Least Adder's-tongue (Ophioglossum lusitanicum)
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: | Ophioglossum lusitanicum |
| UKSI Recommended Authority: | L. |
| 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 et al., 2014) due to the small number of individuals (<1,000). It is restricted to one location in England, on the Isles of Scilly. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Surveys over recent times, combined with expert knowledge of the species at its sole location, have led to evidence of a continued decline in the number of individuals (clones) which is thought to be linked to a decline in the rabbit population and a lack of suitable grazing. |
| 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: | The species has only ever been known from a single location in England. The focus should be on the rehabilitation of the extant population. |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 4. Autecology and pressures understood |
| Recovery potential/expectation: | Low - Relict or natural rarity |
| National Monitoring Resource: | Opportunistic - sufficient |
| Species Comments: | Confined as a native to one locality on Scilly (Wingletang Down, St Agnes). The area is kept relatively open by grazing with cattle and by mowing, but the species thrives in close-cropped, rabbit-grazed turf which is difficult to replicate with livestock. Gorse is invading the margins of the site. |
Key Actions
Key Action 1
Proposed Action: Continue to survey the population. Attempt to assess the number of clones, rather than the number of individual fronds.
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Status survey/review
Duration: >10 years
Scale of Implementation: 1 site
High priority sites: Wingletang Down SSSI
Comments: Although the number of individuals is relatively easy to count, it would be far more useful to known the number of clonal patches. There is anecdotal evidence of a decline in the latter. Investigations should make use of molecular methods to estimate numbers of clonal patches, as has been performed for other taxa in GB (e.g. Circaea alpina).
Key Action 2
Proposed Action: Attempt to find a solution to the lack of rabbit grazing, via trial management using goats
Action targets: 6. Recovery solutions trialled
Action type: Habitat management
Duration: 3-5 years
Scale of Implementation: 1 site
High priority sites: Wingletang Down SSSI
Comments: Goat grazing is suggested as they produce the close-cropped turf that rabbits produce. However, there are potential constraints that will need to be addressed e.g. animal welfare, whether cattle are retained as a grazing animal, etc. 'No fence' collars could be a solution at this site. The use of small, hardy breeds of sheep e.g. Soay might also be an option, if such livestock are available.
Key Action 3
Proposed Action: Continue the practice of scrub (Gorse) removal/control
Action targets: 5. Remedial action identified
Action type: Habitat management
Duration: Unknown
Scale of Implementation: 1 site
High priority sites: Wingletang Down SSSI
Comments: Management of Gorse is likely to be an ongoing operation, unless suitable grazing is implemented.
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.