Zur Webspinnenfauna (Arachnida; Araneae) in Getreidefeldern und angrenzenden Feldrainen im Mitteldeutschen Raum

Abstract

Spiders are abundant epigeal predators in agricultural sites in Europe. Little is known about the importance of the spider fauna in field boundaries in regard to the regulation of pest populations in the field. lnvestigations were carried out in 1989 and 1990 in cereal fields and field boundaries using of pitfall-traps. In the 3 fields and field boundaries studied, a total of 9510 individuals from 14 families and 82 species were recorded. Species numbers in the field boundaries were nearly twice as high as those found in the fields. Within the cereal fields members of the Linyphiidae, including Oedothorax apicatus. Erigone atra. E. dentipalpis and Meioneta rurestris, reached higher densities compared to other groups. In the field boundaries the Lycosidae and Thomisidae were more common. Dominant species here included Pardosa prativaga, Trochosa ruricola, Aulonia albimana and Oxyptila praticola. Spider species diversity and dominance structure in the different habitats depended mainly on the particular plant formation at the respective investigation sites. Differences in the spider communities between fields and boundaries were much higher than those in the communities of ground beetles studied in the same places. Most species of Araneae found in the fields were also recorded in the field boundaries. Even with intensive management of the fields, reimmigration of species from boundaries into the fields might be possible. As a whole faunal exchange between both habitats seems to be small. But the results for some species, especially for Pardosa palustris and P. pullata, indicate that some immigration does exist. Field boundary balks are characterised by high species diversity. They are important refuges for a lot of animal- and plant species.