1. Department of Ecology and Genetics, Animal Ecology, Uppsala University , 75236 Uppsala , Sweden
2. Département de Biologie, École Normale Supérieure de Lyon, Université Claude Bernard Lyon I, Université de Lyon , 69342 Lyon cedex 07 , France
3. ISEM, Univ de Montpellier, CNRS, IRD , 34095 Montpellier cedex 05 , France
4. USDA Forest Service, Southern Research Station, Center for Bottomland Hardwoods Research , Oxford, MS 38655 , USA