Variabilité démographique de Saba senegalensis (A. DC.) Pichon suivant le gradient climatique au Burkina Faso

Abstract

Saba senegalensis (A. DC.) Pichon, also known as the weda vine, is a woody vine from the Apocynaceae family. The non-timber forest products obtained from this species are of major socio-economic importance in Burkina Faso, but its demographic characteristics are little known despite their importance for the implementation of sustainable management programmes. This study assessed the demographic characteristics of S. senegalensis according to the climate gradient in Burkina Faso. Targeted random sampling was used to establish 1,000 m2 plots for a population inventory. Dendrometric measurements of stem diameter were made at the root collar and at 1.30 m above the ground for adult individuals, 20 cm from the ground for young plants and at the root collar for seedlings. The Green index, density, average stem diameter and basal area were calculated and comparisons made between climatic zones. The results showed a clumped distribution of S. senegalensis according to the Green index. Density, average diameter and basal area varied significantly (p < 0.05) between climatic zones. High densities of adult S. senegalensis are found in the Sahelian and Sudanian zones. The general linear model shows that temperature and precipitation have an influence on the establishment and regeneration of S. senegalensis. The demographic structure shows an abundance of juvenile plants with high potential for the renewal of populations. Although S. senegalensis populations show a degree of resilience, the deteriorating climate and human pressures are jeopardising the conservation of the species in its natural habitat.