Population structure and reproduction of red-eared slider Trachemys scripta elegans in Liguria (NW Italy)

In this study we provide data on the population structure, sex ratio and evi- dence for reproduction in the wild for two populations of the invasive fre- shwater chelonian trachemys scripta elegans, in liguria (nW Italy). During a lIFe nature project, aiming to preserve the endangered autoctonous pond turtle Emys orbicularis ingauna in the Centa river plane, 520 allochthonous turtles belonging to the genera graptemys, Mauremys, pseudemys and tra- chemys were caught and removed from the wild, in the province of savona (W liguria) and also of la spezia (e liguria). The majority of the removed turtles (n = 446) belonged to the subspecies t. scripta elegans, that formed reproductive populations in both areas. In the two areas, the sex ratio was balanced and the overall population structure, in which a great proportion of juveniles was present, did not differ, suggesting the existence of viable populations living in favorable environmental conditions. In the area of savona, where the native endemic Emys orbicularis ingauna is found, the population of t. scripta elegans is now almost completely eradicated, while in the la spezia river basin the invasive red-eared slider is so widespread and locally abundant, that it seems challenging to achieve a complete eradica- tion, at least in the short term.