Overwintering of arthropods in soils of arable fields and adjacent semi-natural habitats

Summary

In order to determine the significance of field margins for the overwintering of arthropods in agricultural landscapes, different sites of an integrated and of an organically managed farm were investigated in the northwest of Switzerland. During December 1995 and January 1996, soil samples were taken with an electronic-hydraulic soil borer (depth: 25 cm, diameter: 8 cm). After hand sorting the larger arthropods, the small ones were extracted with a modified MacFadyen apparatus.
The abundance of arthropods in the arable fields was significantly lower than in the adjacent semi-natural habitats. Highest abundances and species diversities were found in a sown wildflower strip, a hedge, a permanent meadow and a meadow under the cherry trees of the organic farm. With a total of 90 arthropod species in the semi-natural habitats, five times more species were found than in the arable fields. Staphylinids, carabids, spiders and chilopods were the most abundant arthropod groups. The data showed that undisturbed semi-natural habitats and extensively managed field margins play a key role as overwintering sites for many predatory arthropods.