A FINE SCALE MAPPING OF MANGROVE SITES IN BENIN, WEST AFRICA

Classified endangered, mangroves are coastal/brackish wetland ecosystems which call upon establishment of fine scale roadmaps for sustainable management. This study is designed to clarify mangroves repartition and provide roadmaps for sustainable management of Benin mangrove ecosystems. Field data -Occurrence, density, and salinity data- together with secondary data –Human population density, historical physico chemics constants, and shapefiles- were collected. Occurrence data and shapefiles were uploaded to ArcGis 10.3.1to map actual species distribution and ecosystems concentration. Using R and its packages agricolae, ANOVA and Student Newman Keuls (SNK) were successively conducted to test the variability of mangroves and structuring means. Results showed that in Benin, mangroves are composed of five species confined to lakes and lagoons of the paralic meridional zone. From the border with Nigeria to the border with Togo, it showed uneven concentration and disproportionate species representation; which are correlated to salinity and human population density. The hypothesised scenario which could explain the noted concentration of mangroves is that salinity at first sight defines concentration of mangroves; the later attracts human settlement which then exerts pressure through excessive resources extraction. Obtained results represent roadmaps that should quickly be broken in appropriate formats for conservationists and management agencies as to slow down critical ongoing genetic erosion of Conocarpus erectus (L.) and Laguncularia racemosa (L.) C. F. Gaertn. It is thus recommended upcoming restoration consider sites with low concentration and less represented species naming C. erectus and L. racemosa.

Keywords: mangroves, Benin, roadmaps, sustainable management, lakes, lagoons, genetic erosion.