Kalahari Desert
The Kalahari Desert is an extensive, sand-covered semiarid region located in southern Africa, stretching from the Orange River to the Caprivi Strip in northern Namibia. Despite its desert label, it is characterized as a thirstland with variable annual rainfall, ranging from 500-800 millimeters in the north to just 150-200 millimeters in the southwest. The region's vegetation mainly consists of tree and bush savanna, supported by underground water sources accessed through boreholes. Traditionally, the Kalahari was home to diverse wildlife and indigenous communities who practiced subsistence hunting and limited cattle raising. However, increased human activity, particularly commercial cattle ranching, has led to significant environmental stress, including habitat degradation and competition for resources between livestock and wildlife.
The introduction of boreholes since the 1930s has facilitated livestock population growth, but it has also contributed to the depletion of natural rangelands. Wildlife populations have been further impacted by disease control measures, which fragmented their habitats. Conservation efforts in the form of national parks and wildlife reserves exist, but they are often constrained by agricultural activities. In contemporary discussions, the value of wildlife as a sustainable economic resource is gaining recognition, especially in the realm of ecotourism. However, the region faces ongoing threats from climate change, which is projected to increase temperatures and potentially lead to further ecological challenges.
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Kalahari Desert
IDENTIFICATION: Extensive sand-covered semiarid region in southern Africa
The Kalahari is under increasing stress from growing human pressure on a drought-prone environment. Increasing commercial cattle raising has brought conflicts with wildlife and resulted in degradation of savanna vegetation. Surface and groundwater resources are under pressure from human and livestock populations, and mining and tourism have had negative environmental impacts on local areas.
Bounded to the east by the highlands of eastern Botswana and western Zimbabwe and on the west by the uplands of central Namibia, the Kalahari Desert is an extensive sand-covered plain extending from the Orange River to the Caprivi Strip in northern Namibia. Most of the drainage in the region is internal, and pans (dry lakes or playas) are common. The Okavango, Kwando, and Cuíto rivers flow southeast from the humid highlands of Angola and form large inland deltas and swamps in northwestern Botswana and adjacent areas of Namibia and Zambia, where 96 percent of their is lost by evaporation and transpiration. Some water spills over from the Okavango delta to the Makgadikgadi Pans.
Although often called a desert, the Kalahari is really a semiarid thirstland or edaphic desert. Rainfall occurs mainly as convectional storms in the austral summer and is highly variable in space and time, with quasi-periodic severe drought. Annual rainfall decreases from 500-800 millimeters (20-31 inches) in northern areas to 150-200 millimeters (6-8 inches) in the southwest. Vegetation cover in the Kalahari is tree and bush savanna, largely as a result of the high of the surface sands.
The rural economy of the Kalahari is dominated by subsistence and commercial cattle raising, sustained by boreholes that tap deep sources. Traditional land use involved the coexistence of small numbers of cattle and extensive herds of wild ungulates (such as hartebeest, wildebeest, springbok, and eland), which provided for subsistence hunting by local peoples. The drilling of boreholes started during the 1930s and increased over time, and the provision of water enabled steady growth in numbers of livestock, mostly cattle. Many areas, however, especially those close to boreholes, have experienced degradation of natural rangeland vegetation resources, with a decrease in grass cover and encroachment by shrubs, leading to a decline in the quality and quantity of grazing, depletion of soil nutrients, and competition for resources between cattle and wildlife populations.
Traditionally, the Kalahari was home to large populations of wildlife, most of which were able to survive for long periods without surface water. Initially decimated by European hunters during the late nineteenth and early twentieth centuries, wildlife populations were severely affected from the 1950s onward by the construction of an extensive network of fences designed to control disease vectors in cattle populations, which blocked natural wildlife migration routes. The expansion of commercial ranching and continued growth of human populations has further reduced wildlife numbers and fragmented habitats. Protection to Kalahari wildlife populations is provided by national parks and wildlife reserves in Botswana, South Africa, and Namibia, but many of these are circumscribed by commercial and traditional farming and ranching activities. In the twenty-first century, however, the value of wildlife has been increasingly recognized as a sustainable land use and as a means to diversify national economies through ecotourism.
The and economy of the Kalahari are additionally threatened by climate change. Most climate models project little change in annual rainfall totals but increased temperatures, which will lead to higher and therefore less effective rainfall. Some studies suggest that widespread decreases in vegetation cover as a result of climate change may result in remobilization of surface sands by wind erosion.
Bibliography
Grainger, Lisa. "An Oasis of Cool in the Wilds of the Kalahari Desert." The Times, 8 Oct. 2022, www.thetimes.com/article/an-oasis-of-cool-in-the-wilds-of-the-kalahari-desert-3xfr325hw. Accessed 19 July 2024.
"Northern Kalahari Desert Panorama." NASA Earth Observatory, 17 Sept. 2022, earthobservatory.nasa.gov/images/151026/northern-kalahari-desert-panorama. Accessed 19 July 2024.
Scholes, R. J., and D. A. B. Parsons, eds. The Kalahari Transect: Research on Global Change and Sustainable Development in Southern Africa. Stockholm: International Geosphere-Biosphere Programme, 1997.
Sporton, Deborah, and David S. G. Thomas, eds. Sustainable Livelihoods in Kalahari Environments: A Contribution to Global Debates. New York: Oxford University Press, 2002.
Thomas, David S. G., and Paul A. Shaw. The Kalahari Environment. 1991. Reprint. New York: Cambridge University Press, 2009.