Plant formations of Pterocarpus erinaceus Poir. in Sudanian and Sahelian zones

In the Sudano-Sahelian zones of West Africa, climate controls the distribution and composition of spontaneous vegetation. The study was conducted in Niger and Burkina Faso. It aims to (1) analyze the ecological and floristic characteristics in a heterogeneous environment of 8 forests: (2) determine the woody groups of plant formations in P. erinaceus along an agroecological gradient. A total of 206 plots of 1000 m2 were established in 8 forests along an agroecological gradient in Niger and Burkina Faso. In each plot, dendrometric measurements such as DBH, Total height and two perpendicular diameters of the crown were performed on all woody individuals of all recorded species with DBH˃5 cm. Our study identified 117 species belonging to 25 families. The four most represented families are Fabaceae (31.8%), Combretaceae (16.8%), Malvaceae (7.9%) and Rubiaceae (6.9%). Our results revealed that Micro-phanerophytes is the dominating biological type in all forests. The Shannon index shows that the species richness and diversity increase with increasing humidity from the Sahelian to the Sudano-Guinean zone. Sorensen's index shows that the similarity is greater between the forests of Tiogo, Cassou and Laba in Burkina Faso. The Ascending Hierarchical Classification and the Non-Multidimensional Scaling made it possible to determine six large groupings of P. erinaceus. We conclude that P. erinaceus has great ecological amplitude and its distribution zone extends from the Sahelian to the Guinean zones while associating with a diversity of plant species.