The map of ecological regions of West Africa captures the variety and complexity of West Africa’s landscapes and presents a way of organizing them into smaller units. Ecological regions, or ecoregions, are areas of relative homogeneity with respect to ecological systems involving the interrelationships of plants, animals, and their environment. Ecoregions are a holistic concept: The spatial patterns that help identify them arise from the interplay and integration of many factors — geology, geomorphology, soils, vegetation cover, climate, hydrology, and finally human modification of the land.
As some of these factors vary along gradients, not all ecoregion boundaries represent sharp or concrete differences in the landscape. Nonetheless, the identification of discrete regions of similar environmental makeup offers a helpful spatial framework for land use planning and management. Operating as integrated systems, ecoregions provide logical reporting units on a variety of biophysical and socioeconomic conditions and can be useful in many complex tasks, such as setting priorities for conservation and development, studying the impact of climate change, and assessments of carbon stocks and sequestration potential.
Satellite remote sensing is an effective tool for ecoregion mapping because it already integrates many biophysical and man-made elements, depicting the complex character of the land surface in image form. Landsat imagery in particular offers the ideal characteristics for delineating and classifying ecoregions from spatial patterns of the land surface at national and regional scales. Ecoregion mapping was one of the early steps in the process that culminated in mapping the land use and land cover of 17 West African countries.
The ecoregions map of West Africa was compiled from national draft maps prepared by 12 country teams during a workshop held at the AGRHYMET Regional Center in Niamey. The country teams delineated ecoregions based on visual interpretation of a Landsat image mosaic, drawing on their extensive knowledge of the biophysical and human geography of their respective countries. Their interpretation of the Landsat imagery was also supported by thematic maps of individual environmental properties (e.g., soils, geology, climate, vegetation) where available. Because the regional map was stitched together from individual national maps, ecoregion boundaries and names are not always consistent across international borders. Ecoregion names were retained in their original language.