Composição de entomofauna aquática em diferentes substratos e inventário preliminar dos impactos antrópicos em ambiente lótico

Abstract

The use of aquatic insects allows greater accuracy of the characteristics of a body of water because they are excellent bioindicators. With the objective of inventorying the aquatic entomofauna and relating it to specific substrates we testing the hypothesis of the relationship between human presence and alteration of aquatic insect communities, this work was developed at the Carimã tourist complex, in the stream Grande sub-basin. The collection has on 06/02/2019, where the insects collected were differentiating between points classified by the flow of visitors: Low, Medium and Intense use. In addition, they were differentiated between four substrates: Sand, Waterfall, Leaf and Stone along the water body. In total, 952 individuals belonging to nine orders and 14 families were collected. The most abundant order was Diptera with 431 individuals (45.27%) followed by Ephemeroptera with 366 (38.45%). The most abundant family was Baetidae (325, 34.14%), followed by Chironomidae (237, 24.89%), the others had less than 10% significance. Regarding the intensity of human use, there was a significant difference in fauna composition (NMDS - Stress: 0.1; ANOSIM: p=0.04). The results related to the substrate are: Stone presented the highest amount of taxa (n=15), followed by Sand (n=12), Leaf (n=10) and Waterfall (n=9). Regarding the abundance of individuals, Sand was the most abundant (n=365) with Chironomidae predominating (n=159). We see a tendency for community composition to differ between substrates (NMDS Stress: 0.15; ANOSIM, p=0.05) mainly between the substrate Sand vs Leaf (p=0.03) and Sand vs Waterfall (p=0, 05). The specific needs of each biological group reflects the occupation of habitat, presenting different numbers of individuals.