3.1 Species richness, species composition and community stability
Nineteen species from 17 genera of 11 families were recorded in these plots, and Poaceae, Amaranthaceae and Amaryllidaceae comprise of 57.9% of the species recorded (Table S2). Species richness was significantly higer in the site of fencing since 1979 than that in site of fencing since 1983 or 2003; and species richness was significantly higher in the high shrub cover plots than that in the low shrub cover plots (Figure 1). The results of NMDS plots showed strong segregation in species composition among different fencing duration communities (p< 0.05) (Figure 2A; Table S3). In addition, there was a significant segregation (p <0.001) in species composition between plots of high shrub cover and any of the other two shrub cover treatments, but there was no siginifcant segregation between plots of low and medium shrub cover (p =0.407) (Figure. 2B; Table S3). The site of fencing since 2003 had a lower M-Gordon stability index of the plant community, and the plots of high shrub cover had higher M-Gordon stability index (Figure. S2; Table 1).