Rangeland

Rangelands support plant communities that are dominated by species of perennial grasses, grass-like plants (or graminoids), forbs (non-graminoid, dicotyledonous plants), and shrubs. There are five basic types of rangelands worldwide: natural grassland, desert shrubland, savanna woodland, forest, and tundra. Grasslands do not have shrubs or trees growing on them. Desert shrublands are the most extensive and driest of the rangelands. Savanna woodlands are a transition between grasslands and forests, and contain herbaceous plants interspersed among scattered, low-growing shrubs and trees. Forests contain taller trees growing closer together than in savanna. Tundra areas are treeless, level plains in the Arctic or at high elevations of mountains.

North American rangelands consist of: (1) the prairie grasslands of the midwestern United States and extending into Canada, as well as parts of California and the northwestern states; (2) cold desert rangeland in the Great Basin of the United States, and hot desert (Mojave, Sonoran, and Chihuahuan) of the southwestern United States and northern Mexico; (3) open woodlands from Washington state to Chiuhuahua, Mexico, and in the Rocky and Sierra-Cascade Mountains; (4) forests (western and northern coniferous, southern pine, and eastern deciduous); and (5) alpine tundra (mostly in Alaska, Colorado, and western Canada) and arctic tundra (in Alaska and northern Canada).

There are more than 283-million hectares of natural range ecosystems in the United States. However, much of the United States prairie grasslands have been converted to agricultural land-use. In addition, excessive grazing and fire suppression have allowed the invasion of prairie by species of woody plants, such as mesquite, in some regions.