Effects of the environmental degradation on aquatic insects assemblages in Cerrado streams, Brazil

The lotic systems of the “Cerrado”, a Brazilian tropical savanna biome, have suffered disturbances in the environmental integrity due to changes in land usage causing severe impacts to the aquatic assemblages. The taxonomic richness constitutes important tools for understanding the process that sustains the Cerrado’s biological diversity and the effect of anthropogenic impacts on the maintenance of this ecosystems' biological diversity. This paper aims to evaluate the environmental degradation and physical integrity of aquatic insects in seven sample streams in the Uru River sub-basin by means of recording and analyzing habitat observations. The results demonstrate that degradation of the environmental integrity in the analyzed area did not have a direct influence on the taxonomic richness of the assemblege of aquatic insects. (F=0.1051; p=0.758). However, the orders of Ephemeroptera, Plecoptera, and Trichoptera (EPT) demonstrated a strong relation to a more preserved environment. Some taxa of Trichoptera such as Plylloicus, Helicopsychae, Marilia and Oecetis showed a restricted distribution in preserved environments while Alisotrichia, Cyrnellus, Nectopsyche, and Chimarra were verified to have low standards of environmental integrity. This research also demonstrates the importance of the use of EPT order usage in genera level in studies and evaluating environmental impact.