Environmental predictors of macroinvertebrate communities in coastal wetlands of southern Brazil

The rapid degradation of wetlands worldwide accentuates the urgent need for ecological data to help manage and protect the threatened biodiversity in the remaining often-fragmented wetlands. In the Neotropics where fragmentation is common, environmental factors structuring aquatic macroinvertebrate communities are poorly known. We tested the hypothesis that physical features, such as wetland area, habitat diversity, water depth and temperature, and water and sediment chemistry are important correlates with richness, density and composition of wetland macroinvertebrate assemblages in Brazil. If so, do these correlations differ between summer and winter? A total of 16 895 individuals across 61 families were collected. Richness was positively associated with habitat diversity and water depth and negatively associated with water temperature. Macroinvertebrate density was negatively associated with water depth, and positively correlated with habitat diversity, percentage of sediment organic matter and water conductivity. Macroinvertebrate composition was associated mainly with wetland area and habitat diversity in the wetlands studied; these relationships persisted in both seasons. Our data illustrate environmental factors that potentially structure and maintain aquatic macroinvertebrate biodiversity in southern Brazil wetlands, and should be managed because 90% of these ecosystems have already been lost as a result of human activities.