Historically,
west Africa shows a high degree of regional complementarity between the peoples
of tropical forests and the peoples of the dry interior.West Africa has regions
covered by tropical rainforests, running along the coastlines of Guinea Bissau,
Sierra Leone, Nigeria, Ghana and ending at the Congo basin, as well as dry
interiors partially covered by the Sahara Desert. The Sahara covers part of Mali,
Niger and Chad. The occupants of these completely different ecosystems show a
high degree of complementarity between both of them.
