SPECIES-DIVERSITY OF GROUND BEETLES (CARABIDAE) IN SOWN WEED STRIPS AND ADJACENT FIELDS

From April-September 1992 and from April-August 1993, ground beetles w ere caught in pitfall traps in three weed strips of different ages and in the adjacent fields. The oldest weed strip contained the highest n umber of ground beetle species in both years. A decrease in number of species with increasing distance from the weed strips was observed in 1992. Fields bordering on two-year-old weed strips showed an increase in species diversity compared with the previous year. Within the crops , rape contained more species than wheat or maize. The extent of diffe rences in species diversity between weed strips and adjacent fields in terms of the methodology used and the importance of weed strips for s everal species are discussed.