Convergent Stonewort (Chara connivens)
Key Details
| Taxonomic Groups: | Non-vascular plant (incl. chromists) > stonewort > Stonewort |
| Red List Status: | (Not Relevant) [(not listed)(nr)] |
| D5 Status: | |
| Section 41 Status: | (not listed) |
| Taxa Included Synonym: | (none) |
| UKSI Recommended Name: | Chara connivens |
| UKSI Recommended Authority: | Salzm. ex A.Braun |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | (not listed) |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | Provisional England EN, Britain EN (Stewart & Lansdown 2021, Stewart 2022). Decreasing and most remaining populations unstable and periodic in appearance. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Largely constrained by nutrient enrichment problems. In Norfolk sites, also affected by boat traffic, cutting, loss of underwater topographic structure (too much soft organic silt). However, this species rarely seems to be happy even where its associated species are and more detailed look at its autecology and optimal environmental parameters would be valuable |
| 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: | Two recently discovered sites are gravel pits. Has a preference for near coastal sites and probably benefits from slight brackishness, so could also benefit from the freshwater end of the spectrum in managed coastal retreat. |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 5. Remedial action identified |
| Recovery potential/expectation: | Low - Policy conflict (detail in comments) |
| National Monitoring Resource: | Opportunistic - insufficient |
| Species Comments: | Nutrient enrichment issues in the Norfolk Broads, Slapton Ley (Devon) and former site at Widecombe Ley (Devon), but good population at Hodbarrow Lagoon (Cumbria). Also present at Barge Pit (Kent) where strength of population not fully known. Apparently lost from Tinhay Quarry (Devon), possibly due to competition from other vegetation. |
Key Actions
Key Action 1
Proposed Action: Investigation of population at Tinhay Quarry (Devon) where competition from other charophytes may be an issue and at Barge Pit (Kent) where size and health of population unknown. Also update on population at Slapton Ley and former site at Widdecombe Ley (Devon)
Action targets: 4. Autecology and pressures understood
Action type: Status survey/review
Duration: 1 year
Scale of Implementation: ≤ 5 sites
High priority sites: Tinhay Quarry (Devon), Barge Pit (Kent), Slapton Ley (Devon), Widdecombe Ley (Devon).
Comments: Specific gaps in knowledge
Key Action 2
Proposed Action: Reduce impact of boat traffic: reduce boating, facilitate a switch to less damaging boating (e.g. fanboats) and/or reduce damage with physical structures
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 1 year
Scale of Implementation: ≤ 5 sites
High priority sites: Broadland
Comments:
Key Action 3
Proposed Action: Create new habitat as part of coastal rollback
Action targets: 5. Remedial action identified
Action type: Habitat management
Duration: >10 years
Scale of Implementation: ≤ 5 sites
High priority sites: eastern England
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.