1. Terrestrial Ecology Unit, Ghent University, 9000 Ghent, Belgium
2. Research Group Nature and Society, Research Institute for Nature and Forest INBO, Havenlaan 88 bus 73, 1000 Brussels, Belgium
3. Community Ecology Laboratory, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
4. Department of Product Development, University of Antwerp, 2000 Antwerp, Belgium
5. Department of Biology, University of Antwerp, 2000 Antwerp, Belgium