Successful reproduction of Trachemys scripta in the Altrhein of Kehl (Germany) and simultaneous increase in population estimate

International audience; The European Union categorises pond sliders (Trachemys scripta) as invasive species for which all member countries have to develop an action plan. To date it has been assumed that the climate in Germany is too cold for T. scripta to survive for long or to reproduce. Data collected annually from 2016 to 2020 showed that the population of exotic pond turtles in an oxbow lake (Althrein of Kehl, Germany) did not decrease but increased. In addition, the diversity of species released was found to be high, five other exotic species in addition to T. scripta were observed. The population of T. scripta in particular appeared to be increasing, with no indication of high mortality due to cold winters and apparently regular successful reproduction (hatchlings observed in four out of five study years and caught in two years). The current action plan in Germany for T. scripta will have to change if potential negative impacts are to be avoided. Other west and central European countries might also have to modify their action plans accordingly.