In Montana, for example, the American Prairie organization is working to reverse the decline, understanding the bison’s critical role in shaping the biodiversity of the Great Plains. Allowed to roam freely across its 707-square-mile (1,831 sq km) nature reserve, the bison distribute a wide variety of seeds as they graze the vegetation—leaving clearings in which birds such as the thick-billed longspur and the ferruginous hawk can breed—and wallow in the dust and the mud, creating mini wetlands, ideal for all manner of insects, birds, and amphibians.
