Abstracts Biological Sciences

Large mammal water use on the Barry M. Goldwater Range-East in Southwestern Arizona

by Jordan Calvert

As the global climate changes, the Sonoran Desert is predicted to have more extreme heat and less frequent precipitation. Because water is important for regulating body temperature as well as many other processes of basic survival, it is important to understand how dependent mammal populations are on free-standing water. My first chapter reports the current climate and future climate projections for the Sonoran Desert. It also discusses common adaptations that mammals have developed for survival in the desert. I review how dependent upon water desert mammal species are, and then discuss how these species will likely respond to future climatic conditions based on their water requirements. I determined that desert bighorn sheep (Ovis canadensis nelsoni), small mammals, bobcats (Felis rufus), and mountain lions (Puma concolor) are currently independent or semi-independent of water sites, while Coues white-tailed deer (Odocoileus virginianus couesi), mule deer (Odocoileus hemionus), and coyotes (Canis latrans) are currently dependent on water sites. This knowledge lets managers assess which species to devote the most resources to in coming years and sets a baseline for comparison of future patterns. The second chapter assesses site and weather related influences on the number of visits to water sites of six target species: desert bighorn sheep, bobcat, coyote, mountain lion, mule deer, and Coues white-tailed deer. Frequency of rain is the most important weather variable affecting water site use for all species in one or both years. Site-related variables varied in importance by species. All species except bighorn sheep preferred anthropogenic water sites, with white-tailed deer and mountain lions exclusively using these sites one or more years. Bobcats were not influenced by water site characteristics. This knowledge allows managers to place new water sites in areas that target species prefer. It also suggests that water sites should be closely monitored during seasons with infrequent rain. Advisors/Committee Members: Dabbert, Brad (committee member), Mulligan, Kevin (committee member), Griffis-Kyle, Kerry (Committee Chair).