Environment
Africa’s natural habitats are suffering from human interference. One of the most serious problems occurs in areas such as the Sahel where scrub and forest clearance, often for cooking, combined with overgrazing, is causing deforestation and desertification. Game reserves help to preserve many endangered animals, although the needs of growing populations lead to land overuse and poaching.
Conservationists look at Africa’s wildlife as a last remnant of past biological wealth. In most of the world, large mammals like elephants died around 10,000 years ago. In Africa, where animals and people lived together for more then 2 million years, large mammals roaming forests and savannas survived. Sparse human population enabled large animals and many rain forest species including rare plants to survive.
During the last hundred years, the people in sub-Saharan Africa increased in numbers six fold. Industrial countries have made it profitable for Africans to kill elephants for ivory, cut down trees for timber, and plant forests and fertile lands in cash crops like cocoa.
Wildlife and wildlands have been lost. The continent’s human population is projected to double in 24 years. Two thirds of people are rural, and survive on raising crops and livestock on any available land. Competition for land is intense around Lake Victoria and along the coast of West Africa.
Hungry people seldom rally around the cause of the wildlife preservation. Therefore, many programs promote conservation by giving rural people an economic stake in the survival of ecosystems and habitat.
Water
Freshwater bioregions, defined by groups of rivers and lakes, are among the most diverse and vulnerable areas. To the east is the Great Rift Valley which contains several lakes.
Major rivers like Congo and Niger support fish, birds, otters, and hippos. The Niger River is the Africa’s third longest river. It flows across western Africa to its delta in Nigeria. The Niger’s water is used for irrigation and hydroelectric power and limited transportation because of many waterfalls and rapids.
Lakes have been evolving for more then 20 million years. Over-fishing, the introduction of exotic species, and pollution have wiped out half of the Lake Victoria’s 500 clichild species, a large part of diet of local people.
The Lake Victoria, lying on the Equator, is the second largest freshwater lake in the world.
Water is one of the world’s most valuable resources. Although countries may enjoy significant amounts of rain, the water may be polluted or unsafe to drink. In many parts of Africa, less than 50% of the population has access to safe water. Lack of infrastructure and government regulation of the water supply keeps many Africans from getting clean water. As a result, millions of people die each year from water–related diseases such as cholera.
Water for crops and livestock is also scarce in many parts of the continent. Africa has three large deserts. The Sahara is the world’s largest desert and dominates the northern part of the continent. Thousands of years ago the Sahara had a moist climate. The Namib and Kalahari deserts cover huge areas of southwestern Africa. The Namib Desert is very barren and extremely dry.
Climate
Climate is an average pattern of weather and temperature over a period of time. It is a region’s climate, together with physical landscape, that determines plant life found there.
The climate is influenced by its latitude or how far to the north or south of the equator it lays. Regions around the equator are the hottest in the world. Closer to the poles, the colder it gets. Africa’s climatic zones fall into three broad categories: humid equatorial, dry, and humid temperate.
In West and Central Africa, along the Guinea Coast, in Gabon, Cameroon, Democratic Republic of the Congo, northeastern Republic of the Congo, and in East Africa south of the equator in Tanzania, Mozambique, and Madagascar the climate is humid.
The regions nearest the equator receive year-round rainfall, while those north and south of it experience short dry winters and a lower average annual amount of rainfall.
Where the dry seasons are long enough, equatorial regions give way to dry regions. In the north the Sahel desert stretches from east to west through Mali, Niger, Chad, and Sudan and borders the Sahara.
In the deserts themselves, rainfall is extremely scarce and temperatures are very extreme. Although the daytime temperatures in the desert are high, due to the lack of plants and moisture, nights can be extremely cold. The coastal regions of North Africa and southern tip of Africa experience temperate or “Mediterranean” weather, including dry summers and wet winters, due to their proximity to the oceans.
Ecosystem
Scientists divide the earth into number of different vegetation zones. The plant and animal life depend on a region’s climate, landscape, and latitude. Plants and animals have adapted to life in these climates, often developing features to help them to survive.
Mediterranean: hot, dry summers and cold, wet winters (plants and trees have adapted to lack of water).
Tropical Grassland: hot climate divided into wet and dry season; between tropical rain forests and hot dessert, called African savanna with tall grasses and low trees and shrubs.
Hot Desert: hottest, driest places on Earth; heat during a day to often below the freezing temperatures at night. In some deserts, years pass with no rain. Deserts have sandy soil that supports.
Mountains Regions: the higher, the colder, with peaks often in snow. Trees and plants grow on lower slopes only. Above the tree line, it is too windy and clod for plants to survive.
Dry Grassland: hot, dry summers and very cold winters (often used for wheat or cattle).
Tropical Rain Forest: hot and wet all year round, ideal for lush, green forests around equator. Rain forests may contain 50,000 different types of trees, and millions of plants and animals.
Ecology
African rain forests shelter probably more then half of the earth’s 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.
