Patterns in ground beetle (Coleoptera: Carabidae) assemblages along an urbanisation gradient in Denmark

Abstract

The responses of ground beetles to an urbanisation gradient (forest-suburban area-urban park) were studied in and near Sorø, South Zealand, Denmark, during April–October 2004. The average number of species per trap did not differ significantly among the three urbanisation stages. The average number of forest species was significantly higher in the forest area (6.2 species/trap) than in either the suburban (4.12 spp/trap) or the urban (3.7 spp/trap) areas. Both the number of open-habitat species (1.8 spp/trap), and the generalist species (2.3 spp/trap) were highest in the urban area. The number of predaceous species was highest in the forest area (8.1 spp/trap), while the number of omnivorous species was highest in the urban area (0.9 spp/trap). Multivariate statistical procedures (NMDS, Sorensen similarity index) also confirmed that species composition changed remarkably along the forest-suburban-urban gradient. The highest number of species (S = 37) was found at the urban area, deviating from trends at other northern hemisphere sites (Canada, Finland) where the overall species richness was highest at the forest habitats. Urban green areas, including forest patches contribute to the quality of urban life and thus should be conserved. Apart from their recreational value, which is widely appreciated and enjoyed by human inhabitants, such green urban spaces provide seemingly adequate habitat for numerous species of ground beetles found in less developed forest areas some distance from the city core.