Pigmyweed (Crassula aquatica)
Key Details
| Taxonomic Groups: | Vascular plant > flowering plant > Herbaceous plant |
| 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: | Crassula aquatica |
| UKSI Recommended Authority: | (L.) Schönland |
| 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: | EX in Eng. One known site in Scotland - now extinct in England |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Will not recolonise without assistance |
| 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: | Yorkshire site highly managed; species in England not associated with landscape-scale features |
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: | Not been seen in England since 1938 |
Key Actions
Key Action 1
Proposed Action: Investigate condition of Adel Dam pool
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 1 year
Scale of Implementation: 1 site
High priority sites: Adel Dam
Comments: Need to ensure site is suitable before Action 2 initiated
Key Action 2
Proposed Action: Reintroduce plant to Adel Dam, subject to favourable outcome of Action 1
Action targets: 6. Recovery solutions trialled
Action type: (Re-)introduction
Duration: 3-5 years
Scale of Implementation: 1 site
High priority sites: Adel Dam
Comments: Donor material presumably from Scotland
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.