Effects of Flood Pulse Dynamics on Functional Diversity of Macrophyte Communities in the Pantanal Wetland

Abstract

Environmental variations and plant traits can act as a filter in plant communities, selecting better-adapted species. In wetlands, macrophytes display physiological, morphological and life history plasticity that allows them to adapt to flood dynamics reflecting habitat filtering. Our aim was to evaluate if the functional diversity of macrophytic community varies between the flood phases, noting whether water factors influence the functional diversity and whether the traits that denote adaptation are associated with these phases. We evaluated 11 morphological traits of macrophytes. The floristic survey within and on the edge of twenty ponds was carried out on a monthly basis and the water parameters were measured for two years. The functional diversity was lower in the ‘drought’ and increased over the flood cycle reaching maximum values in the ‘water recession’ phase. ‘Drought’ acted as a filter by selecting only a few adapted species and the ‘water recession’ acted as a transition area combining favourable conditions for the species of both dry and flood. The trait that contributed most to differentiate the functional groups was the life form. We conclude that the environments under spatial and temporal changes support different communities with different functional characteristics.