Structural analysis of a striped thicket in northern Yatenga (Burkina Faso): Current state and dynamic insights

This study deals with spatial distributions of woody plants in a fourre tigre (tropical striped vegetational pattern) in northwestern Burkina Faso(ca 14 degrees 00'N, 2 degrees 30'W). Data collection (censuses, measurements) was carried out on 700 m long transects, oriented along the slope, and divided into plots (156 m(2)) and quadrats (4 m(2)). Pattern analysis was based upon computations of variograms. The overall structure of the striped thickets was qualitatively modelled in order to test ifs influence on spatial distributions (using linear regression on 'dummy' variables). Among the two dominant species, only Combretum micranthum G Don displayed spatial distributions clearly linked to the overall structure. Those of Pterocarpus lucens Lepr were comparatively more independent, due to their ability to expand on the fringes of vegetation stripes during periods of normal rainfall. The population of C micranthum did not display any clear trend because of a very low survival rate of seedlings during the first dry season following the germination. Hence, an upslope migration of the species is not perceptible at present.