PETER H. VERBURG*
Department of Environmental Sciences
Wageningen University
P.O. Box 37
6700 AA Wageningen, The Netherlands
and
Faculty of Geographical Sciences
Utrecht University
P.O. Box 80115
3508 TC Utrecht, The Netherlands
WELMOED SOEPBOER
A. VELDKAMP
Department of Environmental Sciences
Wageningen University
P.O. Box 37
6700 AA Wageningen, The Netherlands
RAMIL LIMPIADA
VICTORIA ESPALDON
School of Environmental Science and Management
University of the Philippines Los Ban˜ os
College, Laguna
4031, Philippines