Desertification and Degradation in Sub-Saharan Africa

Throughout much of this century, people have been justly concerned with long-term changes in the species composition, productivity, stability, and usefulness of arid and semiarid terrestrial ecosystems around the world. The debate focuses on the causes, particularly human and livestock, the permanence of the changes and the questions of what could or should be done. Since nearly all arid and semiarid environments are characterized by extreme year-to-year weather fluctuations, it is difficult to distinguish between short and long term trends and temporary and permanent changes. Section one of this paper, perceptions of desertification and degradation, focuses on definitions, pre-1960 and post-1960 views. Section two looks at paradigms for understanding and management. Section three discusses the following topics under the influence of grazing on rangelands: effects on vegetation, on spatial heterogeneity of soil resources, on climate, and on sub-Saharan Africa. Discussion about the implications for development conclude the paper. 48 refs.