Remote Sensing Applications in Monitoring Mangrove Health in the Niger Delta Region

Mangrove forests in Nigeria's Niger Delta are among the most ecologically significant and most threatened coastal ecosystems in West Africa, supporting biodiversity, carbon stocks, and coastal protection services that are critical to the South South geopolitical zone's environmental and human security. This study applies multi-date remote sensing techniques to monitor mangrove health and change dynamics across selected sections of the Niger Delta spanning Delta and Bayelsa States. Sentinel-2 multispectral imagery acquired across four annual time points from 2020 to 2023 was processed to derive mangrove-specific vegetation health indices including the Red Edge Chlorophyll Index and the Mangrove Quality Index, which were calibrated against field measurements of canopy condition, leaf chlorophyll content, and stem density collected at 35 permanent monitoring plots. Change detection analysis using bitemporal differencing identified areas of active dieback, oil-induced defoliation, and natural regeneration. Results confirm that mangrove health is most severely compromised in a 40-kilometre corridor around Escravos and Warri where chronic hydrocarbon contamination suppresses photosynthetic capacity, producing distinctly anomalous index values relative to uncontaminated reference sites. Naturally regenerating mangrove patches following replanting interventions by the Niger Delta Development Commission show measurable improvements in Red Edge Chlorophyll Index values over the three-year monitoring period. The study provides a monitoring framework applicable by state environmental agencies, oil company environmental compliance units, and community resource management groups for regular assessment of mangrove condition. Recommendations include quarterly remote sensing monitoring and community-based patrol systems to detect early-stage degradation. Keywords: mangrove health, remote sensing, Niger Delta, South South Nigeria, coastal monitoring.