BENTHONIC MACROINVERTEBRATES AS BIOINDICATORS OF ENVIROMENTAL QUALITY FROM WATER BODIES OF CAATINGA.

Abstract

In the Brazilian Northeast, many water bodies are temporary. Being thus, the composition and structure of zoobenthos are important tools to understand the dynamics and infer about the standards of trofic relations and environment quality of these ecosystems. The purpose of this study is to analyze the taxonomic structure and the population dynamics of the invertebrates associated to the littoral sediment of aquatic bodies of the Taperoá River hidrografic basin. Bimonthly samples were collected from August/2002 to April/2005 using a van Veen grab (400cm2) and a D-frame aquatic net with 500-?m-mesh size, respectively to quantitative and qualitative samples. Simultaneously, some environment variables were determined to be related to the biological data. During the study period, a maximum richness of 50 taxa for the zoobenthos were registered, being Insecta, Mollusca, Crustacea and Annelida the most representative group. The analysis of the invertebrates taxoncenose indicated Chironomidae and Conchostraca as dominant groups in temporary ponds, and Gastropoda in dams and rivers. The presence of organisms known as bioindicators of water quality, such as Trichoptera and Ephemeroptera, was also verified, especially in temporary lagoons, demonstrating a low level of organic enrichment of these environments.