Seasonal dynamics of common ground beetles (Coleoptera: Carabidae) along an urbanisation gradient near Sorø, Zealand, Denmark

The seasonal activity of six carabid species (Nebria brevicollis, Carabus nemoralis, C. hortensis, C. coriaceus, Pterostichus melanarius and Abax parallelepipedus) was studied along an urbanisation series (rural forest - suburban forest - forest fragments in urban park) in Sorø, Denmark, during April-October 2004 and 2005. Two groups were identified: 1) Species with constant seasonality, where seasonal activity profiles did not differ among the sites (C. hortensis, C. coriaceus, and A. parallelepipedus); 2) Species with flexible seasonality, with remarkable differences among sites and years (C. nemoralis, N. brevicollis and P. melanarius). In four out of six studied species, 2005 was less favourable than 2004. Spring activity in urban habitats started earlier than in suburban or forested ones. A better understanding of urban green infrastructures in biodiversity assessments may need the study of seasonality in order to distinguish whether the bioindicator's response is to habitat quality or stochastic seasonal events.