The Malham Sedge (Agrypnetes crassicornis)
Key Details
| Taxonomic Groups: | Invertebrate > insect - caddis fly (Trichoptera) > Caddisfly |
| Red List Status: | Critically Endangered (Not Relevant) [CR(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: | Agrypnetes crassicornis |
| UKSI Recommended Authority: | (McLachlan, 1876) |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Wallace, 2016 |
| Notes on taxonomy/listing: | 1. It may revert to genus Agrypnia in the future. 2. Suggested popular name seems well established |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | One English (and GB) population at Malham Tarn. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | A single site and declining species. There are plans to alter the water levels and the possible implications for this species must be considered. |
| 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: | Highly calcareous lakes are an extremely rare habitat not part of any habitat noted as of interest for Q3. |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 2. Biological status assessment exists |
| Recovery potential/expectation: | Low - Climate change |
| National Monitoring Resource: | Opportunistic - insufficient |
| Species Comments: | Declining across its European range and seems to be retreating north. |
Key Actions
Key Action 1
Proposed Action: There is not a population estimate or a way of finding that so any decline or improvement cannot be detected. Filling that knowledge gap seems a very important task. Establishing baseline monitoring of population size, phenology and larval distribution within the tarn as well as enabling the degree of decline or improvement will also be necessary to inform timing of future surveys. The habitat distribution could help maintain or enhance particular vegetation types in the tarn.
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: >10 years
Scale of Implementation: 1 site
High priority sites: Malham Tarn
Comments: Pupal exuvial counts may give population estimates and adult flight period information.
Key Action 2
Proposed Action: Develop captive breeding protocols so possible setting up new populations could be considered.
Action targets: 6. Recovery solutions trialled
Action type: Ex situ conservation
Duration: 3-5 years
Scale of Implementation: 1 site
High priority sites:
Comments: The major problem with this proposal is that we do not have possible recipient sites in England but some do exist in Scotland. Semer Water is a nearby lake but has poor water quality, notable high levels of phosphates, which are inimical to charophytes that are the main larval habitat at Malham.
Key Action 3
Proposed Action: Provide a report on the likely impact on the Charophyte beds of proposed water level management at Malham Tarn.
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 1 year
Scale of Implementation: 1 site
High priority sites: High priority
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.