ACKNOWLEDGEMENTS
We would like to thank professor
Azhaz Von Hardonverg for his valuable
comments on earlier draft of the manuscript. We thank Wu Yue for his
assist during the field study in 2020. We are very grateful to the staff
of agriculture, livestock and water supplies bureau of Ruoergai country.
This study was supported by the
National Natural Science Foundation
of China 30180509 and the State
Forestry and Grassland Administration Bureau of China.