1. Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 40, 6666 ZG Heteren, The Netherlands
2. Laboratory of Nematology, Wageningen University and Research Centre, P.O. Box 8123, 6700 ES Wageningen, The Netherlands
3. Science Department, East Malling Research, East Malling, Kent ME19 6BJ United Kingdom
4. Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Profesor Albareda, 1, 18008 Granada, Spain
5. Copenhagen University, Department of Terrestrial Ecology, Ø. Farimagsgade 2D, DK 1353 Copenhagen, Denmark
6. Department of Environmental Sciences, Copernicus Institute, Utrecht University, P.O. Box 80115, 3508 TC Utrecht, The Netherlands
7. Department of Ecology, Lund University, S 223 62 Lund, Sweden
8. Georg August University of Goettingen, J.F. Blumenbach Institute of Zoology and Anthropology, Animal Ecology, Berliner Strasse 28, 37073 Goettingen, Germany
9. Department of Ecological and Environmental Sciences, University of Helsinki, Niemenkatu 73, 15140 Lahti, Finland
10. Biodiversity Department, Central Laboratory of General Ecology, 2, Yurii Gagarin Street, 1113 Sofia, Bulgaria
11. Nancy Université, (INPL)-INRA, Agronomie et Environment, Nancy-Colmar, BP 172, F-54505 Vandoeuvre-les-Nancy, France
12. Soil Centre, Wageningen University and Research Centre, Droevendaalsesteeg 4, 6708 PB Wageningen, The Netherlands
13. Faculty of Science, University of South Bohemia, Branišovská 31, CZ-370 05 České Budějovice, Czech Republic