Epigäische Spinnen auf Äckern der Nordwest-Schweiz im mitteleuropäischen Vergleich (Arachnida: Araneae)

Summary

Ground-living spiders on arable land in north-westem Switzerland with a Central European comparison (Arachnida: Araneae). The ground-living spider fauna of north-westem Switzerland is analysed in a general view during the years 1993-1998 based on 67 data sets. Two species (Oedothorax apicatus, Pardosa agrestis) dominated c1early. 14 species had representing values of 80 to 100 %, 9 species from 50 to 80% and 18 species from 20 to 50 %. Eperigone trilobata and Pardosa proxima are geographically typical. A total of 131 species and 52'878 adult spiders were included in this analysis. An additional analysis of 47 investigations around Central Europe yielded four species (Oedothorax apicatus, Erigone atra, Erigone dentipalpis, Meioneta rurestris) occurring in all regions abundantly and regularly in the arable fields. Six additional species occur in all regions in the fields - in some investigations or regions less abundant. We found a biogeographic gradient in some species (increasing abundance from Western to Central and Eastem Europe: Pardosa agrestis). Other species are only abundant in some regions - this is caused by present expansion (Eperigone trilobata) or the border of distribution (Dip/ocephalus graecus). ln general the ground-living spider fauna on arable land in Central Europe is characterised by a uniform pattem.