TY - JOUR T1 - Drivers of burrow use patterns in the Desert tortoise, <em>Gopherus agassizii</em>: Insights towards social structure JF - bioRxiv DO - 10.1101/025494 SP - 025494 AU - Pratha Sah AU - Kenneth E. Nussear AU - Todd C. Esque AU - Christina M. Aiello AU - Peter J. Hudson AU - Shweta Bansal Y1 - 2015/01/01 UR - http://biorxiv.org/content/early/2015/08/25/025494.abstract N2 - For several species, refuges (such as burrows, dens, roosts, nests) are an essential resource to obtain protection from predators and extreme environ-mental conditions. Refuges also serve as focal sites of social interactions including mating, courtship and aggression. Knowledge of refuge use patterns can therefore provide important information about social structure 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, Gopherus agassizii, through their asynchronous burrow associations, and (b) examine the effect of various drivers and population stressors influencing burrow use patterns in desert tortoises.Using a graph theoretic approach we found tortoise social networks formed due to asynchronous burrow use to be more clustered, modular, degree centralized and degree homophilic than random networks. Geographical locations had moderate influence on asynchronous burrow associations.We next used regression models combining long-term datasets across nine sites in desert tortoise habitat to test how burrow use patterns are influenced by the environment, density conditions, tortoise characteristics, burrow characteristics and three population stressors - drought, disease, and translocation. We found a large effect of seasonal variation and local tortoise/burrow density on burrow switching patterns. Among the three population stressors tested, translocation had the largest effect on burrow switching, with translocated animals surprisingly visiting fewer unique burrows than residents. We also found less seasonal variation in burrow popularity and a greater effect of burrow age and surrounding topographical condition instead.Our study emphasizes the role of combining graph theoretic and statistical approaches to examine the social structure of (relatively) solitary species through their refuge use patterns. Detailed knowledge of refuge use behavior at an individual level and its population level consequences can be used to design effective conservation and management strategies including control of future infection spread. ER -