Acknowledgements
The authors are grateful to Dr. M. Gangloff, Dr. M. Lopes-Lima and two anonymous reviewers for valuable comments on the manuscript. The authors express their gratitude to the Phongsali Branch of Amazing Lao Travel Co. Ltd. and Phongsali Department of Information Cultural and Tourism for the organisation of field observations in Nam Ou drainage. Additional thanks go to Mr. Sivangxay Panyahak for his excellent fieldwork assistance. Also, we are grateful for the consulting support of the Russian-Laotian Friendship Society. This study has been partly supported by grants from the Russian Foundation for Basic Research, RFBR (Grant no. 12-04-00594; Grant № 14-05-31196-mol_a); the Ural Branch of the Russian Academy of Sciences (no. 12-M-45-2062, 12-P-5-1014 and 14-5-NP-97), and the Ministry of Science and Education of Russia (no. P362).