Research Institute for Organic Agriculture, Frick

Extented field margins – a new element of ecological compensation in farmed landscapes – deliver positive impacts for Articulata

The sub-project “Effects of newly established extended field margins upon ground beetles and spiders” examined the influence of extended field margins (Säume) upon epigeal arthropods, especially ground beetles and spiders. Surveys were conducted in the Klettgau area in Schaffhausen canton, Switzerland, and in Litzibuch in Aargau canton. In each of the two areas, two extended field margins were examined, as well as two sown wildflower strips (Buntbrachen) and two permanent meadow strips (Wegrandstreifen) as reference elements. The selected bioindicators – ground beetles and spiders – and, as by-catch, bugs and cicadas were surveyed by means of pitfall traps. At the 12 sites, a total of 21’000 ground beetles in 93 species, 11’000 spiders in 100 species, 1’691 bugs in 44 species and 270 cicadas in 29 species were counted. Compared to the sown wildflower strips and permanent meadow strips, extended field margins had an intermediate position. The extended field margins were found to provide habitat for both characteristic fallow species and grassland specialists. They provide a valuable complement to sown wildflower strips and meadows. They thus contribute to increasing and preserving the species diversity of ground beetles, epigeal bugs and cicadas – and, to a slightly lesser degree, that of epigeal spiders – in farmed landscapes.

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