Kanalu Sproat, Brigham Young University
Native to western North America, bighorn sheep populations experienced significant declines after European settlement (Buechner 1960, Krausman 2000). Though historical abundance estimates vary between 500,000 and 2 million (Seton 1929, Buechner 1960), numbers decreased to <15,000 for all subspecies (Towell and Geist 1999). Overhunting, direct competition with livestock, habitat fragmentation, displacement, and disease introduced by domestic livestock had all played a role in this decline (Buechner 1960, Berger 1990). Consequently, bighorn sheep conservation has become a priority for several state and provincial agencies.
Canyonlands National Park (CNP), and its bordering canyons, is home to one of the only remaining natural populations of desert bighorn sheep (Ovis canadensis nelsoni) in Utah. Bighorn sheep research in CNP first began in the 1960s. The first radio-telemetry collars were fitted on bighorns in the 1980s (Bates and Workman 1983), and several telemetry projects have taken place since then. In January 2009 the Utah Division of Wildlife Resources (UDWR), in cooperation with the Bureau of Land Management (BLM) and the National Park Service (NPS), captured and fitted 21 bighorn sheep with Global Positioning System (GPS) collars.
Together, these agencies established the following six objectives, forming the foundation of this research project:
I. Determine movements of bighorn rams and ewes using ongoing GPS radio-telemetry data. Analysis of movement data will include mapping ram migration routes and comparing home range information from ewes in high and low impact areas.
II. Develop bighorn/habitat association model, based on habitat data collected at known sheep locations, which will predict suitable sheep habitat and migration corridors.
III. Compile and standardize previously-collected radio-telemetry and survey data from several research projects conducted in the Canyonlands area.
IV. Develop and populate a database compatible with NPS and DWR databases to house data compiled under Objective 3 as well as ongoing data.
Potash Desert Bighorn Sheep Research Kanalu Sproat
V. Determine bighorn survival and recruitment rates, home ranges, and probable causes of mortality from previously-collected data.
VI. Determine correlation of previously-collected bighorn movements and demographics with human activities.
This is the final status report for the Potash Desert bighorn sheep research project, with a follow up presentation of the database to be scheduled in March 2012. To read the entire reportis available here.