Recently Dave Christianson at the School of Natural Resources and the Environment and Eric Cole from the U.S. Fish and Wildlife Service, National Elk Refuge, presented the culmination of several years of work on elk and bison in the Greater Yellowstone Ecosystem at the 12th Biennial Scientific Conferenced on the Greater Yellowstone Ecosystem in Yellowstone National Park in Mammoth, Wyoming. Despite every attempt by a large aggressive bull elk in the heat of the annual fall rut to keep Dave pinned down in the parking lot of the conference center, he managed to give a presentation titled “Ungulate use of primary productivity in the Greater Yellowstone: climate change, migration, and complex management”. Summarizing data collected over 10 years from elk and bison populations across southwest Montana and northwest Wyoming, this research represented collaborative work with multiple state and federal agencies. Dave demonstrated new non-invasive tools to measure how ungulates use primary productivity in such highly seasonal environments. This work is also outlining the challenges of measuring the effects of climate change on animals that migrate over vast distances, crossing multiple management jurisdictions, all while expressing complex foraging behavior that is still poorly understood.
The gif below shows the trend over the last 14 years of NDVI at different elevations with the seasonal range of the Jackson Elk Herd in Wyoming. Elk move along the elevation gradient in spring to exploit newly emerging vegetation and then are forced back down the elevation gradient in fall when deep snow begins to impede movement.