Door Snails Under Threat

The family Clausiliidae (door snails) are characterized by a sinistral shell that is often ribbed and fusiform or spindle shaped with a tapering spire forming a large number of whorls (Molluscs, Vaclav Pfleger, 1999 pp.102). They feed mainly on algae and lichens and often can bee seen emerging from crevices in dark damp areas such as rock faces and heavily mossed tree trunks.

The Craven Door Snail, Clausilia dubia

However, door snails and the non-marine molluscs of Ireland as a whole are under threat. Of the 150 species present, two are considered to be regionally extinct, five critically endangered, fourteen endangered, twenty-six vulnerable, six near threatened, and the rest of least concern, or data deficient (Red List of Non-Marine Molluscs 2009, Byrne et al.). Ireland’s non-marine molluscan fauna is of international importance. Ten species have populations of significant international worth, having large proportions of their global population in Ireland.

Of the Clausiliidae present in Ireland, two species are vulnerable (Balea perversa and Cochlodina laminata) while another two of least concern (Balea heydeni and Clausilia bidentata). Loss of these species could have an unknown knock on effect on the ecology of the island of Ireland.

Clausilia dubia