The role of herbivores in grassland ecosystems is an important topic debated by ecologists and ecosystem managers for over a century. The Great Plains of North America are central to this discussion as most of the flora and fauna evolved with significant impact from large herbivores and other periodic disturbances. Until their near extirpation in the late 1800s, American bison (Bison bison) was the keystone herbivore on unfragmented landscapes, having shared them with other herbivores and predators for nearly 10,000 years (Knapp et al. 1999; Anderson 2006). Since their near extinction, the vast and complex landscapes that contained the roaming herds have in most places been replaced by fragmented agricultural lands where domestic cattle are the dominant grazers on prairie remnants and the few remaining large natural landscapes. Through the 1900s, restoration and conservation of bison was pursued by private citizens, conservation organizations, and government agencies. Since then, additional groups have become interested in the conservation and management of grassland ecosystems, with principle goals of restoring critical processes and functions.