An investigation on the relations between vegetation and groundwater in the Qiandam Basin, western China

In this study the plants species and their distribution and groundwater was investigated in The Qiandam Basin, northeastern section of the Plateau of Tibet, and the relation between these plants and the groundwater was illustrated through the field investigation. The results showed that the major plant species are deserta, xerophyte and halophyte in the study area, including Ephedra equisetina Bunge, arbor, Carex, shorten Phragmites australis, and Apocynum venetum L. the Ephedra equisetina Bunge is distributed in groundwater recharge area in piedmont area, and Carex, shorten Phragmites australis, and Apocynum venetum L. are distributed in the groundwater discharge area in alluvial plain. the plant species and distribution exhibit a strip-shaped appearance from the top to the bottom of alluvial fan. The results also illustrated that the major dominant factors controlling them are the moisture and salinity. The species of Ephedra equisetina Bunge is mainly controlled under the moisture which is from the vadose zone and independent-groundwater. The species of Ephedra equisetina Bunge, arbor, Carex, Phragmites australis and Apocynum venetum L. are closely related to the depth to water table and the salinity in the vadose zone. The boundary between naked soil and soil with appearance of plant in the groundwater discharge area is dominated by the salinity in vadose zone.