Abstract: adopted to explore the responses of plant species richness and distribution pattern of alpine meadow in this region to topographic factors (altitude, slope grade, slope aspect, and slope position) under high intensity human disturbances and climate change. A total of 150 plant species were recorded in 275 plots (1 m ×1 m) of 55 sampling sites, and the species number in the plots ranged from 3 to 27. Statistical analysis demonstrated that the plant species richness was highly significantly correlated to altitude and slope grade, but less correlated to slope aspect or slope position. The CCA axis 1 basically reflected the gradient variation of plant communities with slope grade, axis 2 reflected the gradient variation with slope position, whereas axis 3 reflected the combined effect of topographic factors. Under the high intensity human disturbances and climate change, the topographic factors affecting the plant species composition and structure of alpine meadow in this region ranked as slope grade > slope position > altitude > slope aspect, suggesting that slope grade was the major factor affecting the water and soil conditions of alpine meadow in the source region of Lancang River.

Key words: biomass,  , carbon storage, stand age, Cunninghamia lanceolata.