Foraging Ecology of Bison and Cattle on a Mixed Prairie: Implications for Natural Area Management

Abstract

There exists considerable uncertainty whether differences between bison () and cattle (Bos taurus) should be exploited in natural area stewardship. Because foraging ecology may prescribe the fundamental relevance of either herbivore, we describe the foraging of bison and cattle on a northern mixed prairie natural area and discuss management implications. As generalist foragers, bison and cattle exhibited seasonal differences in selection for or against C"3 graminoids, C"4 grasses, forbs, and browse. Forty-eight hour in vitro dry matter digestibilities of C"3 graminoids and C"4 grasses were greater by bison than cattle, but equal digestive efficiencies were exhibited for forbs and browse. Dietary in vitro dry matter digestibility and crude protein differed little between herbivores. Cattle allocated more time to grazing than bison did during summer. Our study suggests that the relationship between feeding-time investment and forage patchiness is important in determining differences in diet choice between bison and cattle. In contrast to cattle, it appears that bison balance nutrient and time demands during the rut by consuming almost exclusively graminoids. Apparently, bison and cattle may achieve similar dietary quality through different foraging behavior. We suggest that specific scale-dependent programmatic conditions exist where either herbivore may be the most appropriate for natural area management.