The lakes of Africa provide outstanding examples of biodiversity. Some hundreds of species of aquatic fauna, especially fishes, have been created through evolution taking place in environments which became isolated from each other. The lakes also provide an outstanding example of the loss of biodiversity: in Lake Victoria at least 200 species of fish have almost certainly become extinct through human activities. These lakes have, since Mankind's origin in Africa, provided high-quality animal protein food and with improved management they could provide much more, which adds greatly to their scientific and economic interest.

Recently, intensification of both rain-fed and dry-season irrigated agriculture has necessitated widespread use of pesticides in the extensive sub-humid zones of Nigeria. In this region is located over 80% of Nigeria's existing surface area of reservoirs in the country. The majority of these reservoirs were built artificially for a multiplicity of uses among which fisheries and Nature conservation ranked very high.—

Calls for small-scale farmers to move away from the use of purchased inputs in order to make farming more environmentally sustainable are being increasingly voiced on the strength of ecological arguments. These arguments, backed up by technical information on natural resource-loss or degradation, and by descriptions of sustainable indigenous systems which use few external inputs, are often persuasive. However, they can also be simplistic and misleading.

Owing to their sub-Sahelian climate, the Cape Verde Islands, lying off the coast of West Africa, experience severe problems of soil erosion and surface-water loss. Thus the development of this country has included widescale planting of trees, mainly Prosopis juliflora, and the building of contour walls and small dams. Agroforestry species are being tested for both erosion control and the production of wood and timber. The conservation of native crop species, and the use of integrated pestcontrol, have been given priority in Cape Verde's agricultural development.

An examination of the behaviour of conservation area staff in northern Benin indicates that they are not working as effectively as they ought to be, owing to a series of interrelated physical and social conditions. This study suggests that a compensatory approach alone — improved housing, vehicles, equipment, and salaries — is unlikely to be sufficient to improve motivation, and may perversely reduce effectiveness.

An ecological survey of undisturbed saline wastelands and adjacent fields of Kallar Grass (Leptochloa fusca) was undertaken to study species distribution in relation to soil conditions and changes in species composition during amelioration processes. Five plant communities, represented by Atriplex crassifolia C.A. Mey., Cynodon dactylon (L.) Pers., Desmostachya bipinnata (L.) Stapf, Suaeda fruticosa (L.) Forssk., and Eleusine flagellifera Nees, had colonized undisturbed areas. Soils of plant communities dominated by these species showed significant variations in salinity and sodicity. S. fruticosa was dominant on highly saline–sodic soil, Cynodon on slightly saline and moderately sodic soil, whereas D. bipinnata showed little variation in cover percentage with changes in salinity and sodicity of soil. These three species had wide ecological amplitude compared with E. flagellifera and A. crassifolia, which were restricted to non-saline and marginally saline–sodic soils, respectively.

This paper examines some of the impacts of Biosphere Reserve planning on the socio-economic conditions of rural communities in the United States. Through a review of the literature, it is argued that three broad types of problems can develop when Biosphere Reserve plans are put into effect. These include unexpected development shifts, shifts in the distribution of benefits and costs of economic development, and a loss of local governments' ability to provide public services. Though Biosphere Reserve planning has been cast as a strategy for experimentation in community and ecological sustainability, the planning and management process itself causes paradoxical local impacts.

The idea of ecotourism is being promoted and supported, by growing numbers of people and groups in different parts of the world, as a major means of dealing with the damaging effects of tourism. Yet the meaning of the term varies among different people, projects, and places. Evidence from national parks, where this type of tourism has been promoted for many years, shows that such tourism can cause substantial long-term cumulative changes in environment. Concepts such as ecotourism, green tourism, and sustainable tourism development, are general in their nature and have to be described, planned, and assessed, in detail on the ground in terms of the socioeconomic and environmental conditions applying in different places. In this respect, careful planning and management procedures are needed not only for ecotourism but indeed for all forms of tourism.