Plant Diversity of Alpine Kobresia Meadow in the Northern Region of the Tibetan Plateau

Based on the survey in 75 zones, plant diversity of alpine Kobresia meadows is discussed in the northern region of the Tibetan Plateau. It is found that the α-diversity index of different grassland communities decreases gradually: Kobresia pygmaea meadow, K. tibetian meadow, K. humilis meadow, and that the α-diversity index of native communities is bigger than those of restorable communities. Again, the α-diversity index of aboveground communities first increases and then decreases in the degrading process of permafrost. The study also indicates that the β-diversity appears in steady state for sampling area of 8～16 m~(2), and the β-diversity index of different grassland communities decreases gradually: K. pygmaea meadow, K. humilis meadow, and K. tibetian meadow. In addition, the β-diversity index of native communities is bigger than those of restorable communities, and the β-diversity index of aboveground communities first increases and then decreases in the degrading process of permafrost.