Estrutura da vegetação de macrófitas aquáticas de uma dolina cárstica inundada

Abstract

This study aimed to perform a phytosociological analysis and survey the floristic composition of aquatic macrophytes in Lagoa Misteriosa (LM), located in the municipality of Jardim (MS). Sampling of the macrophyte community was conducted over two years, from October 2021 to September 2023, with sampling occurring every 2 months. Samples were taken in the southern portion of LM, as it receives more sunlight. Plots measuring 0.5 x 0.5 m, spaced 1 m apart, were used. All vegetative cover within the vertical projection area of the plots up to a depth of 1 m was included. Phytosociological parameters of the community were obtained using coverage, frequency, and importance value (IV). Between 32 and 39 plots were allocated in 12 samplings. The recorded species included Chara rusbyana (Characeae), Chryso-hypnum elegantulum (Hypnaceae), Heteranthera zosterifolia (Pontederiaceae), Leptodictyum riparium (Amblystegiaceae), Pistia stratiotes (Araceae), and a type of filamentous algae. The species have a fixed submerged life form, except for Pistia stratiotes and the filamentous algae, which have a free-floating life form. Linear regression analysis and Principal Component Analysis were performed based on the phytosociological parameters to correlate these data with rainfall, water level, and visibility variables. The macrophyte coverage tended to increase during the eutrophic period of LM, suggesting that these species, due to the constant disturbances in LM, may have become more tolerant to nutrient additions and low visibility, becoming better adapted to this environment.