Isoperla obscura
Key Details
| Taxonomic Groups: | Invertebrate > insect - stonefly (Plecoptera) > Stonefly |
| Red List Status: | Regionally Extinct (GB scale) (Not Relevant) [RE(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: | Isoperla obscura |
| UKSI Recommended Authority: | (Zetterstedt, 1840) |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Macadam, 2015 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | This species is regionally extinct in Britain, with the last record being made from River Trent near Nottingham in 1920. This species is only known from the River Trent. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | To return the species to the wild will require a conservation breeding and reintroduction programme. |
| 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: | This species would benefit from the return of natural processes to the River Trent. |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 3. National Monitoring Plan agreed and implemented |
| Recovery potential/expectation: | Low - Combination or other (detail in comments) |
| National Monitoring Resource: | Combination - insufficient |
| Species Comments: | This species would benefit from improved water quality in the River Trent. In addition, action to tackle light pollution is required as it is thought that this species is attracted to lights. Conservation translocation recovery is high but currently not possible due to water quality issues. Targeted sampling is required in winter. |
Key Actions
Key Action 1
Proposed Action: A thorough survey of the River Trent is required in winter to determine this species status in England.
Action targets: 2. Biological status assessment exists
Action type: Status survey/review
Duration: 1 year
Scale of Implementation: Not applicable
High priority sites: N/A
Comments: Necessary step to inform future translocation
Key Action 2
Proposed Action: If Action 1 finds that the species is no longer present in the River Trent, investigate the feasibility of conservation translocations for this species.
Action targets: 5. Remedial action identified
Action type: Ex situ conservation
Duration: 3-5 years
Scale of Implementation: Not applicable
High priority sites: N/A
Comments:
Key Action 3
Proposed Action: Translocation of captive bred population to River Trent and other sites identified in Action 2
Action targets: 6. Recovery solutions trialled
Action type: (Re-)introduction
Duration: 3-5 years
Scale of Implementation: ≤ 5 sites
High priority sites: To be determined by Action 1
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.