Habitat use by a desert ungulate: Predicting effects of water availability on mountain sheep

Provision of surface water has been a long-standing management strategy to enhance habitat for large mammals in southwestern North America. In this paper, we use a resource selection function (RSF) developed from telemetered mountain sheep (Ovis canadensis) in three occupied mountain ranges in the Sonoran Desert, California, USA, to examine the effects of water development on habitat quality within those ranges. Further, we apply that model to four nearby and similar mountain ranges, but for which telemetry data are not available, and again examine the effects of water development. When distance to water was decreased to 2,000 m from an average of 3033 m (±522 [SD]) in three occupied mountain ranges, availability of high-quality habitat increased by as much as 92%. When distance to water was decreased to 2,000 m from an average of 3660 m (±799 [SD]) in three mountain ranges not occupied permanently by mountain sheep, and one occupied range for which telemetry data were not available, the proportion of high-quality habitat resulting from application of our model indicated increases that varied from 116 to 508%. We conclude that development of additional sources of surface water can increase availability of high-quality habitat for mountain sheep inhabiting Sonoran Desert mountain ranges, and that the technique has implications for population persistence and conservation of those large, specialized ungulates.