African rain forests shelter probably more then half of the earths plant and animal species. With tropical forests being cut at a rate of 55,000 square miles a year, however, many species perish before they can be identified or studied.
About 9000 years ago, lakes and crocodiles could be found in the Sahara, but for the past thousand years the continent has been dry. Much of Africa is easily damaged by overgrazing and destructive agriculture. Scientists fear that deserticification will bring drought to the Sahel south of the Sahara.
Downpours have washed essential nutrients from the ground in rain forest areas. Even the practice of slashing and burning does not allow the soil to sustain abundant crops.
Africans once allowed the soil to rejuvenate itself and used less-fertile land for herding, but population increases have forced farmers to misuse the soil by planting too often on the same land. Animals overgraze. The African forest is rapidly turning to grassland which becomes desert in turn.