Much of the area is unsuited to agriculture. This leads to a preponderance of nomadic Orma, and Somali herdsmen of Hamitic origin. The Somalis occupy the extensive bush regions of the north, while their long time rivals, the Orma, are restricted to the Tana River flood plains of the south. Neither tribe uses the central portion of this distribution because the area is infested with tsetse fly. The only people occupying this central region are the Waboni, a small, ancient tribe, previously hunters and gatherers who have now adopted shifting cultivation.
Other people in the study area include small communities of agriculturalists and fishermen. These are the Pokomo along the Tana River and the Swahili, Bajun, and Arabs on the coast and offshore islands. However, the amount of crop production is limited and has remained at subsistence level. The main crops include bananas, cassava, maize, mangoes, coconuts and rice.