Survival and habitat utilization of desert bighorn sheep translocated to the Santiago Mountains, Texas

• Main Author: Cross, Joshua G
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2016
• Subjects: Natural Resource Management; Wildlife Conservation; Wildlife Management
• ISBN: 1339929287; 9781339929286

Desert bighorn sheep (Ovis canadensis) restoration began in Texas in the 1950s when native populations were rapidly declining. By the 1960s all native bighorn had been completely extirpated, and translocations from other areas were implemented as a restoration tool. In December 2012, 44 desert bighorn sheep (22 M, 22 F) were transplanted from Elephant Mountain Wildlife Management area to the Santiago Mountains. Forty (18 M, 22 F) of the translocated bighorn were fitted with radio collars in order to monitor survival and determine their movements. Annual survival estimates for rams were 0.73 and 0.56 (2013 and 2014, respectively), and estimates for ewes were 0.95 and 1.00 (2013 and 2014, respectively). The mortality causes were attributed to contagious ecthyma (n = 5), undeterminable causes ( n = 3), broken jaw/infection (n = 1), ingestion of toxic vegetation (n = 1), and mountain lion ( Puma concolor) predation (n = 1). A total of 68,176 location points was acquired from the deployed collars and utilized for home range and habitat analysis. The average general (0.95) utilization distributions (UD) for rams were 52.13 km2 and 31.20 km2 (2013 and 2014, respectively), and general UDs for ewes averaged 17.35 km 2 and 19.00 km2 (2013 and 2014, respectively). The translocated desert bighorn sheep selected for average slopes of 52.1% and 61.2% (rams and ewes, respectively) and average ruggedness values (Terrain Ruggedness Index) of 307.1 and 324.9 (rams and ewes, respectively). Home range estimation and habitat utilization were all analyzed throughout 4 3-month biological seasons, in addition to the overall estimates. The results of this study verify the viability of this study site as quality desert bighorn sheep habitat. These results suggest that future restoration efforts focus on areas with similar attributes when considering translocation sites.