1. Environmental Change Inst., School of Geography and the Environment, Univ. of Oxford; South Parks Road Oxford OX1 3QY UK
2. Dept of Ecology and Evolutionary Biology; Princeton Univ.; Princeton NJ 08544 USA
3. INRA UMR Ecologie des Forêts de Guyane, French Guiana, and International Center for Tropical Botany, Dept of Biological Sciences; Florida International Univ.; Miami USA