Savannah Biome: Extent, Ecology, Types, Soil, Fauna and Flora

A Savannah is a grassland ecosystem. In Savannah, the trees are sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting grasses.

Distribution of Savannahs

Savannah covers approximately 20% of the Earth’s land area. The largest area of Savannah is in Africa. The following graphics shows Savannah as well as Rainforests so you are able to distinct the two regions.

Salient Features of Savannah

Savannahs are the grasslands with trees. But this is not a strict definition and Savannah biome also includes treeless tracts of grasslands. The water availability in Savannahs is seasonal and majority of the rainfall is confined to one season.

Forest Fire as a feature of Savannah

Like Taiga, the forest fires are common in Savannahs also but that is mainly because of human interference and not because of the natural reasons as the lightning in case of Taiga Biome. In Taiga, usually the forest fires are crown fires which destroy the canopy, but in Savannahs, these fires are usually confined to the herbaceous layer and do little long term damage to mature trees. These fires either kill or suppress tree seedlings, thus preventing the establishment of a continuous tree canopy which would prevent further grass growth.

Large areas of Savannah have been cleared of trees, and this clearing is continuing today. For example until recently 480,000 ha of Savannah were cleared annually in Australia alone primarily to improve pasture production.

Types of Savannahs

There are several types of Savannahs as following:

Tropical and subtropical Savannahs

Tropical and subtropical grasslands and shrublands as the tropical and subtropical grasslands, Savannahs, and shrublands biome. The Savannahs of Africa, including the Serengeti, famous for its wildlife, are typical of this type.

Temperate Savannahs

Mid-latitude Savannahs with wetter summers and drier winters. Examples are Great Plains of the United States.

Mediterranean Savannahs

Mid-latitude Savannahs in Mediterranean climate regions, with mild, rainy winters and hot, dry summers, part of the Mediterranean forests, woodlands, and scrub biome. The oak tree Savannahs of California, part of the California chaparral and woodlands eco-region are examples.

Flooded Savannahs

That are flooded seasonally or year-round.

Montane Savannahs

These are high-altitude Savannahs; example is highland Savannahs of the Angolan Scarp Savannah and woodlands ecoregions.

Threats to Savannahs

Savannah covered more than 40 per cent of the earth’s surface once upon a time, before the human caused fire started damaging them. Fire occurs annually throughout the biome. The timing of these fires is important. Early in the dry season, they are beneficial and increase tree cover; if late in the season, they are very hot and kill trees and seeds.

Adaptations in Savannahs

Savannah shrubs and trees are xerophytes or drought resistant, with various adaptations like small thick leaves, rough bark, or waxy leaf surface to protect them from the dryness. Africa has the largest region of this biome, including the famous Serengeti plains and the Sahel region. Some of the local names of these grasslands include the

• Llanos in Venezuela,
• Campo cerrado in brazil, and
• Pantanal of southern brazil. They are also found in Australia, India, Ethiopia, Kenya, and Somalia.

Soil of Savannahs

Savannah grasslands are much richer in humus than the equatorial forests. The C4 grasses are found in majority in Savannah.

Animals in Savannahs

Savannah are the home of large mammals that graze on Savannah grasses or the Savannah grasses or feed upon the grazers themselves ; these are lions, cheetah, zebra, giraffe, buffalo, gazelle, wild beast, antelope, rhinoceros, and  elephant. Some of the animal species like the black and white rhino have become extinct during recent time.