Understanding biodiversity patterns and their drivers is fundamental to ecology and crucial for developing conservation strategies. In this study, freshwater fish species were surveyed in 18 perennial wetlands in the River Brahmaputra floodplains of Assam—an area recognised as one of India’s hotspots for fish diversity. Species incidence data were collected to measure alpha and beta diversity and to assess the relative contribution of different environmental and habitat factors. Generalised linear models were applied to identify the drivers of alpha diversity, while generalised dissimilarity models were used to determine the drivers of beta diversity. The results revealed that fish species richness varied across wetlands, being higher in the wet season than in the dry. Both wetland area and dissolved oxygen account for much of the variation in fish species richness across wetlands in both periods, highlighting the significance of large areas and the quality of wetlands in sustaining high diversity. Overall, high beta diversity was observed, primarily explained by its turnover component, suggesting a role of dispersal limitations and environmental heterogeneity in shaping community composition. These findings offer valuable insights for conservation strategies aimed at preserving freshwater fish diversity in the wetlands of the Brahmaputra valley, a region that is still relatively underexplored.
Hazarika et al. (Sun,) studied this question.