Technical Abstract: Gray wolf populations in Idaho, Montana, and Wyoming have rapidly increased since their reintroductions in 1995. Past research efforts have examined some of the direct effects (e.g., cattle depredation losses) of recolonizing wolves on wild and domestic ungulates but their indirect effects on ungulate habitat use patterns and consequent impacts on riparian and stream water resources are still unknown. ARS scientists and research cooperators are evaluating the habitat use and activity patterns of cattle, elk, and gray wolves on grazing allotments in the Copper Basin of central Idaho. A high-resolution habitat map is being developed for the study area by the ARS and the USFS Remote Sensing Applications Center using aerial photography, satellite imagery, and GIS data. The GPS-based, Clark Animal Tracking System is being used to track the locations, activity, and interactions of collared cattle, elk, and wolves. The habitat map, tracking system data, and other research results will be used to provide livestock producers and natural resource managers with an understanding of how the presence of gray wolves may alter ungulate behavior and consequent ungulate impacts on riparian systems and stream water quality.