Large-mouthed Valve Snail (Valvata macrostoma)
Key Details
| Taxonomic Groups: | Invertebrate > mollusc > Mollusc (non-marine) |
| Red List Status: | Vulnerable (Not Relevant) [VU(nr)] |
| D5 Status: | Included in the baseline Red List Index for England (Wilkins, Wilson & Brown, 2022) |
| Section 41 Status: | (not listed) |
| Taxa Included Synonym: | (none) |
| UKSI Recommended Name: | Valvata macrostoma |
| UKSI Recommended Authority: | (Mörch, 1864) |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Seddon et al., 2014 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | All of the GB population occurs in England, only in 5 main populations: At 4 it is considered stable (Pevensey Levels, West Sedgemoor, Norfolk Broads, Cambs Great Ouse Washes) The status of the population on Hants Avon is small and at risk as it requires specific habitat management every few years. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | The Hants Avon population is dependent upon active specialist management of a few ditches. |
| Question 3: | At a landscape scale, would the species benefit from untargeted habitat management to increase habitat mosaics, structural diversity, or particular successional stages? |
| Response: | Yes |
| Justification: | For 4 of the populations 'landscape scale conservation by traditional ditch management (so a range of successional stages is present) is required not at a species specific level. |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 6. Recovery solutions trialled |
| Recovery potential/expectation: | Low - Combination or other (detail in comments) |
| National Monitoring Resource: | Combination - insufficient |
| Species Comments: | The National Monitoring resource does not provide a choice to match the situation for this species. Only one population requires action. |
Key Actions
Key Action 1
Proposed Action: Undertake periodic maintenance of pools on the floodplain at Sopley on Hants Avon so that some shallow water remains at all times. This needs to be carried out every 2-3 years.
Action targets: 6. Recovery solutions trialled
Action type: Habitat management
Duration: >10 years
Scale of Implementation: 1 site
High priority sites: Sopley south of Ringwood on Hants Avon.
Comments:
Key Action 2
Proposed Action: It only occurs in 5 populations, Action 2 could assess feasibility of translocations to new suitable sites
Action targets: 5. Remedial action identified
Action type: Scientific research
Duration: 1 year
Scale of Implementation: ≤ 5 sites
High priority sites:
Comments:
Key Action 3
Proposed Action: Following results of Action 2, Action 3 could undertake a trial translocation to a new site.
Action targets: 5. Remedial action identified
Action type: Scientific research
Duration: >10 years
Scale of Implementation: ≤ 5 sites
High priority sites:
Comments:
Acknowledgment:
Data used on this website are adapted from Threatened species recovery actions 2025 baseline (JP065): Technical report and spreadsheet user guide (Natural England, 2025). Available here.