Latitudinal variation in the woody species diversity and population structure of Lannea microcarpa Engl. and K. Krause in Burkina Faso

Latitude is source of variations of plant species diversity and stand structure. This study aimed to characterize the populations of the African grape tree, Lannea microcarpa, in its range in Burkina Faso. Data were collected according to oriented sampling scheme, based on the presence of the species. Overall, 140 inventory plots of 1000 m(2) each were considered across the sub-Sahelian, north-Sudanian and south-Sudanian phytogeographical zones. Tree diameter at breast height (DBH) and total height of L. microcarpa individuals were measured and all woody species in each plot were recorded. A comparative analysis was made between zones for woody flora diversity associated with L. microcarpa, dendrometric and stand structure parameters. The results revealed a total woody flora richness of 109 species. Correlogram analysis revealed that species associated with L. microcarpa differed between phytogeographical zones. Ten species showed a probability of association with L. microcarpa. The density of L. microcarpa populations and the floristic diversity of its habitats decreased significantly (p < 0.001) from sub-Sahelian to south-Sudanian zones. The diameter classes’ structure in the three phytogeographical zones revealed unstable populations with a predominance of intermediate classes compared to extreme classes. The height structure of juveniles is marked by a poor transition between the different classes, showing unpredictable regeneration of L. microcarpa in the three phytogeographical zones. The results of this study draw attention to the need to adopt conservation measures for the species. In this sense, the data on the comparative demographic characteristics can serve as a basis for the implementing of adequate management strategies of natural populations of the species across its distribution range in Burkina Faso.