Effects of grazing intensity on the ecological stoichiometry characteristics of alpine meadow

Ecological stoichiometry characteristic is important for the stability of alpine meadow ecosystem; however, its response to grazing is still not clear. Grassland sample plots with different grazing intensity, including fencing (CK), light grazing (LG), moderate grazing (MG), and heavy grazing (HG), were established in the Haibei alpine meadow in 2011. These plots were chosen to investigate the effects of grazing intensity on aboveground vegetation productivity, carbon (C), nitrogen (N) and phosphorus (P) content of leaves of the vegetation community from May to September in 2014. The results showed that MG could significantly improve the aboveground productivity and proportion of Gramineae plants. Variation in the C content was maximum under MG treatment, supporting the hypothesis of intermediate disturbance. HG could significantly improve the N content. There was no significant effect of grazing on the P content. Fencing was beneficial to the turnover of N and P. The results indicated that moderate grazing was helpful for improving the productivity of the alpine meadow and fencing could enhance the cycle of N and P by changing the dominant species of the community.