Abstract
This work aimed to study the floristics and phytosociology of aquatic macrophytes in a continental wetland. A total of, 100 plots, (1 m2) were distributed systematically (intervals of 1 m), in 10 transects (20 m), in the Banhado 25 area (31°59'33"S; 52°17'32"O). Monthly collection data over a one-year period included observing plants "in loco", collecting, identifying and classifying the plants according to habit and life form. For each species recorded we calculated absolute and relative frequency and coverage and importance value index (IVI). We analyzed the floristic similarity (Sorensen's index) and applied linear regression. The survey yielded 82 species of vascular aquatic macrophytes, belonging to 33 families. In species richness, Cyperaceae (16 taxa), followed by Poaceae and Asteraceae (12 taxa each), showed greater contribution. The herbaceous habit (88%) and amphibious life form (94%) were the most representative. Scirpus giganteus Kunth had the highest IVI (27.58%). Higher coverage rates of this species showed a significant decrease in species richness (r2 = 0.503; p < 0.0001). The change in floristic composition between margin and interior of the wetland was evidenced by similarity analysis, forming two groups, possibly separated by humidity.
Key word:
macrophytic flora; wet environment; coastal zone