Afrotropical realm

The Afrotropical realm, marked in blue
See Tropical Africa, Sub-Saharan Africa for other aspects.

The Afrotropical realm is one of the Earth's eight biogeographic realms. It includes Africa south of the Sahara Desert, the southern and eastern fringes of the Arabian Peninsula, the island of Madagascar, southern Iran and extreme southwestern Pakistan, and the islands of the western Indian Ocean. It was formerly known as the Ethiopian Zone or Ethiopian Region.

Major ecological regions

Most of the Afrotropic, with the exception of Africa's southern tip, has a tropical climate. A broad belt of deserts, including the Atlantic and Sahara deserts of northern Africa and the Arabian Desert of the Arabian Peninsula, separate the Afrotropic from the Palearctic realm, which includes northern Africa and temperate Eurasia.

Sahel and Sudan

South of the Sahara, two belts of tropical grassland and savanna run east and west across the continent, from the Atlantic Ocean to the Ethiopian Highlands. Immediately south of the Sahara lies the Sahel belt, a transitional zone of semi-arid short grassland and acacia savanna. Rainfall increases further south in the Sudanian Savanna, also known simply as the Sudan, a belt of taller grasslands and savannas. The Sudanian Savanna is home to two great flooded grasslands, the Sudd wetland in South Sudan, and the Niger Inland Delta in Mali. The forest-savanna mosaic is a transitional zone between the grasslands and the belt of tropical moist broadleaf forests near the equator.

Southern Arabian woodlands

South Arabia, expressed as being mostly Yemen and parts of western Oman and southwestern Saudi Arabia, has few permanent forests. Some of the notable are Jabal Bura', Jabal Raymah, and Jabal Badaj in the Yemeni highland escarpment, and the seasonal forests in eastern Yemen and the Dhofar region of Oman. Other woodlands scatter the land and are very small and are predominantly juniper or acacia forests.

Forest zone

The forest zone, a belt of lowland tropical moist broadleaf forests, runs across most of equatorial Africa's intertropical convergence zone. The Upper Guinean forests of West Africa extend along the coast from Guinea to Togo. The Dahomey Gap, a zone of forest-savanna mosaic that reaches to the coast, separates the Upper Guinean forests from the Lower Guinean forests, which extend along the Gulf of Guinea from eastern Benin through Cameroon and Gabon to the western Democratic Republic of the Congo. The largest tropical forest zone in Africa is the Congolian forests of the Congo Basin in Central Africa. A belt of tropical moist broadleaf forest also runs along the Indian Ocean coast, from southern Somalia to South Africa.

East African grasslands and savannas

Eastern Africa's highlands

Afromontane region, from the Ethiopian Highlands to the Drakensberg Mountains of South Africa, including the East African Rift. Distinctive flora, including Podocarpus and Afrocarpus, as well as giant Lobelias and Senecios.

Southern African woodlands, savannas, and grasslands

Southern Africa as described in Plant Taxonomic Database Standards No. 2

Deserts of southern Africa

Cape floristic region

The Cape floristic region, at Africa's southern tip, is a Mediterranean climate region that is home to a significant number of endemic taxa, as well as to plant families like the proteas (Proteaceae) that are also found in the Australasian realm.

Madagascar and the Indian Ocean islands

Madagascar and neighboring islands form a distinctive sub-region of the realm, with numerous endemic taxa like the lemurs. Madagascar and the Seychelles are old pieces of the ancient supercontinent of Gondwana, and broke away from Africa millions of years ago. Other Indian Ocean islands, like the Comoros and Mascarene Islands, are volcanic islands that formed more recently. Madagascar contains several important biospheres, as its biodiversity and ratio of endemicism is extremely high.

Endemic plants and animals

Plants

The Afrotropical realm is home to a number of endemic plant families. Madagascar and the Indian Ocean Islands are home to ten endemic families of flowering plants; eight are endemic to Madagascar (Asteropeiaceae, Didymelaceae, Didiereaceae, Kaliphoraceae, Melanophyllaceae, Physenaceae, Sarcolaenaceae, and Sphaerosepalaceae), one to Seychelles (Mesdusagynaceae) and one to the Mascarene Islands (Psiloxylaceae). Twelve plant families are endemic or nearly endemic to South Africa (including Curtisiaceae, Heteropyxidaceae, Penaeaceae, Psiloxylaceae and Rhynchocalycaceae) of which five are endemic to the Cape floristic province (including Grubbiaceae). Other endemic Afrotropic families include Barbeyaceae, Montiniaceae, Myrothamnaceae and Oliniaceae.

Animals

The East African Great Lakes (Victoria, Malawi, and Tanganyika) are the center of biodiversity of many freshwater fishes, especially cichlids (they harbor more than two-thirds of the estimated 2,000 species in the family).[1] The West African coastal rivers region covers only a fraction of West Africa, but harbours 322 of West African's fish species, with 247 restricted to this area and 129 restricted even to smaller ranges. The central rivers fauna comprises 194 fish species, with 119 endemics and only 33 restricted to small areas.[2]

The Afrotropic has various endemic bird families, including ostriches (Struthionidae), sunbirds, the secretary bird (Sagittariidae), guineafowl (Numididae), and mousebirds (Coliidae). Also, several families of passerines are limited to the Afrotropics; These include rock-jumpers (Chaetopidae) and rockfowl (Picathartidae).

Africa has three endemic orders of mammals, the Tubulidentata (aardvarks), Afrosoricida (tenrecs and golden moles), and Macroscelidea (elephant shrews). The East-African plains are well known for their diversity of large mammals.

Four species of great apes (Hominidae) are endemic to Africa: both species of gorilla (western gorilla, Gorilla gorilla, and eastern gorilla, Gorilla beringei) and both species of chimpanzee (common chimpanzee, Pan troglodytes, and bonobo, Pan paniscus). Humans and their ancestors originated in Africa.

Afrotropic Terrestrial Ecoregions

Albertine Rift montane forests Democratic Republic of the Congo, Burundi, Rwanda, Tanzania, Uganda
Atlantic Equatorial coastal forests Angola, Cameroon, Democratic Republic of the Congo, Republic of the Congo, Equatorial Guinea, Gabon
Cameroonian Highlands forests Cameroon, Nigeria
Central Congolian lowland forests Democratic Republic of the Congo
Comoros forests Comoros
Cross-Niger transition forests Nigeria
Cross-Sanaga-Bioko coastal forests Cameroon, Equatorial Guinea, Nigeria
East African montane forests Kenya, South Sudan, Tanzania, Uganda
Eastern Arc forests Tanzania, Kenya
Eastern Congolian swamp forests Democratic Republic of the Congo
Eastern Guinean forests Benin, Ghana, Ivory Coast, Togo
Ethiopian montane forests Eritrea, Ethiopia, Somalia, Sudan
Granitic Seychelles forests Seychelles
Guinean montane forests Guinea, Ivory Coast, Liberia, Sierra Leone
Knysna-Amatole montane forests South Africa
KwaZulu-Cape coastal forest mosaic South Africa
Madagascar lowland forests Madagascar
Madagascar subhumid forests Madagascar
Maputaland coastal forest mosaic Mozambique, Swaziland, South Africa
Mascarene forests Mauritius, Réunion
Mount Cameroon and Bioko montane forests Cameroon, Equatorial Guinea
Niger Delta swamp forests Nigeria
Nigerian lowland forests Benin, Nigeria
Northeastern Congolian lowland forests Cameroon, Central African Republic, Gabon, Republic of the Congo
Northern Zanzibar-Inhambane coastal forest mosaic Kenya, Somalia, Tanzania
Northwestern Congolian lowland forests Cameroon, Central African Republic, Gabon, Republic of the Congo
São Tomé, Príncipe, and Annobón moist lowland forests Equatorial Guinea, São Tomé and Príncipe
Southern Zanzibar-Inhambane coastal forest mosaic Malawi, Mozambique, Tanzania, Zimbabwe
Western Congolian swamp forests Democratic Republic of the Congo, Republic of the Congo
Western Guinean lowland forests Guinea, Ivory Coast, Liberia, Sierra Leone
Cape Verde Islands dry forests Cape Verde
Madagascar dry deciduous forests Madagascar
Zambezian Cryptosepalum dry forests Zambia, Angola
Angolan Miombo woodlands Angola
Angolan Mopane woodlands Angola, Namibia
Ascension scrub and grasslands Ascension Island
Central Zambezian Miombo woodlands Angola, Burundi, Democratic Republic of the Congo, Malawi, Tanzania, Zambia
East Sudanian savanna Cameroon, Central African Republic, Chad, Democratic Republic of the Congo, Eritrea, Ethiopia South Sudan, Sudan, Uganda
Eastern Miombo woodlands Mozambique, Tanzania
Guinean forest-savanna mosaic Benin, Burkina Faso, Cameroon, Gambia, Ghana, Guinea, Guinea Bissau, Ivory Coast, Nigeria, Senegal, Togo
Itigi-Sumbu thicket Tanzania, Zambia
Kalahari Acacia-Baikiaea woodlands Botswana, Namibia, South Africa, Zimbabwe
Mandara Plateau mosaic Cameroon, Nigeria
Northern Acacia-Commiphora bushlands and thickets Ethiopia, Kenya, South Sudan, Uganda
Northern Congolian forest-savanna mosaic Cameroon, Central African Republic, Democratic Republic of the Congo, South Sudan, Uganda
Sahelian Acacia savanna Burkina Faso, Cameroon, Chad, Eritrea, Ethiopia, Mali, Mauritania, Niger, Nigeria, Senegal, South Sudan, Sudan
Serengeti Kenya, Tanzania
Somali Acacia-Commiphora bushlands and thickets Eritrea, Ethiopia, Kenya, Somalia
Southern Acacia-Commiphora bushlands and thickets Kenya, Tanzania
Southern Africa bushveld Botswana, South Africa, Zimbabwe
Southern Congolian forest-savanna mosaic Angola, Democratic Republic of the Congo
Southern Miombo woodlands Malawi, Mozambique, Zambia, Zimbabwe
Saint Helena scrub and woodlands Saint Helena
Victoria Basin forest-savanna mosaic Burundi, Ethiopia, Kenya, Rwanda, South Sudan, Tanzania, Uganda
West Sudanian savanna Benin, Burkina Faso, Gambia, Ghana, Guinea, Ivory Coast, Niger, Nigeria, Senegal
Western Congolian forest-savanna mosaic Angola, Democratic Republic of the Congo, Republic of the Congo
Western Zambezian grasslands Angola, Zambia
Zambezian and Mopane woodlands Botswana, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia, Zimbabwe
Zambezian Baikiaea woodlands Angola, Botswana, Namibia, Zambia, Zimbabwe
Al Hajar Al Gharbi montane woodlands Oman
Amsterdam and Saint-Paul Islands temperate grasslands Amsterdam Island, Saint-Paul Island
Tristan da Cunha-Gough Islands shrub and grasslands Tristan da Cunha, Gough Island
East African halophytics Kenya, Tanzania
Etosha Pan halophytics Namibia
Inner Niger Delta flooded savanna Mali
Lake Chad flooded savanna Cameroon, Chad, Nigeria
Saharan flooded grasslands South Sudan
Zambezian coastal flooded savanna Mozambique
Zambezian flooded grasslands Angola, Botswana, Democratic Republic of the Congo, Malawi, Mozambique, Tanzania, Zambia
Zambezian halophytics Botswana
Angolan montane forest-grassland mosaic Angola
Angolan Scarp savanna and woodlands Angola
Drakensberg alti-montane grasslands and woodlands Lesotho, South Africa
Drakensberg montane grasslands, woodlands and forests Lesotho, South Africa, Swaziland
East African montane moorlands Kenya, Sudan, Tanzania, Uganda
Eastern Zimbabwe montane forest-grassland mosaic Mozambique, Zimbabwe
Ethiopian montane grasslands and woodlands Ethiopia, Sudan
Ethiopian montane moorlands Ethiopia, Sudan
Highveld grasslands Lesotho, South Africa
Jos Plateau forest-grassland mosaic Nigeria
Madagascar ericoid thickets Madagascar
Maputaland-Pondoland bushland and thickets Mozambique, South Africa, Swaziland
Ruwenzori-Virunga montane moorlands Democratic Republic of the Congo, Rwanda, Uganda
South Malawi montane forest-grassland mosaic Malawi, Mozambique
Southern Rift montane forest-grassland mosaic Malawi, Tanzania
Albany thickets South Africa
Lowland fynbos and renosterveld South Africa
Montane fynbos and renosterveld South Africa
Aldabra Island xeric scrub Seychelles
Arabian Peninsula coastal fog desert Oman, Saudi Arabia, Yemen
East Saharan montane xeric woodlands Chad, Sudan
Eritrean coastal desert Djibouti, Eritrea
Ethiopian xeric grasslands and shrublands Djibouti, Eritrea, Ethiopia, Somalia, Sudan
Gulf of Oman desert and semi-desert Oman, United Arab Emirates
Hobyo grasslands and shrublands Somalia
Ile Europa and Bassas da India xeric scrub Bassas da India, Europa
Kalahari xeric savanna Botswana, Namibia, South Africa
Kaokoveld desert Angola, Namibia
Madagascar spiny thickets Madagascar
Madagascar succulent woodlands Madagascar
Masai xeric grasslands and shrublands Ethiopia, Kenya
Nama Karoo Namibia, South Africa
Namib desert Namibia
Namibian savanna woodlands Namibia
Red Sea coastal desert Egypt, Sudan
Socotra Island xeric shrublands Yemen
Somali montane xeric woodlands Somalia
Southwestern Arabian foothills savanna Oman, Saudi Arabia, Yemen
Southwestern Arabian montane woodlands Saudi Arabia, Yemen
Succulent Karoo South Africa
Central African mangroves Angola, Cameroon, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Ghana, Niger Delta
East African mangroves Kenya, Mozambique, Tanzania
Guinean mangroves Senegal, Gambia, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast
Madagascar mangroves Madagascar
Southern Africa mangroves Mozambique, South Africa

See also

References

  1. I.P.Farias et al., Total Evidence: Molecules, Morphology, and the Phylogenetics of Cichlid Fishes, Journal of Experimental Zoology (Mol Dev Evol) 288:76–92 (2000)
  2. T.Moritz and K. E. Linsenmair, West African fish diversity – distribution patterns and possible conclusions for conservation strategies (in African Biodiversity: Molecules, Organisms, Ecosystems, Springer, 2001)

Bibliography

  • Burgess, N., J.D. Hales, E. Underwood, and E. Dinerstein (2004). Terrestrial Ecoregions of Africa and Madagascar: A Conservation Assessment. Island Press, Washington, D.C., .
  • Thieme, M.L., R. Abell, M.L.J. Stiassny, P. Skelton, B. Lehner, G.G. Teugels, E. Dinerstein, A.K. Toham, N. Burgess & D. Olson. 2005. Freshwater ecoregions of Africa and Madagascar: A conservation assessment. Washington DC: WWF, .
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