Linking above- and below-ground biodiversity: abundance and trophic complexity in soil as a response to experimental plant communities on abandoned arable land

1. This study investigates the effects of experimental plant communities on different trophic levels in the soil food web of abandoned arable land. 2. In April 1996, a biodiversity experiment commenced using a continuation of agricultural crop rotation (CCR), spontaneous succession with naturally colonizing plant species (NC) and late-successional plant species sown in l ow-diversity (LD, four plant species) and high-diversity (HD, 15 plant spec ies) communities. The nematode community was used as an indicator of the in fluence of the experimental plant communities on different trophic levels i n the soil food web. 3. The nematode abundance in the experimental plant communities differed fr om that of the continued crop rotation, but there were hardly any differenc es between the natural, the low-diversity and the high-diversity plant comm unities. 4. The abundant plant-feeding nematodes and the somewhat less abundant bact erivorous nematodes were stimulated most by the sowing treatments. Fungivor ous nematodes were stimulated less, while the numbers of omnivorous and car nivorous nematodes did not change significantly. 5. The diversity of the nematode community did not change over 2 years. 6. It is concluded that experimental plant communities have either small sh ort-term effects or a delayed impact on the soil food web compared with the effect they have on above-ground invertebrate community development.