Figure 4 Non-metric multidimensional scaling (NMDS) plots
depicting community turnover of different grazing gradients sites of dry
season based on a Bray–Curtis similarity matrix of species abundance
data.
The contour plots (Figure 5 and Figure 6) clearly show the local
variation trend of diversity on the gradient of temperature,
precipitation and grazing intensity. Vegetation diversity varied along
the temperature and precipitation gradients, and the variation was
greater along the precipitation gradients. The fluctuation
characteristics of the contour lines showed that the variation range of
vegetation diversity on the grazing gradient was greater than that on
the temperature and precipitation gradients. In the dry season,
vegetation diversity increased slightly with the increase of
precipitation, while in the rainy season, vegetation diversity decreased
first and then increased with the increase of precipitation.
In the rainy season, the vegetation diversity in DL, HL, EE and WA first
decreased with the increase of grazing intensity, reached the lowest
level at medium and low grazing intensity (1 or 2), then increased with
the increase of grazing intensity, and reached the highest level at high
grazing intensity (3), and finally the diversity index decreased again.
In SP (DT=7.37 ℃, RT=11.01 ℃, DP=62.5 mm, RP=139.8 mm), vegetation
diversity showed a significant increase with the increase of grazing
intensity. During the rainy season, Pielou and Simpson indices were
higher in high grazing intensity (3 and 4) than in medium grazing
intensity (1 and 2), while Shannon index was also at a higher level, but
significantly lower than Pielou and Simpson indices.