Analyzing Management Methods for Isolated Bighorn Sheep Populations: a Teton Sheep Case Study

This thesis addresses the issue of conserving isolated populations of bighorn sheep (Ovis Canadensis) by focusing on the Teton bighorn population in western Wyoming, U.S.A. Bighorn sheep have experienced widespread habitat fragmentation across western North America due to human development. Bighorn sheep have inhabited the Teton Range for over 10,000 years, and endured significant winter range destruction beginning in the early twentieth century. As the town of Jackson became known as a tourist destination, human development in the valleys on either side of the Tetons took off. At some point in the early twentieth century, Teton bighorns ceased migrating into these valleys during the winter. In place of a seasonal migration pattern, Teton sheep now employ “abbreviated migration” - descending into canyons in spring and fall to graze on vegetation before returning to alpine environments at elevations of around 10,000 feet (3000 meters) for winter and summer. Threats to Teton sheep are numerous - the population has separated into two distinct herds, both of which consist of approximately 60 animals. Inbreeding, a lack of genetic diversity, human disturbance, and invasive mountain goats all pose threats to this vulnerable population. Teton bighorn sheep are in need of a conservation strategy that will strengthen these herds’ resilience to these threats. This project used Global Imaging Software (GIS) to analyze risk factors present in the Tetons. Conservation techniques for isolated populations of migratory ungulates were researched and applied to the Teton bighorn population. Conclusions from this work are as follows: increasing the size of seasonal bighorn sheep closures is a necessity to give animals room to graze and disperse without human interactions. An augmentation should be performed with sheep from a neighboring herd to increase genetic diversity, disease resilience, and overall fitness. Awareness of the vulnerable Teton bighorn population should be spread in communities surrounding the Tetons to foster a greater understanding for how recreationists can limit their impact on wild sheep