Laufkäfer (Coleoptera: Carabidae) auf einer jungen Waldweide: eine Fallstudie aus Südwest- Deutschland

Abstract

Historical experience shows that wood-pastures provide high habitat diversity and thus also a high degree of species diversity, and as such they have been under discussion for some years as a conservation measure. However, the development of vegetation and various groups of animals on newly grazed wood-pastures is only poorly understood. Comparative approaches, such as the exclosure of certain areas, are required for an evaluation of these developments from a nature conservation perspective. By fencing off a wood-pasture which had been used by heck cattle for six years we were able to analyse the direct effects of grazing on habitat structure and the occurrence of ground beetles. We compared catches from pitfall traps placed in paired 10 x 10 m plots. We recorded a total of 1520 ground beetle individuals from the grazed and the non-grazed plots and found a 52 % greater activity density on the grazed plots, in particular of Carabus nemoralis and the most frequently found species, Nebria brevicollis. Grazing did not have an effect on species richness: it did, however, result in higher light intensity and a higher proportion of grass and had direct effects on the structure of the ground beetle community. Typical colonisers of open vegetation structures or of semi-open woodland, such as Carabus monilis and Carabus arvensis were only found in grazed areas. Further species were hand caught in the grassland and lowland moor areas of the wood-pasture, with a total of 31 ground beetle species now recorded. The increasingly heterogeneous nature of the relatively young wood-pasture clearly promotes species richness. Year-round grazing leads to more open areas of woodland, providing long-term benefits for thermophilous forest species.