Comparative patterns of winter habitat use by muskoxen and caribou

Reestablished muskoxen populations are currently expanding in northeastern Alaska, both in numbers and in areas occupied (Reynolds, 1989). Because muskoxen have dispersed westward into areas occupied by Central Arctic Herd caribou, chances for forage and habitat overlap between these two species have increased. The objectives of this study were twofold: (1) to quantify the extent of resource use overlap at muskoxen and caribou winter feeding sites (those areas where snow had been cratered by the animals to gain access to forage), and (2) to describe late winter habitat selected by dispersing muskoxen. Comparison of muskoxen and caribou feeding site characteristics, including snow depth, snow hardness, location, and types of vegetation in feeding craters, was used to assess resource use overlap. The % relative cover of vegetation at feeding sites was also quantified. Microhistological analysis of feces collected at the feeding sites wil l also provide an index to diet of the two species. The study site was located in the Ivishak River drainage in northeastern Alaska. The Ivishak flows into the Sagavanirktok River, entering it approximately 95 km south of Prudhoe Bay. Both muskoxen and caribou overwinter in this area and were present during the late winter field studies in both years of the study. Feeding sites were located and marked in late March and Apr i l of 1990 and 1991. In 1990, 40 Rangifer, 12 (1): 3-4