Abstract: To understand how livestock assemblage regulates aboveground net primary productivity in alpine grasslands under moderate grazing intensity and improve the management standards of alpine grasslands, we conducted an experiment with different livestock assemblages (yak and Tibetan sheep grazing alone and 1∶2 mixed grazing) under moderate grazing intensity and no grazing as the control in an alpine grassland on the eastern Qinghai-Tibet Plateau. We analyzed the changes in plant community characteristics, soil physicochemical properties and aboveground net primary productivity. The results showed that livestock assemblages did not affect species richness and diversity index, but significantly reduced the height and coverage of plant communities, and changed the proportions of importance values of different functional groups. Tibetan sheep grazing alone significantly increased soil available N and P content and soil bulk density of alpine grassland. Grazing weakened the regulation of species diversity on aboveground net primary productivity but strengthened the effect of soil environmental factors. The aboveground net primary productivity and livestock intake were the highest under the mixed grazing. To improve the management standard of alpine grasslands, it is recommended to carry out mixed grazing of yaks and Tibetan sheep in appropriate proportions based on moderate grazing intensity and to adopt coupled vegetation wivestock soil management to achieve sustainable use and maintain ecological function of alpine grasslands.

Key words: herbivore assemblage, alpine grassland, aboveground net primary productivity, moderate grazing, plant community composition