Assessing the Contribution of Mangrove Forests to Coastal Protection in Bayelsa State

Mangrove forests in Bayelsa State constitute a critical ecological barrier along the most exposed segments of Nigeria's Niger Delta coastline in the South South geopolitical zone, providing wave attenuation, shoreline stabilisation, and habitat services that underpin the livelihoods and safety of coastal communities. This study assesses the extent and condition of mangrove forests in Bayelsa State and quantifies their contribution to coastal protection through field measurements and biophysical modelling. Multi-date Sentinel-2 imagery was classified to map mangrove canopy extent and identify areas of degradation caused by oil spills, logging, and coastal erosion. Field transects measuring canopy height, trunk density, and root structure were established at 24 locations spanning intact, moderately degraded, and severely degraded mangrove stands. Coastal wave attenuation modelling using the SWAN wave propagation model was applied to estimate the reduction in significant wave height attributable to intact versus degraded mangrove belts across three coastal exposure scenarios. Results indicate that Bayelsa State's mangrove cover has declined by 19 percent since 2010, with the most severe losses occurring in Nembe and Brass local government areas. Intact mangrove belts reduce incoming significant wave height by an average of 62 percent across the modelled transects, while severely degraded stands provide negligible protection. The study recommends urgent expansion of community-based mangrove replanting programmes and prohibition of destructive activities in legally designated mangrove protection zones. Keywords: mangroves, coastal protection, Bayelsa State, Niger Delta, South South Nigeria.