Macroinvertebrados associados a macrófitas na cavidade natural Lagoa Misteriosa, Mato Grosso do Sul, Brasil

Abstract

Lagoa Misteriosa is the deepest flooded cave in Brazil, at least 220 meters deep in the center. The fauna of aquatic macroinvertebrates in the lake has not yet been studied, being mentioned in works involving phytoplankton and other taxonomic groups, such as crustaceans and fishs. The goals of this work were to determine the composition and structure of the macroinvertebrates assemblage associated with macrophytes; and verify if there are temporal variations (With Algae Flowering - CFA and Without Algae Flowering - SFA) in the composition of the macroinvertebrates in this lacustrine environment. Samples were carried out bimonthly from October 2021 to August 2022. Three areas close to the shores of the lagoon were selected and three portions of submerged macrophytes were randomly sampled, totaling nine samples per collection. The macrophytes were placed in plastic bags and washed in the laboratory to retain the adhered macroinvertebrates. For data analysis, ecological descriptors were used to describe the structure of the aquatic macroinvertebrates assembly. Approximately 10 thousand individuals were sampled, classified into 31 taxa, distributed into five phyla, with Mollusca and Arthropoda being the most abundant and dominant. The Phylum Mollusca represented 51.5% of the total sample, with the Class Gastropoda having the highest abundance. The Phylum Arthropoda presented 25 taxa, basically represented by families of aquatic insects. The highest abundances and occurrences were of the Coleoptera and Diptera orders, with emphasis on the Elmidae and Chironomidae families, respectively. We sampled 30 taxa in the CFA period and 19 taxa in the SFA period. There was a significant difference in richness and diversity between the analyzed periods, demonstrating that seasonal characteristics influenced the assemblage of aquatic macroinvertebrates in this location. In addition, this work brings the first information about the community of aquatic macroinvertebrates associated with macrophytes in Lagoa Misteriosa.