Amazon streams impacted by bauxite mining present distinct local contributions to the beta diversity of aquatic insects, fish, and macrophytes

Integrating the physicochemical characteristics of aquatic environments with their biotas is essential for the conservation and monitoring of biodiversity, given the sensitivity of both the biotic and the abiotic components to environmental changes linked to water quality and human activities. In the present study, we evaluate how the contributions of different taxa to beta diversity, through local and species effects, can indicate the priority sites for conservation and ecological restoration in an Amazon region impacted by bauxite mining. We also investigate how environmental conditions at local and landscape scales influence the beta diversity of the aquatic biota. We hypothesize that unique species assemblages (a high local contribution) are more likely to be found in more degraded streams, with these assemblages being influenced strongly by local conditions and landscape characteristics. Our findings indicate that local contributions to beta diversity can be explained significantly by physicochemical variables, such as the pH and electrical conductivity of the water, with streams impacted by mining exhibiting distinct species compositions. The environmental factors affected different biological groups in distinct manners, including fish, aquatic insects (water bugs, and the larvae of mayflies, stoneflies, caddisflies, and dragonflies), adult dragonflies, and macrophytes. Streams with unique communities also often exhibited low species richness, which highlights the need for environmental restoration. These results reinforce the value of the use of beta diversity metrics as guidelines for conservation and restoration efforts in aquatic ecosystems that have been affected by anthropogenic disturbances. Furthermore, our findings underscore the importance of a multi-taxon approach to ensure the formulation of a more comprehensive picture of the responses of a region's biodiversity to anthropogenic impacts.