Impacts of the rainfall gradient and anthropization on the state of contracted vegetation on the plateaus of western Niger
Abstract
The contracted vegetation of the plateaus of western Niger is subject to anthropogenic and climatic pressures that threaten its existence, preservation and sustainability. The aim of this study is to investigate the current state of this vegetation in three sites located along a rainfall and anthropisation gradient in order to determine which of the anthropogenic or climatic factors is having the greatest impact. A survey of local populations was carried out to identify pressure factors. At each site, five transects were randomly selected according to the steepest slope and the succession of bare and wooded strips. Eight 2500 m2 plots were laid per transect, i.e. forty per site. A total of 120 plots were used to collect dendrometric data. Rainfall data was obtained from the National Meteorological Directorate of Niger. The results showed that anthropic pressure had the greatest influence on vegetation condition. Of all anthropogenic pressures, logging is the one that weighs most heavily on this vegetation. The rainfall gradient determines partial desiccation and standing mortality. The preservation and sustainability of these contracted vegetation formations must imperatively call upon new, more inclusive policies, integrating all stakeholders in the preservation, management and rational exploitation of resources.
Keywords: Contracted vegetation, anthropisation, rainfall gradient, Niger