Structure of microcrustaceans assemblage (Cladocera and Copepoda) from reservoir Neotropical semiarid, Pedra Dam, Bahia, Brazil - DOI: 10.4025/actascibiolsci.v31i1.538

Abstract

In the semiarid region, the reservoirs perform important role for the regional development, which results in the increase of the anthropogenic pressure, causing changes in the water quality. The knowledge of the zooplankton structure supplies basic information for the ecology, zoology, limnology and biogeography of these organisms. The objective of this study was to characterize the plankton microcrustaceans assemblage (Copepoda and Cladocera) in the Pedra Dam Reservoir (PDR) in two distinct periods (rainy and dry/2003). The samplings were carried out in four station of the PDR, using plankton net (70µm of mesh), by vertical hauls from the bottom until the surface, and preserved in formaldehyde 4%. A total of 12 species of microcrustaceans were identified. The dominant species were Notodiaptomus iheringi and Daphnia gessneri. Adult density ranged from 4303 to 7423 ind.m-3 in January and from 669 to 7272 ind.m-3 in July. Shannon diversity index varied from 1.90 bits.ind-1 in July to 2.71 bits.ind-1 in January. Higher densities of individuals, diversity index and equitability were found during rainy season. The structure of the microcrustaceans assemblage differed between rainy and dry seasons and was significantly correlated with the physical and chemical water variables.