Role of urban forests as a source of diversity of carabids (Coleoptera: Carabidae) in urbanised areas

We analysed the structure of ground-beetle (Col.: Carabidae) assemblages populating urban forests which differed from one another in the composition of woody plants, soil cover with herbaceous plants, habitat humidity, and extent of stress caused by people. Field tests were carried out in Olsztyn, Northeastern Poland, in 2009. A total of 4,440 individuals, representing 70 species, were captured in pitfall traps. Different ecological groups of carabids were observed depending on the distinguishing features of the analysed urban forests. Redundancy analyses showed that anthropogenic pressure and habitat humidity had significant impact on the formation of carabid assemblages. We observed that the variety of urban forests helped to sustain and improve the species diversity of ground beetles. Owing to their heterogeneity, trees and shrubs in towns provide for the presence of various ecological groups of Carabidae.