Structure et dynamique des espèces ligneuses des forêts-galeries des rivières et ruisseaux du secteur sud-soudanien du Burkina Faso

Burkina Faso's gallery forests are under threat of extinction  due to the pressures of human activity and climate change. In the southern Sudanian zone of Burkina Faso, they are surviving only as fragments. The aim of this study was to describe the structural characteristics of plant groups along two kinds of waterways, rivers and streams, and to determine the demographic structure of the dominant species in order to assess their dynamics. The data were collected by making a systematic inventory across 1 000 m² plots for the adult stage and 100 m² plots for regenerating vegetation, along transects running perpendicularly to the main waterway. The study identified 127 species belonging to 98 genera and 47 families. The densities of these plant groups varied significantly, with the highest densities being found in groups along rivers. Basal areas also varied significantly, with the largest being found in groups along streams.  The dominant species along rivers were generally stable in structure, probably thanks to their location in protected areas and to their biology. The structure of the dominant species along streams was uneven, with large-diameter individuals predominating. The dominant species in the adult stage were not regenerating well in the juvenile stage. This study shows that the type of waterway can influence the structure of plant groups. Regeneration of the dominant species in the adult stage is not necessarily satisfactory. Protection measures drawing on these results need to be considered to help conserve gallery forests in the southern Sudanian zone.