No subpopulations of molluscs have been evaluated by the IUCN.
For a species to be assessed as vulnerable to extinction the best available evidence must meet quantitative criteria set by the IUCN designed to reflect "a high risk of extinction in the wild". Endangered and critically endangered species also meet the quantitative criteria of vulnerable species, and are listed separately. See: List of endangered molluscs, List of critically endangered molluscs. Vulnerable, endangered and critically endangered species are collectively referred to as threatened species by the IUCN.
Additionally 1988 mollusc species (27% of those evaluated) are listed as data deficient, meaning there is insufficient information for a full assessment of conservation status. As these species typically have small distributions and/or populations, they are intrinsically likely to be threatened, according to the IUCN.[2] While the category of data deficient indicates that no assessment of extinction risk has been made for the taxa, the IUCN notes that it may be appropriate to give them "the same degree of attention as threatened taxa, at least until their status can be assessed".[3]
This is a complete list of vulnerable mollusc species and subspecies evaluated by the IUCN.
Gastropods
There are 828 species and 16 subspecies of gastropod assessed as vulnerable.
Stylommatophora
Stylommatophora includes the majority of land snails and slugs. There are 339 species and six subspecies in the order Stylommatophora assessed as vulnerable.
^"IUCN Red List version 2016-2". The IUCN Red List of Threatened Species. International Union for Conservation of Nature and Natural Resources. Retrieved 8 September 2016.
^"Limitations of the Data". The IUCN Red List of Threatened Species. Union for Conservation of Nature and Natural Resources. Retrieved 11 January 2016.
^"2001 Categories & Criteria (version 3.1)". The IUCN Red List of Threatened Species. Union for Conservation of Nature and Natural Resources. Retrieved 11 January 2016.