Plant species composition, richness, and diversity in the palm swamps (veredas) of Central Brazil

Palm swamps (veredas) are floristically diverse wetlands that occur in the typical dry savannah of Central Brazil (Cerrado). In the present study, we evaluated the distribution of plants among different palm swamps (Mauritia flexuosa palm swamps), focusing on species richness, composition, and diversity of the herbaceous-shrubby layer. We assumed that the humid soils of the palm swamps act as environmental filters, determining a high degree of floristic similarity among the areas. We compared the distribution of species among nine palm swamp sites and evaluated the absolute cover of the most abundant species at each site and species richness and diversity at each site, based on Hill numbers. We also ordinated the sites in the multidimensional space on the basis of species composition and cover by using non-metric multidimensional scaling. We recorded a total of 331 species, 167 genera, and 58 families in the studied palm swamps. The different sites had seven to 41 exclusive species. Only two species were common to all sites. Despite the humid conditions and homogeneous appearance of the palm swamps, the comparative analysis revealed a considerable heterogeneity in the species cover, richness and diversity among the sites. Thus, the large variations in species composition found in the palm swamp sites indicate that these wetlands are paths isolated from each other by the typical vegetation of Cerrado on dry soils.