THE EFFECT OF DIFFERENT FARMING SYSTEMS ON EPIGEIC ARTHROPODS - A 5-YEAR STUDY ON THE ROVE BEETLE FAUNA (COLEOPTERA, STAPHYLINIDAE) OF WINTER-WHEAT

The susceptibility of rove beetles to extensification practices in agr iculture was studied in four farming systems on the same farm for a pe riod of five years. The systems differed in application of fertilizer and pesticides in methods of soil cultivation and in crop rotation. Th e most common staphylinid species (Tachyporus hypnorum, Oxytelus inust us, Lesteva longelytrata, Philonthus fuscipennis) were the same in all farming systems, but total faunal composition was different. Species richness and diversity were highest with reduced tillage and fewer pes ticide applications. This was the result of an increased (but still to lerable) weed density which probably caused more favourable microclima tic conditions. Moreover, some species were negatively affected by the use of a plough and the abundance and biomass of potential prey is co nsidered to be higher on unploughed plots. A reduction in the use of i nsecticides alone led to an increase of the abundance of a few of the most common species, but had no positive effect on species richness. T he treatment ''no fertilization'' led to sparse crops with unfavourabl e microclimate. In this case, population density and the number of spe cies of the rove beetle fauna decreased even when no pesticides were a pplied. (C) 1998 Elsevier Science B.V. All rights reserved.