Soil physicochemical properties and plant functional traits regulate ecosystem multifunctionality of alpine grassland under different livestock grazing assemblies

As a globally important alpine ecological zone, the Qinghai-Tibetan Plateau and the stability of its ecosystem are of substantial significance to the East Asian and global climates. Livestock grazing is a traditional and important method to use grassland resources and has influenced the structure and functions of alpine grassland ecosystems; therefore, a rational grazing management strategy is important for the stability of the structure and functioning of alpine grassland. In this study, we conducted a manipulated grazing experiment with yak and Tibetan sheep, which are indigenous livestock, to investigate the effects of livestock type and its mixing ratio on soil properties, functional traits of plants, and ecosystem multifunctionality (EMF) in alpine grassland. The results showed that (1) the livestock assembly regulated EMF of alpine grassland by changing the vegetation functional traits and soil physicochemical properties; (2) all grazing treatments increased EMF of alpine grassland, with Tibetan sheep single grazing and mixed with 1:6 yak to Tibetan sheep being significantly higher than no grazing; (3) and grazing achieved EMF regulation based on the indirect effects of community functional dispersion and soil quality index. Our results demonstrate that soil quality improvement due to livestock activities is more conducive to enhancing the ecosystem multifunctionality of alpine grassland vegetation than that under moderate grazing intensity, and Tibetan sheep are more conducive to improving and optimising the ecosystem multifunctionality of alpine grassland compared with yaks under moderate grazing intensity.