Comparison between the vegetation characteristics of alpine and subalpine meadow with different degradation degrees in Northwest of Sichuan province
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Abstract
Abstract: To explore the similarity and dissimilarity of vegetation characteristics during degraded process between alpine and subalpine meadow, the vegetation characteristics of these two types meadow with different degradation degrees in Northwest of Sichuan province were investigated by using quadrates method. Results showed a highlowhigh trends in terms of species richness as grassland degradation degrees changed from nondegraded to heavy degradation in alpine meadow, but a contrary tendency was observed in the subalpine meadow (lowhighlow). The variation of species richness in alpine ranged from 9.56 to 15.00 species/m2 (the minimum was Light degradation 10.00 species/m2), but the subalpine meadow ranged from 11.80 to 25.08 species/m2 (the maximum was Light degradation 25 species/m2) . The variation of ShanonWiener index and Pielou index was relatively higher in subalpine meadows compared to alpine meadows. With the increase of grazing intensity, the vegetation coverage and height of alpine and subalpine meadows decreased except the heavy degradation of subalpine meadows. Percentage of unpalatable plants living aboveground biomass of alpine increased as meadow degraded but not statistic significant (P0.01); by contrast, a significant decrease trends in the percentage of unpalatable plants living aboveground biomass was observed from light degradation (16.86%), medium degradation (14.80%) to heavy degradation (8.33%) in subalpine meadow, in addition, in the nondegraded meadow of subalpine, it accounted for a less proportion, merely 0.37%.
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