The changing distribution of two riverine tsetse flies over 15 years in anincreasingly cultivated area of Burkina Faso

Changes in the distribution of two riverine tsetse flies, Glossina tachinoi des Westwood and Glossina palpalis gambiensis Vanderplank are described in an agropastoral area of Burkina Faso subject to increasing human population pressure and land use change. Two similar entomological surveys (one trap every 100 m, 120 km of river) were conducted in 1981 and 1996. Changes in t setse distribution were compared to land use changes through high resolutio n remote sensing imagery (LANDSAT, SPOT). There was a close relationship be tween proximity of crops relative to riverine forest and the density of Glo ssina. Where fields encroached on riverine vegetation, tsetse populations d eclined. Where the geomorphological structure was not well suited to agricu ltural activity, riverine vegetation and tsetse fly populations were relati vely unaffected, even with intense agricultural activity nearby. In contras t, increased human activity and higher cattle densities in the surrounding savannah areas were associated with increased tsetse numbers. The results d emonstrated a wide diversity of tsetse distribution and habitat within a fe w kilometres in an agro-pastoral landscape in West Africa.