WILDLIFE AND AGRICULTURE
Habitat destruction, degradation, and fragmentation, brought about primarily from agricultural development, have greatly changed the landscape of the Great Plains and, concomitantly, the wildlife that reside there. More than 325 million acres in the Great Plains are farmed. Only 1 percent of the original tallgrass prairie remains. The oak savanna, small in area in the Great Plains, is also greatly reduced. Both ecosystems were largely converted to farms. The mixed grass prairie has been impacted to a lesser extent, although it also has been substantially reduced. The shortgrass prairie is relatively intact, although portions have been degraded through overgrazing and fire suppression. Mixed grass and shortgrass prairies that were grazed were less severely altered by agriculture. Wetlands were drained, converted to agriculture, or lost due to lowering the water table caused by irrigation. Habitat fragmentation may result in the demise of area-sensitive species (those needing a minimum size habitat). Further, isolation of habitats makes it easy for small populations to become extinct and difficult for colonizers to repopulate an area.
Prior to European American settlement the Great Plains was teeming with wildlife: large ungulates such as bison, pronghorns, deer, elk, and bighorn sheep; predators, such as wolves, grizzly bears, and black bears; prairie dogs in the billions; and numerous turkeys and prairie chickens. Millions of acres of wetlands provided breeding habitat for waterfowl and resting and feeding areas for other migratory birds. All that changed with settlement by European Americans. The large ungulates were decimated through wanton shooting, unregulated harvest, and as a military strategy to deprive Native Americans of a source of food. Although this was not the direct effect of agriculture, the decline of those animals was seen as necessary so that cattle could flourish and the prairie could be converted to farmland. Predators perceived as a threat to livestock or animals that competed for forage with livestock were eliminated; or at least, efforts were made to eliminate those animals.
Relatively few species are endemic, or unique, to the Great Plains. Endemic birds that are declining include mountain plover, Sprague's pipit, Cassin's sparrow, and lark bunting. Endemic mammals that are declining include white-tailed jackrabbit, Franklin's ground squirrel, black-tailed prairie dog, and swift fox. Two birds native to the Great Plains– McCown's longspur and the ferruginous hawk–experienced an increase in population over the past twenty-five years. Both species are characteristic of shortgrass prairies and thrive in moderate to heavily grazed systems.
The Great Plains now consists of extensive areas of cultivated crops. The net result of this habitat uniformity has been a loss of richness in the number of species. At a distance croplands may appear like grasslands, but their management results in barren areas after harvest. Existing small areas that cannot be farmed because of thinness of soil or terrain, as well as areas that have been planted with trees, create "edge," which is ideal habitat for some species. Examples of species that have responded positively to farm habitats include ring-necked pheasants (an exotic), northern bobwhite, blue jay, house sparrow (another exotic), raccoon, opossum, red fox, and coyote.
In turn, wildlife has a significant impact on agriculture. In the United States, annual losses of agriculture to wildlife are about $500 million, with over half of that attributed to damages to field crops. Economic benefits from wildlife are also substantial. For example, estimated annual benefits associated with whitetailed deer in the United States are nearly $20 billion. However, those benefits are diffuse and shared by various businesses and communities, whereas damages impact the agriculturalist directly.
See also PHYSICAL ENVIRONMENT Endangered Species.
Ronald M. Case University of Nebraska-Lincoln
Licht, Daniel S. Ecology and Economics of the Great Plains. Lincoln: University of Nebraska Press, 1997.
Noss, Reed F., and Allen Y. Cooperrider. Saving Nature's Legacy: Protecting and Restoring Biodiversity. Washington DC: Island Press, 1994.
Samson, Fred B., and Fritz L. Knopf, eds. Prairie Conservation: Preserving North America's Most Endangered Ecosystem. Washington DC: Island Press, 1996.