Elk, mule deer, and white-tailed deer are valued as ecological, cultural and economic resources in Washington State. Ungulate population dynamics reflect competition for resources, habitat quality, terrain, weather and multiple causes of mortality. Wolves, cougars, bobcats, coyotes and black bears consume deer and elk in Washington, while human harvest, vehicle collision, domestic dogs, disease, and malnutrition cause additional ungulate mortality. We expected that the recolonization of wolves could lead to changes in the density and behavior of other predators in the wildlife community, with cascading impacts on these shared prey species.
Our aim was to determine how wolf presence influenced deer and elk populations within a complex wildlife community. Specifically, we sought to explain the degree to which deer and elk were controlled by bottom-up effects (i.e., available forage) and top-down effects (i.e., predation or harvest), and which factors these populations were most sensitive to. We also investigated how predator presence and density influenced the movement and habitat use of deer and elk.
To answer these questions, we fit Global Positioning Satellite (GPS) collars on juvenile and adult female mule deer, white-tailed deer, and elk. Mule deer were the focal species within the Okanogan County study area, whereas sympatric white-tailed deer and elk were the focus in the northeast. We monitored the movement and survivorship of these animals from January 2017 - June 2021. Mortalities were investigated using genetic evidence, tracks, and sign to determine the cause of death. From this information, we are determining how wolves and other carnivores shape the productivity of deer and elk populations, and how deer and elk change their movement in response to nutrition, habitat structure, and predation risk. Funding: WDFW, The Rocky Mountain Elk Foundation, The Hall Conservation Genetics Research Fund UW Project Leads: Laura Prugh (PI), Taylor Ganz (PhD Student)