Assessing the effects of multiple land uses on the functional beta diversity of stream fishes in the Amazon region

Large-scale deforestation not only modifies the landscape, but also affects in the structure of the habitat, and threaten the functional structure of the aquatic biota. This study evaluates the partitioning of the functional beta diversity of stream fish along a gradient of environmental impact and determines which functional traits are associated with the gradient. Biological, environmental, and landscape variables were sampled in 2014 and 2015. The functional structure of the fish fauna was characterized using 12 functional traits. The functional beta diversity and functional replacement were influenced by changes in local abiotic and landscape conditions, caused by modifications in forest cover, with the functional traits varying systematically in accordance with environmental features. We found no association between environmental variables and functional traits. Our results raise concerns with regard to the transformation of the landscapes in which streams are found caused by changes in land use, and we would recommend the preservation of an adequate buffer of good quality riparian vegetation in management or restoration projects to guarantee the long-term conservation of stream ecosystems.