Tsetse fly in Western Narok, Kenya

Abstract

This article studies the expansion of tsetse fly in one part of Kenya Maasailand between 1900 and 1950. It follows the lines of investigation first suggested by Ford's work and examines in detail the interaction between changes in four elements in the Mara ecosystem: climate, vegetation, land use and tsetse. Tsetse was able to expand because its habitat expanded and the spread of bush and fly into the grasslands both caused, and was facilitated by, shifts in patterns of Maasai grazing and occupation in the area. Up to the 1890s, the Mara Plains were regularly grazed by Maasai herds; but the general depopulation of Maasailand in the aftermath of the rinderpest pandemic and civil war left the region vacant until after 1900 and allowed the spread of bush cover which was then colonised by tsetse. When Maasai returned, they altered their grazing patterns to avoid such areas. However, the progressive encroachment of tsetse-infested bush continued and was not halted until bush-clearing schemes and closer grazing forced the fly to retreat by destroying its habitat. The study is set within the wider context of ecological change and capitalist development in East Africa and suggests that the common assumption that colonial capitalism was responsible for the disruption of the ecosystem and, therefore, for the spread of disease and environmmental degradation needs careful re-examination in the light of a more sophisticated understanding of the processes of ecological change.