Range Animal Diet Composition in Southcentral Wyoming

Abstract

Because of the ongoing controversy about shrub forage value for different ungulates and significance of the shrub communities for spring-fall grazing in southcentral Wyoming, the relative importance of various forage classes was determined by fecal analyses in the spring, summer, and fall diets of pronghorn (Antilocarpa americana Ord), mule deer (Odocoileus hemionus hemionus), elk (Cervus elaphus), cattle (Bos taurus), and domestic sheep (Ovis aries) in the mountain brush and Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young) plant communities. Mountain big sagebrush (A.t. ssp. vaseyana Rydb. Beetle) comprised 76% of pronghorn spring diets in the mountain brush plant community, and Wyoming big sagebrush comprised 91% of the pronghorn spring diets in the Wyoming big sagebrush plant community. Antelope bitterbrush (Purshia tridentata Pursh.) comprised about 80 to 90% of the pronghorn and deer summer and fill diets in the mountain brush plant community. Graminoids, primarily Bromus, Carex, Juncus, and Stipa spp., made up 80+% of elk, cattle, and sheep diets in either plant community. Forbs and shrubs other than sagebrush or bitterbrush were a minor component of either plant community and diets of any of the 5 kinds of animals. A shrub management program to maintain species diversity while increasing bitterbrush and graminoid production under common use grazing by both browsers and grazers is recommended for this area.