Oniscus asellus occidentalis
Key Details
| Taxonomic Groups: | Invertebrate > crustacean > Woodlouse |
| Red List Status: | Near Threatened (Not Relevant) [NT(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: | Oniscus asellus occidentalis |
| UKSI Recommended Authority: | Bilton, 1994 |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Lee, 2015 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | The subspecies Oniscus asellus occidentalis was confirmed as a subspecies in 1999. It has been found in 24 hectads since 1990 in England. The intermediate populations and current distribution indicate a decline in the area of its habitat. Habitat loss has been linked with the decline, alongwith hybridisation with O. a. asellus. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | No |
| Justification: | The subspecies requires further investigation occurrence as the rate of decline is currently unknown. |
| 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: | Habitat management and restoration of wetlands, culm grasslands and damp woodlands will relieve the pressures on the populations in England. |
Species Assessment
Not relevant as no Key Actions defined.
Key Actions
No Key Actions Defined
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.