Table of Contents
Advances in Ecology
Volume 2015, Article ID 357080, 19 pages
http://dx.doi.org/10.1155/2015/357080
Research Article

Resource Selection by an Endangered Ungulate: A Test of Predator-Induced Range Abandonment

1Department of Biological Sciences, Idaho State University, 921 South 8th Avenue, Stop 8007, Pocatello, ID 83209, USA
2Sierra Nevada Bighorn Sheep Recovery Program, California Department of Fish and Wildlife, 407 West Line Street, Bishop, CA 93514, USA
3California Department of Fish and Wildlife, P.O. Box 3222, Big Bear City, CA 92314, USA
4Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003-8000, USA

Received 30 September 2014; Accepted 3 January 2015

Academic Editor: Tomasz S. Osiejuk

Copyright © 2015 Jeffrey T. Villepique et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We investigated influences of risk of predation by mountain lions (Puma concolor), topographic metrics at multiple scales, and vegetation, land, and snow cover on resource selection by Sierra Nevada bighorn sheep (Ovis canadensis sierrae), an endangered taxon, during winters 2002–2007, in the Sierra Nevada, California, USA. We hypothesized that those mountain ungulates would trade off rewards accrued from using critical low-elevation habitat in winter for the safety of areas with reduced risk of predation. Sierra Nevada bighorn sheep did not trade off benefits of forage for reduced risk of predation but selected areas of high solar radiation, a correlate of vegetation productivity, where risk of predation by mountain lions was greatest, while mitigating indirect risk of predation by selecting for steep, rugged terrain. Bighorn sheep selected more strongly for areas where mountain lions were active, than for low-elevation habitat in winter, likely because mountain lions were most active in those areas of bighorn sheep winter ranges overlapping ranges of mule deer (Odocoileus hemionus), where both ungulates accrued forage benefits. We demonstrated reduced benefit of migration to low elevation during drought years, providing an alternative explanation to the predator-induced abandonment hypothesis for the disuse of low-elevation winter range observed during drought years.