Climatic variability and spatial distribution of herbaceous fodders in the Sudanian zone of Benin (West Africa).

Abstract

This study focused on future spatial distributions of Andropogon gayanus, Loxodera ledermanii and Alysicarpus ovalifolius regarding bioclimatic variables in the Sudanian zone of Benin, particularly in the W Biosphere Reserve (WBR). These species were selected according to their importance for animals feed and the intensification of exploitation pressure induced change in their natural spatial distribution. Twenty (20) bioclimatic variables were tested and variables with high auto-correlation values were eliminated. Then, we retained seven climatic variables for the model. A MaxEnt (Maximum Entropy) method was used to identify all climatic factors which determined the spatial distribution of the three species. Spatial distribution showed for Andropogon gayanus, a regression of high area distribution in detriment of low and moderate areas. The same trend was observed for Loxodera ledermannii spatial distribution. For Alysicarpus ovalifolius, currently area with moderate and low distribution were the most represented but map showed in 2050 that area with high distribution increased. We can deduce that without bioclimatic variables, others factors such as: biotic interactions, dispersion constraints, anthropic pressure, human activities and another historic factor determined spatial distribution of species. Modeling techniques that require only presence data are therefore extremely valuable.