Edaphic patterns as related to β-diversity in swamp forests and meadows of the lower Orinoco delta plain (Venezuela)

Abstract

ABSTRACT In the Neotropics, differences in phytogeographic patterns and species richness respond non-randomly to edaphic factors in many upland forests. However, whether wetland forests follow the same species differentiation patterns is not well known. In this paper we analyze the relationship among species occurrences and selected soil characteristics, particularly salinity and acidity, in several wetland plant communities. Plant specimens were collected and soil samples analyzed for exchangeable cations, chloride, and organic carbon. Statistical methods were applied to assess β-diversity and to detect relationships between patterns of floristic variation and spatial variations of the soil conditions. β-diversity was high among vegetation communities. Edaphic conditions were heterogeneous, and landward gradients were present only for salinity and some exchangeable bases. This resulted in a lack of a straightforward relationship of vegetation patterns to salinity. More than 30% of the reported species co...