Wetland Modification, Mangrove Biodiversity and Rural Ecotourism Resilience in the Cross River Estuary, Nigeria: Geospatial Evidence for Sustainable Environmental Management

This study examines how wetland modification in the Cross River Estuary, Nigeria, affects mangrove biodiversity, mollusc resources, rural livelihoods and ecotourism-oriented environmental management. A geospatial and ecological survey design was used, combining land-use/land-cover change analysis, floristic quadrat records, mollusc distribution data, field observations and analysis of modification zones. Built-up land increased from 55.81 km² to 95.05 km² between 2003 and 2025, while mangrove cover declined from 172.69 km² to 135.40 km². Nypa palm increased from 98.70 km² to 121.13 km², indicating replacement pressure on native mangrove communities. Tree composition decreased from 64.00 individuals in relatively unmodified zones to 24.00 in highly modified zones, whereas shrub composition increased from 3.00 to 46.00. Mollusc abundance declined sharply with rising modification intensity. The results show that unregulated extraction, settlement expansion and invasive species growth weaken ecological integrity and rural livelihood security. The study integrates geospatial evidence, biodiversity assessment and ecotourism planning to support conservation-led wetland governance.