of the western USA. The federal management units where horses occur fall disproportionately in fragile, arid landscapes managed under a multiple-use paradigm. These environments harbor a variety of native ungulate species, each with their own state or federal protections. Additionally, grazing permits and livestock production are statutory and regulated uses within most federal units delineated for the conservation of free-roaming equids. Previous research has examined how free-roaming horses grazing can influence floristic diversity, biomass production, soil structure, and riparian health. These effects have the potential to negatively affect livestock production and alter habitat sympatric wildlife species. This project is aligned with supporting rural economies and protecting wildlife to support recreational hunting.Because horses exhibit rapid population growth, a wide dietary niche, and require regular access to water, concerns about direct and indirect competition with sympatric ungulates are well-founded. Nonetheless, the degree to which horses and wildlife share or compete for space and resources is poorly understood.The project"s aim is to fill DOI data needs with collaborative research conducted jointly by USGS and University partners, capitalizing on the unique skillset and talents provided by modelers and data analysts who have experience modeling with extreme large datasets across multiple species.Specific research will model data collected over the first year in Utah USA, from 5 sympatric species. Results have implications for wild horses across the American west, that span the Rocky Mountain region and Great Plains ecosystems.The goal of this project is to evaluate and model the spatial and temporal distribution of resource partitioning and potential resource competition between free-roaming horses, livestock, and two native ungulate species in a shared environment, and to relate this information to public land managers to protect natural resource assets that belong to the American people, to support rural economies, protect a tradition of hunting in the western USA, improve management of horses on the landscape, and improve management of habitat. Research Objectives:1. Model seasonal resource selection of free-roaming horses, mule deer, pronghorn, cattle, and domestic sheep, pre- and post-horse gather.2. Model the role of perennial surface water and high-quality forage in movements, home range, and resource use of each species.3. Measure seasonal home range size and configuration for each species, pre- and post-horse gathers.