The plant species richness in dam farmlands on the Loess Plateau, China.

As the dam farmland was formed by the deposition of sediment from the controlled catchment, many plant seeds were accumulated in this new habitat. Vascular plant species surveys were conducted in two dam farmlands managed without tillage, within their controlled catchment, abandoned dam farmlands, and farmed dam farmlands to find out whether dam farmland management contributes to biodiversity and how soil physical variables may affect plant species composition in this habitat. The results revealed that the species richness significantly differed with the sloping land on the controlled catchment by the check-dams, abandoned dam farmland, and farmed dam farmland. Plant species richness was negatively related to soil water content and positively related to the sand fraction proportion. By redundancy analysis, soil water and sand fraction were the most important factors determining plant species composition. Therefore, except for conserving soil and water, the check-dams can also conserve plant biodiversity.