Winter Range Expansion by the Northern Yellowstone Elk Herd

Abstract

We examine and describe changes in northern Yellowstone elk (Cervus elaphus) winter distribution, population size and harvests from 1975-1997. Since the late 1970s, northern Yellowstone elk have expanded their winter range by 41 percent to about 152,663 ha. During this period, elk winter range north of Yellowstone National Park (YNP) has more than doubled from 22,179 ha to 53,262 ha. Since 1988-89 the number of elk wintering north of YNP has averaged 5,460 elk/year (1,533-8,626) with 2,000-4,500 elk wintering north of Dome Mountain where few Yellowstone elk wintered prior to 1988-89. Minimum fall elk population estimates increased from 11,149-12,941 animals in the late 1970s to a mean of 17,409 ± 1,377 (SD) elk based on nine annual counts conducted between 1981-82 and 1994-95. Minimum winter (posthunting) numbers averaged 15,520 ± 2,324 (SD) elk for the same period. With more elk migrating out of YNP, late season elk harvests increased 64 percent from 892 ± 506 (SD) elk/year from 1979-80 to 1987-88 to 1,459 ± 815 (SD) elk/year from 1988-89 to 1996-97. Winter range expansion, elk migration behavior, and increased winter harvests dispelled earlier concerns that winter hunts would prevent elk from using all available winter range. Challenges facing the management of Yellowstone elk north of YNP include harvesting enough elk to maintain the long-term diversity and productivity of winter range vegetation, resolving land use conflicts with elk expanding into Paradise Valley, and addressing growing concerns about the possible transmission of the disease brucellosis from elk to domestic livestock.