Species Diversity and Distribution of Mangrove Vegetation in the Nun River Estuary, Bayelsa State, South South Nigeria

Mangrove ecosystems along the Nun River estuary in Bayelsa State represent some of the most ecologically productive coastal habitats in the Niger Delta region. This study documented species diversity and distribution patterns of mangrove vegetation across five transects established in the estuary. Field surveys were conducted during both wet and dry seasons to capture seasonal variations in species occurrence and canopy density. Identified species were recorded and classified using standard botanical references, and the Shannon Diversity Index was applied to quantify species richness. Results identified Rhizophora racemosa, Avicennia germinans, and Laguncularia racemosa as the dominant species, with variations in zonation corresponding to salinity gradients and tidal inundation patterns. Human disturbance indicators including charcoal production sites, illegal logging stumps, and oil spill-affected patches were mapped along the transects. Canopy cover analysis using hemispherical photography revealed significant depletion in areas adjacent to oil production infrastructure. The study also assessed regeneration rates in disturbed zones compared to relatively undisturbed reference sites. Findings underscore the vulnerability of Nun River mangroves to anthropogenic pressures and provide baseline data for conservation planning. It is recommended that the Bayelsa State government establish mangrove restoration programmes with community participation and enforce existing regulations on coastal vegetation clearance. Keywords: mangrove diversity, Nun River, Niger Delta, species distribution, coastal ecology.