Habitat selection by female Stone's sheep in relation to vegetation, topography, and risk of predation

Abstract

Stone's sheep (Ovis dalli stonei) are susceptible to anthropogenic disturbances, but few data have been available to help minimize impacts. We used the movements of individuals to define use and availability, and resource-selection functions (RSF) and the information-theoretic approach to examine seasonal habitat selection and interannual variation in selection of attributes by groups of Stone's sheep. Movement rates of Stone's sheep followed consistent yearly patterns, with highest rates occurring in summer and fall. Models that contained vegetation, topography, and risk of predation best explained resource selection. Topographic features ranked better, however, than components of vegetation or risk of predation from grizzly bears (Ursus arctos) and wolves (Canis lupus) at explaining habitat selection. Selection strategies were variable among groups of Stone's sheep and between years within groups even though consistencies in selection for steep slopes, ridge-like topography, south aspects, and upper elevations were common. This research provides the first comprehensive analysis of habitat selection by Stone's sheep, which show strong fidelity to seasonal ranges but also exhibit behavioural plasticity in selection of attributes within those ranges.