Pollen assemblages and their environmental implications in the Qaidam Basin, NW China

The Qaidam Basin is one of the most sensitive areas to climate change in China, owing to its unique geographical position and ecological condition. In this study, 32 surface-soil pollen samples were collected to reveal the relationship between modern pollen assemblages, vegetation and precipitation in the eastern region of the Qaidam Basin. The results show that Chenopodiaceae (3.887%, average 48%), Artemisia (1.764.2%, average 17.5%) and Ephedra (090%, average 16.3%) are the dominant pollen types in all samples, and that different pollen assemblages correspond to different vegetation types. DCA and CCA of major pollen types demonstrate that precipitation is an important factor in the control of the distribution of vegetation in the study area. The content and concentration of the three major pollen types (Artemisia, Chenopodiaceae and Ephedra) change with the mean annual precipitation, and the optimum mean annual precipitation for Ephedra, Chenopodiaceae and Artemisia is <80, 80200 and >160?mm, respectively. Correlation analysis between the variation in grain size of the three major pollen types and the main environmental variables shows that the grain size of the three pollen types is positively correlated with precipitation in the Qaidam Basin. The results confirm that precipitation is the most important environmental factor in the Qaidam Basin, and that it has an important effect on pollen grain size in the study area.