Study on niche of dominant species of subalpine scrubland and meadow community in Guandi Mountains Interspecific Relationships of Dominant Species of Sub-alpine Scrub Community and Sub-alpine Meadow Community in the Guandi Mountains Influence of yak grazing on plant niche characteristics in alpine meadow communities at the northeastern edge of the Qinghai-Tibetan Plateau Effect of Tourism Disturbance Intensity on Plant Species Diversity of Meadow Community in Kanasi Nature Reserve