Elk Habitat Use Patterns in the Shrub-Steppe of Washington

Abstract

Spatial and temporal habitat use patterns of elk (Cervus elaphus) in the shrub-steppe of Washington were studied from March through October 1983 and 1984. Four male and 4 female radio-collared elk were relocated a total of 782 times. Female elk preferred low elevation sagebrush associations during spring, late summer, and fall and riparian areas during the calving period and late summer months. Sagebrush stands were important bedding areas, particularly during late summer. Male elk selected sagebrush types during spring, summer, and fall. Elk preferred low elevation topographic zones. The distribution of natural springs was an important determinant of habitat use patterns for lactating female elk, but bull elk habitat use was less constrained by free water. Elk were active nocturnally. In the absence of extensive thermal cover, elk decreased thermoregulatory costs by bedding in sagebrush stands and by limiting major diurnal foraging bouts. The behavior of this population suggested that elk can be successful with limited cover under conditions of infrequent disturbance and adequate forage. J. WILDL. MANAGE. 50(4):664-669 North American elk have historically occupied a variety of habitats, but the desert and semi-desert regions of the West may not have supported elk in the past (Skovlin 1982). Presumably, low forage quality and quantity, scarcity of water, and high energetic costs of thermoregulation in the absence of extensive thermal cover made these regions poor elk habitat (Skovlin 1982). In contrast, a small nonmigratory herd of Rocky Mountain elk (C. e. nelsoni) colonized the Arid Lands Ecology (ALE) Reserve, a treeless shrub-steppe region of southcentral Washington in 1972 (Rickard et al. 1977); the population currently numbers approximately 55 elk. Summer use of steppe habitats by elk is atypical and exposes these animals to a thermal environment that is extreme compared to that experienced by most summering elk populations. Most Rocky Mountain elk populations are associated with coniferous forests (Bryant and Maser 1982), and the importance of forest cover has previously been shown (Beall 1976, Marcum 1976, Lyon 1979). Forest cover provides elk with thermoregulatory advantages in winter and summer (Beall 1976, Skovlin 1982) and security from disturbance (Morgantini and Hudson 1979). We studied the habitat relationships and behavior of elk on the ALE Reserve from March through October 1983 and 1984. In this paper we report on their spatial and temporal habitat use patterns. This work was supported by the U.S. Dep. Energy (Contract DE-AC06-76RLO 1830). We gratefully acknowledge the support of the Northwest Coll. and Univ. Assoc. for Sci. (NORCUS) and the Pacific Northwest Lab. We thank W. H. Rickard for his support and L. E. Eberhardt for assistance in the early stages of this investigation.