Mangrove Rehabilitation and Carbon Stock Assessment in the Ondo State Coastal Zone

Mangrove forests provide globally significant carbon storage services, yet large-scale restoration programmes in Nigeria lack rigorous baseline data on carbon stock potential needed to qualify for carbon market financing. This study assessed the carbon stock potential of degraded mangrove areas and evaluated the feasibility of rehabilitation in the Ondo State coastal zone. Field surveys in degraded mangrove patches were conducted at three sites using fixed-area plots to measure biomass components including above-ground wood, below-ground roots, litter, and soil organic carbon. Carbon stock was estimated using species-specific allometric equations and loss-on-ignition methods for soil carbon. Remote sensing analysis using Sentinel-2 imagery provided landscape-scale degradation mapping. Nursery trials were established to test survival and growth rates of locally sourced Rhizophora racemosa and Avicennia germinans propagules under different planting configurations. Total ecosystem carbon stocks at intact reference sites averaged 312 tonnes of carbon per hectare, substantially higher than 78 tonnes per hectare at degraded sites. Direct planting trials showed 78 percent survival for Rhizophora at creek margin sites and 62 percent for Avicennia at more exposed sites after six months. Remote sensing analysis estimated the total rehabilitatable area at approximately 870 hectares. Economic analysis confirmed the viability of REDD+ carbon credit financing for at least 60 percent of priority rehabilitation sites. The study provides a practical framework for carbon-financed mangrove rehabilitation in Ondo State. Keywords: mangrove rehabilitation, carbon stock, REDD+, Ondo State, carbon sequestration.