Ecological characterization of streams invaded by the New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843): the case study of a National Park in Italy.

Since the 19th century, the mud snail Potamopyrgus antipodarum (Gray, 1843), native to New Zealand, has been introduced into several European countries, Italy included. As a first step to contain its spread and establishment, it seems necessary to understand the characteristics of the environment that are more favorable for this species’ invasion. To this aim, we analyzed a number of physico-chemical and biotic parameters of four streams, two invaded and two not yet invaded, in the National Park of the “Foreste Casentinesi, Monte Falterona, Campigna” (Central Italy), where the species was first recorded in 2008. The two categories of streams, invaded and non-invaded, differ for only three of the 20 analyzed characteristics of the habitat, that is availability of crevices, width stream, and maximum water depth. This suggests that, despite the documented P. antipodarum’s tolerance to pollution, the high-quality waters of the park are highly susceptible to its invasion, if its vectors and pathways are not identified and adequately monitored. Most of the environmental parameters analyzed in the studied streams showed to be similar to those reported in the literature as preferred/tolerated by the species. Our findings pinpoint the vulnerability of nature reserves to species invasions, and call for more effective preventative measures.