- Ecology of Africa
The vegetation of
Africafollows very closely the distribution of heat and moisture. The northern and southern temperate zones have a flora distinct from that of the continent generally, which is tropical. In the countries bordering the Mediterranean, there are groves of orange and olivetrees, evergreen oaks, cork trees and pines, intermixed with cypresses, myrtles, arbutusand fragrant tree-heaths.
South of the Atlas Range the conditions alter. The zones of minimum rainfall have a very scanty flora, consisting of plants adapted to resist the great dryness. Characteristic of the
Saharais the date palm, which flourishes where other vegetation can scarcely maintain existence, while in the semidesert regions the acacia, from which gum arabic is obtained, is abundant.
The more humid regions have a richer vegetation; dense forest where the rainfall is greatest and variations of temperature least, conditions found chiefly on the tropical coasts, and in the west African equatorial basin with its extension towards the upper
Nile; and savannainterspersed with trees on the greater part of the plateaus, passing as the desert regions are approached into a scrub vegetation consisting of thorny acacias, etc. Forests also occur on the humid slopes of mountain ranges up to a certain elevation. In the coast regions the typical tree is the mangrove, which flourishes wherever the soil is of a swampcharacter.
forests of West Africa contain, in addition to a great variety of hardwoods, two palms, "Elaeis guincensis" ( oil palm) and "Raphia vinifera" ( bamboo palm), not found, generally speaking, in the savanna regions. " Bombax" or silk-cotton trees attain gigantic proportions in the forests, which are the home of the India rubber-producing plants and of many valuable kinds of timber trees, such as odum("Chlorophora excelsa"), ebony, mahogany("Khaya senegalensis"), Oldfieldia("Oldfieldia africana") and camwood("Baphia nitida"). The climbing plants in the tropical forests are exceedingly luxuriant and the undergrowth or "bush" is extremely dense.
In the savannas the most characteristic trees are the monkey bread tree or
baobab("Adanisonia digitata"), doum palm ("Hyphaene") and euphorbias. The coffeeplant grows wild in such widely separated places as Liberiaand southern Ethiopia. The higher mountains have a special flora showing close agreement over wide intervals of space, as well as affinities with the mountain flora of the eastern Mediterranean, the Himalayaand Indo-China.
In the swamp regions of north-east Africa
papyrusand associated plants, including the soft-wooded ambach, flourish in immense quantities, and little else is found in the way of vegetation. South Africa is largely destitute of forest save in the lower valleys and coast regions. Tropical flora disappears, and in the semi-desert plains the fleshy, leafless, contorted species of kapsias, mesembryanthemums, aloes and other succulent plants make their appearance. There are, too, valuable timber trees, such as the Yellow-wood ("Podocarpus elongatus"), stinkwood("Ocotea"), sneezewoodor Cape ebony("Pteroxylon utile") and ironwood. Extensive miniature woods of heaths are found in almost endless variety and covered throughout the greater part of the year with innumerable blossoms in which red is very prevalent. Of the grasses of Africa alfa is very abundant in the plateaus of the Atlas range.
The fauna again shows the effect of the characteristics of the vegetation. The open savannas are the home of large
ungulates, especially antelopes, the giraffe(peculiar to Africa), zebra, buffalo, wild donkeyand four species of rhinoceros; and of carnivores, such as the lion, leopard, hyena, etc. The okapi(a genus restricted to Africa) is found only in the dense forests of the Congo basin. Bears are confined to the Atlas region, wolves and foxes to North Africa. The elephant(though its range has become restricted through the attacks of hunters) is found both in the savannas and forest regions, the latter being otherwise poor in large game, though the special habitat of the chimpanzeeand gorilla. Baboons and mandrills, with few exceptions, are peculiar to Africa. The single-humped camel, as a domestic animal, is especially characteristic of the northern deserts and steppes.
The rivers in the tropical zone abound with hippopotami and
crocodiles, the former entirely confined to Africa. The vast herds of game, formerly so characteristic of many parts of Africa, have much diminished with the increase of intercourse with the interior. Game reserves have, however, been established in South Africa, British Central Africa, British East Africa, Somaliland, etc., while measures for the protection of wild animals were laid down in an international convention signed in May 1900.
ornithologyof northern Africa presents a close resemblance to that of southern Europe, scarcely a species being found which does not also occur in the other countries bordering the Mediterranean. Among the birds most characteristic of Africa are the ostrichand the secretary-bird. The ostrich is widely dispersed, but is found chiefly in the desertand stepperegions. The secretary-bird is common in the south. The weaver birds and their allies, including the long-tailed whydahs, are abundant, as are, among game-birds, the francolinand guineafowl. Many of the smaller birds, such as the sunbirds, bee-eaters, the parrots and kingfishers, as well as the larger plantain-eaters, are noted for the brilliance of their plumage.
reptiles the lizardand chameleonare common, and there are a number of venomous snakes, though these are not so numerous as in other tropical countries.
scorpionis abundant. Of insects Africa has many thousand different kinds; of these the locustis the proverbial scourge of the continent, and the ravages of the termites are almost incredible. The spread of malariaby means of mosquitoes is common. The tsetse fly, whose bite is fatal to all domestic animals, is common in many districts of South and East Africa. It is found nowhere outside Africa.
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