1. Key Laboratory for Subtropical Mountain Ecology; Ministry of Science and Technology and Fujian Province Funded; School of Geographical Sciences; Fujian Normal University; Fuzhou 350007 China
2. Department of Ecology, Evolution & Behavior; University of Minnesota; St. Paul MN 55108 USA
3. Department of Forest Resources; University of Minnesota; St. Paul MN 55108 USA
4. Hawkesbury Institute for the Environment; Western Sydney University; Penrith New South Wales 2753 Australia
5. Institute of Biological & Environmental Sciences; School of Biological Sciences; University of Aberdeen; Aberdeen AB24 3UU UK