Southern Silver Stiletto-fly (Cliorismia rustica)
Key Details
| Taxonomic Groups: | Invertebrate > insect - true fly (Diptera) > Soldier fly or ally |
| Red List Status: | Least Concern (Not Relevant) [LC(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: | Cliorismia rustica |
| UKSI Recommended Authority: | (Panzer, [1804]) |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Drake, 2017 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | Increasing population figures may be skewed by targeted surveys in 2007/8 which highlighted the need to survey for larvae rather than adults |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Known habitat requirements for larvae and historical records should allow for targeted actions where required |
| 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: | If these approaches were aimed at the flow of rivers, out of season flood prevention then this would be of benefit. This would rely on the ability to control the flow of rivers to prevent 'out of season' flooding, whilst still allowing strong flows in the winter to deposit the required sand substrate out of reach of later river flow |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 4. Autecology and pressures understood |
| Recovery potential/expectation: | Medium-high |
| National Monitoring Resource: | Combination - insufficient |
| Species Comments: | C. rustica was found to be widespread on the middle reaches of the Dane and the Bollin, with another population centred on the lower reaches of the Etherow and Tame, linked by the Goyt (Cheshire) in 2007/2008 see: Hewitt, S & Parker, J., 2008. The species larval requirements for dry (at most moist) sand deposits deposited by rivers in spate (therefore safe from currents later in the year) under trees or by tall herbage require river flows to be predictable. |
Key Actions
Key Action 1
Proposed Action: Tailored surveys of potential habitat in known localities to determine the current populations and species distribution, thus identifying areas where C. rustica is missing as well as present.
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Targeted monitoring
Duration: 3-5 years
Scale of Implementation: ≤ 50 sites
High priority sites: Middle reaches of the Rivers Dane and the Bollin, other areas centred on the lower reaches of the Rivers Etherow and Tame, linked by the Goyt (Cheshire). Other previously populated sites on the Rivers Rother, Usk and Monnow
Comments:
Key Action 2
Proposed Action: Prevent human interference at sites where sand deposits are viable for the species to breed, through use of signage and public barriers.
Action targets: 4. Autecology and pressures understood
Action type: Pressure mitigation
Duration: 6-10 years
Scale of Implementation: ≤ 50 sites
High priority sites: Middle reaches of the Rivers Dane and the Bollin, other areas centred on the lower reaches of the Rivers Etherow and Tame, linked by the Goyt (Cheshire). Other previously populated sites on the Rivers Rother, Usk and Monnow
Comments:
Key Action 3
Proposed Action: Education and advice to land managers, river wardens and government agencies responsible for sites in question and those that could potentially affect the known areas i.e. upstream
Action targets: 4. Autecology and pressures understood
Action type: Advice & support
Duration: 6-10 years
Scale of Implementation: ≤ 50 sites
High priority sites: Middle reaches of the Rivers Dane and the Bollin, other areas centred on the lower reaches of the Rivers Etherow and Tame, linked by the Goyt (Cheshire). Other previously populated sites on the Rivers Rother, Usk and Monnow
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.