The succession of Staphylinidae (Coleoptera) after 15 years of conversion from conventional to organic farming

摘要

The results of a 15 years investigation after the conversion from conventional to organic farming are presented for the beetle family Staphylinidae. The aim of the study was to find general trends in the succession of assemblages, changes in the biodiversity and changes of dispersion for invading or retreating species. The succession of all fields studied are shifted in the same direction, which indicates an overall driving ecological factor after the conversion. However, individual fields showed a different speed within the succession. The number of species remained on the same level in the first 8 years but increased from the eighth to the 15th year. However, the species diversity on the organic fields were still lower than in the field margins. The conventionally farmed fields in 2001 before the conversion of the main study area was compared with adjacent conventionally farmed fields investigated 15 years later. This comparison showed that the species diversity was currently much lower there than 15 years before in the main study area. During the succession single species retreated from fields after the conversion and other species invaded the fields. In particular, species of open habitats and inquilines of mammals invaded the fields. It was concluded that organic farming had benefit effects on biodiversity, but a mosaic with field margins will enhance this effect.