ABSTRACT
This chapter utilizes the term steppe as conceived by African and Asian scientists to include all vegetation types within what has been designated as the semiarid region. While precipitation alone is considered to be a less exact indicator than indicators based on evapotranspiration, it is often used as a guide to arid climates subdivisions. A published MAB-UNESCO map divides the arid world into semiarid, arid and hyper-arid with an extension into sub-humid. The vegetation of the steppe is dominated by many species of grass and grasslike plants, forbs and shrubs. Members of Leguminoseae and Rosaceae are prominent, also assorted members of the Compositae, notably species of Artemisia. When mountains intrude, the increased moisture at higher elevation results in a more humid type of vegetation; when the plain is dissected by geologic or recent erosion, a more xerophytic vegetation is found. Fire is a destructive factor in maintenance of woody components.
