1. Chair group of Aquatic Ecosystems; UNESCO-IHE Institute for Water Education; P.O. Box 3015 2601 DA Delft The Netherlands
2. Wageningen University; Forest Ecology and Forest Management Group; P.O. Box 47 6700 AA Wageningen The Netherlands
3. Heriot Watt University; Institute for Infrastructure and the Environment; Riccarton Edinburgh EH14 4AS UK