Wetland plant species diversity in sandy land of a semi-arid inland region of China

Though often ignored, small patches of wetland in sandy land within semi-arid inland regions can support diverse plant community types that greatly contribute to both local and regional species richness. This study characterizes the full range of wetland vegetation within the Mu Us sandy land, and compares the plant diversity and composition of different wetland plant community types. In the Mu Us sandy land, wetland vegetation types including swamps, wet meadows, and salt meadows were sampled. Clustering, dominant species analysis, and nonmetric multidimensional scaling ordination were applied to identify and compare plant community types. Over 320 species of vascular plants, comprising 72.1% of the Mu Us sandy land flora, were found in the wetland, which occupies only 12.15% of the area. Local diversity is 11 +/- 1.75 species per m2 on average, much greater than in the surrounding dune. Plant community types were classified into six types, whose dominant species were Phragmites australis, Eleocharis intersita, Salix cheilophila, Carex duriuscula, Calamagrostis pseudophragmites and Achnatherum splendens. The detrended correspondence analysis (DCA) axes represent gradients of water and soil salinity. Both local species richness and compositional variation differed among the six types. The plant assemblages of the wetland make important contributions to landscape-level diversity.