RESPONSE OF ELK TO INSTALLATION OF OIL-WELLS

Environmental disturbance can affect use of home range by large, free- ranging ungulates, but quantitative assessments of such effects are ra re. We compared seasonal and annual use of range and habitat in the po pulation of elk (Cervus elaphus) at Line Creek in southcentral Mortana , 1988-1991, before, during, and after installation of an oil well. Us e of range by elk during the post-drilling period in autumn was differ ent from use during drilling and pre-drilling periods, but use of rang e also changed during the same periods in another local population of elk not subjected to disturbance from oil drilling. Use of range grid cells containing or adjacent to the well site declined during the post -drilling period, but seasonal and annual sizes in range and boundarie s for the population were similar in all periods. Distances between in dividually marked elk did not differ across periods, suggesting that d rilling did not affect the social stability of elk. Use of forest habi tats in autumn increased after initiation of drilling. Results suggest ed that elk compensated for site-specific environmental disturbance by shifts in use of range, centers of activity, and use of habitat rathe r than abandonment of range.