Open Access

Christa Volkmar, Thomas Kreuter

• Im Rahmen eines Forschungsprojektes der Sächsischen Landesanstalt für Landwirtschaft erfolgten zönologische Studien in vier praxisrelevanten Bewirtschaftungsvarianten. Das primäre Untersuchungsziel bestand in der Einschätzung des Förderprogramms „Umweltgerechte Landwirtschaft (UL)“ hinsichtlich seiner Effekte auf die Biodiversität typischer Ackerstandorte im Freistaat Sachsen. Unter anderem wurden dazu Laufkäfer (Coleoptera: Carabidae) und Webspinnen (Araneae) als Indikatoren genutzt. Über die ökologische Bewertung der verschiedenen Bewirtschaftungsvarianten hinaus wird die Nutzung der Biodiversität von Ackerflächen und deren Indikation anhand von Raubarthropoden und anderen Organismengruppen diskutiert.
• The evaluation of the public support programme “Sustainable agriculture” (Free State of Saxony, Germany) demands the monitoring of the scheme’s effect on the biodiversity in fields. According to this aim, this study investigated different intensities of agricultural management in their effects on spiders and carabid beetles coenoses in Central Germany. The treatments included extensive sustainable agriculture, conventional agriculture and conventional fields with reduced soil tillage (mulched sowing and direct sowing). Arthropods were monitored by the means of pitfall traps (six repetitions per variant) on two different locations of Saxony called “Lößhügelland” and “Leipziger Tiefland”. To analyse their development, qualitative and quantitative parameters such as activity density, species diversity, pattern of dominance as well as other computed parameters were employed. Data on spiders (Araneae) was collected during a three-month catch period in 2003. In total, 17.178 individuals belonging to 74 species out of 15 families have been documented. Within the conventional variants at the location Lößhügelland, reduced soil tillage did have positive effects on the species diversity of the spider coenosis (ploughed: 32, mulched: 35, direct: 40). Some Lycosidae species, e.g. Trochosa ruricola and Pardosa pullata, did profit significantly of non-ploughing tillage systems. In comparison, 37 species were identified on the sustainable plot. At the location Leipziger Tiefland, a total of 38 species was documented for both the sustainable and the conventional ploughed variants. Again, the highest species diversity was found on the variant with direct sowing. However, sustainable agricultural management did seem to have a positive effect on the activity density of web-spinning spiders. On both sites, more individuals were found with sustainable treatment as compared to the conventional plots. Data on carabid beetles (Coleoptera, Carabidae) were collected during three-month sampling periods in 2002 to 2004. A total of 16.006 individuals belonging to 81 species were identified. The longer period of reduced soil tillage did not have significant effects on species diversity. However, some important species (e.g. Carabus auratus) showed significantly positive reactions on the conservation tillage systems. In most cases, the number of species was even higher on the ploughed plots. On the contrary, a significant positive effect on species diversity could be observed for ecological farming (59 species as compared to 45-48 species on the conventional variants). Additionally, activity densities and numbers of endangered species on the sustainable plots generally exceeded the conventional treatments. The ratio of correspondence (identity) between the treatments regarding species and dominance patterns was rather small. This hints to a high degree of variation within the carabid coenoses depending on the chosen soil tillage system. In summary, extensive sustainable agriculture and reduced soil tillage systems did have positive effects on spider and carabid coenoses in Central Germany. On the other hand, the coexistence of different intensities of agricultural management led to in a greater variety of epigeic coenoses. These results should be taken into account in developing further public support programmes.