Potamopyrgus antipodarum (New Zealand mud snail) is a prosobranch mollusk native to New Zealand with a wide invasive distribution range. Its non-indigenous populations are reported from Australia, Asia, Europe and North America. Being an extremely tolerant species, Potamopyrgus is capable to survive in a great range of salinity and temperature conditions, which explains its high invasiveness and successful spread outside the native range. Here we report the first finding of Potamopyrgus antipodarum in a basin of the Cantabrian corridor in North Iberia (Bay of Biscay, Spain). Two haplotypes already described in Europe were found in different sectors of River Nora (Nalon basin), suggesting the secondary introductions from earlier established invasive populations. To enhance the surveillance of the species and tracking its further spread in the region, we developed a specific set of primers for the genus Potamopyrgus that amplify a fragment of 16S rDNA. The sequences obtained from PCR on DNA extracted from tissue and water samples (environmental DNA, eDNA) were identical in each location, suggesting clonal reproduction of the introduced individuals. Multiple introduction events from different source populations were inferred from our sequence data. The eDNA tool developed here can serve for tracing New Zealand mud snail populations outside its native range, and for inventorying mud snail population assemblages in the native settings if high throughput sequencing methodologies are employed.

No abstract

No abstract

Stabilised organic solids derived from sewage sludge (‘biosolids’) are applied to land in many countries as an alternative to disposal as landfill. This study evaluates the long-term effects of biosolids applied to forestry plantations on the adjacent intertidal habitats of Moturoa / Rabbit Island (Aotearoa New Zealand). On this island, biosolids are applied to enhance soil fertility and growth of trees (Pinus radiata). However, applications may affect the quality of groundwater and surface water (e.g., increasing concentrations of nutrients and trace metals) and, via seepage into adjacent coastal areas, potentially adversely affect intertidal habitats and biota. Shoreline topography, macroalgal cover, sediment grain size, concentrations of nutrients, trace metals and faecal indicator bacteria, and benthic infaunal community characteristics were studied on three occasions (2008, 2014 and 2019) at twelve intertidal transect sites (four ‘reference’ and eight ‘application’) adjacent to forestry blocks where biosolids have been applied intermittently over a period of 24 years. No long-term adverse changes to the environment and community characteristics attributed to biosolids application were detected between reference and application sites. The study provides evidence that biosolids application can co-occur without detectable adverse effects on the nearby intertidal environment.