Kalahari Desert

The Kalahari Desert is a large arid to semi-arid sandy area in southern Kgalagadi Africa extending 900,000 km² (362,500 sq. mi.), covering much of Botswana and parts of Namibia and South Africa, as semi-desert, with huge tracts of excellent grazing after good rains. The Kalahari Desert is the southern part of Africa, and the geography is a portion of desert and a plateau. The Kalahari supports some animals and plants because most of it is not true desert. There are small amounts of rainfall and the summer temperature is very high. It usually receives 3-7 1/2 inches of rain per year. The surrounding Kalahari Basin covers over 2.5 million km² extending farther into Botswana, Namibia and South Africa, and encroaching into parts of Angola, Zambia and Zimbabwe. The only permanent river, the Okavango, flows into a delta in the northwest, forming marshes that are rich in wildlife. Ancient dry riverbeds—called omuramba—traverse the Central Northern reaches of the Kalahari and provide standing pools of water during the rainy season. Previously havens for wild animals from elephant to giraffe, and for predators such as lion and cheetah, the riverbeds are now mostly grazing spots, though leopard or cheetah can still be found.

Climate

Derived from the Tswana word Kgala, meaning "the great thirst", or Khalagari, Kgalagadi or Kalagare, meaning "a waterless place", the Kalahari has vast areas covered by red sand without any permanent surface water. Drainage is by dry valleys, seasonally inundated pans, and the large salt pans of the Makgadikgadi Pan in Botswana and Etosha Pan in Namibia. However, the Kalahari is not a true desert. Parts of the Kalahari receive over 250 mm (9.8") of erratic rainfall annually and are quite well vegetated; it is only truly arid in the southwest with under 175 mm (6.9") of rain annually, making the Kalahari a fossil desert. Summer temperatures in the Kalahari range from 20 to 45°C (68–113°F).

The Kalahari Desert was once a much wetter place. The ancient Lake Makgadikgadi dominated the area, covering the Makgadikgadi Pan and other areas, until its final drainage some 10,000 years ago. It may have once covered as much as 275,000 km² and was approximately 30 m deep.

Ecology

Despite its aridity, the Kalahari supports a variety of fauna and flora. The native flora includes acacia trees and many other herbs and grasses. Some of the areas within the Kalahari are seasonal wetlands, such as the Makgadikgadi Pans of Botswana. This area, for example, supports numerous halophilic species, and in the rainy season, tens of thousands of flamingos visit these pans.

(Read more)