1. Bio-Protection Research Centre; Lincoln University; Lincoln 7647 New Zealand
2. Department of Terrestrial Ecology; Netherlands Institute of Ecology (NIOO-KNAW); Wageningen 6708 PB The Netherlands
3. Laboratory of Nematology; Wageningen University; 6700 ES Wageningen The Netherlands
4. Institute for Applied Ecology; University of Canberra; Canberra ACT 2601 Australia