Aussichten des Einsatzes von Migrationsbarrieren zur Abwehr von Wühlmausschäden im ökologischen Obstbau

Cyclic vole species, particularly the Water vole (Arvicola terrestris), cause substantial agricultural damage throughout their wide geographical range. In organic pomiculture synthetic pesticides are not allowed. Trapping and fumigation remain the only applicable measures for managing voles but require a lot of time and personal skills. The success of using these methods is reduced by the fast recolonisation of the empty areas. To stop the permanent overground immigration of voles a mechanical barrier system was developed and tested in enclosures and at two study sites in Baden-Wuerttemberg and Rhineland-Palatinate between October 2002 and October 2003. The barrier, consisting of a low fence of whire mesh or polyolefin foil, reached 20 cm below and 30 cm above the soil surface. During the study time only few water voles immigrated into protected plots by using fresh mole galleries. The results of these field trials and concomitant enclosure experiments in Muenster indicate that migration barriers are an efficient method that can easily be implemented to protect orchards from overground vole immigration. Current studies are designed to further enhance the efficacy of the barrier systems with a focus on barrier installation at the time of orchard planting, removal of existing old burrow systems and investigation of spatial and temporal behaviour of voles