4Zhang Y,Wang G X,Wan Y B. Changes in alpine wet- land ecosystems of the Qinghai-Tibetan plateau from 1967 to 2004 [J]. Environmental Monitoring Assess- ment,2011,180(4) :189 199.
5Wang Z R,Yang G J,Yi S H,et al. Effects of environ- mental factors on the distribution of plant communities in a semi-arid region of the Qinghai-Tibet Plateau[J]. Ecology Research, 2012,27 (4) : 667-675.
6Hyodo F, Tsugeki N, Azuma J, et al. Changes in stable isotopes, lignin-derived phenols, and fossil pigments in sediments of Lake Biwa, Japan: Implications for an- thropogenic effects over the last 100 years[J]. Science of the Total Environment, 2008,403 (1/3) : 139-147.