Effect of grazing on biomass and species diversity among functional native herbage in alpine meadows

Functional native herbage species are indispensable components of grassland biomass and biodiversity. To investigate the effects of grazing on their species diversity and biomass, three zoned rotational grazing experiments with Tibetan sheep grazing rates (0, 8, and 16 sheep·ha⁻¹) were conducted at the Qinghai-Tibet Plateau alpine meadow Maqu Grassland Agricultural Experiment Station. We analyzed species composition and aboveground biomass of functional native herbage and the relationship between these factors in each community. Aboveground biomass (P < 0.01) and species richness (P < 0.01) of functional native herbage were significantly increased under 8 sheep·ha⁻¹ grazing, and this level of grazing significantly increased the Shannon-Wiener index (P < 0.05) compared with no grazing. The Simpson and Pielou indices of functional native herbage were significantly increased (P < 0.05) under 16 sheep·ha⁻¹ grazing conditions. Functional native herbage biomass was linearly and positively correlated with Shannon-Wiener, Simpson, and Pielou indices and species richness, indicating that increases in species of functional native herbage correlate with increasing aboveground biomass. Moreover 8 sheep·ha⁻¹ grazing promoted the growth of functional native herbage in alpine meadows. These results provide a theoretical basis and practical guidance for sustainable grazing management in alpine meadow ecosystems.