The anthropic gradient determines the taxonomic diversity of aquatic insects in Amazonian streams

Anthropic activities are one of the main drivers of change in the environmental characteristics of streams and the diversity of aquatic macroinvertebrates. We evaluated the influence of an anthropic gradient (varying degrees of impact) on the genera level alpha and beta diversity of the Ephemeroptera, Plecoptera, and Trichoptera (EPT) in 48 eastern Amazonian streams. These insects were sampled using a dipnet, and the anthropic gradient was represented by the activities observed in the channel and the catchment of each stream. We found that increasing anthropic impact reduced the alpha diversity of the EPT. The Total Beta Diversity (BDTotal) showed a moderate degree of variation in streams. The streams with the greatest Local Contribution to Beta Diversity (LCBD) had the lowest alpha diversity of EPT, while the genera with the greatest Species Contribution to Beta Diversity (SCBD) were the most abundant and widely distributed among the streams. Thus, the increase in anthropic impacts reduced the alpha diversity of the EPT and indirectly influenced the uniqueness, emphasizing the importance of using different components of the diversity to understand the effects of anthropic impacts on Amazonian streams.

Automated summary

The study found that increasing anthropic impacts led to a decrease in the alpha diversity of EPT in eastern Amazonian streams, especially in streams with the greatest Local Contribution to Beta Diversity. However, genera with the greatest Species Contribution to Beta Diversity were the most abundant and widely distributed among the streams.