Effects of climatic variability and local environment patterns on the ecology and population structure of the multipurpose plant species, Vitex doniana Sweet (Lamiaceae) in Benin

Abstract

We assessed impacts of climatic variability, land cover and proximity of river on the ecology and population structure of Vitex doniana Sweet in Benin (West Africa) in order to provide relevant information for its sustainable management and conservation in the context of global change. Numbers of contacts and numbers of adult individuals per contact of the species along transects revealed through negative binomial model that even though the species is present in all climatic zones, it does not show preference to a particular zone, but it is more frequent in mosaics of croplands and fallows (MCF) and in areas at less than 500 m to river. Analyses of floristic composition, suggested that V. doniana occurs globally in different woody plant communities regarding climatic zones, land cover types and distance to the closest river. Significant interaction effects of climatic zone and land cover type were noted on structural parameters (mean diameter and basal area) of V. doniana with the highest values in the Sudanian MCF (46.11±23.83 cm and 3.35±3.07 m2 ha−1). Moreover, diameter structures revealed globally a predominance of relatively young individuals (dbh ≤ 20 cm) of the species. Although studied environmental factors do not have significant effect on densities of the species (adult and regeneration), the relatively low values recorded may lead to a rapid decline of its populations in future. Sustainable management practices should be thought to favour and preserve the regeneration of the species for it conservation.