The effects of ski area expansion on elk.

We documented responses of 2 populations of Rocky Mountain elk (Cervus elaphus nelsoni) to disturbances associated with ski-area expansion. Development at the first study site (Vail) consisted only of physical disturbances (disturbed ground = 3-5o/o), while development at the second study site (Beaver Creek) was primarily increases in human activity. Elk use at Vail after development decreased to 30/% of pre-development elk use. This decrease was primarily influenced by a decrease in elk use of the most developed bowl, where elk use in the first post-development year was 4% of pre-development levels. We detected no changes in use of the remaining, less developed bowls. We were unable to detect a statistical difference when we pooled elk-use data at the Beaver Creek study site, but when we analyzed each area within this study site, we detected a dramatic decrease in the number of elk observed in 1 area (elk use in the first post-development year was 2% of pre-development use). After development, elk use at the Beaver Creek study site was lowest when human activity was highest. Post-development elk use at both study sites indicated elk partially acclimated behaviorally because the number of elk seen increased linearly each year after development. Since these relationships may level off in later years, complete recovery should not be assumed.