Patterns of floristic composition under different grazing intensities in Bulgan, South Gobi, Mongolia

We surveyed the floristic composition and analyzed the patterns of floristic composition under different grazing intensities in the semi-arid area of Bulgan, in the South Gobi of Mongolia. We sampled 90 quadrats at six points (15 quadrats each) along a transect from a spring and grouped them into five vegetation types by using TWINSPAN. All or most of the quadrats at each point corresponded to one of the five vegetation types. The DCA axis 1 arranged all the quadrats in order of grazing intensity, and the floristic composition changed dramatically in a lopsided stepwise-pattern along this axis. The composition ratio for five groups clustered by TWINSPAN according to plant functional types (toxicity or palatability, and life-form) and family varied to a greater or lesser extent. Background environmental factors such as soil moisture or landform did not effect much on the pattern of the floristic composition at this site. The patterns of floristic composition were determined by grazing intensity (determined as distance from the spring) together with palatability, which was the dominant environmental effect at the site