Abstract - Range Ecology of Bison on Mixed Grass Prairie at Wind Cave National Park
Popp, Jewel Kay. 1981. Range Ecology of Bison on Mixed Grass Prairie at Wind Cave National Park. M.S. Thesis. Iowa State University, Ames, Iowa. 59 p.
Information pertaining to habitat use by bison (Bison bison) at Wind Cave National Park (WCNP) should contribute to management of that herd as well as to the understanding and appreciation of other bison herds inhabiting similar habitat. The seasonal range use patterns and food habits of bison at WCNP were studied in 1978 and 1979. Mixed herds preferred cool season sites and avoided warm season sites for all of their activities throughout the year. Mixed herds preferred prairie dog towns in the late summer during their breeding, but prairie dog towns were strongly avoided at other times of the year. Bull groups also generally preferred cool season sites and avoided warm season sites but avoided prairie dog towns at all times of the year. There was a high degree of similarity during all seasons in range use by mixed herds and bull groups, and significant (p < 0.05) positive rank order corrections during the spring, early summer, and winter. Seasonal variation was detected in bison diets. Cool season graminoids, such as bluegrass (Poa spp.), sedges (Carex spp.) and western wheatgrass (Agropyron smithii), usually dominate bison diets, but the proportion of warm season grasses, such as grama-like shortgrasses (Bouteloua spp. and Buchloe dactyloides) and blue stem (Andropogon spp.) increased during the summer. Forbs and browse were a minor portion of bison diets. There was a high degree of similarity and significant (p < 0.05) positive rank order correlations for seasonal diets of bison mixed herds, calves and bull groups. Key forage species for all bison were Kentucky bluegrass (Poa pratensis), blue grama (Bouteloua gracilis) and bluestem. Threadleaf sedge (Carex filifolia) was a key forage species for bull groups.