Afrotropical realm

Afrotropical realm
carol · CC BY-SA 3.0 · source
Name	Afrotropical realm
Biogeographic realm	Afrotropical
Continents	Africa, Madagascar, Arabian Peninsula (southern)
Area km2	22,000,000

Afrotropical realm The Afrotropical realm covers sub-Saharan Africa, the island of Madagascar, parts of the Arabian Peninsula and adjacent oceanic islands. It includes major regions such as the Sahel, the Congo Basin, the East African Rift, and the Cape Floristic Region, shaping biodiversity patterns across landscapes and influencing research by institutions like the Royal Botanic Gardens, Kew, the Smithsonian Institution, and the Natural History Museum, London.

Geography and boundaries

The realm extends from the Sahara Desert's southern edge through the Horn of Africa to the Cape of Good Hope and includes offshore islands such as the São Tomé and Príncipe and the Comoros. Northern delineation often follows ecological transitions near the Atlas Mountains and the Nile River, whereas eastern limits involve the Gulf of Aden and the Red Sea corridor; western margins meet the Neotropical realm across the Atlantic Ocean. Significant physiographic features include the Ethiopian Highlands, the Drakensberg, the Great Rift Valley and inland drainage basins like the Niger River and the Zambezi River, which underpin freshwater and terrestrial ecoregions studied by organizations including the International Union for Conservation of Nature and the United Nations Environment Programme.

Climate and biomes

Climates range from hyper-arid conditions in the Namib Desert and parts of the Sahara to equatorial rainforest climates in the Congo Rainforest and montane climates in the Rwenzori Mountains. Biomes include tropical and subtropical moist broadleaf forests, tropical and subtropical grasslands, savannas, and shrublands such as the Serengeti, Mediterranean forests, woodlands, and scrub in the Cape Provinces, and deserts and xeric shrublands exemplified by the Kalahari Desert. Climatic drivers involve the Intertropical Convergence Zone, the Indian Ocean Dipole, and the West African Monsoon, which interact with topography in systems monitored by agencies like the World Meteorological Organization and the Food and Agriculture Organization.

Flora and fauna

Vegetation includes endemic lineages such as the baobabs of Madagascar and iconic flora in the fynbos of the Cape Floral Region. Mammalian diversity features charismatic taxa like the African elephant, lion, giraffe, and endemic clades including lemurs on Madagascar and the okapi in the Ituri Rainforest. Avifauna includes endemics such as the shoebill and migratory assemblages linked to the East African Flyway. Freshwater assemblages involve cichlid radiations in the Lake Victoria and Lake Malawi systems, while invertebrate diversity includes insect groups described by researchers at the Natural History Museum, London and the American Museum of Natural History. Plant families with major representation include the Arecaceae, Fabaceae, and Proteaceae, with conservation and taxonomic work undertaken by the International Union for Conservation of Nature and the Royal Botanic Gardens, Kew.

Biogeographical history and evolution

The realm's biogeography reflects plate tectonics, including the breakup of Gondwana, which separated Madagascar and influenced endemic radiations alongside later dispersal from Eurasia during periods associated with the Miocene. Palaeoclimatic events such as Pleistocene glacial–interglacial cycles altered savanna–forest boundaries, affecting speciation in groups like African ruminants studied by paleontologists at the Smithsonian Institution and the Natural History Museum, London. Madagascar's unique lineages arose through long-term isolation and adaptive radiations comparable to those documented for New Zealand and the Galápagos Islands, while faunal exchanges via the Arabian Peninsula facilitated colonization episodes involving taxa shared with the Palearctic realm.

Conservation and threats

Major threats include habitat loss from agricultural expansion in regions such as the Congo Basin and the Miombo woodlands, illegal wildlife trade affecting species like the African elephant and black rhinoceros, invasive species exemplified by problems in Madagascar and on Mauritius, and climate change impacts projected by the Intergovernmental Panel on Climate Change. Conservation responses involve protected area networks under frameworks promoted by the Convention on Biological Diversity, community-based initiatives in the Sahel, transfrontier conservation areas like the Great Limpopo Transfrontier Park, and international funding mechanisms such as the Global Environment Facility and the World Bank. Research and monitoring are conducted by institutions including the IUCN Species Survival Commission, the Wildlife Conservation Society, and national parks administrations like Kruger National Park and Serengeti National Park.

Category:Biogeographic realms