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In 2007, the invasive crayfishProcambarus clarkii(Girard 1852) was identified for the first time in the “Parc Naturel Régional de la Brenne” (Indre department, Centre region, France). Ten infestation sites were found in the park, with 62 fishponds colonised. To better understand how the fishponds could be affected, and changes in invaded ponds, we followed crayfish burrowing activity in recently drained fishponds in two areas. Weekly investigations of burrowing activity by analysing their density, occupation and location with respect to the banks, and micro-habitat features were carried out for 2 months in spring. Burrow densities of 1.16 and 1.05 burrows m–2were found at Le Terrier Blanc and Coudreau 3 respectively.Procambarus clarkiisought humid soil in a dry pond and preferred burrowing on silt substrates. While no statistical differences were found between sites, some differences were observed among weeks independently of the sites. The mean mouth diameter of burrows in the two sites was 5.7 cm (SD = 2.17,n = 214; min. value: 1.2 cm; max. value: 14 cm). Notwithstanding the situation in the last weeks of the study (when most chimneys were built), there was a certain turnover between open and plugged burrows, and in occupancy. Given the scale and duration of the study and the number of fishponds surveyed, this study successfully quantified the dynamics of burrowing in these ponds and conclusions provide a useful basis for future studies and give suggestions of how other colonised fishponds may be affected. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM AUTHOR]