The influence of sown wildflower strips on ground beetles and spiders (Carabidae & Araneae) in an intensively cultivated agricultural area "Grosses Moos", Switzerland
The study examined the influence of sown wildflower strips on ground beetles and spiders in Grosses Moos, apart of the Berner Seeland region of Western Switzerland and a former low moor that has recently changed to an intensively cuItivated agricuItural area. Three wildflower strips of differing ages sown in native wild and cultivated plant species were sampled by means of pitfall (funnel) traps from May to July 1999. Also, adjacent cereal crops at distances of 15 m (field edge) and 70 to 100 m (field centre) were investigated. More than 44,000 individual ground beetles and spiders in 123 species were recorded. One hundred and ten species were found in the wildflower strips, 85 in field edges and 82 in field centres. Activity densities of ground beetles and spiders were lowest in the wildflower strips. Many stenotopic grassland species occurred exclusively or primarily in the wildflower strips. The species communities of ground beetles and spiders in the field edges were influenced positively by the wildflower strips, and accordingly exhibited greater species diversity than the field centres. Wildflower strips provide suitable habitats for many ground beetIes and spiders species; they consequently contribute to increase species diversity and enhance beneficial species in the locations studied.