Authors’ Contributions
LGC provided funds, LGC, WL and ZYM originally formulated the idea, WL
and ZYM developed methodology, ZYM, TWZ, ZQ, THT and JYF conducted
fieldwork and data collection, WL and ZYM performed statistical
analyses, ZYM wrote the first version of the manuscript, WL and LGC
revised the manuscript. All authors contributed to the final version of
the manuscript.