Acknowledgements
We acknowledge and thank all the volunteers, Wenwen Zhang, Yue Sun, Xiangsheng Wang, Yue Sun, Xiangsheng Wang and He Zhang, for their help in the field sampling work. We also thank Fei Chen, Xiumei Xu, Weiping Li and Dr. Xiaoliang Zhi for their help with the classifications and statistical advice. In addition, we would like to express our gratitude to the administrative staff of Heilongjiang Sanhuanpao National Nature Reserve and the local fishermen and villagers in Jinshan town, Fujin city, for their great support.