ACKNOWLEDGEMENTS
We thank Ruzhen Wang, Zhirui Wang, Yongyong Zhang, Wentao Luo, Xiaobin
Li, Xue Wang, Xue Feng, Zhan Shi, Peng He and Fei Yao for assistance in
the field, and Shiping Chen and Zijia Zhang for providing meteorological
data. We acknowledge staff at the Erguna Forest-Steppe Ecotone Ecosystem
Research Station for their logistical support. This study was
financially supported by grants from the National Natural Science
Foundation of China (32060284 & 31870441), the Natural Science
Foundation of Inner Mongolia, China (2019JQ04), and the National Science
Foundation of the United States (DEB-1856318 & CBET-1833988).