1. Centre for Development and the Environment - SUM; University of Oslo; P.O. Box 116, Blindern 0317 Oslo Norway
2. Department of Geography and the Environment; University of Denver; Denver CO 80208-0710 USA
3. Centro de Estudios Ambientales y de Biodiversidad; Universidad del Valle de Guatemala; 18 Avenida 11-95 zona 15, Vista Hermosa III Guatemala City Guatemala 01015