Estudo da comunidade de microcrustáceos de represas rurais com potencial para aquicultura como ferramenta para o biomonitoramento de impactos ambientais

Abstract

Rural dams are ecosystems whose dynamics and structure of communities are little known. Thus, knowing the variations in the limnological parameters and how the aquatic fauna is structured is important for the sustainable use of these environments in fish farming, especially before cultivation is started, so that it can serve as a tool for managing and monitoring environmental impacts. Therefore, we evaluated the relationship between the limnological parameters of the water and the abundance and diversity of microcrustaceans of the Cladocera and Copepoda groups in two rural dams in the district of Itamarati-MS. Six collections were carried out between November 2020 and July 2021. The physical and chemical parameters were collected with a Hanna® multiparameter probe, HI 98194. water) and then fixed in 4% formalin. Principal component analysis (PCA) was performed to evaluate the variation of limnological parameters between points and between dams. The Shannon-Wiener Diversity Index was calculated, in addition to the Canonical Correspondence Analysis (CCA), to assess the correlation between limnological parameters and microcrustacean species. The PCA explained, for the limnological parameters, 99% of the variation in the data, with transparency being what separated the exit point from the other points of the dams. The diversity of organisms was low in both dams (1.61). We identified 9 species of Cladocera (Bosminopsis deitersi, Moina minuta, Bosmina longirostris, Ceriodaphinnia, cornuta, Macrothrix laticornis, Allonela daday, Diaphonossoma birgei, Oxyurella reticulata and Alona yara ), and 3 of Copepoda (Notodiaptomus sp, Torpoclyclops parnasinus meredionnalis and Thermocyclops decipiens ). M. minuta had the highest density between points and between dams. The CCA explained the relationship of the limnological parameters with Cladocera with 77.4% of the total variation of the data, where in axis 1, electrical conductivity and total dissolved solids were associated with the L1 dam and the species B. longirostris and, in axis 2, dissolved oxygen and transparency associated with AGRIFAT and the species B. deitersi. The L1 dam had the highest densities when compared to the AGRIFAT dam. The Individual Indicator Value (INDVAL) indicated 04 species: B. deitersi (L1) T. decipiens, T. prasinus meredionalis and B. longirostris (Agrifat) as indicator species. For management and monitoring, we consider that L1 may be more susceptible to eutrophication than AGRIFAT.