Effects of nonmotorized recreation on ungulates in the western United States—A science synthesis to inform National Environmental Policy Act analyses

Federal land managers increasingly need clear science to evaluate how nonmotorized recreation affects ungulates. This U.S. Geological Survey synthesis compiles published research on recreation characteristics, ungulate exposure and behavioral responses, and methods for assessing impacts across the western United States. Key factors shaping effects include the timing, intensity, duration and spatial distribution of recreation, as well as species‑specific traits such as diet, migration and seasonal biology. Analytical approaches range from simple buffer‑based spatial assessments to advanced models of displacement and avoidance. Mitigation options include timing restrictions, type‑of‑use limits, recreator education and project design features that reduce conflict. The synthesis supports NEPA analyses and helps managers identify knowledge gaps and evaluate recreation‑related disturbance to ungulates.