Monitoring Key Vital Rates of Northern Yellowstone Elk After Wolf Recovery

The restoration of wolves to Yellowstone National Park during 1995–96 created a new degree of complexity that makes it difficult to project long-term trends in elk abundance. Since wolf restoration, the Yellowstone Center for Resources has partnered with biologists from other federal, state, and private institutions to conduct investigations of

1. wolf functional (e.g., kill rates) and numerical (e.g., abundance) responses
2. elk population demographics
3. elk and wolf behavioral adjustments
4. woody vegetation responses to changes in elk densities.

Once this intensive five-year program was completed, we implemented a long-term monitoring program of the following key vital rates and limiting factors indicative of elk dynamics:

1. cause-specific mortality and survival rates for adult females
2. indices of recruitment
3. population counts
4. age-specific reproductive rates
5. age structure
6. human harvest
7. weather conditions (e.g., drought, snow pack)
8. disease

This monitoring enables us to evaluate the relative effects of disease, harvests, land use, predation, and environmental factors (e.g., drought, snow pack) on elk demographics and population trends, and ensure that impacts do not harm the integrity of this valuable resource.

Updated 7/28/10