Brown Diving Beetle (Agabus brunneus)
Key Details
| Taxonomic Groups: | Invertebrate > insect - beetle (Coleoptera) > Water beetle |
| Red List Status: | Vulnerable (Not Relevant) [VU(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: | Agabus brunneus |
| UKSI Recommended Authority: | (Fabricius, 1798) |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Foster, 2010 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | A range of 8 post 1980 hectads (Foster et al, 2016). This species is at the extreme edge of its global range in England so 'naturally rare' but its dependence on hyporheic habitat in small streams makes it particularly vulnerable. This vulnerability could be reduced by targeted conservation actions. Agabus brunneus is a S41 'species of principal importance'. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Agabus brunneus is a highly localised habitat specialist so loss of any single (meta)population would increase national extinction risk. The species is confined to England in a GB context, so risk is not mitigated by populations elsewhere. It has limited climatic tolerances and is believed to be poorly dispersive, so unaided recovery is unlikely. |
| 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: | Untargeted habitat creation is unlikely to be beneficial due to this species' very restricted range and habitat specialism. Also, its dispersal capability is likely to be limited, so actions need to be targeted on specific sites and/or stream catchments. |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 3. National Monitoring Plan agreed and implemented |
| Recovery potential/expectation: | Unknown |
| National Monitoring Resource: | Opportunistic - insufficient |
| Species Comments: | The distribution of A. brunneus is reasonably well known due to survey work undertaken by the Aquatic Coleoptera Conservation Trust as part of the UK SAP. Targeted surveys under UK SAP, mainly in 2001. Ad hoc recording as part of GB water beetle recording scheme (Balfour-Browne Club/Aquatic Coleoptera Conservation Trust). |
Key Actions
Key Action 1
Proposed Action: Review potential threats and mitigation measures for each site or stream catchment where A. brunneus has been recorded post-1990, focussing on risk factors such as anthropogenic sediment inputs, pollution and disruption of groundwater hydrology.
Action targets: 7. Best approach adopted at appropriate scales
Action type: Pressure mitigation
Duration: 1 year
Scale of Implementation: Unknown
High priority sites: The species is concentrated in South Hampshire, Dorset and West Cornwall (Foster et al, 2016). The New Forest NP would be a natural starting point but W Cornwall (SW54/64/74) also needs to be a focal point to protect its distribution.
Comments:
Key Action 2
Proposed Action: Implement recommendations arising from Action A1
Action targets: 5. Remedial action identified
Action type: Pressure mitigation
Duration: 6-10 years
Scale of Implementation: National
High priority sites: Priority sites will depend on the findings of A1 (see high priority sites column for Action 1).
Comments:
Key Action 3
Proposed Action: Investigate genetic relationships between the Cornish and New Forest/Dorset populations, and between these and Continental European populations. Understanding genetic population structure would shed light on the mobility of this species, helping prioritise conservation actions. It may also be necessary to inform re-introductions in future.
Action targets: 1. Taxonomy established
Action type: Scientific research
Duration: 2 years
Scale of Implementation: Unknown
High priority sites:
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.