The gradient analysis of plant communities at southern Qinghai of Qinhai-Tibet Plateau

Twenty-six plant communities were surveyed by quadrats in southern Qinghai of Qinghai-Tibet plateau. The communities were analyzed using the principal component analysis(PCA) ordination and the regression procedure to determine the distribution patterns of the plant communities and the relationship between the communities and environmental factors. The results showed that the distribution of the plant communities was closely related to the annual average temperature and the annual precipitation, and also to soil nutrients. The correlation between species diversity of the communities and the gradient of environmental factors was significant, and community richness, species diversity decreased with a drop in annual average temperature and annual precipitation.