Original Contributions to Environmental Management Assessment Methodology for Wetland Ecosystem Services in Nigeria’s River Deltas

This dissertation makes original methodological contributions to the assessment of wetland ecosystem services in Nigeria's river delta systems, developing novel approaches that address the specific ecological complexity, data scarcity, and community-management co-dependency conditions of delta wetlands in the South South geopolitical zone. Wetland ecosystem service assessment is a critical tool for environmental management decision-making, informing restoration investments, compensation claims, and conservation planning, but assessment methods developed for temperate wetland systems perform poorly in the ecologically distinct and data-scarce tropical delta wetland systems of the Niger Delta and Cross River Delta. The dissertation's methodological contributions span four domains: an integrated biophysical-social assessment protocol specifically designed for Nigerian mangrove and freshwater swamp systems that combines remote sensing analysis, rapid ecological field assessment, and structured community knowledge elicitation to characterise ecosystem service provision with reduced data requirements; a novel damage quantification methodology for oil spill ecosystem service loss assessment that improves on the current NOSDRA approach by incorporating habitat quality, recovery trajectory, and secondary damage cascade effects; a benefit transfer framework for Nigerian delta wetlands that adapts international ecosystem service valuation databases to local ecological, economic, and cultural conditions; and a community-grounded ecosystem service monitoring protocol that enables communities to generate their own longitudinal ecosystem service trend data using standardised but accessible methods. Each methodological contribution is tested through field application at six delta wetland sites in Rivers, Bayelsa, Delta, and Cross River States, with validation of results against independent data sources where available. Keywords: ecosystem services, wetland assessment, Niger Delta, methodology, environmental management.