Ecology and Control of invasive Slugs: Interactions with Environmental Factors and Soil Fauna

As a consequence of globalization many different life forms are transported around the world in areas they would never have reached without human assistance. Some of these life forms become invasive and can cause great ecological and economic damage both in native and agricultural/horticultural ecosystems (Mooney et al., 2005; Nentwig, 2010). Often, studies considering invasive species concentrate either on their control or on their ecology, however rarely are these topics investigated simultaneously. The proposed project focuses on the ecology and control of the invasive Spanish slug, Arion vulgaris, one of the 100 most invasive species in Europe damaging crops, vegetables and ornamentals in agriculture/horticulture and in private gardens. The project will investigate three aspects regarding the ecology and control (i) the effect of past and current rainfall and temperature on the abundance of A. vulgaris assessed via a citizen science approach, (ii) ecological interactions between co-occurring native snail (Helix pomatia) and A. vulgaris at different rainfall levels and the role of earthworms in altering these interactions, and (iii) the efficacy of chemical (Fe-III-phosphate pellets) and biological (nematode Phasmarhabditis hermaphrodita) slug control methods at different rainfall levels and earthworm activity. We recently showed that earthworms significantly affect this slug species (Zaller et al. 2013, Trouvé et al. 2013) and seek to include this aspect as earthworms are ubiquitous in many ecosystems where this slug species thrives. The proposed project combines different methodological approaches in order to study these relationships. As an outcome of this project a better knowledge on effects of environmental influences and organismic interactions will yield a more holistic interpretation of the consequences of common slug control measures. Ultimately recommendations for slug control in agricultural/horticultural production will be developed.