Effects of grazing and rainy season precipitation on plant species composition
In the surveyed areas, Gramineae is the most dominant species. The results of contour line (Figure 7) showed that the coverage of grasses did not have an obvious relationship with the precipitation in the rainy season, but changed significantly with the increase of grazing intensity, indicating that grazing intensity was an important factor affecting the dominance of grasses. Gramineae showed greater coverage at low grazing intensities, but at high grazing intensities, the coverage of grasses decreased sharply or even disappeared. In the rainy season, HL and DL, which has a large precipitation, the advantages of the grass family have increased rapidly with the intensity of the grazing. Grazing intensity and rainfall in rainy season were important indexes affecting plant height. The grazing intensity was less than 3, and the coverage of low-height plants increased with the increase of precipitation in the rainy season, and reached the maximum when the precipitation was greater than 280mm in the high rainy season. In high grazing intensity, the coverage of plants with low plant height decreased with the increase of rainy season precipitation (Figure 7). The trend of coverage of tall plants was opposite to that of short individual plants.