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TROPICAL GRASSLANDS (SAVANNAS)

Location

Tropical grasslands are located near the equator, between the Tropic of Cancer and the Tropic of Capricorn. They cover much of Africa as well as large areas of Australia, South America, and India.

Plants

Tropical grasslands are dominated by grasses, often 3 to 6 feet tall at maturity. They may have some drought-resistant, fire-resistant or browse-resistant trees, or they may have an open shrub layer. They develop in regions where the climax community should be forest, but drought and fire prevent the establishment of many trees.

Animals

Tropical grassland animals (which do not all occur in the same area) include giraffes, zebras, buffaloes, kangaroos, mice, moles, gophers, ground squirrels, snakes, worms, termites, beetles, lions, leopards, hyenas, and elephants. The world's greatest diversity of ungulates (hoofed mammals) is found on the savannas of Africa. The antelopes are especially diverse and include eland, impalas, gazelles oryx, gerenuk and kudu. Buffalo, wildebeest, plains zebra, rhinos, giraffes, elephants and warthogs are among other herbivores of the African savanna. Carnivores include lions, leopards, cheetahs, jackals, wild dogs and hyenas. Termites are especially abundant in the tropical grasslands of the world.

Climate

Tropical grasslands are found in tropical wet and dry climates. These areas are hot year-round, usually never dropping under 64 degrees Farenheit. Although these areas are overall very dry, they do have a season of heavy rain. Annual rainfall is from 20-50 inches 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. If the rain were well distributed throughout the year, many such areas would become tropical forest.

Soil

The soil of tropical grasslands is porous, with rapid drainage of water. It has only a thin layer of humus (the organic portion of the soil created by partial decomposition of plant or animal matter), which provides vegetation with nutrients.

Threats

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.