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Preface Annex 1
The wide range of ecosystems – forests, savannahs, deserts, rivers, mountains, mangroves and seas – makes the sub-region rich in biodiversity. The Sahelian zone has several wetlands, including the Niger and Senegal rivers, Lake Chad and floodlands in Senegal and Niger which are very important for migratory birds. The inner Niger delta is a vast floodplain (more than 30 000 km²) situated in the middle of the Sahelian landscape, rich in natural resources and featuring varied ecosystems (lakes, forest floodplains, flooded grasslands and savannah) which supports the livelihoods of 1 million people. The delta is also well known as a wintering and staging area for million of migratory birds. Other important sub-regional biodiversity values include the west African manatee, a globally endangered species (Beintema and others 2001). The Guinea forest contains half the mammal species on the African continent, including the rare pygmy hippopotamus, the zebra duiker and the drill, the most threatened primate (UNEP and NESDA 2004).
CHALLENGES FACED IN REALIZING OPPORTUNITIES FOR DEVELOPMENT
Land degradation and desertification are major causes of biodiversity loss. Three factors contribute:
These processes affect grasslands, steppes, savannahs and woodlands:
Dust storms, forest fires, locust outbreaks and population displacement are all linked to the phenomenon of desertification, and have strongly negative consequences for people, in particular through the loss of livelihood and economic opportunities.
Land degradation is a persistent reduction in the capacity to support life and supply ecosystem services. It affects biological diversity directly and indirectly. It may affect the survival of species and alter processes that support their life, or it may trigger socioeconomic phenomena that impact on living species and their ecosystems. Land degradation phenomena directly affecting biodiversity include water and wind erosion. Along major river basins siltation processes accumulate debris and materials that engulf natural vegetation, such as the Acacia nilotica riparian forests. Trees may survive for years, but the diverse understorey may not. Soil erosion contributes to moving the seed capital of the ground, uprooting grassy as well as woody species, and in accumulation areas it smothers valuable species. This occurs in the sand dune areas of countries such as Mauritania, Mali, Niger, Nigeria and Senegal.
Indirect factors associated with land degradation that impact on biodiversity include the coping strategies people adopt to deal with environmental change. The movement of people south towards sub-humid to humid tropical areas has resulted in depletion of natural resources: loss of primary forests and woodlands, repeated logging of the secondary vegetation, and depletion of a number of species. The influx of refugees from war-stricken areas also triggers severe land degradation in host regions and the overuse of wildlife resources. More diffuse degradation of land resources also occurs in the arid and sub-humid parts. These include the extraction of tree resources outside forests for charcoal making (about 150 million tonnes/year from the savannahs and woodland areas), and the use of high-value woods. Most affected are the Meliacaea family (Khaya species), Pterocarpus erinaceus, and Dalbergia melanoxylon.
The degradation and fragmentation of natural landscapes is caused by agricultural expansion. Agricultural expansion affects the survival and regeneration of animal populations, destroys the structure of wildlife habitat, and strongly contributes to reduction of wildlife populations. The number of species threatened continues to grow; these include lion, elephant, most of the greater antelopes, and water-dependent species such as manatees and crocodiles, which could form the basis of a tourism industry.
STRATEGIES TO ENHANCE THE OPPORTUNITIES FOR DEVELOPMENT
A number of conservation efforts, some involving communities, have been undertaken. An example of a successful conservation initiative involving local communities is shown in Box 6.
Table 7 shows international protected areas in Western Africa. An example of successful cooperative is the endeavour of Benin, Burkina Faso and Niger, supported by external partners such as France, to protect the extensive transboundary complex of the Pendjari and Arly national parks. Concerted efforts have succeeded in maintaining the overall system and resources in the protected areas in the three participating countries. Biodiversity is relatively well conserved in this area: avifauna is represented by around 378 species; fish species, amphibians and reptiles are prominently present; and the greater mammals of the savannahs and woodland areas are extensively featured (10 000 buffalo, 4 500 elephants, 7 500 roan antelopes, 2 000 bubals, 1 100 warthogs and 1 000 kobs). Lions, cheetahs, panthers and hyenas are also well represented. The habitat is also well conserved, and the overall trend of biological diversity is deemed very positive and on the rise.