Foliar δ13C values of Calligogum kozlovi and Haloxylon ammodendron ranged from -13.13 to -15.11 ‰, while those of the rest 11 species were in the range of -22.22 to -27.73 ‰. This indicates that two of 13 dominant plant species in the Qaidam Basin possess a C4 photosynthetic pathway. Significant differences were observed for the average foliar δ13C values between C3 or C4 plant communities, between grass and shrub communities, even between the same species derived from different sites. Precipitation accounted for the major part of the differences. and H. Chen ... [et al.].