Distribuição de Chironomidae (Diptera) em ecossistemas lênticos e lóticos no semiárido do Rio Grande do Norte

Abstract

The distribution of macrobenthic fauna is strongly influenced by changes in habitat, considered a great environmental bioindicator and is therefore among the most researched in aquatic ecosystems. Among the most studied representatives of macrobenthos are the Diptera, Chironomidae family, usually regarded as poor environmental quality indicators in lotic or lentic ecosystems. This work was developed from the Entomology Laboratory and Aquatic Ecology Laboratory of the Federal University of Rio Grande do Norte data, including published data from studies in north-rio-grandense region of the Piranhas-Açu River Basin. Involved thirteen collection points in three different types of aquatic ecosystems: perennial lotic, intermittent lotic and lentic. It has been proposed as a general objective, to evaluate the distribution of Chironomidae family genera in Piranhas-Açu River Basin, the biggest of Rio Grande do Norte. A total of 3022 individuals were collected and analyzed in 3 subfamilies. The estimated richness by Chao 2 method of, was 47 genera. The total richness found was of 37 genera in the three types of environments, distributed in 25 genera for the perennial lotic ecosystem, 19 for the intermittent lotic and 14 for the lentic environment. The distribution of subfamily Chironominae was more abundant in all ecosystems, while Orthocladiinae did not appear in the sample for the lentic ecosystem and Tanypodinae showed the same richness in perennial and intermittent lotic environment. The larvae of Chironomus, Dicrotendipes, Goeldichironomus, Polypedilum, Tanytarsus and Larsia were recorded in all environments. The Sorensen-Dice similarity matrix showed that the lentic and lotic ecosystems presented a similarity ranging from 0 to 50% in the faunistic composition of the surveyed environments. The results obtained from the analysis (F = 7.8528, R2 = 0.41653, P = 0.001) showed that the genera of the Chironomidae family are distinctly distributed in different types of aquatic ecosystems.