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

Abstract

Since the nineteenth 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 favourable for this species' invasion. To this aim, we analysed 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 in only three of the 20 analysed characteristics of the habitat; that is, availability of crevices, width stream, and maximum water depth. This suggests that, despite P. antipodarum's documented 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 analysed in the studied streams were shown 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.

Key Words:

• benthic fauna
• inland waters
• invasive species
• Mollusca
• protected areas

ACKNOWLEDGEMENTS

Thanks are due to E. Ristori for the English revision and to L. Sacchini, A. Bottaci, A. Zoccola, M. Lucchesi, F. Cianferoni, F. Zinetti, L. Bartolozzi, F. Terzani, E. Lori, A. Fani, M. Magherini, A. Gennai, G. Crudele, A. Cini, and R. Cervo for their precious help during this research. Thanks are also due to Dr L. Pisani, Dr M. Baccini and Dr M. Pennisi for water and air temperature data and to S. Cannicci, G. Santini and A.F. Inghilesi for statistical suggestions. We also thanks three anonymous reviewers for their constructive criticism and useful suggestions. This study is part of a scholarship funded by the National Park of the Foreste Casentinesi, Monte Falterona e Campigna, entitled ‘Conservation of species and habitats in the wetlands of the National Park’.