Composition of the freshwater decapod crustacean communities in an area of mining in Brazilian Amazonia and the variation related to environmental parameters.

Brazilian Amazonia encompasses a number of major complexes of conservation areas, some of which contain important deposits of mineral resources, and thus represent strategic areas for the exploitation of ores. The present study investigated the composition of the local communities of freshwater decapod crustaceans and their variation in relation to environmental parameters of the Carajás Mosaic. The data were collected during the rainy and dry seasons of 2022 at four points (two impacted, two controls) in each of the two hydrographic basins-of the Itacaiúnas and Parauapebas rivers-that make up the area of the Carajás Mosaic. The relationship between the crustacean communities and environmental variables was analyzed using multiple linear regressions, which considered crustacean species richness and abundance as the dependent variables, in relation to the threshold of contamination of the sediment by metals (Al, As, Fe, Pb, and Mn), and the temperature of the water. A total of ten crustacean species were identified, representing the families Trichodactylidae, Palaemonidae and Pseudothelphusidae. High mean temperatures were associated with a reduction in both alpha and beta diversity, which indicates negative impacts on the health of the aquatic communities. Overall, the impacted areas had significantly reduced crustacean diversity and abundance in comparison with the control areas.