The grassland biome includes terrestrial habitats that are dominated by grasses and have relatively few large trees or shrubs. There are three main types of grasslands-temperate grasslands, tropical grasslands (also known as savannas), and steppe grasslands.
Most grasslands experience a dry season and a rainy season. During the dry season, grasslands can be susceptible to fires which often start as a result of lightning strikes. The annual rainfall in a grassland habitat is greater than the annual rainfall that occurs in desert habitats. Grasslands receive sufficient rainfall to support the growth of grasses and other plants, but not enough to support the growth of significant numbers of trees. The soils of grasslands also limit the vegetation structure that grows in them. In general, grassland soils are too shallow and dry to support tree growth.
Variety of Wildlife
Grasslands support a variety of wildlife including reptiles, mammals, amphibians, birds and many types of invertebrates. The dry grasslands of Africa are among the most ecologically diverse of all grasslands and support populations of animals such as giraffes, zebras, lions, hyenas, rhinoceroses, and elephants. The grasslands of Australia provide habitat for kangaroos, mice, snakes, and a variety of birds. The grasslands of North America and Europe support wolves, wild turkeys, coyotes, Canada geese, cranes, bison, bobcats, and eagles. Some common plant species that occur in North American grasslands include buffalo grass, asters, coneflowers, clover, goldenrods, and wild indigos.
The following are the key characteristics of the grassland biome:
- Vegetation structure that is dominated by grasses
- Semi-arid climate
- Rainfall and soils not sufficient to support significant tree growth
- Most common at mid-latitudes and near the interiors of continents
- Grasslands are often exploited for agricultural use
The grassland biome is classified within the following habitat hierarchy:
Biomes of the World > Grassland Biome
The grassland biome is divided into the following habitats:
- Temperate grasslands - Temperate grasslands are habitats that are dominated by grasses and have lack trees and large shrubs. Temperate grasslands include tall-grass prairies which are wet and humid and short-grass prairies which are dry and experience hot summers and cold winters. The soil of temperate grasslands has an upper layer that is nutrient-rich. Seasonal droughts are often accompanied by fires that prevent trees and shrubs from growing.
- Tropical grasslands - Tropical grasslands are grasslands that are located near the equator. They have warmer, wetter climates than temperate grasslands and experience more pronounced seasonal droughts. Tropical grasslands are dominated by grasses but also have some scattered trees. The soil of tropical grasslands are very porous and drain rapidly. Tropical grasslands occur in Africa, India, Australia, Nepal, and South America.
- Steppe grasslands - Steppe grasslands are dry grasslands that border on semi-arid deserts. The grasses found in steppe grasslands is much shorter than that of temperate and tropical grasslands. Steppe grasslands lack trees except along the banks of rivers and streams.
Animals of the Grassland Biome
Some of the animals that inhabit the grassland biome include:
- African elephant (Loxodonta africana) - African elephants have a large head, large ears, and a long muscular trunk. The two front incisors of African elephants grow into large tusks that curve forward.
- Lions (Panthera leo) - Lions are the largest of all African cats. Lions inhabit the savannas of Africa and the Gir Forest in northwest India.
- Spotted hyena (Crocuta crocuta) - Spotted hyenas inhabit the grasslands, savannas, and semi-deserts of sub-Saharan Africa. Their population densities are highest in the Serengeti, a vast plains ecosystem that stretches from northern Tanzania to southwestern Kenya.
- American bison (Bison bison) - Millions of bison used to roam North America's grasslands, boreal regions, and scrublands but the relentless slaughter of bison for meat, hides, and sport drove the species to the brink of extinction.