Professional Assessment of Wetland Vegetation Dynamics and Conservation Priorities in the Lake Chad Basin, Borno State

The Lake Chad Basin in Borno State, North East Nigeria, is experiencing rapid wetland vegetation transformation driven by lake shrinkage, climate variability, and human pressures, and a professional assessment of vegetation dynamics is critical for conservation planning. This study assessed changes in wetland vegetation composition, cover, and distribution using multi-temporal remote sensing (Landsat imagery 2000, 2010, and 2022) combined with ground-truth vegetation surveys at 24 sites in Nigerian Lake Chad wetlands in Borno State. Vegetation classification maps were produced for each time period, and change trajectories were computed for eight vegetation classes: open water, floating vegetation, emergent marsh, seasonally flooded grassland, riparian woodland, shrubland, dry grassland, and bare ground. Field surveys characterised plant species composition, biomass, and disturbance status at ground-truth sites. Results showed a 47% reduction in open water area and a 62% decline in floating vegetation cover between 2000 and 2022. Emergent marsh vegetation (Phragmites australis, Typha australis, and Vossia cuspidata) expanded by 23% in area, reflecting shallowing and increased terrestrialisation. Riparian woodland declined by 38%. Twelve wetland plant species of conservation concern were documented at ground-truth sites. Five sites of exceptional species richness and conservation importance were identified for priority protection. The study concludes that Lake Chad Basin wetland vegetation is undergoing irreversible degradation and recommends immediate gazettement of the five priority sites as ramsar candidate areas.

Keywords: wetland vegetation, Lake Chad Basin, remote sensing, vegetation dynamics, Borno State