| Extensive field surveys over 7600 km;Species richness of areas of 400 ha declined from 64 ;Arid Sahel species have expanded from the North, tracking a concomitant retraction of mesic Sudan and Guinean species to the South. Vegetation zones have shifted at a rate of 500-600 m y;The rural population of 45 people km;Seventy-seven percent of local people favor natural regeneration of local species over the plantation of exotic species. Natural regeneration is practiced traditionally, requires no special inputs, and encourages the propagation of multiple-use trees.;This research has produced the first documentation of a large-scale decline in species richness and tree densities in the West African Sahel, the first range maps of all 126 tree and shrub species in the Senegal Sahel, the first complete and accurate list of the Wolof names of the 126 species, and the first large-scale carrying capacity analysis in the Sahel based on field data.;The research provides a practical plan for sustainable natural resource management for international development organizations in the field. This could help improve the life of the Senegalese villager, for whom the work is ultimately destined. |
