Micaria silesiaca
Key Details
| Taxonomic Groups: | Invertebrate > spider (Araneae) > Spider |
| 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: | Micaria silesiaca |
| UKSI Recommended Authority: | L. Koch, 1875 |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Harvey et al., 2017 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | NT, criteria: B2ab(ii,iv): Some evidence of decline since 2017 review, with most loss from the S heaths, especially Dorset/Hants. and Surrey. Largely restricted to C-S England and E Anglia. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Apparently absent from former sites where habitat still seems suitable |
| 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: | This species would not benefit from untargeted management |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 2. Biological status assessment exists |
| Recovery potential/expectation: | Unknown |
| National Monitoring Resource: | Opportunistic - insufficient |
| Species Comments: | Usually found on sparsely vegetated, usually dry heathland, though sometimes on moderately wet heath/damp gullies |
Key Actions
Key Action 1
Proposed Action: Targeted re-survey of all former and nearby sites, using standardised methodology to assess current status (and establish baseline for national monitoring programme)
Action targets: 2. Biological status assessment exists
Action type: Status survey/review
Duration: 2 years
Scale of Implementation: ≤ 50 sites
High priority sites: Brecks, Surrey heaths, Dorset/Hants. Heaths, Norfolk/Suffolk sandlings.
Comments: Suggest combining with other rarities from same locations, with similar phenologies and requiring same methodologies.
Key Action 2
Proposed Action: Autecological research to better characterise habitat requirements and inform management
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 3-5 years
Scale of Implementation: ≤ 5 sites
High priority sites: Winterton Dunes, Norfolk; Lackford Lakes, Suffolk; Gorley Common, New Forest
Comments: Focus on reliable but contrasting sites
Key Action 3
Proposed Action: Ensure site managers are aware of species past/recent presence and vulnerability on their sites. Update them with Action 1 and 2 results to provide any resulting guidance on locations/management and inform commissioning of invertebrate survey work (methods likely to detect/damage species, need for retention and examination of spider by-catch when not a survey target)
Action targets: 5. Remedial action identified
Action type: Advice & support
Duration: >10 years
Scale of Implementation: ≤ 50 sites
High priority sites:
Comments: Ensure land managers are kept abreast of management implications arising from Action 2. Assemble mailing list and update site managers at species-appropriate intervals; most easily delivered by BAS/SRS.
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.