Community characteristics and species diversity of subalpine meadows in Xiaowutai Mountain

We took samples along the elevation gradient using the combined method of quadrats and belt transects, and we analysed subalpine meadows in the Xiaowutai Mountain Nature Reserve using quantitative ecological methods. TWINSPAN and RDA were used to analyse the relationship between vegetation and environmental variables. Species diversity indexes were used to explain the relationships between the changes inspecies diversity and environmental factors. The results showed that TWINSPAN classified all samples into nine groups representing nine plant communities. RDA ordination clearly reflected the relationships between the distribution patterns of subalpine meadow communities and environmental gradients. The distribution pattern of communities was obvious in the first axis and second axis gradient. The first axismainly represented the relationship with slope aspect, soil temperature, elevation, soil thickness(P<0.01), and soil moisture gradients(P<0.05). In addition, the second axis mainly represented the relationship with slope and soil thickness(P<0.01). The statistical significance of the effect of each variable was tested by a Monte Carlo permutation test, and slope aspect, elevation, and slope were significantly related to species data(P<0.05). The three environmental factors played an important role in the community distribution pattern. The Patrick richness index declined with increasing elevation, and showed an increasing trend with increasing slope aspect and soil temperature. The Shannon-Wiener diversity index exhibited a declining trend with increasing soil thickness. The Pielou evenness index exhibited an increasing trend with increasing altitude and soil moisture, and decreased with increasing slope aspect and soil temperature. The Simpson dominance index showed a slightly decreasing trend with increasing slope, and an increasing trend with increasing soil thickness.