist environments with high solar radiation. in contrast, nothofagus spp. generally reach their greatest levels of occurrence in cooler and/or lower insolation environments, and all have lower levels of occurrence on rhyolitic substrates which have resulted from large-scale geomorphic disturbance, mostly over the past few thousand years. although coniferous species have widely differing climatic optima, many are biased towards lithological classes characterized either by large-scale geomorphic disturbance or harsh edaphic conditions. the relevance of these results to particular synecological questions is briefly discussed. continuing adjustments in the range of slow-dispersing nothofagus spp. are strongly suggested, and the climatic suitability of extensive rhyolitic basins in the central north island, from which these species are largely absent, is confirmed.",80,1995,6,2,237,248,10.2307/3236219,0,0,1,1"KIRZHNER, VM; KOROL, AB; RONIN, YI",cyclical environmental-changes as a factor maintaining genetic-polymorphism .1. 2-locus haploid selection,JOURNAL OF EVOLUTIONARY BIOLOGY,Article,POLYMORPHISM; CYCLICAL SELECTION; HAPLOID; RECOMBINATION,"to classify different types of cyclic selection, a measure of fitness disequilibrium was used, and a class of systems were considered where this measure has the same sign in all states (sign-concordant environments). the necessary conditions for existence of a fixed point (considering any moment within the period as a referring one) are obtained for sign-concordant systems. however, analytical study of such systems, in the case of selection for equal additive genes, and numerical testing of more general situations, allowed us to conclude that no polymorphism is possible. in the alternative class of sign-nonconcordant systems, polymorphism is possible. however, we found that global stability is an exception rather than a rule for sign-nonconcordant systems. massive numerical simulations of selection in a four-state environment were made for cycle lengths in the range 8-28 and with evenly distributed selection coefficients. the proportion of polymorphic regimes ranged up to about 1.5%, and was dependent on the recombination rate between the loci. it should be stressed, that polymorphism maintenance in the haploid systems, when it is possible, can not be considered as an effect derived from constant selection, or be a result of any hidden form of heterozygous advantage. in other words, polymorphism stability is causally connected with environmental fluctuations. equally important is that this effect of fluctuations is only possible because of recombination: in single locus systems haploid cyclical selection is unable to produce protected polymorphism.",11,1995,8,1,93,120,10.1046/j.1420-9101.1995.8010093.x,0,0,1,1"BROWN, DG",predicting vegetation at treeline using topography and biophysical disturbance variables,JOURNAL OF VEGETATION SCIENCE,Article,GEOGRAPHIC INFORMATION SYSTEMS; REMOTE SENSING; GLACIER-NATIONAL-PARK; GRADIENT MODELING; LOGISTIC REGRESSION; TOPOGRAPHIC INFLUENCE,"the relationships between four vegetation types and variables representing topography and biophysical disturbance gradients were modeled for a study area in east-central glacier national park, montana. four treeline transition vegetation types including closed-canopy forest, open-canopy forest, meadow, and unvegetated surfaces (e.g. rock, snow, and ice) were identified and mapped through classification of satellite data and subsequent field verification. topographic characteristics were represented using a digital elevation model and three variables derived from topoclimatic potential models (solar radiation potential, snow accumulation potential, and soil saturation potential). a combination of generalized additive and generalized linear modeling (gam and glm, respectively) techniques was used to construct logistic regression models representing the distributions of the four vegetation types. the variables explained significant amounts of variation in the vegetation types, but high levels of variation remained unexplained. a comparison of 'expected' and 'observed' vegetation patterns suggested that some unexplained variation may have occurred at the basin scale. a suite of tools and techniques is presented that facilitates predicting land-scape-scale vegetation patterns and testing hypotheses about the spatial controls on those patterns.",112,1994,5,5,641,656,10.2307/3235880,0,0,1,1"TEJEDO, M; REQUES, R",plasticity in metamorphic traits of natterjack tadpoles - the interactive effects of density and pond duration,OIKOS,Article,,"plasticity in developmental time and size at metamorphosis were studied in natural and experimental populations of natterjack toad tadpoles (bufo calamita), a species which breeds in temporary ponds of variable duration. amount of rainfall directly affected pond hydroperiod and larval density through an increase in the number of spawning females. as both factors directly affected larval period and thus metamorphic success, we performed a factorial field experiment to examine the response of developmental rates to drought regime and its interaction with population density, by controlling pond duration, larval density and food level. timing of metamorphosis was affected by larval density and food level. however, the response among larvae due to pond duration was not additive. at low larval density, tadpoles raised in short duration ponds exhibited shorter larval periods than in long duration ponds. in constrast, plasticity in developmental rates due to pond duration was less marked at high larval densities and no difference in length of larval period was found. this may be the result of higher competition levels in short duration ponds through an increase in actual larval density because of decreasing water level and lower metamorphic rates. this higher competitive stress was also evident by smaller metamorphic size in short ponds. at low densities tadpoles in longer duration ponds exhibited no additional growth, indicating that tadpoles that remained for a longer period did not achieve larger metamorphic size. this outcome does not support an adaptive explanation of developmental plasticity that merely may be the consequence of expressing a single program of development in different habitats.",62,1994,71,2,295,304,10.2307/3546278,0,0,1,1"TREPL, L",competition and coexistence - on the historical background in ecology and the influence of economy and social-sciences,ECOLOGICAL MODELLING,Article; Proceedings Paper,COEXISTENCE; COMPETITION; HISTORICAL BACKGROUND,"competition plays an important role in a large number of ecological models. the paper discusses historial aspects of this concept in ecology with respect to the influence of the social background. competition became a concept of a priori necessity in modern thinking, when life was not longer conceived teleologically. the biological sciences therefore are unthinkable without the idea of competition - but not for empirical reasons. competition became the basic principle of social life for liberal and democratic, progressive social theories and ideologies. for conservative theories it is the cooperative coexistence, respectively the adaptation within the framework of a social whole, which is thought to be in accordance with the model of the living organism. theory dynamics in biology can be understood to be parallel to this pattern: on the one hand, the idea of the biological community as an accumulation of individuals emerges with the darwinian theory of evolution. here individuals primarily have an antagonistic, competitive relationship with each other. but in early ecology (different from evolutionary biology) the community was not conceived primarily in terms of competition, but in terms of adaptation and interrelated mutual dependence. thus, ''progressive'' evolutionary theory is opposed to ''conservative'' ecology. in ecology, this inner splitting. appears again: the organismic, holistic, ecosystem-oriented concepts are opposed by individualistic, population-oriented ones. however, usually approaches based on the integration level of populations start out stressing the role of competition and lead to theories of deterministic successions ending in a state of equilibrium and complete mutual adaptation of the components, just like the early organismic theories (''monoclimax''). the recent criticism of the competition concept in ecology may be understood as a part of the general tendency against teleology. the discussion about competition and coexistence provides an example how the social background and ecological theory dynamics relate.",6,1994,75,,99,110,10.1016/0304-3800(94)90010-8,0,1,0,1"GIGNAC, LD",peatland species preferences - an overview of our current knowledge-base,WETLANDS,Article,PEATLANDS; SPECIES PREFERENCE; CLIMATE CHANGE; GRADIENTS,"the autecology of several peatland plant species has been studied on a wide variety of gradients that include elevation relative to the water table, surface water chemistry, mire margin to mire expanse, shade, and climate. the accuracy with which species' realized niches are defined and the ability to predict community structure as conditions change along gradients vary considerably between studies. many studies have quantified species niche dimensions along individual gradients, and although they have the ability to predict species abundance and distribution, they do not account for synergistic effects between gradients. other methods analyze two gradients simultaneously producing rectangles and ellipsoids, but these methods have limited predictive ability. a variety of ordination techniques are often used to analyze species preferences along several gradients simultaneously. however, with the exception of detrended canonical correspondence analysis, these methods have limited predictive ability because gradients are defined as ordination axes and it is difficult to analyze each gradient individually. species response surfaces calculated along several gradients simultaneously offer a more accurate definition of species' realized niche dimensions. response surfaces can be used to predict baseline community structure along several gradients, but they do not integrate such biotic factors as competition and succession, as well as such disturbances as fire, pollution, and peat harvesting.",11,1994,14,3,216,222,,1,0,0,1"LEHMAN, ME; BLUM, U; GERIG, TM",simultaneous effects of ferulic and p-coumaric acids on cucumber leaf expansion in split-root experiments,JOURNAL OF CHEMICAL ECOLOGY,Article,ALLELOPATHY; FERULIC ACID; P-COUMARIC ACID; PHENOLIC ACID MIXTURES; CUCUMIS-SATIVUS; SPLIT-ROOT TREATMENTS; LEAF EXPANSION,"experiments were conducted to determine how plant responses to mixtures of allelochemicals may change as the proportion of roots in contact with allelochemicals is modified. thirteen-day-old cucumber seedlings were treated with ferulic and/or p-coumaric acid in a split-root nutrient culture system. leaf areas were determined just prior to treatment and at harvest, 24 hr after treatment. ferulic acid was more inhibitory to cucumber leaf expansion than p-coumaric acid. the effects of ferulic and p-coumaric acids on leaf expansion were additive. for individual acids, mixtures of ferulic and p-coumaric acids in the same container and combinations of ferulic and p-coumaric acids in separate containers, the inhibition of leaf expansion was directly related to the product of the concentration of the acid(s) and the proportion of roots treated with the acid(s). pretreatment with 0.2 or 0.4 mm ferulic acid and subsequent treatment with 0.5 mm ferulic acid failed to show evidence of acclimation by cucumber seedlings.",20,1994,20,7,1773,1782,10.1007/BF02059898,0,0,1,1"GALLET, C",allelopathic potential in bilberry-spruce forests - influence of phenolic-compounds on spruce seedlings,JOURNAL OF CHEMICAL ECOLOGY,Article,ALLELOPATHY; P-HYDROXYACETOPHENONE; PHENOLIC PATTERNS; PICEA-ABIES; REGENERATION FAILURE; TANNINS; VACCINIUM-MYRTILLUS,"regeneration failure of picea abies in a subalpine bilberry-spruce forest was studied in relation to phenolic compounds, their occurrence and toxicity. germination bioassays with natural leachates of bilberry (vaccinium myrtillus) and spruce showed negative effects on root elongation of spruce seedlings. growth bioassays on litter and humus demonstrated inhibitory effects of these organic layers. p-hydroxyacetophenone, a spruce-specific metabolite, was isolated in spruce throughfall (10(-6) m), in water extracts of litter (between 1 and 8 mug/g dry wt) and organic layer (less than 1 mug/g dry wt) in addition to tannins and several common phenolic acids. potential relationships between vegetation cover and phenolic pattern of the soil are discussed, since organic layers under bilberry heath exhibited higher amounts of phenolic acids and tannins than those under spruce. p-hydroxyacetophenone and caffeic acid reduced, even at 5 x 10(-5) m, spruce seedling growth, especially root development, with additive effects for these two monomers. autotoxicity involving spruce trees and allelopathy of understory species, mediated by p-hydroxyacetophenone and other phenolic compounds, including tannins, deserves further attention in regeneration studies.",59,1994,20,5,1009,1024,10.1007/BF02059738,0,0,1,1"HUANG, LB; MURRAY, F; YANG, XH","interaction between mild nacl salinity and sublethal so2 pollution on wheat triticum-aestivum cultivar wilgoyne (ciano-gallo) .1. responses of stomatal conductance, photosynthesis, growth and assimilate partitioning",AGRICULTURE ECOSYSTEMS & ENVIRONMENT,Article,,"wheat (triticum aestivum cultivar 'wilgoyne' (ciano/gallo)) plants were exposed to a factorial combination of two levels of salinity (control and 50 mm nacl), and three levels of so2 (< 10 (ambient), 231, and 441 nl l-1) in fumigation chambers with rain-exclusion tops for 4 h per day for up to 51 days. the objective was to investigate whether mild salinity stress could decrease the sensitivity of plant growth to sublethal so2 stress. exposure to 441 nl l-1 so2 significantly decreased co2 stomatal conductance, net photosynthesis rate, and at the end of experiment, chlorophyll concentrations in the youngest fully expanded (yfe) leaves. inhibition of photosynthesis by 441 nl l-1 so2 fumigation resulted in a change in assimilate allocation in favour of shoot growth, leading to an increase in shoot to root ratio. exposure to 441, but not 231 nl l-1 so2 significantly decreased plant dry weight and relative growth rate (rgr) of both root and shoot. 50 mm nacl treatment first decreased shoot growth, resulting in a decrease in shoot to root ratio, but later a significant decrease in root growth developed, probably owing to limited assimilate supply from the shoot, and resulted in an increase in shoot to root ratio. there was generally no significant interaction between so2 fumigation and nacl salinity on net photosynthesis rate and leaf chlorophyll concentration. however, co2 stomatal conductance in the yfe leaves of 50 mm nacl-treated and so2-fumigated plants recovered more quickly after the completion of fumigation than the non-saline and so2-fumigated plants. 50 mm nacl salinity and 441 nl l-1 so2 fumigation had an antagonistic interaction on both shoot and root dry weight. exposure to 231 nl l-1 so2 increased the shoot to root ratio in plants with 50 mm nacl. no significant interaction between so2 fumigation and 50 mm nacl was observed on the rgr of both shoot and root. the results showed that 50 mm nacl salinity did not provide an effective protection against so2 uptake in the leaves by increasing stomatal resistance during so2 fumigation. other physiological mechanisms could be involved in the antagonistic interaction between 50 mm nacl salinity and 441 nl l-1 so2 fumigation on plant growth.",7,1994,48,2,163,178,10.1016/0167-8809(94)90087-6,0,1,0,1"POUNDS, JA; CRUMP, ML",amphibian declines and climate disturbance - the case of the golden toad and the harlequin frog,CONSERVATION BIOLOGY,Article,,"the endemic golden toad (bufo periglenes) was abundant in costa rica's monteverde cloud forest preserve in april-may 1987 but afterwards disappeared, along with local populations of the harlequin frog (atelopus varius). we examine the possible relationship between these sudden declines and unusually warm, dry conditions in 1987 for our analyses of local weather patterns, we define a 12-month (july-june) amphibian moisture-temperature cycle consisting of four periods: (1) late wet season; (2) transition into dry season; (3) dry season; and (4) post-dry-season (early-wet-season) recovery. the 1986-1987 cycle was the only one on record (of 20 analyzed) with abnormally low rainfall in all four periods, and temperature anomalies in 1987 reached record highs. flow in local aquifer-fed streams during the dry season and post-dry-season recovery period reached a record low. this climate disturbance, associated with the 1986-1987 el nino/southern oscillation, was more severe than a similar event associated with the 1982-1983 el nino, though this earlier oscillation was the strongest of the past century. demographic data for one harlequin frog population, gathered during these two climatic events, support the hypothesis that in 1987, shortly before the population collapsed, the frogs underwent an unprecedented shift in distribution within the habitat in response to desiccating conditions. the juxtaposition of these rare demographic events suggests they were causally linked yet sheds little light on mechanisms underlying the sudden decline. while desiccation or direct temperature effects may have been factors leading to high adult mortality, moisture-temperature conditions may have interacted with some other, unidentified agent. we discuss two hypotheses concerning possible synergistic effects. in the climate-linked epidemic hypothesis, microparasites are the additional agent in the climate-linked contaminant pulse hypothesis, atmospheric contaminants scavenged by mist and cloud water in montane areas reach critical concentrations when conditions are abnormally warm and dry.",235,1994,8,1,72,85,10.1046/j.1523-1739.1994.08010072.x,1,0,0,1"HUANG, LB; MURRAY, F; YANG, XH",interaction between mild salinity and sublethal so2 pollution on wheat (triticum-aestivum cultivar wilgoyne (ciano gallo)) .2. accumulation of sulfur and ions,AGRICULTURE ECOSYSTEMS & ENVIRONMENT,Article,,"wheat (triticum aestivum cultivar 'wilgoyne' (ciano/gallo)) plants were exposed to a factorial combination of two levels of salinity (control and 50 mm nacl), and three levels of so2 ( < 10, 231, and 441 nl l-1) in fumigation chambers with rain-exclusion tops for 4 h day-1 for up to 42 days. the study was to investigate whether mild salinity stress could influence the accumulation and reduction of so2 absorbed and so2 fumigation could modify the salt ion concentrations in the plant tissues. so2 fumigation significantly increased sulphur concentration in the shoots, but not in the roots. the so2 absorbed in the leaves was mostly oxidized into sulphate and little reduced into organic sulphur compounds. nacl salinity decreased the sulphate concentration in leaves, but did not affect the organic sulphur concentration. there was an antagonistic interaction between so2 fumigation and nacl salinity on the concentration of sulphate in the leaves. so2 fumigation, salinity, and their combination affected the concentrations of cl-, k+, na+, ca2+ and mg2+ in the plant tissues exposure to so2 increased the k+ concentration in the leaves, but decreased the cl-, ca2+ and mg2+ concentrations. so2 fumigation and nacl salinity had an antagonistic interaction on the concentrations of k+, cl-, ca2+ and mg2+ in the leaf tissue. the na+ concentration in the youngest fully expanded leaves of the saline plants was decreased by exposure to 441 nl l-1 so2. plant tolerance to nacl salinity may have been enhanced by so2 fumigation by decreasing na+ and cl- concentration and increasing the k+ concentration in the leaves. the antagonistic interactions between so2 fumigation and nacl salinity on the so2 uptake and salt accumulation in the leaves may be responsible for their antagonistic interaction on plant growth.",4,1994,47,4,335,351,10.1016/0167-8809(94)90100-7,0,1,0,1"MORENO, G","genetic architecture, genetic behavior, and character evolution",ANNUAL REVIEW OF ECOLOGY AND SYSTEMATICS,Review,CHARACTER EVOLUTION; EPISTASIS; QUANTITATIVE VARIATION; GENETIC ARCHITECTURE,"nonadditive gene interaction or epistasis is a central component of hypotheses that postulate a creative role for small populations and founder events in character evolution and speciation. because quantitative or small effect variation is considered to be the basis of evolutionary change, the claim that this variation shows mostly additive behavior has represented a serious obstacle for these hypotheses. the literature on classical phenotypic genetics as well as the contemporary counterpart of this work, developmental genetics, harbors a considerable wealth of information relevant to the issue of gene-character relationship. in particular, recent studies of gene interaction in drosophila developmental genetics provide important insights into the structure and behavior of nonadditive gene action. it is proposed that the importance of these studies for population genetics lies in suggesting that the small-effect of at least some genetic variation can hide a potential for strong phenotypic effects which can be expressed through interlocus interactions within sets of functionally related loci. at the population level this genetic behavior implies that strong effects should become apparent in quantitative variation when the genotypic frequencies of the population are substantially disturbed. that at least some quantitative variation can show strong interaction effects with substantial disturbance of the population genotypic combinations is supported by results from quantitative genetic analyses of chromosome and inbred lines and long-term artificial selection on quantitative characters. an experiment comparing the genetic variance resulting from the same set of wild third-chromosomes in a wild type and mutant backgrounds revealed substantial amounts of unexpressed strong effects for a typical quantitative character in a wild population of drosophila melanogaster. the claim that quantitative variation will show strong epistatic behavior under population disturbance is of fundamental importance for theories that postulate a positive role for small population size and population bottlenecks in phenotypic evolution and speciation.",40,1994,25,,31,44,,0,0,1,1"GUEI, RG; WASSOM, CE",genetics of osmotic adjustment in breeding maize for drought tolerance,HEREDITY,Article,ADDITIVE EFFECTS; DOMINANT EFFECTS; DROUGHT TOLERANCE; GENETIC VARIABILITY; HERITABILITY; OSMOTIC ADJUSTMENT,"osmotic adjustment in higher plants refers to the maintenance of turgor by lowering of osmotic potential arising from the net accumulation of solutes in response to water deficits. genetic variation for osmotic adjustment has been reported in several crops, but little is known about its inheritance and potential use as selection criteria in tropical maize (zea mays l.). two tropical lowland maize populations were used in this study to quantify the magnitude of genetic variability in osmotic adjustment; to estimate components of its genetic variance and heritability; and to determine the importance of this trait in breeding tropical maize for improved drought tolerance. full-sibs within half-sib groups were developed using the design i mating scheme and evaluated at two locations in mexico for two seasons using water stress and non-stress environments. results showed that in both populations, dominance genetic effects were more important than additive effects in controlling the expression of the trait. however, very little genetic variability was present in either population for the trait, although more genetic variation was detected with data collected at flowering stage, when water stress was more severe than at the vegetative stage. non-significant phenotypic and genotypic correlations were found between osmotic adjustment and yield. not much genetic gain could be expected from selection for osmotic adjustment in these populations.",8,1993,71,,436,441,10.1038/hdy.1993.158,0,0,1,1"CAREY, C",hypothesis concerning the causes of the disappearance of boreal toads from the mountains of colorado,CONSERVATION BIOLOGY,Article,,"recent reports of world-wide declines and extinctions of amphibian populations have raised questions about the relation of environmental change to the demise of certain amphibian species. between 1974 and 1982, 11 populations of boreal toads (bufo boreas boreas) in the west elk mountains of colorado totally disappeared. the apparent cause of extinction of these toads was infection with the bacteria aeromonas hydrophila. in this paper, the presence of disease in declining populations of these toads is used in conjunction with a variety of data from the literature to formulate a working hypothesis for explaining the cause of the decline of this species, and perhaps others: (1) some environmental factor or synergistic effects of more than one factor changes sufficiently to cause sublethal ''stress'', (2) this stress directly causes suppression of the immune system, or indirectly causes immunosuppression by effecting elevated secretion of adrenal cortical hormones; (3) immunosuppression, coupled with the apparent effect of cold body temperatures on the ability of immune systems of ectothermic animals to fight disease, leads to infection by aeromonas or other infectious agents, and to subsequent death of individuals and extinction of populations.",146,1993,7,2,355,362,10.1046/j.1523-1739.1993.07020355.x,1,0,0,1"BACON, CW","abiotic stress tolerances (moisture, nutrients) and photosynthesis in endophyte-infected tall fescue",AGRICULTURE ECOSYSTEMS & ENVIRONMENT,Article; Proceedings Paper,,"the ecological significance resulting from the association of each tall fescue (festuca arundinacea schreb.) genotype and its companion fungal endophyte (acremonium coenophialum morgan-jones and gams) is probably inherent in the nutritional interactions, and the resulting physiological and biochemical requirements of each. the colonization of this grass by the fungus follows the natural sequence of fescue seed germination, seedling and tiller growth. infected grasses are natural and extensive, therefore tall fescue should be considered a symbiotic plant. the nature of this relationship at the population level is more appropriately described as an obligately biotrophic conjunctive mutualism. the use of this terminology at the population level describes the overall ecological effect; however, allowances must be made for infected tall fescue genotypes within the population that may not show any positive adaptive strategies. genotypes of this later category may be categorized, possibly only transiently, as obligately neutral symbiotic. infected genotypes of the earlier category offer adaptations to environmental stresses and may be exploited for these characteristics. evidence from research is reviewed to indicate that selected genotypes within the population of tall fescue are more tolerant of environmental abiotic stresses than uninfected grasses. infected tall fescue seed require more moisture to germinate than uninfected seed. endophyte-infected seedlings require more nutrients than uninfected seedlings. although infected tall fescue contains less soluble nitrogen which would encourage more predation, strains resulting from the stresses of insect herbivory are prevented because of an accumulation of an insect deterrent, toxins and their synergists. at the morphological level infected grasses show tolerance to water stress by early shedding of older leaves and rolling of younger leaves. tolerance to water stress is further evidenced by low stomatal conductances and by development of an enhanced osmoregulatory system that produces increased cellular turgor pressure. one genotype of tall fescue contains polyols, some of which are absent in the uninfected clone. infected tall fescue also shows increased efficiency to low soil nitrogen, possibly due to an increased level of glutamine synthetase which would enhance its competitive ability under low soil nitrogen. there is no endophyte effect of consequence on photosynthesis and associated processes in several genotypes of infected grasses.",109,1993,44,04-Jan,123,141,10.1016/0167-8809(93)90042-N,1,0,0,1"DETTNER, K","defensive secretions and exocrine glands in free-living staphylinid beetles - their bearing on phylogeny (coleoptera, staphylinidae)",BIOCHEMICAL SYSTEMATICS AND ECOLOGY,Article; Proceedings Paper,STAPHYLINOIDEA; ROVE BEETLES; CHEMICAL DEFENSE; SECRETIONS; GLANDS; EVOLUTION; CHEMOTAXONOMY; BIOGENESIS; SYNERGISM,"due to their reduced elytra many adults of free living rove beetle taxa (coleoptera: staphylinidae) bear exocrine defensive glands where an astonishing variety of defensive compounds, antimicrobics, fungicides, adhesives or spreading active compounds are produced. chemically these exocrines cover hydrocarbons, aliphatic alcohols, aldehydes, ketones, acids, esters, sprioacetales, iridoids, aromatics, quinones or various nitrogen-containing compounds. factors such as presence, position, structure and variation of these exocrine glands are used more and more in order to establish a natural system of staphylinidae. this paper surveys the chemical defensive systems of staphylinid beetles and considers the biological significance and multifunctional role of these exocrines. within the omaliine group, oxytelinae/pseudopsinae, aleocharinae, paederinae, staphylininae/xantholininae, steninae and silphidae where a common homologous gland system is present in each case, character patterns and evolutionary trends, especially with respect to secretion chemistry are presented. in the subfamily oxytelinae these glandular and micromolecular patterns are used especially in order to construct a phylogeny for this subfamily which is based on phylogenetic systematics. it was shown that identification of character state transformations of these micromolecules in advanced and primitive species is necessary for estimating apomorphic and plesiomorphic character states. optimizing of a defensive secretion may on the one hand be achieved by gradual intervention of new secretion types (from one precursor) with increasing topical irritancy from primitive towards advanced taxa. a further improvement of the secretion may be achieved by changing and adjusting secretion formulation in order to optimize these mixtures by synergisms from primitive towards advanced species. finally the necessity of biogenetic data is stressed in order to discuss the gradual sequence of evolution of gland constituents.",40,1993,21,1,143,162,10.1016/0305-1978(93)90020-R,1,0,0,1"CIPOLLINI, ML; STILES, EW",antifungal activity of ripe ericaceous fruits - phenolic-acid interactions and palatability for dispersers,BIOCHEMICAL SYSTEMATICS AND ECOLOGY,Article,ERICACEAE; OPPORTUNISTIC FUNGI; PHENOLICS; ORGANIC ACIDS; TANNINS; ANTIFUNGAL DEFENSES; AVIAN SEED DISPERSAL; FRUIT PALATABILITY,"chemical characteristics of antifungal extracts of ripe fruit pulp of six ericaceous plants that differ in fruit ripening phenology and other dispersal characteristics were examined. the antifungal activity of these fruits is particularly interesting because of contrasting effects of pulp secondary chemistry upon birds that disperse the seeds. whereas extracts of summer-ripening fruit do not affect (or affect positively) the feeding rates of birds feeding on artificial-pulp media, extracts of fall-ripening fruit are very much a deterrent results of fungal growth tests indicate that synergistic interactions of small phenolic constituents with small organic acids were most likely sources of antifungal activity for all but one species (arctostaphylos uva-ursi), for which astringent polyphenolics and steroidal saponins were implicated. fall-ripening fruit are apparently more of a deterrent to frugivores due to higher concentrations of organic acids in interaction with phenolic constituents, or higher concentrations of tannins and saponins. in conclusion, we stress the challenges that chemical synergism may present to chemical ecologists, and the importance of interactive effects of ""primary"" chemicals in plant defense.",19,1992,20,6,501,514,10.1016/0305-1978(92)90004-W,1,0,0,1"GRANT, PR; GRANT, BR",demography and the genetically effective sizes of 2 populations of darwin finches,ECOLOGY,Article,DARWIN FINCHES; DEMOGRAPHY; EFFECTIVE POPULATION SIZES; GALAPAGOS; HYBRIDIZATION; RANDOM DRIFT; REPRODUCTIVE VALUE,"the purpose of this study was to identify and quantify the demographic and genetic factors that favor long-term persistence of resident bird populations on small islands. two species of darwin's ground finches, geospiza scandens (cactus finch) and g. fortis (medium ground finch), were studied on isla daphne major, galapagos, from 1975 to 1991. four cohorts born in the years 1975-1978 were followed to the point where almost every individual had died. life tables were constructed from survival and reproductive data, and used to calculate genetically effective population sizes. annual rainfall was highly variable and erratic. extremes were 0 and 1359 mm. as a consequence the finch populations fluctuated in all demographic parameters. in years of little or no rainfall breeding did not occur, in years of abundant rainfall as many as eight breeding attempts were made by individual pairs. maximum ages were 15 yr for g. scandens and 14 yr for g. fortis. males of both species tended to live longer than females and to breed later; most females bred for the first time at ages 1-3 yr, whereas most males bred for the first time at ages 2-6 yr. an unusual feature of the survival and reproductive schedules is an increase in reproductive value sometimes occurring moderately late in life more than once, associated with occasional extremely favorable conditions for reproduction. harmonic mean breeding population sizes (nbar) were 94 g. scandens and 197 g. fortis. effective population sizes (n(e)) were much lower, principally as a result of a large variance in the production of recruits per parent, especially by g. fortis. average effective sizes were 38 g. scandens and 60 g. fortis by one method of calculation, and slightly larger by another. the proportional rate of loss of selectively neutral heterozygosity or additive genetic variance in quantitative traits potentially caused by random genetic drift (1/2n(e)) in these populations is approximately 0.003-0.005, or 0.3-0.5%/yr, and between 0.8 and 1.4% per generation. we suggest that a general estimate for the effective size of terrestrial bird populations is about one-quarter of average breeding numbers. these results are discussed in relation to the long-term viability of the populations and the maintenance of genetic variation. the demographic features that enable the finch species to persist in the face of extreme environmental stochasticity are a high maximum life-span, a generally high adult survival under the stressful conditions of drought, a flexible period of maturity, and a high reproductive rate. despite their relatively small effective population sizes and the likelihood of genetic impoverishment through random drift they remain genetically variable through gene flow, principally hybridization. this study highlights fluctuating (unstable) age structures as a methodological constraint on some of the theoretical calculations. an expanded demographic and population-genetic theory is needed to overcome this constraint.",67,1992,73,3,766,784,10.2307/1940156,0,0,1,1"HENLEY, WJ; LINDLEY, ST; LEVAVASSEUR, G; OSMOND, CB; RAMUS, J",photosynthetic response of ulva-rotundata to light and temperature during emersion on an intertidal sand flat,OECOLOGIA,Article,CHLOROPHYLL FLUORESCENCE; PHOTOINHIBITION; PHOTOSYNTHESIS; TEMPERATURE STRESS; ULVA,"we have investigated the diurnal response of photosynthesis and variable photosystem ii (psii) chlorophyll fluorescence at 77 k for thalli of the chlorophyte macroalga, ulva rotundata, grown in outdoor culture and transplanted to an intertidal sand flat in different seasons. the physiological response in summer indicated synergistic effects of high pfd and aerial exposure, the latter probably attributable to temperature, which usually increased by 8 to 10-degrees-c during midday emersion. except at extreme emersed temperatures in summer (38-degrees-c), the light-saturated photosynthesis rate (p(m)) did not decline at midday. in contrast, light-limited quantum yield of photosynthetic o2 exchange (phi) and the ratio of variable to maximum fluorescence yield (f(v)/f(m)) reversibly declined during midday low tides in all seasons. shade-grown thalli exhibited a fluorescence response suggestive of greater photodamage to psii, whereas sun-grown thalli had greater photo-protective capacity. the fluorescence decline was smaller when high tide occurred at midday, and was delayed during morning cloudiness. these results suggest that the diurnal response to pfd in this shallow water species is modified by tidal and meteorological factors. u. rotundata has a great capacity for photoprotection which allows it to tolerate and even thrive in the harsh intertidal environment.",58,1992,89,4,516,523,,1,0,0,1"CAMPBELL, BD; GRIME, JP",an experimental test of plant strategy theory,ECOLOGY,Article,COMMUNITY STRUCTURE; COMPETITION; COMPETITION IMPORTANCE; COMPETITION INTENSITY; COMPETITIVE EXCLUSION; DISTURBANCE; ENVIRONMENTAL GRADIENTS; NUTRIENT STRESS; PLANT STRATEGIES,"two of the central hypotheses of the triangular model of primary plant strategies were tested by a novel technique involving seven grasses of contrasted ecology grown in pure stands and an additive mixture on an experimental matrix of crossed gradients of mineral nutrient stress and vegetation disturbance. the experimental design allowed reductions in vegetative and reproductive vigor resulting from interspecific competition to be distinguished from those arising from direct effects of nutrient stress and vegetation disturbance. it was also possible to determine the extent to which competitive suppression of each species was affected by stress and disturbance. in isolation, all species showed maximum vegetative and reproductive vigor at high soil fertility and low disturbance. in the mixture, absolute reductions in biomass and flowering due to competition were greatest at high soil fertility and low disturbance, and the species of most extreme strategy became restricted to areas of the matrix broadly consistent with those predicted by strategy classification. when standardized for differences in biomass in pure stands, the effect of competition remained relatively constant across the stress-disturbance matrix for all species except poa annua, which was less restricted by competition at high intensities of stress. there were marked and consistent differences between species in their susceptibility to competition. at both high and low soil fertility, two species of natural occurrence on infertile soils (festuca ovina, bromus erectus) were poor competitors relative to arrhenatherum elatius, a widespread dominant of productive grasslands. the effect of competition was least severe on flowering of annuals in low-stress portions of the matrix. if competition is assessed simply as the percentage of reduction in biomass between pure and mixed stands it appears that competition intensity is constant across different intensities of stress and disturbance. however, observations that maximum reductions in biomass coincided with low stress and low disturbance, that competition decreased in importance as a factor reducing yield and flowering (relative to stress and disturbance) as stress and disturbance intensities increased, and that there was a consistently inferior competitive ability of plants from infertile soils at all positions on the matrix all support the hypothesis that competition declines in importance as a vegetation determinant in the vegetation of infertile soils.",169,1992,73,1,15,29,10.2307/1938717,0,0,1,1"MULKEY, SS; PEARCY, RW","interactions between acclimation and photoinhibition of photosynthesis of a tropical forest understorey herb, alocasia-macrorrhiza, during simulated canopy gap formation",FUNCTIONAL ECOLOGY,Article,CHLOROPHYLL FLUORESCENCE; PHOTOINHIBITION; PHOTOSYNTHETIC ACCLIMATION; TREE-FALL GAPS,"1. the effects of a sudden increase in irradiance and the high leaf temperatures characteristic of a canopy gap environment were studied with chlorophyll fluorescence and gas-exchange measurements on shade- and sun-acclimated leaves of alocasia macrorrhiza. 2. photoinhibition occurred in both sun and shade leaves during a 2-h simulated gap treatment (1900 mumol photons m-2 s-1) in which leaf temperatures rose to 40-degrees-c. dissipation of excess energy was more efficient in sun leaves, which showed rapid quenching of fluorescence. the quantum yield of photosystem ii as calculated from fluorescence in low light was considerably lower for shade than sun leaves after the gap treatment. 3. fluorescence relaxation kinetics showed that sun leaves recovered overnight from photoinhibition even when leaf temperatures during treatment reached 40-degrees-c. by contrast, shade leaves given the same treatment had not recovered after 4 days in low light. shade leaves given the same light treatment but held at 30-degrees-c instead of 40-degrees-c recovered within 4 days. shade leaves treated at 40-degrees-c in moderate, saturating light (375 mumol photons m-2 s-1) recovered overnight. thirteen days of 3-h gap treatments on whole plants previously grown in shade showed that after initial depressions both fluorescence and photosynthetic capacity partially recovered. 4. thus, the degree of photoinhibition and the potential for recovery are dependent on the synergistic roles of leaf temperatures and high light during initial gap conditions. although quantum efficiency and photosynthetic capacity can be impaired by strong light and heat stress, shade leaves have significant capacity for repair and contribution to the whole-plant carbon budget during acclimation following gap formation.",96,1992,6,6,719,729,10.2307/2389969,1,0,0,1"WEBER, RE; DEZWAAN, A; BANG, A","interactive effects of ambient copper and anoxic, temperature and salinity stress on survival and hemolymph and muscle-tissue osmotic effectors in mytilus-edulis",JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY,Article,CU; HEMOLYMPH AND CELLULAR OSMOLYTES; INTRACELLULAR ISOSMOTIC REGULATION; MORTALITY; MUSSEL; MYTILUS-EDULIS,"to discern mechanisms of synergies between natural and pollutional environmental stress factors, we investigated the effects of sublethal (20 ppb) and lethal (200 ppb) cu concentrations on mortality and on hemolymph and cellular osmotic effectors in mytilus edulis under various combinations of anoxia, normoxia, high and low salinity and temperature. chronic (6-wk) exposure to sublethal cu and subsequent subjection to temperature and salinity stress had no significant effect on survival under aerial exposure at either 6 or 15-degrees-c. compared with virtually 100% survival observed in cu-free animals under normoxia, both 200 ppb cu and anoxia (singly) drastically decreased survival, which further deteriorated when the animals were subjected to both stresses combined, high temperature or low salinity. the q10lt50 values lt50t + 10-degrees-c/lt50t-degrees-c) of 2-2.5 observed under all condition sets in the presence of 200 ppb cu and/or under anoxia, and of approximately 3 under aerial exposure following chronic subjection to 20 ppb cu suggest that temperature rise increases mortality through accelerated depletion of metabolic reserves. in the adductor muscle, inorganic components are implicated in isosmotic intracellular regulation following salinity change. sublethal cu did not appreciably affect hemolymph osmolytes, that predominantly consist of chloride salts, or cellular osmotic components. anoxia markedly decreased cellular k+ and increased cellular na+ and cl- concentrations. the cellular effects of anoxia increased in the additional presence of 200 ppb cu and generally correlated with opposite changes in hemolymph ion levels, indicating disruption of transmembrane concentration gradients.",23,1992,159,2,135,156,10.1016/0022-0981(92)90033-7,1,0,0,1"PYKE, DA; ARCHER, S",plant-plant interactions affecting plant establishment and persistence on revegetated rangeland,JOURNAL OF RANGE MANAGEMENT,Article,COMPETITION; MUTUALISM; RESOURCE PARTITIONING; REVEGETATION; SELF-THINNING; SPECIES MIXTURES; STRESS TOLERANCE,"restoration and revegetation of rangeland ecosystems is based on knowledge of abiotic and biotic interactions that affect plant establishment. once plants become autotrophic, interactions within and between plant species may occur and these interactions may range from antagonistic to mutualistic. this full range of potential interactions needs to be considered to ensure successful revegetation. at the intraspecific level, we propose the development and use of density-yield diagrams for rangeland species. these diagrams would be based on the self-thinning principle, that aboveground biomass is related to plant density and to the dynamic process of density-dependent mortality. the proposed approach would be used to determine optimum seeding rates, and to predict future biomass of revegetated rangeland. at the interspecific level, competitive relationships of species used to reseed rangelands need to be identified to enhance the probability that species will coexist and thereby facilitate greater species diversity on the site. a diversity of species and growth forms may provide a more stable cover and productivity than a monoculture on sites characterized by environmental variability while potentially enhancing nutrient status for the site.",49,1991,44,6,550,557,10.2307/4003035,0,1,0,1"JOSE, JJS; FARINAS, MR; ROSALES, J",spatial patterns of trees and structuring factors in a trachypogon savanna of the orinoco llanos,BIOTROPICA,Article,,"tree dispersion was evaluated in a trachypogon savanna by measuring the distance from individual trees to their nearest conspecific neighbor. the vegetation is a closed bush island savanna with coexistent isolated trees and small patches of semideciduous forest. the isolated trees were in clumps similar to trees growing in savannas and tropical forests. in our study, adults were less clumped compared to juveniles. environmental and biotic differences related to edaphic heterogeneity, life history, and reproductive strategy could account for the clumped pattern. different spatial patterns emerged for stems in groves. thus, uniform spatial distribution was evident in the individuals of the fire resistant species (curatella americana, byrsonima crassifolia and bowdichia virgilioides) and a gap filling species (casearia decandra). changes in the demographic components between different age groups provide evidence for density-dependent mortality. a hypothesis mainly based on two scales of disturbance (human impact and gap formation) acting synergetically with a large scale factor (substrate patchiness) is put forward to explain the dynamics of tree invasion and the maintenance of the trachypogon savanna.",3,1991,23,2,114,123,10.2307/2388296,1,0,0,1"KASULE, FK",quantitative variation in adult size and fecundity of the cotton stainer bug dysdercus-fasciatus,HEREDITY,Article,ADULT SIZE; DYSDERCUS-FASCIATUS; FECUNDITY,"genetic variation in adult size and fecundity was studied in the cotton stainer bug dysdercus fasciatus in the laboratory using a split-family, two-environment, half-sib, full-sib design. groups of siblings were grown in either a benign or a stressful moisture environment. sib analysis in each environment revealed additive genetic variance for adult size and fecundity only in the benign environment. heritability estimates were zero for adult size and low for fecundity when averaged over the two environments. a substantial component of the phenotypic variance in adult size and fecundity was due to genotype-by-environment interaction. this result indicates that different genotypes would be favoured in different conditions if the selection occurred in a heterogeneous moisture environment.",6,1991,66,,273,279,10.1038/hdy.1991.34,0,0,1,1"KASULE, FK",associations of fecundity with adult size in the cotton stainer bug dysdercus-fasciatus,HEREDITY,Article,ADULT SIZE; DYSDERCUS-FASCIATUS; FECUNDITY,"components of phenotypic covariance of fecundity with adult size were examined in the bug dysdercus fasciatus in benign and stressful moisture environments. in addition, genetic relationships were explored between the character states in different environments. there was a positive and significant genetic association between fecundity and adult size in a benign environment. by contrast, the observed phenotypic covariability of fecundity with adult size in a stressful environment arose entirely from non-additive genetic plus maternal effects. genetic correlations between the same character across environments were significantly less than unity for both adult size and fecundity. these results suggest that populations in benign and stressful moisture environments would respond to selection on adult size and fecundity in different ways.",6,1991,66,,281,286,10.1038/hdy.1991.35,0,0,1,1"DESTEVEN, D; KLINE, J; MATTHIAE, PE",long-term changes in a wisconsin fagus-acer forest in relation to glaze storm disturbance,JOURNAL OF VEGETATION SCIENCE,Article,BEECH; FOREST SUCCESSION; GAP DYNAMICS; LANDSCAPE; REGENERATION; SUGAR MAPLE,"changes in the composition of a fagus-acer (beech-sugar maple) forest in southeastern wisconsin over a 16-yr period from 1971 to 1987 are analyzed in relation to a severe glaze (ice) storm disturbance occurring within the census period. landscape topography created 'windward' and 'leeward' forest aspects with respect to storm severity, which resulted in greater canopy opening on the windward aspect. in the tree stratum, most species remained stable in density and most of the common species increased in basal area into larger size classes. however, fagus grandifolia, ulmus rubra, and the small tree ostrya virginiana suffered net losses that suggest synergistic effects between glaze storm disturbance and other factors upon tree mortality. in the sapling stratum, canopy opening strongly promoted release of shade-tolerant acer saccharum. on the windward forest aspect, sapling densities of less shade-tolerant species also increased, in contrast to the absence of such increases on the leeward forest aspect. in the shrub (regeneration) stratum, species responses were heterogeneous. regeneration of most species increased over the 16-yr period, and some less shade-tolerant species showed increased regeneration differentially on the windward forest aspect. overall, disturbance appears to have accelerated forest succession toward increased dominance by a. saccharum and persistence of both fagus and tilia americana through their capacities for root sprouting. however, forest succession was retarded somewhat on the windward aspect through increased recruitment of less-shade tolerant species. these results parallel those of other studies of glaze storm disturbance, and they illustrate how spatially heterogeneous disturbance intensity may contribute to maintenance of forest diversity.",37,1991,2,2,201,208,,1,0,0,1"SPEAKMAN, JR",why do insectivorous bats in britain not fly in daylight more frequently,FUNCTIONAL ECOLOGY,Article,ACTIVITY CYCLES; AERIAL INSECTIVOROUS BIRDS; BATS; COMPETITION; DIURNAL FLYING; FEEDING; HIRUNDINES; MOBBING; PREDATION; THERMAL STRESS,"previous studies suggest insectivorous bats occasionally emerge from their roosts during the day to make good shortfalls of energy intake. other studies indicate that an inadequate nocturnal food supply may negatively affect bat reproduction. the question arises therefore why do temperate insectivorous bats not fly in daylight more frequently? four hypotheses have been advanced to explain the infrequency of daylight flying. these are overheating, competition, predation and mobbing by non-competitor species. analysis of behavioural observations in 420 reports of daylight flying, submitted in a national (uk) daylight-flying bat survey revealed that mobbing by non-competitors was very rare (4/420 reports) and its consequences trivial. flying with aerial insectivorous birds was more frequent (19/420 reports) but antagonism was again uncommon. predatory attacks, mostly by avian diurnal predators occurred in 13 cases, and in at least five of these instances the attacks were fatal. large bats survived attacks significantly more than small bats. this may explain why large species of bats flew more frequently in daylight relative to their populations than small bats. in the laboratory pipistrelle (pipistrellus pipistrellus schreber) and brown long-eared bats (plecotus auritus l.) avoided flying in the light. this effect occurred independently of body temperature and was not mediated by overheating. furthermore, in the wild, bats did not avoid flying on days which were particularly hot or sunny, suggesting that in britain overheating does not inhibit daylight flights. heavier pipistrelle bats avoided the light more than lighter pipistrelle bats. this may reflect lower manoeuvrability and hence greater susceptibility of heavy bats (within a species) to predation, and may explain the reduced frequency of daylight-flying bats in britain during late june and early july when they are heavily pregnant.",58,1991,5,4,518,524,10.2307/2389634,0,1,0,1"JARVI, T","synergistic effect on mortality in atlantic salmon, salmo-salar, smolt caused by osmotic-stress and presence of predators",ENVIRONMENTAL BIOLOGY OF FISHES,Note,,,26,1989,26,2,149,152,10.1007/BF00001031,1,0,0,1"LARSEN, BR","synergistic effects of acid-rain and (+/-)-2-(2,4-dichlorophenoxy)-propanoic acid (2,4-dp) on growth, mineral-content and stress-induced ethylene in lettuce",ENVIRONMENTAL POLLUTION SERIES A-ECOLOGICAL AND BIOLOGICAL,Article,,,4,1986,41,2,179,196,10.1016/0143-1471(86)90092-9,1,0,0,1