ABSTRACT
Grasslands are the ecological arena where human genetic and cultural evolution occurred. This has proven to be a mixed blessing at best for these ecosystems. Any consideration of the evolutionary ecology of the Great Plains must include a description of their geographic extent and biogeographical affinities. This is a challenging problem for two reasons. First, the plains have been so heavily disturbed historically that it is difficult to reconstruct their primitive condition. Second, this great grassland apparently did not develop its maximum treeless extent until (post-Pleistocene) times, and there are few endemic species to indicate its limits. The species richness for gomphocerines is greatest in parts of the Southwest, and the numbers decline as one moves north toward Canada or south into Mexico. The North American central plains also support a large number of gomphocerines, especially when compared to adjacent areas to the east and west.
