South Saharan steppe and woodlands | |
---|---|
Ecology | |
Realm | Palearctic |
Biome | Deserts and xeric shrublands |
Geography | |
Area | 1,101,700 km2 (425,400 sq mi) |
Countries | |
Conservation | |
Conservation status | relatively intact |
The South Saharan steppe and woodlands, also known as the South Sahara desert, is a deserts and xeric shrublands ecoregion of northern Africa. This band is a transitional region between the Sahara's very arid center (the Sahara desert ecoregion) to the north, and the wetter Sahelian Acacia savanna ecoregion to the south. [1] In pre-modern times, the grasslands were grazed by migratory gazelles and other ungulates after the rainfalls. More recently, over-grazing by domestic livestock have degraded the territory. [1] Despite the name of the ecoregion, there are few 'woodlands' in the area; those that exist are generally acacia and shrubs along rivers and in wadis. [2]
The ecoregion covers 1,101,700 square kilometers (425,400 sq mi) in Algeria, Chad, Mali, Mauritania, Niger, and Sudan. It extends east and west across the continent in a band, forming a transition between the hyper-arid Sahara Desert to the north and the Sahel grasslands and savannas to the south. [3] [2] [1]
The climate of the ecoregion is Hot semi-arid climate (Köppen climate classification (BSh)). This climate is characteristic of steppes, with hot summers and cool or mild winters, and minimal precipitation. The coldest month averages above 0 °C (32 °F). [4] [5] Movements of the equatorial Intertropical Convergence Zone (ITCZ) bring summer rains during July and August which average 100 to 200 mm, but vary greatly from year to year. These rains sustain summer pastures of grasses and herbs, with dry woodlands and shrublands along seasonal watercourses. [6]
Almost 99% of the region is bare ground or sparse vegetation that is dependent on uncertain rainfall. The grasses are typically canegrass ( Eragrostis ), needlegrasses ( Aristida ), and species of genus Stipagrostis . The herbs include ( Tribulus ), ( Heliotropium ), and ( Pulicaria ). Characteristic tree species are the umbrella thorn acacia ( Acacia tortilis ), salam ( Acacia ehrenbergiana ), Egyptian balsam ( Balanites aegyptiaca ), and ( Maerua crassifolia ). Along the southern edge are steppes featuring clumps of bunchgrass ( Panicum turgidum ). [1]
Most of the animals of the region have been reduced to small populations, including the critically endangered addax (also known as the white antelope) ( Addax nasomaculatus ), the endangered slender-horned gazelle ( Gazella leptoceros ), the vulnerable Dorcas gazelle ( Gazella dorcas ), the critically endangered dama gazelle ( Gazella dama ), the near threatened striped hyena ( Hyaena hyaena ), the vulnerable cheetah ( Acinonyx jubatus ), the endangered wild dog ( Lycaon pictus ), and the ostrich ( Struthio camelus ). [1]
In 2001, WWF devised Terrestrial Ecoregions of the World (TEOW) "a biogeographic regionalization of the Earth's terrestrial biodiversity". [7] The 2001 regionalization divided the deserts of the Sahara into several ecoregions. The South Saharan steppe and woodlands ecoregion included the transitional region between the Sahelian Acacia savanna and the Sahara's hyper-arid center, designated the Sahara desert ecoregion. [8] [9]
In 2017, the authors of the 2001 system proposed a revised ecoregion system for the Sahara. The South Saharan steppe and woodlands ecoregion was extended into the central Sahara, and renamed South Sahara desert. Two new ecoregions, the West Sahara desert and East Sahara desert, were designated in the hyper-arid center. [10]
Approximately 11% of the ecoregion is officially protected in some form. [2] These include:
The Sahara desert, as defined by the World Wide Fund for Nature (WWF), includes the hyper-arid center of the Sahara, between latitudes 18° N and 30° N. It is one of several desert and xeric shrubland ecoregions that cover the northern portion of the African continent.
The Sahel region or Sahelian acacia savanna is a biogeographical region in Africa. It is the transition zone between the more humid Sudanian savannas to its south and the drier Sahara to the north. The Sahel has a hot semi-arid climate and stretches across the southernmost latitudes of North Africa between the Atlantic Ocean and the Red Sea. Although geographically located in the tropics, the Sahel does not have a tropical climate.
The East Saharan montane xeric woodlands is an ecoregion of central Africa, a number of high mountains in the middle of the huge area of savanna on the edge of the Sahara Desert.
The wildlife of Chad is composed of its flora and fauna. Bush elephants, West African lions, buffalo, hippopotamuses, Kordofan giraffes, antelopes, African leopards, cheetahs, hyenas, and many species of snakes are found there, although most large carnivore populations have been drastically reduced since the early 20th century. Elephant poaching, particularly in the south of the country in areas such as Zakouma National Park, is a severe problem.
Mauritania's wildlife has two main influences as the country lies in two biogeographic realms. The north sits in the Palearctic which extends south from the Sahara to roughly 19° north latitude and the south is in the Afrotropic realm. Additionally Mauritania is an important wintering area for numerous birds which migrate from the Palearctic.
The Atlantic coastal desert is the westernmost ecoregion in the Sahara Desert of North Africa. It occupies a narrow strip along the Atlantic coast, where the more frequent fog and haze generated offshore by the cool Canary Current provides sufficient moisture to sustain a variety of lichens, succulents, and shrubs.
The Mediterranean Acacia–Argania dry woodlands and succulent thickets is a Mediterranean forests, woodlands, and scrub ecoregion in North Africa centered mainly on Morocco but also including northwestern Western Sahara and the eastern Canary Islands.
The North Saharan steppe and woodlands is a desert ecoregion, in the deserts and xeric shrublands biome, that forms the northern edge of the Sahara. It extends east and west across Northern Africa, south of the Mediterranean dry woodlands and steppe ecoregion of the Maghreb and Cyrenaica, which is part of the Mediterranean forests, woodlands, and scrub biome. Winter rains sustain shrublands and dry woodlands that form an ecotone between the Mediterranean climate regions to the north and the hyper-arid Sahara Desert ecoregion to the south.
The Mediterranean dry woodlands and steppe is a Mediterranean forests, woodlands, and scrub ecoregion of North Africa. It occupies interior plateaus and mountain ranges of the Maghreb region, lying generally between the coastal Mediterranean woodlands and forests to the north and the Sahara to the south.
The Tibesti-Jebel Uweinat montane xeric woodlands is a deserts and xeric shrublands ecoregion in the eastern Sahara. The woodlands ecoregion occupies two separate highland regions, covering portions of northern Chad, southwestern Egypt, southern Libya, and northwestern Sudan.
The Termit Massif Total Reserve is a nature reserve in the southeast of Niger which was established in January 1962. In March 2012, a national nature and cultural reserve was established covering an area of 100,000 square kilometres (39,000 sq mi), including the entire area of the Termit Massif and Tin Toumma desert, making it the largest single protected area in Africa. The area provides habitat for many critically endangered species. Prominent among them is the addax antelope, which is categorized under the IUCN Red List as one of the rarest and most endangered species in the world; about 300 of them are reported in the reserve. A conservation effort has been launched by the Government of Niger in collaboration with many international conservation agencies. The reserve has also been declared an UNESCO World Heritage Site for the biodiversity value of the Termit Massif and surrounding Sahara Desert and for the cultural value of its archaeological sites.
The Ouadi-Rimé Ouadi-Hachim Faunal Reserve, is located in the Batha administrative region/province in the center of Chad. It an IUCN Category IV area, which was established in 1969. At 77,950 square kilometres (30,100 sq mi) –equivalent to the size of Scotland– it is one of the largest reserves in the world.
The Red Sea coastal desert is deserts and xeric shrublands ecoregion of Egypt and Sudan.
The Mitchell Grass Downs is a tropical and subtropical grasslands, savannas, and shrublands ecoregion in northeastern Australia. It is a mostly treeless grassland, characterised by Mitchell grasses .
The Central Persian desert basins ecoregion covers the arid steppe and desert basins of central Iran, stretching into northwestern Afghanistan. The ecoregion extends over the Central Iranian Plateau, which is surrounded by mountain ranges and has no outlets to the sea. Much of the terrain is hot sand-and-gravel desert and large salt flats. The vegetation includes many specialized species of halophytes (salt-tolerant), xerophytes (drought-tolerant), and psammophile (sand-loving) plants.
The Paropamisus xeric woodlands ecoregion covers the portion of northeastern Afghanistan north of the central mountain range and the Hindu Kush Mountains. The name is derived from the Old Persian name for the region, Parupraesanna. While there are low canopy woodlands in the northeast of the ecorgegion, most of the territory is desert or xeric (dry) scrubland.
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