Ground Beetle Assemblages Affected by Oilseed Rape Management Practice

Abstract

Ground beetle assemblages were compared in two oilseed rape fields with different management practices, in fallow and in succeeding winter wheat crop. A total of 11,615 specimens representing 52 species were collected over two years of sampling using epigeic pitfall and funnel traps. The ten most common species, represented 91% of the total number of specimens in oilseed rape, were Amara aenea (De Geer, 1774), Amara similata (Gyllenhal, 1810), Harpalus distinguendus (Duftschmid, 1812), Brachinus explodens Duftschmid, 1812, Poecilus cupreus (L., 1758), Calathus fuscipes (Goeze, 1777), Calathus ambiguus (Paykull, 1790), Poecilus punctulatus (Schaller, 1783), Poecilus sericeus Fischer von Waldheim, 1824 and Anchomenus dorsalis (Pontoppidan, 1763). Eight carabid species showed a clear preference for integrated oilseed rape management practice. Trapped beetles were three times more numerous in oilseed rape in integrated than in the field under organic management practice. Canonical Variate Analysis revealed that management practices applied on both fields in oilseed rape had a significant effect on carabid assemblages. Redundancy Analyses (RDA) showed that in the following year, in succeeding winter wheat crop, management practices applied in oilseed rape had a significant effect on carabid assemblages. Ground beetle activity on plants was registered in both oilseed rape management systems, but not on winter wheat plants. The most active carabids in crop canopy included A. similata, C. fuscipes, Calathus erratus (Sahlberg, 1827), A. aenea, C. ambiguus, Calathus melanocephalus (L., 1758) and H. distinguendus. In oilseed rape both management practices had a significant effect on carabid assemblages in crop canopy.