Using of intensity analysis approach in Benin coastal zone (West Africa) to assess land use/land cover change for further decision making.

Coastal areas are fruitful environments with a complex diversity of ecosystems. These areas are very sensitive and therefore, changes in the region of interest (ROI) require special attention due to the consequences. The changes observed in the coastal zone of Benin, such as: coastal erosion, the decrease of mangrove ecosystems and its consequences, and the pressure on agricultural land, have motivated this study, which aims to assess land use land cover in the coastal zone of Benin in order to better anticipate the phenomena of loss and fragmentation of ecosystems and to provide guidelines for policy-making. To achieve this objective, remote sensing and field surveys were used. Spot and Landsat satellite images of the years 1991-2006 and 2021 have been uploaded to regards. cnes.fr and USGS. Direct field observations and group discussions to determine the driving forces behind the changes were conducted. Supervised classification using the Maximum Likelihood approach of ENVI software was used and QGIS 3.16 to process the data. Significant changes have been observed in the coastal zone our study area over the past thirty years. During the period 1991-2006, palm fields constituted the largest land use with 84786 ha or 28.9% of the total area. This occupation will decrease over time to reach 66773.2 ha in 2006 (22.7% of the total area) and 27406.5 ha or 7.2% of the total area in 2021. Classes such as Mosaic of crop and out of crop, dense forest have experienced the same evolution while the opposite trend is observed in built-up areas. From 11543 ha or 3.9% of the total area in 1991, this class has increased to 25138 ha or 8.7% of the total area in 2006 and 44418.5 ha or 15.1% in 2021. Urbanization and the need for agricultural land have been identified as driving forces behind these changes and Markov chain analysis reveals future regression of coastal ecosystems such as mangroves, dense forest, swamp, and crop ender palm. These outcomes have far-reaching policy direction of environmental sustainability target in Benin coast.