Introduction of exotic pets, impact on local ecosystems and management processes: What can we learn from Slider turtle, Trachemys scripta elegans, in France?

New-born red-eared slider turtles (Trachemys scripta elegans) have been massively exported from the United States to European and Asian countries to be sold as pets. These juvenile turtles, when kept in good conditions, can reach a size at which they became inconvenient to their owners. Therefore, many turtles have been released into natural freshwater ecosystems leading to feral adult turtles detected all over France, despite an importation ban in the European Union since 1997.
As a part of a project concerning the invasive potential of slider turtles in France, we designed a mesocosm experiment to compare the temporal variations of the communities between ponds in which turtles were present at two different densities or absent. During two years we surveyed water quality, macro-invertebrates, plankton, and macrophyte communities in 12 ponds. We used additive mixed models to estimate impacts of turtle abundance as well as temporal changes and found that only two mollusc communities severely declined when turtles were present.

Moreover, wetland preservation is a multi-faceted problem that involves not only preservation of aquatic ecosystems but also human components such as managers, decision-makers and the general public. To allow for this diversity of stakeholders, we built a multi-agent system based on ecological, social and anthropological data. This model allowed us to balance the ecological and the social implications of this kind of introductions.