Barrier Interaction Behaviour Analysis

MoveApps

Github repository: https://github.com/nilanjanchatterjee/Barrier_Interaction_Bahaviour_Analysis

Description

The app identifies and classifies different behaviors of animal encounters with linear features (road, rail tracks, barriers, fences etc.). It requires a user specified buffer distance, minimum and maximum time interval for identification of different behaviors. The app is based on the BaBA package (Xu et al. 2021) https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.13806

Documentation

Animals do not behave in the usual manner when they encounter linear features and barriers. The app identifies these different behavior classes based on the changes in movement. The identified behaviors can be classified into three broad classes Usual movement, Altered movement and Trapped. Usual movement consists of Average movement and Quick cross, Altered movement consists of Bounce, Back and Forth and Trace while Trapped is signified when the animal movement is restricted within a close vicinity of the feature for a significant time. For more details about the behavior classes please go through the manuscript on BaBA app by Xu et al. 2021 (https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.13806).

Input data

move/moveStack in Movebank format Linear feature layers in Shapefile(.shp) format

Output data

MoveStack in Movebank format
Road encounter in .csv format

Artefacts

• Encounter_data.csv: details of the road encounters (see below)
• Point_count_density.jpeg: Figure showing the number of animal locations at each pixel along the barrier
• Event_plot_output.pdf: Document with plots of each identified encounter. Plots include a label with the burstID and the identified behaviour for each encounter, the features (red line), buffer area (grey), the animal locations (blue dot), and lines between consecutive animal locations (black line).

Attributes in the artefacts files include the following:

• Individual_ID: the animal ID
• trackId: the animal ID
• burstID: an identifier for the burst of events associated with the encounter
• geometry: the coordinate geometry of the first location in the encounter (format c(-long, lat) in WGS84)
• long and lat: the coordinates of the first location in the encounter (WGS84)
• tmestamp: the timestamp associated with the start of the encounter (format yyyy-MM-dd HH:mm:ss.SSS in UTC)
• start_time and end_time: the timestamps associated with the beginning and end of the encounter (format yyyy-MM-dd HH:mm:ss.SSS in UTC)
• duration: the duration of the encounter (in hours)
• cross: the number of feature crossings during the encounter
• straightness: The straightness of travel over a period around the encounter. This is an index (value range 0-1) calculated as D/L, where D is the straightline distance between the first and last location fixes, and L is the distance between all location fixes, over this period (Batschelet 1981, Circular statistics in biology).
• eventTYPE: the type of encounter behaviour (e.g., Bounce, TBD, Trapped, unknown, Quick_Cross)

• Encounter_event_data.csv: Details of the identified behaviours
• Point_count_density.jpeg: Figure showing the number of animal locations at each pixel along the barrier
• Event_plot_output.pdf: Document of plot of all identified behaviors

Parameters

buffer: Distance to evaluate the effect of the linear feature/Barrier. Unit: metres.
b_time: Maximum duration, that an encounter event would be considered as a short event bounce or quick cross. Unit: hours
p_time: Minimum duration, that an encounter event would be considered as a trapped condition. Unit: hours
w: The length of time, to include around the encounter event to calculate average movement straightness using a moving window. Locations included are all locations within w/2 before the first location of the encounter event and w/2 after the last location of the event.

Null or error handling

The app contains road shapefile from the Y2Y region but users can upload their own shapefiles also. Please be careful that the projection of the barrier feature shapefile should be lat-long (epsg 4326). Moreover, the identified behaviours are function of the user specified input (buffer and time), please be careful and use time intervals with respect to the fix-intervals.

Example : Parameter b_time should not be smaller than the fix-intervals. If your data set has very different fix-intervals please create multiple workflows of individuals with similar fix-intervals.