Storage buildings and greenhouses as stepping stones for non-native, potentially invasive spiders (Araneae) – a baseline study in Basel, Switzerland

Abstract

Transportation of goods via land, sea or air causes a dissemination of species on a global scale. In central Europe species that are associated with fruit, vegetables and/or buildings are suspected to be imported and potentially build up populations in the following four categories of buildings: I) greenhouses, garden centres, flower shops and flower wholesale stores, II) storage buildings and logistic centres, III) botanical gardens and zoos and IV) touristic hotspots. During this research 20 such localities in and around Basel were investigated by means of visual searching. 340 adult spider individuals were collected, representing 37 species and 15 families. Three were first records for Switzerland. Eight species were not published before for the region of Basel even if six of these were already known in private, not published collections - partly going back to the 1930s. Our investigation shows that the interpretation of the spread and invasion of species needs good published knowledge about the actual status of our fauna which, especially for synanthropic spiders, is not the case. We therefore urge everybody to publish all knowledge about faunistics even for so-called common species.