Threat or fiction: is the pond slider (Trachemys scripta) really invasive in Central Europe? A case study from Slovenia

Using samples of non-native pond sliders (Trachemys scripta) from three different climatic zones in Slovenia, we perform parentage analyses and use population genetic approaches to find out whether they successfully reproduce and are able to establish populations. Based on 14 highly polymorphic microsatellite loci, we provide evidence for successful reproduction and invasiveness of pond sliders not only for the Mediterranean and sub-Mediterranean regions of Slovenia, but also for the central part of the country having a temperate continental climate. Our results suggest that the pond slider should be classified as an invasive species (introduced species spreading in a non-native region) for Slovenia and other European regions with similar climatic conditions. Since the negative impact of pond sliders is out of question for native European turtle species, we suggest the immediate removal of pond sliders from all habitats. Our study provides for the first time hard evidence for the capability of pond sliders to reproduce in Central Europe. Thus, it contributes to the understanding of the invasiveness of pond sliders in Europe and delivers an important foundation for decision-makers in conservation.