INCREASE IN ACTIVITY DENSITY AND SPECIES NUMBER OF CARABID BEETLES INCEREALS AS A RESULT OF STRIP-MANAGEMENT

In 1990 and 1991, we monitored the abundance of a carabid community in a 8 ha winter cereal field. The field was subdivided by five 1.5 m wi de weed-strips leaving 12, 24 and 36 m between the strips. In 1990 sig nificantly higher activity densities and number of species were found in the strips. In 1991, however, both number of species and activity d ensities of ground beetles in the weed-strips and the cereal parts in between were similar. In 1991, activity density in cereal parts betwee n weed-strips was significantly higher than in a bordering control are a. Most of the activity densities of all 23 abundant species were sign ificantly higher in the strip-managed area than in the control area. F urthermore, the number of species in the strip-managed area was higher . In addition, most sampling dates (1990 and 1991) revealed a signific ant negative regression between activity density and distance from the first strip, i.e. width of the cereal parts between the strips. Strip -management seems to be a way to increase ground beetle densities cons iderably by providing better food supplies and more suitable overwinte ring sites.