Greenish Bladder-fern (Cystopteris diaphana)
Key Details
| Taxonomic Groups: | Vascular plant > fern > Fern |
| 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: | Cystopteris diaphana |
| UKSI Recommended Authority: | (Bory) Blasdell |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | in Stroh et al., 2014 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | Assessed as VU in England (Stroh 2014) & confined to handful of sites in Devon & Cornwall |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Species populations apparently stable at present, but monitoring worthwhile |
| 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: | No |
| Justification: | This species would not benefit from untargeted management |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 3. National Monitoring Plan agreed and implemented |
| Recovery potential/expectation: | Medium-high |
| National Monitoring Resource: | Opportunistic - sufficient |
| Species Comments: |
Key Actions
Key Action 1
Proposed Action: Implement regular monitoring at all native colonies to ensure that populations remain viable into the longer term.
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Status survey/review
Duration: Unknown
Scale of Implementation: ≤ 5 sites
High priority sites: River Camel & tributaries SSSI. Tavistock railway cuttings.
Comments: Species perhaps at most threat from increased water levels caused by climate change (?) and/or vegetation succession, hence need to monitor.
Key Action 2
Proposed Action: Consider the potential of protecting all extant native populations through appropriate designations (e.g. Local Wildlife Site designation).
Action targets: 7. Best approach adopted at appropriate scales
Action type: Site protection
Duration: 2 years
Scale of Implementation: ≤ 5 sites
High priority sites: Tavistock railway cuttings
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.