Effects of management practices on the ground beetle assemblages of grassland and related habitats (Coleoptera: Carabidae)

Abstract

In a comparison of grassland, moorland and woodland habitats in north-east England, moorland sites were found to be the most diverse and species-rich and to support a carabid fauna of larger body size than grassland sites. Within the grassland sites, intensification of management resulted in a reduction both in species richness and in body size. The species composition of intensively managed sites differed from that of the less intensive, with management appearing to favour species associated with drier conditions. Similarly, a study of data from 110 sets of pitfall traps in managed and unmanaged grassland in Scotland found a general reduction in diversity, rarity and body size as management intensified, with silage fields having especially low values of WML. Diversity and rarity fell sharply between the second and third levels of management. Multivariate analysis of the species composition also made a clear distinction between these levels, grouping sites in bands 1 and 2 separately from those in bands 3 to 5. A more detailed examination of the effects of the different components of management found that body size was dependent mostly on the type and age of the sward, while diversity and rarity responded to nutrient inputs. In a subset of 36 of the 110 Scottish sites, the carabid assemblages of sown wildflower swards, sown grass and clover, and uncultivated grassland were compared. Body size, species richness and diversity were all highest in the unmanaged swards, and species richness and diversity were higher in wildflower swards than in sown grasses. The effects of organic nutrient input were investigated at sites receiving input of slurry, sewage sludge or faecal material from flocks of grazing geese, but not significant relationships could be elucidated due to overwhelming effects of sward type and management intensity