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Ecology of Africa,
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Flora
The vegetation of
Africa follows 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 are groves of
oranges and
olive trees, evergreen
oaks,
cork trees and
pines, intermixed with
cypresses,
myrtles,
arbutus and 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
Sahara is the
date palm, which flourishes where other vegetation can scarcely maintain existence, while in the semidesert regions the
acacia (whence is obtained gum arabic) 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
savanna interspersed 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
swamp character.
The dense
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),
doom palm (
Hyphaene) and
euphorbias. The
coffee plant grows wild in such widely separated places as
Liberia and southern
Abyssinia. 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
Himalaya and
Indo-China.
In the swamp regions of north-east Africa
papyrus and 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),
sneezewood or
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.
Fauna
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
donkey and 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
chimpanzee and
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,
Somahland, etc., while measures for the protection of wild animals were laid down in an international convention signed in May 1900.
The
ornithology of 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
ostrich and the
secretary-bird. The ostrich is widely dispersed, but is found chiefly in the
desert and
steppe regions. 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
francolin and
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.
Of
reptiles the
lizard and
chameleon are common, and there are a number of venomous
snakes, though these are not so numerous as in other tropical countries.
The
scorpion is abundant. Of
insects Africa has many thousand different kinds; of these the
locust is the proverbial scourge of the continent, and the ravages of the
termites are almost incredible. The spread of
malaria by 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.
References
Category:Africa