An application programming interface for generating null models
of social contacts based on individuals' space use
Description
Digiroo2 is an R package developed by researchers at the
University of Queensland to investigate association patterns
and social structure in wild animal populations. Proximity
between individuals is generally considered to be an
appropriate proxy for associations and pairwise association
indices are the most widely used technique for analysing animal
social structure. However, little attention is given to
identifying how patterns of spatial overlap affect these
association patterns. For example, do individuals associate
randomly with others with whom they share home ranges, or do
some individuals go out of their way to associate with or avoid
particular individuals? This program builds a null model of
random associations based on an individual's space use
determined using home range methodologies. Random points may be
generated within a specified home range contour or according to
the Utilization Distribution (UD). Expected associations of
individuals are extracted based on probability of occurrence
and the proximity between home range weighted random points.
Association matrices can be generated from multiple
permutations for analysis using SOCPROG 2.4 (Whitehead 2009) to
create 'expected' pairwise half-weight association indices
(HWIs). These may be compared with the 'observed' HWIs from
field observations to reveal whether pairs of animals associate
more (= attraction) or less (= avoidance) than expected by
chance.