Composição da comunidade meiofaunísta do açude Boqueirão do Cais (Cuité – PB) após período de estresse hídrico.

Abstract

Water scarcity is one, if not the greatest, of the problems faced by the human population and also by the biodiversity of the Brazilian semiarid. Paraiba's wild is one of the many Northeastern mesoregions that have suffered from poor rainfall distribution over the past decade. The meiofauna study emerges as a tool to analyze the ecological impacts caused by rainfall variations. Thus, the present research aims to understand how the drought process of the region caused impacts on the structural composition and diversity of the meiofaunistic community of Boqueirão do Cais, municipality of Cuité / PB. Two collections were performed in 2019, one in the rainy season (May) and one in the dry season (October). The sediment was obtained along the left bank of the dam at 4 different points, with 3 replicates each, totaling 24 samples in both seasons. In the laboratory, the particle size of each collection point was analyzed for local sediment analysis. The organisms were separated from the sediment by the washing process following the methodology of Elmgren (1976). The results were compared with past data before the region drought period and showed the highest occurrence of gravel in the rainy season sediment, probably originating from the water flow of the Jacu and Campo Comprido rivers. In the dry season, fine sand was predominant. Regarding biotic factors, MDS showed significant differences between seasons, but similarities between their points. We found 8 taxa in the rainy season and 9 taxa in the dry season. Nauplios, Rotiferos and Tardigrada were exclusive to our work, the mites and Polychaeta taxa were not registered. Nematoda was well represented in both seasons, with higher occurrence in the rainy season. In the dry season, Turbellaria, Nematoda and Copepoda, respectively, occurred in greater numbers. Also noteworthy is the increase in occurrence, density and abundance of the Rotifer group also in the dry season. The Diversity and Equity Indexes, as well as the other results, show that there was an increase in diversity and the structural reestablishment of the meiofaunistic community after the drought process.