Relative Palatability of Seven Artemisia Taxa to Mule Deer and Sheep

Abstract

Relative preference for seven important sagebrush taxa in Oregon was established for mule deer and domestic sheep. Mule deer showed highest preference for low sagebrush (A rtemisia arbuscula ssp. arbuscula), mountain big sagebrush (A. tridentata ssp. vaseyana), foothill big sagebrush (a recently recognized variant of mountain big sagebrush) and Bolander silver sagebrush (A. cana ssp. bolanderi). They showed intermediate preference for basin big sagebrush (A. tridentata ssp. tridentata) and Wyoming big sagebrush (A. tridentata ssp. wyomingensis) and least preference for black sagebrush (A. nova). Sheep showed highest preference for low sagebrush and medium preference for black sagebrush. They utilized but did not prefer, Bolander silver sagebrush and mountain and foothill big sagebrush and they showed least preference for Wyoming and basin big sagebrush. Genetic variation between kinds of sagebrush taxa influenced animal preference more than environmental variation within a taxon. Although many articles have been written regarding utilization of sagebrush by both native and domestic animals, confusion still exists regarding which sagebrush taxa are preferred by animal consumers. Two trends in sagebrush utilization by deer are evident in the literature: ( 1) Heaviest use occurs during the winter months, (2) Taxa most often mentioned include big sagebrush (A. tridentata) and low sagebrush (A. arbuscula) (Smith 1950, Kufeld et al. 1973). Likewise with sheep, most utilization takes place during the winter season. Big sagebrush and black sagebrush (A. nova) are the two taxa most often associated with sheep use. Most past research involving utilization of sagebrush has been based on recognition at the generic or, at best species level. A considerable amount of recent literature has shown that species, subspecies, and forms exist, each with their own morphological characteristics and environmental requirements (Beetle 1960; Beetle and Young 1965; Tisdale et al. 1969; Winward and Tisdale 1977; Hanks et al. 1971; Brunner 1972; Hanks et al. 1973, McArthur et al. 1979). Only a few researchers have studied sagebrush utilization at the subspecies and form level under controlled or semicontrolled experimentation (Hanks et al. 1971; Hanks et al. 1973; and Scholl et al. 1977). The purpose of this study was to evaluate relative animal preference for seven important sagebrush taxa in Oregon under conditions where all seven taxa were available for selection. The seven taxa studied included: (I) Artemisia arbuscula Nutt. ssp. arbuscula-low sagebrush (Lo), (2) A. cana ssp. bolanderi (Gray) Ward Bolander silver sagebrush (Bo), (3) A. nova Nelson black sagebrush (B 1), (4) A. tridentata ssp. tridentata Nutt. basin big sagebrush (Ba), (5) A. tridentata ssp. vaseyana (Rydb.) Beetlemountain big sagebrush (Mo), (6)A. tridentata ssp. wyomingensis Beetle Wyoming big sagebrush (Wy) and (7) a relatively low Authors are former graduate research assistant and associate professor. Rangeland Resources Program, Oregon State University, Corvallis, respectively. Mr. Sheehy is presently a rancher in Wallowa, Oregon, and Dr. Winward is regional ecologist for the US Forest Service, Intermountain Region, Ogden, Utah. This article was submitted as Technical Paper No. 5392. Oregon Agricultural Experiment Station, Corvallis. Manuscript received January 28, 1980. elevational variant of A. tridentata ssp. vaseyana referred to in this paper as foothill big sagebrush (Fo). Nomenclature follows Beetle (1960) and Beetle and Young (1965) except for the last taxon which was encountered in Oregon but at the present time is not an officially recognized subspecies.