Although soils and biotic factors (i.e., those pertaining to living
organisms, including humans) are important, vegetation is primarily
determined by rainfall. There are three principal types of vegetation
from south to north occurring in the coastal savannah, in the forest
zone, and in the northern savannah zone.
The coastal savannah in the south-eastern plains around Accra consists
of a mixture of scrub and tall grass (mostly Guinea grass), with giant
anthills, often 10-14 feet high, providing an anchorage for thicket
clumps that often include Elaeophorbia (a fleshy-leaved plant containing
caustic latex) and other drought and fire resistant species such as
the baobab (Adansonia digitata).
In the forest zone (the southern third of the country and the area
along the Akwapim-Togo Ranges, where the mean annual rainfall exceeds
45 inches and is well distributed throughout the year without a pronounced
dry season), the predominant vegetation is evergreen and tropical
semi-deciduous forest. There are tall trees of varying heights, forming
a closed canopy at the top, above which tower a few forest giants,
such as the silk cotton tree, the Wawa tree (African whitewood, a
hardwood), and the African mahogany. The evergreen forest is in the
extreme southwest, where the rainfall exceeds 65 inches a year, while
there is a semi-deciduous forest farther north.
The dense forest zone formerly covered an area of about 30,000 square
miles, but farming activities and timber exploitation have reduced
it to less than 8,000 square miles, including about 6,000 square miles
of reserved forest. To ensure the sustainable use of the country's
rapidly diminishing forest resources, the government has embarked
on a forestry policy involving the compulsory reforestation of cutover
areas and more accurate measurements of exploitable timber and rates
of extraction and regeneration.
The third vegetation type, the northern savannah, is found in the
northern two-thirds of the country, where the low annual rainfall,
between 45 and 30 inches, occurs in a single season and is followed
by a period of intense drought. There the vegetation consists mostly
of tall Guinea grass, together with a scattering of low trees, such
as the shea butter tree, various species of acacia, and baobabs. Along
the northern border the savannah gives way to a more open type of
grassland that has developed largely as a result of prolonged human
interference.
Ghana is relatively rich in animal life, although it has been reduced
by hunting and the spread of human settlement. Large mammals include
lions, leopards, hyenas, antelope, elephants, buffalo, wild hogs,
chimpanzees, and many kinds of monkeys. Among the snakes are pythons,
cobras, horned and puff adders, and green mambas. Crocodiles, the
endangered manatees, and otters are found in the rivers and lagoons.
Hippopotamuses are found in the Volta River. There are many species
of lizards, tortoises, and giant snails.
Among the numerous birds are parrots, hornbills, kingfishers, eagles,
kites, herons, cuckoos, nightjars, sunbirds, egrets, vultures, snakebirds,
and plantain eaters.
The ocean, rivers, and inland lakes are rich in fish and other forms
of life. Sardines, locally called herring, arrive seasonally in the
coastal waters in large shoals; other fish include mackerel, soles,
skates, mullet, bonitos, flying fish, lungfish, elephant fish, sea
bream, and sharks. Edible turtles, barracuda, and stingrays are fairly
common; mussels, crabs, lobsters, and prawns also are found.
Insect life is particularly abundant. There are beetles, fireflies,
ants, termites, butterflies, crickets, and bugs. Among the most dangerous
insects are mosquitoes, tsetse flies, and blackflies (Simuliidae),
which are responsible for transmitting the endemic diseases of malaria
and yellow fever, trypanosomiasis (sleeping sickness), and onchocerciasis,
or river blindness (a parasitic disease), respectively.
The Mole National Park in the western part of the Northern Region
near Damongo is 1,900 square miles in extent. Other reserves have
been developed farther south, notably on some of the islands in Lake
Volta. |
