RT Journal Article
SR Electronic
T1 Social structure and drivers behind asynchronous burrow associations of the desert tortoise
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 025494
DO 10.1101/025494
A1 Pratha Sah
A1 Kenneth E. Nussear
A1 Todd C. Esque
A1 Christina M. Aiello
A1 Peter J. Hudson
A1 Shweta Bansal
YR 2015
UL http://biorxiv.org/content/early/2015/09/14/025494.abstract
AB For several species, refuges (such as burrows, dens, roosts, nests) are an essential resource for protection from predators and extreme environmental conditions. Refuges also serve as focal sites of social interactions including mating, courtship and aggression. Knowledge of refuge use patterns can therefore provide information about social structure as well mating and foraging success of wildlife populations, especially for species considered to be relatively solitary. In this study, we sought to (a) infer social associations of the desert tortoise through their asynchronous burrow associations, and (b) provide mechanisms behind individual-level variation in burrow use networks using a model of burrow switching (to describe variation in tortoise behavior) and burrow popularity (to describe variation from the perspective of burrows). Although considered to be relatively solitary, we found tortoise social networks to be significantly different than null networks of random associations, with geographical locations having a moderate influence on tortoises’ associations. Seasonal variation and local tortoise/burrow density had a strong impact on individual’s burrow switching behavior. Among the three population stressors included in the model (translocation, drought, disease), translocation had the largest effect on burrow switching. Analysis of variation in burrow popularity revealed older burrows and burrows at rough higher elevation sites are more popular than other burrows in desert tortoise habitat. Our study emphasizes the role of combining graph theoretic and statistical approaches to examine the social structure of (relatively) solitary species to design effective conservation and management strategies including control of future infection spread.