Monitoring mangrove reforestation in Madagascar with Sentinel 2 derived spectral indices

Mangroves play a crucial role in carbon sequestration, coastal protection, and biodiversity. The efficacy of mangrove reforestation projects is important for environmental management and conservation efforts around the world. This study evaluates the use of spectral indices derived from Sentinel-2 data to monitor mangrove reforestation. Specifically, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index 2 (EVI-2), Red Edge Normalized Difference Vegetation Index (RedEdge NDVI), and Mangrove Vegetation Index (MVI) were analyzed across two study areas: Tsimipaika Bay and Assassin's Bays. Our findings indicate that all four indices were capable of detecting change in mangrove reflectance, but differed in their relative efficacy. The research underscores the complex interaction between mangrove growth, reforestation area size, and the effectiveness of different spectral indices in remote sensing. Recommendations for future studies include refining data extraction methods to enhance change detection and to consider seasonal variations to mitigate the influence of vegetation saturation. This study contributes to the optimization of monitoring strategies for mangrove reforestation, offering insights into the scalability and applicability of remote sensing techniques in conservation efforts.