Kalahari Desert

by 03/11/2012 11:10:00 0 comments 7974 Views
Kalahari Desert

The Kalahari Desert (in Afrikaans "Dorsland", meaning "thirst land" or "thirsty land") is a large semi-arid sandy savannah in Southern Africa extending 900,000 square kilometres (350,000 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 supports more animals and plants than a true desert, such as the Namib Desert to the west. Kalahari desert should not be confused with the Namib desert as these are separate deserts that have different causes. The Kalahari is formed in a region of subsidence in the Hadley cell known as the "horse latitudes" and also its continentality, but the cause of the Namib desert is the cold Benguela current in the Atlantic ocean. There are small amounts of rainfall and the summer temperature is very high. It usually receives 3–7.5 inches (76–190 mm) of rain per year. The surrounding Kalahari Basin covers over 2,500,000 square kilometres (970,000 sq mi) 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 elephants to giraffes, and for predators such as lions and cheetahs, the riverbeds are now mostly grazing spots, though leopards and cheetahs can still be found. Among deserts of the southern hemisphere the Kalahari most closely resembles some Australian deserts in its latitude and its mode of formation.

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 millimetres (9.8 in) of erratic rainfall annually and are quite well vegetated; it is only truly arid in the southwest with under 175 millimetres (6.9 in) of rain annually, making the Kalahari a fossil desert. Summer temperatures in the Kalahari range from 20 to 45°C (68 to 113°F). Temperatures occasionally reach up to 50 °C (122 °F). In the driest and sunniest parts of the Kalahari, over 4,000 hours of sunshine are recorded annually on average.

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 square kilometres (106,000 sq mi).

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. The Kiwano fruit, also known as the Horned melon, melano, African horned cucumber, jelly melon, hedged gourd, and/or English tomato, is endemic to a region in the Kalahari Desert (*specific region unknown).

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.

Game reserves

The Kalahari has a number of game reserves—Tswalu Kalahari, South Africa's largest private game reserve, the Central Kalahari Game Reserve (the world's second largest protected area), Khutse Game Reserve and the Kgalagadi Transfrontier Park. Animals that live in the region include brown hyenas, lions, meerkats, giraffes, warthogs, jackals, several species of antelope (including the eland, gemsbok, springbok, hartebeest, steenbok, kudu, and duiker), and many species of birds and reptiles. Vegetation in the Kalahari consists mainly of grasses and acacias, but there are over 400 identified plant species present (including the wild watermelon, or Tsamma melon). Camel rides flourish when it rains.

Population

 

The Bushmen have lived in the Kalahari for 20,000 years as hunter-gatherers. They hunt wild game with bows and poison arrows and gather edible plants, such as berries, melons and nuts, as well as insects. Bushmen rarely drink water; they get most of their water requirements from plant roots and desert melons found on or under the desert floor. They often store water in the blown-out shells of ostrich eggs. These Bushmen live in huts built from local materials—the frame is made of branches, and the roof is thatched with long grass. The Bantu-speaking Tswana, Kgalagadi, and Herero and a small number of European settlers also live in the Kalahari desert. The city Windhoek is situated in the Kalahari Basin.

Settlements within the Kalahari

 

Botswana

Ghanzi

Tshane

Tshabong

Orapa

Namibia

Gobabis

Mariental

South Africa

Rietfontein