Colonização de insetos aquáticos em riachos com diferentes substratos e uso e cobertura do solo

Abstract

Stream ecosystems are vulnerable due to several anthropogenic changes that occur in the use and coverage of the soil in microbasins, interfering with the composition and abundance of aquatic insects. This study aims to characterize the assemblages of aquatic insects, considering the time of colonization in three types of substrates (two kind of foliar substrates: a species of Saccharum officinarum (sugar cane) that represents most of the cultivation in the area of study and one of Croton urucurama, native species commonly found in the region and the third substrate composed of coarse gravel found in streams. These substrates were standardized, individualized and packed in litter bags along the benthic zone in eight streams with different uses and coverage of the soil in the riparian zone (SFR-Streams Riparian forest; SCM-Streams Mixed Cover; SAP-Streams Agriculture and Pasture) located in the Dourados/MS river basin and removed in 7, 14, 30, 60 and 90 days of colonization We evaluated the differences in abundance and richness of aquatic insect families in relation to different kind of substrates, colonization time and according to the use and coverage of the ground. There hasn’t been significant difference in the colonization time of aquatic insects according to the substrate, but there has been a tendency to decrease the abundance of aquatic insect families during the colonization time. There has been a significant difference between all stream categories and colonization time, in the riparian forest stream category there has been a significant difference in all colonization times, the mixed cover category was significant only in the first colonization times, except in the category of agriculture and pasture that showed no difference between colonization time. The Chironomidae and Elmidae families were the ones that most contributed to the dissimilarities, due to their dominance and presence in all times of colonization. Thus, the influence on aquatic insect assemblages is related to land use and land cover in riparian zones, due to the interactions between the terrestrial and aquatic environment, requiring the conservation and preservation of the riparian forest in order to contribute to the establishment of insects and maintenance of aquatic ecosystems.