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About two-thirds of Nigeria lies in the watershed of the Niger River, which empties in to the Atlantic at the Niger Delta, and its major tributaries: the Benue in the northeast, the Kaduna in the west, the Sokoto in the northwest, and the Anambra in the southeast. The Niger is Africa’s third longest river and fifth largest in terms of discharge. Several rivers of the watershed flow directly to the Atlantic, notably the Cross in southeastern Nigeria and the Ogun, Oshun, and Osse in the southwest. Several rivers of northeastern Nigeria, including the Komadugu Gana and its tributaries, flow into Lake Chad. The lake rests in the center of a major drainage basin at the point where Nigeria, Niger, Chad, and Cameroon meet. Kainji Lake, created in the late 1960s by the construction of the Kainji Dam on the Niger River, is Nigeria’s only other large lake. Nigeria’s rivers and lakes have not fared well under development. Sensitive wetland habitats, home to many species of birds and other animals, have been cleared for irrigation, and their flood-dependent ecosystems have been damaged by dam construction.
Before modern development, Nigeria’s diverse habitat of mangrove swamps, tropical forests, savanna, and mountain plateaus supported a diversity of plants and animals. However, over the last several decades, vast tracts of animal habitat have fallen victim to rapid population growth and the expansion of farmland. The widespread hunting of wildlife for food has also threatened the animal population. Consequently, Nigeria’s few remaining elephants, buffalo, lions, leopards, and other large game are generally found only in very remote areas or inside major reserves. Smaller animals such as antelope, monkeys, jackals, and hyenas are more widespread. Hippopotamuses and crocodiles, however, are still common in the largest rivers. Birds, including species that migrate seasonally between Africa and Europe, are also abundant.
The rural economy that supports most Nigerians is based on the productivity of the land, 33 percent of which is cultivated. Soil fertility varies considerably but is generally poor. The most fertile of the soils are the result of alluvial deposition in river valleys. Many, however, are overused and eroded. Trees, which help prevent erosion, are often used for fuel, lumber, material for tools, fodder for animals, and herbal medicines. As a result, the landscape is becoming increasingly barren of trees, especially in densely populated areas and near larger cities. More from Encarta Petroleum and natural gas, the source of most of Nigeria’s export earnings, are concentrated in large amounts in the Niger Delta and just offshore. Smaller deposits are scattered elsewhere in the coastal region. Iron ore, generally of low grade, is widespread. Lignite (brown coal) and subbituminous coal (coal of a lower grade than bituminous but of a higher grade than lignite) can be found in southeastern Nigeria. Other mineral resources include tin and columbite in the Jos Plateau, and limestone in several areas, particularly in the valleys of the Niger, Benue, and Sokoto rivers. The petroleum and natural gas industries—with their oil spills, burnoff of natural gas, and clearance of vegetation—have seriously damaged the land, vegetation, and waterways in the Niger Delta.
Desertification is a major problem in Nigeria, made worse by massive water impoundment and irrigation schemes. Uncontrolled grazing and livestock migration put tremendous pressure on the environment in some areas. Other environmental threats include poaching and settlement within protected areas, brushfires, increasing demand for fuelwood and timber, road expansion, and oil extraction activities. Nigeria has an organized system of nature preserves, game reserves, and national parks in addition to a forest management system, but most management is carried on at the state level. Law enforcement and protected system infrastructure are lacking, and abuses of protected land are common. Nigeria cooperates with Cameroon, Chad, and Niger in the joint management of wildlife in the Lake Chad Basin. The country also participates in the African Convention on the Conservation of Nature and Natural Resources. Several Nigerian groups have campaigned actively, but with little success, to compel the government and major oil companies to introduce environmental safeguards. In 1988 the government created the Federal Environmental Protection Agency (FEPA) to address problems of desertification, oil pollution, and land degradation, but the FEPA has had only a minor impact. In 1995 the weak and fragmented environmental movement was dealt a sharp blow when the government executed Ken Saro-Wiwa, a well-known writer who struggled to stop environmental degradation in the Niger River Delta. In many parts of the country, farmers have practiced environmental protection for centuries. Their techniques include planting several different crops in a single field at once to cover the ground more evenly and thereby reduce erosion and increase fertility; planting and maintaining farmland trees and hedgerows to reduce erosion; applying manure to farmland to maintain soil fertility; and, in certain areas such as the Jos Plateau, terracing steep slopes.
Nigeria has not held a census since 1991. In 2009 Nigeria’s estimated population was 149,229,090, yielding an average density of 164 persons per sq km (424 per sq mi). With a birth rate of 36.6 per 1,000 and a death rate of 16.6 per 1,000, Nigeria’s population is growing at an average of 2 percent annually—a rapid pace, and little changed from the 1970s. The average Nigerian woman gives birth 5 times in her lifetime, although among more educated women the rate is somewhat lower. Nearly half of Nigerians are younger than 15 years. By 2025 the population is projected to grow to 197 million. The highest population densities are in the Igbo heartland in southeastern Nigeria, despite poor soils and heavy emigration. The intensively farmed zones around and including several major cities of the Hausa ethnic group—especially Kano, Sokoto, and Zaria in the north—are also packed with people. Other areas of high density include Yorubaland in the southwest, the central Jos Plateau, and the Tiv homeland in Benue State in the south central region. Densities are relatively low in the dry northeast and in most parts of the middle belt. Ecological factors, including the prevalence of diseases such as sleeping sickness, carried by the tsetse fly, and historical factors, especially the legacy of precolonial slave raiding, help explain these low densities.
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