Institution: | Community and Conservation Ecology Group, University of Groningen, PO Box 14, 9750 AA Haren, the Netherlands,;Research Group Aquatic Ecology and Environmental Biology, Department of Ecology, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, the Netherlands, and;Ministry of Transport, Public Works and Water Management, Road and Hydraulic Engineering Division, PO Box 5044, 2600 GA Delft, the Netherlands |