| Abstrakt: |
Carabid beetles are important predators of arthropods and weed seedsin annual crops but may be limited in impact by the frequent and intense disturbances imposed on these systems. Pitfall trap sampling conducted in 1996 and 1997 examined the effect of refuge strips and cover crops on enhancing the seasonal activity-density of carabid beetles. The study site followed a soybean, Glyciru, max L. Men. oats, Arenasatica L., and corn, ZPa mays L., rotation. Refuges consisted of a central strip of 3 perennial flowering plants, Agastache foenicnlun (Pursh) O. Kuntze, Origamrm vulgare L., and Scroprdaria nodosa L, with orchard grass, Dactyli.sglonrerata L., white clover, Triifolimn repens L., and sweet clover, Melilotus officinalis L., seeded on each side. A cover crop was present only in 1996 and consisted of frost seededred clover, Trifolium pratense L. A total of 5,117 and 2,316 carabidbeetles was captured in pitfall traps comprising 14 species in 1996 and 20 species in 1997. Carabid beetle seasonal activity-density was greater (1996) or equal (1997) in refuge strips than in control areaswithout refuge strips; however, the presence of a refuge strip did not alter carabid populations in the surrounding subplots in either year. In 1996, subplots containing a cover crop had significantly higher carabid beetle activity-density than subplots without it cover crop. There was no carryover effect of cover crop on beetle activity-density in 1997. Among the most abundant species, a greater proportion ofcaptures of the fall breeding species Ptero.sticlm.s rnelanarius (Illiger), Pterostichw pennundus (Say), and the spring breeding species Poecilns Incrrhlandus (Say) occurred in the refuge strips. The springbreeders Poccilrrs chaleites (Say), llarpahrs 1wrbioagus Say, and Agonum cupripenne (Say), and the phytophagous fall breeder Harpalns peusylraninis (De Geer) occurred in greater proportions in the crop areas. The potential rise of these strategies for conserving carabid beetles in [ABSTRACT FROM AUTHOR] |
