The Afrotropical Realm
The Afrotropical Realm includes all of sub-Saharan Africa along with certain coastal islands such as the Cape Verde Archipelago. Madagascar, although traditionally included within Africa, is treated separately here. Biogeographically the Afrotropical Realm is divided between the African and Guineo-Congolian zoogeographic regions. Africa as a whole has a wide range of climates and habitats, ranging from subtropical to temperate. South of the Saharo-Arabian Region the vast North African desert turns into subdesert, grass, and shrub savannas, and finally to more or less dense wooded savannas. Still further south, forests appear; such growths reach their optimum development in the Congo Basin. In fact, Africa both north and south of the equator can show all types of nature from extreme desert to extreme rainforest. Savannas cover about 40 per cent of Africa, in both subtropical and tropical areas, and they vary greatly from region to region. Africa’s savannas, steppes, arid plains, and subdeserts stretch in an arc across the continent. Beginning in East Africa between the latitudes 20° and 10° N, they fill practically the whole of Africa south of 10° S with the exception of the Cape. Some of these plains have become or are becoming deserts; others are still fertile grass or tree savannas, which in places turn into open forests.
No other continent historically possessed such a wealth of fauna as Africa. Indeed, more species of terrestrial vertebrates still live here than anywhere else on Earth, and the density of large mammals on some areas of savanna remains unparalleled. The reason for this is probably that Africa’s fauna is of a very great age; it has had countless eons in which to become adapted to the many types of habitat. Repeated changes of climate, continuously altering the landscape, have caused dislocations in the distribution of plants and animals. These dislocations in turn have favoured speciation and the evolution of species in special directions. To this must be added an evolutionary phenomenon typical of all the Africa fauna – by competition the animals have become fitted to utilize all the possibilities offered by the rich environment. This has enabled numerous species to live side by side in the same habitats and in harmony with the vegetation by utilizing different niches. It is in the tropical areas that we find the largest number of species and most of the spectacular animals which have made Africa famous. The southern part of the continent is not so rich, but there the fauna includes a wealth of vertebrate species.
Species and subspecies
The African buffalo (Syncerus caffer) is still found across sub-Saharan Africa, but is now mostly confined to protected areas, as it is a favourite target for trophy hunters. The northwest Africa buffalo (S. c. brachyceros) occurs patchily in the savannas and gallery forests of western and central Africa. The Nile buffalo (S. c. aequinoctialis) is found in the Sahelo-Sudanian savanna zone of central Africa (south-eastern Chad, northern Central African Republic, northern Democratic Republic of Congo, south-eastern Sudan, and western Ethiopia. It has been extirpated from Eritrea.
The hippopotamus (Hippopotamus amphibius) is a semiaquatic animal that was historically found throughout sub-Saharan Africa and the Nile Valley. From the end of the Roman Empire up to the beginning of the eighteenth century at the latest the animals were still present in two disjunct areas in the northern part of their range (the Nile delta and the upper Nile), although the species appears to have become extinct in Egypt sometime during the eighteenth century. It still occupies much of the area that it did in 1960, although population sizes have declined greatly. The main threats are habitat destruction and poaching for their meat and ivory canine teeth.
The yellow-backed duiker (Cephalophus silvicultor) is a type of small antelope found widely across western, central, and parts of eastern Africa. The short-headed yellow-backed duiker (C. s. curticeps), long-headed yellow-backed duiker (C. s. longiceps), Bocage’s yellow-backed duiker (C. s. ruficrista), and Afzelius’ yellow-backed duiker (C. s. silvicultor) are all threatened by bushmeat hunting and snaring.
The black and white colobus (Colobus angolensis) is a type of leaf-eating monkey divided into a number of subspecies found across Central Africa. All are threatened by loss of habitat and hunting, and will be discussed individually below.
The African golden cat (Caracal aurata) is a rare forest inhabitant, with two widely separated populations in central and western equatorial Africa, respectively. It is heavily hunted for its pelt and threatened by loss of habitat.
The russet free-tailed bat (Chaerephon russatus) is only known from five widely separated localities in Ivory Coast, Ghana, central Cameroon, the Democratic Republic of Congo, and south-western Kenya.
Robbins’ house bat (Scotophilus nucella) is known only from south-eastern Ivory Coast, southern Ghana, western Uganda, and north-eastern Tanzania.
Beaudouin’s snake-eagle (Circaetus beaudouini) occurs sparsely within a narrow band of savanna and woodlands in sub-Saharan Africa from Senegal, Gambia, and southern Mauritania in the west to South Sudan and the northern Democratic Republic, with some nomadic movement to outlying countries such as Kenya. It is everywhere threatened by loss of habitat, overgrazing by cattle, pesticides, and hunting pressure.
The white-backed vulture (Gyps africanus) was historically the most widespread and common vulture in Africa, being found virtually everywhere south of the Sahara except for the rainforest belt and a few coastal areas. In recent decades it has undergone drastic declines due to habitat destruction, decreases in wild ungulate populations, hunting, human persecution, collisions, and indirect poisoning, and is now considered to be seriously threatened. Rüppell’s vulture (G. rueppelli) was also formerly widespread within the grasslands, mountains, and woodlands of Sahelian and eastern Africa, where it has also undergone similarly drastic declines and is now largely confined to protected areas. The nominate form (G. r. rueppelli) occupies the majority of the range, while the Ethiopian Rüppell’s vulture (G. r. erlangeri) inhabits the highlands of Ethiopia, Eritrea, north-western Somalia, and possibly the southern Arabian Peninsula. Interestingly, this species is thought to be the highest-flying of all birds, with one individual in 1973 having been ingested by a jet engine flying over Ivory Coast at 11,300 m elevation. Since the 1990s there have been increasing records involving small numbers of individuals in Spain and Portugal, although breeding is not known to have taken place.
The white-headed vulture (Trigonoceps occipitalis) is found patchily across sub-Saharan Africa but is everywhere threatened by habitat destruction, reduction of prey, indirect poisoning, and collection for use in ‘traditional medicine’.
The hooded vulture (Necrosyrtes monachus) is still widespread across sub-Saharan Africa but is undergoing rapid declines almost everywhere due to indiscriminate poisoning, habitat destruction, hunting, human persecution, and collection for use in ‘traditional medicine’.
The African lappet-faced vulture (Torgos tracheliotos tracheliotos) occurs patchily throughout sub-Saharan Africa, where it is threatened by habitat destruction, human disturbance of its nesting sites, and pesticide poisoning.
Anthropogenic effects on the flora and fauna
In recent historical time (i.e. since ad 1500), the Afrotropical Realm as a whole has lost at least 56 species/6 subspecies of vertebrates. Among the extinct forms 1 species/6 subspecies are mammals, 9 species are birds, 3 species are reptiles, and 43 species are freshwater fishes. Another 15 species are possibly extinct, and 1 species is currently extinct in the wild. In addition, there are 1773 species/121 subspecies currently threatened with extinction (that is to say, either Critically Endangered, Endangered, or Vulnerable according to the IUCN Red List, as well as certain forms either listed as Data Deficient or Not Assessed but which are clearly at some risk of extinction). Of these, 260 species/79 subspecies are mammals, 182 species/24 subspecies are birds, 157 species/5 subspecies are reptiles, 281 species are amphibians, and 893 species/13 subspecies are freshwater fishes.