Blackwort (Southbya nigrella)
Key Details
| Taxonomic Groups: | Non-vascular plant (incl. chromists) > liverwort > Liverwort |
| Red List Status: | Critically Endangered (Not Relevant) [CR(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: | Southbya nigrella |
| UKSI Recommended Authority: | (De Not.) Henriq. |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Callaghan, 2023 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | At risk of extinction in England due to small population size and continuing decline |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | A species with low recovery potential where the main aim is to maintain/protect populations |
| 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 a restricted distribution and so is unlikely to benefit from untargeted actions |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 4. Autecology and pressures understood |
| Recovery potential/expectation: | Unknown |
| National Monitoring Resource: | Opportunistic - insufficient |
| Species Comments: | GB RL criteria: C2a(ii). Mediterranean Oceanic species. |
Key Actions
Key Action 1
Proposed Action: Develop and implement national monitoring plan to ensure comprehensive and up-to-date information is available on range size, population size, occupied sites and threatening factors in England
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Targeted monitoring
Duration: 1 year
Scale of Implementation: ≤ 5 sites
High priority sites: Isle of Portland SSSI, Compton Chine to Steephill Cove SSSI
Comments: A species with low recovery potential where the main aim is to maintain/protect populations. Some monitoring occurs on the Isle of Portland.
Key Action 2
Proposed Action: In consultation with landowners, assess habitat management requirements at surviving locations and produce a costed plan for any new actions required
Action targets: 5. Remedial action identified
Action type: Advice & support
Duration: 1 year
Scale of Implementation: ≤ 5 sites
High priority sites: Isle of Portland SSSI, Compton Chine to Steephill Cove SSSI
Comments: Habitat management is occurring on the Isle of Portland; it is unclear what new actions may or may not be required. Habitat management requirements on the Isle of Wight need to be assessed.
Key Action 3
Proposed Action: Undertake research to better understand the habitat requirements of the species, in particular to define favourable grazing regimes
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 3-5 years
Scale of Implementation: ≤ 5 sites
High priority sites: Isle of Portland SSSI, Compton Chine to Steephill Cove SSSI
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.