Trait-Environment Relationship of Aquatic Vegetation in a Tropical Pond Complex System

The relationship between organisms' traits and the characteristics of their habitats has been a central theme in ecology. Using two complementary approaches to analyze three-matrices of species composition, functional trait, and environment data (RLQ and fourth-corner analyses), we tested if environmental gradient determines aquatic plant traits in ponds in the Pantanal wetland. Furthermore, we tried to understand if plant composition is spatially structured and if environmental gradient is correlated with taxonomic and functional community properties. We sampled aquatic plants coverage in 20 ponds and measured pond size, depth and pH to represent the environmental gradient. We found significant turnover of several traits of aquatic plants along the environmental gradient, being niche partitioning the most probable process structuring plant communities. There was no evidence of spatial autocorrelation determining species composition in the scale of the study, which may indicate that the annual flooding can act as homogenizing factor that promotes species co-occurrence along the ponds. Taxonomic abundance and functional richness were positively related with environmental gradient. Larger and deeper ponds provide higher resource availability thus supporting more functional attributes and vegetation cover. Our results support the hypothesis that niche process is the main driver of aquatic plants in the Pantanal.