Abstract
Grasslands occurred on all continents, comprised almost 42 percent of the world’s plant cover, and once covered approximately 46 million km
2 of the Earth’s surface. Grasslands contain few trees or shrubs, are dominated by grasses (members of the family Poaceae), and have a mixture of nongraminoid herbaceous species called forbs. Plant families most abundant as forbs are sunflower (
Asteraceae) and pea (
Fabaceae) families. No single climate characterizes grasslands and they occur in areas of the Earth that receive as little as 200 mm of precipitation annually to areas that receive 1300 mm, and in areas where average annual temperatures vary from 0 to 30 °C (Oesterheld and others 1999, Risser and others 1981, Sauer 1950). Grasslands are not necessarily treeless and they are transitional to savannas, which are characterized by higher densities of drought-tolerant, fire-resistant trees. The ratio of trees to grass increases as precipitation increases (Anderson and Bowles 1999, Curtis 1971, Oesterheld and others 1999); in landscapes receiving >650 mm of precipitation, the trend is for increasing cover of woody species with “long-term fire exclusion” (Sankaran and others 2004). In areas of low precipitation, grasslands grade into desert communities. Common features found among grasslands include: periodic droughts, frequent fires, landscapes that are level to gently rolling, and an abundance of grazing animals (Anderson 1982, 1990; Risser and others 1981, Sauer 1950).
Parent Publication
Citation
Anderson, Roger C. 2012. Ecology and management of the Prairie Division. In: LaFayette, Russell; Brooks, Maureen T.; Potyondy, John P.; Audin, Lisa; Krieger, Suzanne L.; Trettin, Carl C. Eds. 2012. Cumulative watershed effects of fuel management in the Eastern United States. Gen. Tech. Rep. SRS-161. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 175-201.
