The Influence of Lake Morphology, Landscape Structure, and Urbanization Factors on Bird Community Composition in Wetlands of Four Tropical Lakes

Wetland diversity metrics are critical indicators of habitat carrying capacity and anthropogenic disturbance on ecosystem health. This study aimed at comparing the composition and ecological features of bird communities across gradients of habitat effects within wetland areas of freshwater tropical lakes. For this study, the total number, diversity, and dominance of bird communities ( n = 519; 29 species) within a 1 km radius riparian area of four tropical lakes were measured and compared alongside habitat effect variables. Three categories of habitat effect variables i.e., lake morphology (surface area of lake, lake perimeter, shape index i.e., form factor); landscape structure (vegetation density within 1 km radius measured using Normalized Difference Vegetation Index [NDVI]), and human disturbance/urbanization features (distance to major road, distance to residential area) were assessed across the four lake wetlands. The multivariate relationship of variables was described using non-metric multidimentional scaling (NMDS) of six habitat effect variables alongside Hill numbers diversity as dependent variables showed that variation in bird species composition was strongly negatively correlated with lake shape index, and positively correlated with vegetation density (NDVI) and distance to the road (indicating complementary effects). This implies that wetlands with heterogeneously shaped lakes alongside greater vegetation density (NDVI), and increased furtherance from major highways (urbanization features) were more likely to attract and accommodate more diverse bird communities. Furthermore, the habitat-specific avian guild structure highlighted the carrying capacity of the different lake wetlands. The study findings imply that the conservation of wetland avifauna will require emphasis on habitat-specific variables.