Linking Habitat Conditions, Human Pressures, and Waterbird Diversity in a West African Coastal (…)

ABSTRACT

The Tanji wetland complex, situated on the Atlantic coast of The Gambia, is a coastal mosaic of mangroves, riparian forest, lagoons, and offshore islands of high ornithological significance. Despite its protected status, the reserve faces mounting pressures from human activities and environmental change, yet comprehensive ecological data remain limited. This study examined land-use dynamics, water quality, and waterbird assemblages across three key sites: Tanji River estuary, Nema Creek, and the Bijol Islands. Using field surveys conducted twice during the late rainy season, 55 waterbird species from 25 families were recorded, with the Laridae (terns and gulls) accounting for 93% of all individuals observed. A binomial generalised linear model (GLM) was used to assess how local water-quality variables influenced waterbird presence. The model showed a significant overall fit (χ² = 30.6, df = 6, p < 0.001; AIC = 1402.9; McFadden pseudo-R ² = 0.022), indicating that waterbird occurrence increased with pH and turbidity but decreased with higher temperature, conductivity, and phosphate levels. These relationships suggest that moderately alkaline, turbid waters promote benthic productivity and prey availability. Interviews and focus groups revealed that local communities recognise the ecological and cultural value of TBR but cited persistent threats from overfishing, wood extraction, and weak enforcement. The findings underscore the ecological importance of TBR as a regional wetland refuge and highlight the need for improved habitat monitoring, stricter protection, and community-based conservation measures to maintain its role in sustaining coastal waterbird populations.