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The Ecosystems of the Plains

While in its most general geographic sense, a "plain" simply refers to mostly level terrain, and therefore can be forested or not -- in North America, "plain" often refers to temperate grassland or steppe. Indeed, the Great Plains of North America are some of the most extensive examples of this biome in the world, along with the vast grasslands of interior Eurasia and the pampas of South America. Sometimes seen as stark and sere, these are rich collections of ecosytems.

Grasslands
- Grasses dominate steppe and prairie ecosystems.
  
  The dominant organisms of the open plains are grasses, members of one of the largest families of flowering plants on Earth. Typical species include buffalo grass and big bluestem on the North American prairies and various feathergrasses and fescues on the Eurasian steppes. Possessing mostly hollow stems and slender leaves with parallel veins, grasses grow dense, matted root systems -- good for accessing scanty moisture and protecting the plant against the above-ground ravages of grazing animals, wildfires and winter. In the North American Great Plains, three zones of grasslands stretch from the east front of the Rocky Mountains to the Central Lowlands: shortgrass, mixed grass and tallgrass prairies. These ecosystems are mainly defined by differences in moisture, and they mingle at their frontiers -- the mixed-grass zone may have dry-adapted shortgrass species on uplands and more moisture-dependent tallgrasses in low swales.
Gallery Forests
- Gallery forests follow rivers and streams in rolling steppe.
  
  Gallery forests refer to the ribbons of timber shouldering streamcourses passing through open country. In the mixed- and shortgrass prairies of the Great Plains, gallery forests of cottonwood, willow, boxelder, ash and other hardwoods may be the only substantial timber cover for miles. They thus provide, in their habitat diversity and shady microclimate, crucial refuge for organisms of woodland and thicket for which the plains are otherwise unsuitable. The white-tailed deer is an example: This retiring ungulate favors the brush and shadow of river breaks in the Great Plains, while its relative, the mule deer, happily roams the open steppe and hills.
Outcrops and Badlands
- Tracts of badlands provide habitat diversity within the broader grassland biome.
  
  A flat or gently rolling steppe is often broken here and there with isolated outcrops of more resistant rocks. In other places, pliable sedimentary layers may be heavily eroded tracts of gullies, pinnacles and ridges called badlands, particularly along river drainages. Such patches of more rugged terrain serve as micro-ecosystems in the broader homogeny of open grassland. An outcrop on the shortgrass prairie might provide just enough moisture to permit the survival of a tree or two -- say, a pine or a juniper -- as well as a nesting site for a golden eagle, great horned owl or ferruginous hawk.
Wildlife
- American bison are iconic grazers of the North American grasslands.
  
  Large grazing mammals and fossorial (or burrowing) creatures are notable wildlife in the great steppes of North America and Eurasia. On the Great Plains, big grazers include bison, pronghorn, elk and mule deer; in Eurasia, wild horses, saiga antelope and Mongolian gazelle. Burrowing creatures like prairie dogs and gophers provide subterranean habitat and foraging grounds for a host of other animals like rattlesnakes, American badgers, black-footed ferrets and burrowing owls.

Nature