Mangrove mapping along the Lower Casamance River in Senegal, using the Google Earth Engine Mangrove Mapping Methodology (GEEMMM)

In recent decades, mangrove forests in Africa have been experiencing drastic degradation and decline in population due to heavy anthropogenic pressures and climate change-induced sea level rise. To ensure the future long-term well-being of these unique ecosystems, and to reflect past conservation efforts, quantitative analysis of the past and current mangrove forest condition on a regional scale is much needed.

In this study, we chose to conduct systematic mapping of mangrove forests along the Lower Casamance River region, using Google Earth Engine Mangrove Mapping Methodology (GEEMMM), for the years 1990 and 2021. Overall, we achieve a validation accuracy of 87.13% for the 2021 classification and 90.25% for the 1990 classification. Our study found that, across our study regions, there was a net loss of 123.99 km2 in our open-canopy mangrove I class and a net gain of 63.04 km2 in our closed-canopy mangrove class.