Dr. Jeffrey L. Beck

Ecosystem Science and Management

Habitat Ecology and Effects of Habitat Alteration for Bighorn Sheep Translocated to the Seminoe Mountains, Wyoming

Photo of the southern face of the Seminoe Mountains.

This area was targeted for habitat alteration through prescribed burning. Notice the mosaic created by the burn in the low-elevation areas, as well as burned timber pockets higher on the face to create travel corridors, providing bighorn sheep better access to high-elevation habitat.

M.S. Student: Justin G.Clapp

• PDF in The Rampage
• Thesis

Bighorn sheep (Ovis canadensis) populations dramatically declined throughout their range in the early 20^th century, with multiple populations extirpated from their historical habitats. Efforts to restore bighorn sheep to historical ranges in Wyoming have been ongoing since the early 1900s and numerous translocation efforts have been undertaken to restore bighorn populations to historical habitat and augment waning populations. The Seminoe Mountains (approx. 40 mi north of Rawlins, WY) are one of many isolated, low elevation mountains in central Wyoming that historically held populations of bighorn sheep. Bighorn translocation efforts in the Seminoe Mountains began in 1958 and continued until 1985, including 6 translocation operations totaling 237 individuals (Wyoming Game and Fish Department [WGFD] data). Despite these efforts, bighorn sheep restoration efforts have proven difficult. Recent translocation efforts by the WGFD have been conducted to ensure that habitat conditions for the source population match those of the release area. Therefore, low-elevation, non-migratory bighorns where specifically chosen from areas in central Oregon and north-central Wyoming where habitat and life-strategy adaptations are commensurate to the Seminoe area. In total, three separate translocation efforts in 2009 and 2010 resulted in releasing 52 bighorns into the Seminoe Mountains.

From 2009-2011, GPS and observational data (location data, lamb chronology and survival, resource selection, recruitment, and mortalities) were collected to monitor bighorn sheep translocated to Seminoe Mountain. From these data, a preliminary 6 month analysis of bighorn distribution was conducted using GPS data, indicating that much of the habitat modeled as “high quality” remained unused, with most individuals utilizing only the perimeter of the range. It was hypothesized that dense vegetation and timber encroachment may be hindering bighorn access to high-quality habitat. Because the Seminoe Mountains have restricted amounts of livestock grazing in addition to increased fire suppression efforts, the Rawlins Bureau of Land Management (BLM) scheduled prescribed burning for portions of the mountain beginning in the spring of 2011. The focus of the burn was to mitigate timber encroachment and improve overall forage quality.

Our study focuses on utilizing the 2009–2011 data collected as a base-line assessment for bighorn sheep translocated to the Seminoe Mountains; identifying distribution, demographics, resource selection, and temporal and spatial localizations. We will then use current GPS data from a recapture conducted in December 2011 (data to be collected through 2013) to analyze the efficacy of the prescribed burn by identifying potential changes in resource selection, identifying travel corridors that allow better connectivity and utilization of high-quality habitat, and compare bighorn sheep demographics before and after the habitat alteration. Our specific objectives are to: (1) create and refine multi-seasonal resource selection models for bighorn sheep translocated to the Seminoe Mountains, (2) evaluate the effect of prescribed burning on bighorn sheep distribution and demographics, and (3) compare post-release bighorn sheep localizations with similar translocations in Wyoming. Through this research, it is our intent to provide managers with insight into factors that may increase the success of bighorn sheep translocations in similar or adjacent habitats. This includes improved predictive models during site selection for potential translocations, utilizing effective habitat alterations and their influence on low elevation bighorn sheep, and a better understanding of post-release bighorn movements and localizations.