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Wild Horse Behavior and Pattern Analysis

Wild horses are an important species in western landscapes. They have been recognized as a symbol of American culture and freedom. Additionally, these animals impact rangeland environments including plant communities, hydrology, and soil stability. Our research evaluates the distribution and habitat use of wild horses on the Sheldon National Wildlife refuge in northwestern Nevada.

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Megan Nordquist collecting horse hair to measure stable isotopic composition in comparison to available forages.

Pronghorn Behavior in Association with Wild Horses at Water Sources

MS student Amy Gooch observed wild horses and pronghorn at water sources to identify behavioral patterns in pronghorn when horses were present or absent. Results indicated that horses do displace pronghorn at water sources through direct competition. This results in greater vigilance behavior when horses approach pronghorn near water.

Gooch, A.J. 2014. The impacts of feral horses on the use of water by pronghorn on the Sheldon National Wildlife Refuge, Nevada. M.S. Thesis. Brigham Young University. Provo, UT.

Identify Wild horse diet and habitat selection patterns

Wild horses utilize a variety of different plant species for forage. The species and habitats they use vary across seasons. For example, during summer months, shrubs were the preferred plant species compared to basin wildrye and Baltic rush which were more highly consumed in the fall. In the winter, shrubs were more heavily consumed along with Sandberg’s bluegrass. Springtime showed a shift towards flowering plant consumption. Changes in seasonal consumption of forages are most likely linked to forage availability as well as equine preference. There was greater forage species available near riparian areas. Weedy species, including cheatgrass, had greater biomass in horse occupied sites. Megan Nordquist conducted her MS research comparing the stable isotopic composition of the possible forage plant species with isotopes of horses tail hair. She found that the diet can be detected across seasons using this approach.

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Horses foraging on native bunchgrasses in a sagebrush steppe ecosystem on the Sheldon National Wildlife Refuge.

Nordquist, M.W. 2012. Stable isotope diet reconstruction of feral horses (Equus caballus) on the Sheldon National Wildlife Refuge. M.S. Thesis. Brigham Young University. Provo, UT.

Determine the distribution and homerange of horses using GPS collar technology

We are measuring the movement patterns and distribution of wild horses in northwestern Nevada. Using GPS collar technology, we have been able to track bands of horses for upwards of two years or more. The first phase of our research was to develop a GPS collar that would not injure the animals being monitored (Collins et al.). We are now using that data to develop resource selection functions that help us predict habitat use preferences.

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Collins, G.A., S.L. Petersen, C.A. Carr, and L. Pielstick. 2014. Testing GPS/VHF collar design and safety in the study of free-roaming horses. PLoS One Sep 8; 9(8):e103189.

Spatial Bibliography

Visit an interactive map showing the distribution of published studies throughout the United States and Canada. Searches can be performed by author or title.