Long-Term Range Fidelity in Rocky Mountain Elk

The validity and utility of applying results of home range analysis to long-term wildlife management objectives depends on the assumption that populations remain relatively faithful to such ranges over time, but such an assumption is rarely investigated analytically. We evaluated the home range fidelity of elk (Cervus elaphus) in 3 populations in southcentral Montana and northwestern Wyoming via comparison of home range use, size, and boundaries in 2 different time periods, 1979-82 and 1988-91, using 265 locations of 15 elk and 971 locations of 23 elk. Range use changed significantly in 2 of 3 populations between time periods (P < 0.01), but total size of home range (95% minimum convex polygon) changed in only 1 population (P < 0.05). Significant seasonal changes in elevational use accompanied changes in range boundaries and use in every season. Distances between radiocollared elk located simultaneously decreased in all seasons in 2 populations (P < 0.05), suggesting increasing herd cohesion and social stability. Changes in range use in different time periods consistently tended to increase spatial separation of populations of elk and to reduce densities of elk. Range boundaries of populations were fluid over time, suggesting boundaries and use of home ranges of larger populations of elk should be systematically reinvestigated at intervals of ≤10 years if accurate estimation of these parameters is important to management.