Zonation of aquatic plant communities along the flooding gradient in subtropical  wetlands

Aquatic plants play a crucial role in wetlands, and understanding distribution patterns and species composition can be valuable for several purposes. Here, we assessed aquatic plant distribution along a flooding gradient in the transition region between terrestrial and aquatic environments within a wetland complex. We investigated the presence of distinct zones in terms of species richness, composition (beta diversity), and life forms. We established transects along the shoreline, and defined three zones along each transect: floodable zone (zone 1), water-land interface zone (zone 2), and water body zone (zone 3). Clear zonation patterns were identified, due to occurrences restricted to portions of the gradient and significant variations in the coverage of species and life forms. The gradient displayed high beta diversity, with zones 1 and 3 differing significantly in species composition. Turnover explained the observed variation, associated with environmental filtering and interspecific interactions. There was no significant decrease in richness with increasing water depth. Amphibious plants dominated along the gradient. Our study highlights that the life forms inhabiting wetlands represent an adaptive continuum, ranging from plants that tolerate transitory submergence to those entirely limited to the aquatic environment. Understanding species distribution patterns is crucial for delineating wetland boundaries and gaining valuable insights into wetland conservation and restoration, particularly in light of escalating threats and the impacts of climate change.