Beta diversity of macrophyte life forms: Responses to local, spatial, and land use variables in Amazon aquatic environments.

Aquatic macrophytes encompass a highly diverse group of plants with different strategies, niche requirements, and dispersion capacities. Therefore, macrophyte life forms can respond distinctly to environmental factors. We analyzed whether emergent/amphibious, floating-leaves/rooted submerged, and free-floating/free-submerged macrophytes respond differently to local, spatial, and land use variables in ponds and streams of the Amazon.

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.

Effect of local and regional factors on the structure of the fish communities associated with aquatic macrophyte stands in oxbow lakes on the Amazon floodplain.

The Amazon floodplain is home to an extremely high diversity of fish, with lakes playing an important role in the establishment of this biological richness. These lacustrine environments are subject to constant fluctuations caused by the annual flood pulse, with local factors and other regional patterns also contributing to the variation in fish community structure. The present study verified how local (depth and transparency of the water, the size and species composition of the macrophyte stands) and regional factors (spatial distribution of the stands and the hydrological phase) influence the structure of the fish community of the floodplain lakes of the Môa River, in northern Brazil.