1. Forest Ecology and Conservation Group; Department of Plant Sciences; University of Cambridge; Downing Street Cambridge CB2 3EA UK
2. UMR Peuplements Vegetaux et Bioagresseursen Milieu Tropical; Universite de la Reunion; 97715 Saint Denis Messageries France
3. Landcare Research; Gerald Street Lincoln 7640 New Zealand
4. Department of Geography; University College London; Gower Street London WC1E 6BT UK
5. Department of Biology; University of Florida; Gainesville FL 32611 USA