Tropical grasslands are found in tropical wet and dry climates. These areas are hot year-round and usually very dry, but they do have a season of heavy rain. It is crucial that the rainfall is concentrated in six or eight months of the year, followed by a long period of drought when fires can occur. If the rain were well distributed throughout the year, many such areas would become tropical forest.
Poaching, overgrazing and clearing of the land for crops are the main threats. About 16 percent of tropical grasslands have been converted for agriculture or urban development. Desertification is also a significant threat.
Tropical savanna habitat is largely dominated by grasslands but with shrubland, woodland and gallery forest elements. Savannas of one sort or another also cover almost half the surface of Africa (about five million square miles, generally of central Africa) and large areas of Australia, South America, India the Myanmar-Thailand region, and Madagascar. These are warm or hot climates, subtropical to tropical, where the annual rainfall is from about 500 to 1300 mm per year. It is crucial that the rainfall is concentrated in six or eight months of the year, followed by a long period of drought when fires can occur.
In northern South America, savanna areas with waterlogged soil are known as llanos. Savanna vegetation in South Africa is sometimes known as bushveld, or veld. African savanna grasses are either high grasses (1.5 to 4.5 m tall) or shortgrasses (30 cm tall). The trees in African savanna are usually thorny and small-leaved; many are species of Acacia. Groups of trees such as palms or cactuslike Euphorbia species and single trees such as baobabs are also common.