Agabus undulatus
Key Details
| Taxonomic Groups: | Invertebrate > insect - beetle (Coleoptera) > Water beetle |
| 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: | Agabus undulatus |
| UKSI Recommended Authority: | (Schrank, 1776) |
| 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: | Post-1980 records come from around 19 hectads and it has been rediscovered in Herefordshire, but A. undulatus remains very rare outside the Brecks and Fens and has been lost from much of its historic range (Foster et al, 2016). It is believed to be restricted to single sites in the north and west of England, so that loss of these populations would result in a strong contraction in its English range. This species is unlikely to recolonise sites from which it is lost naturally as it may be flightless. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Agabus undulatus may be flightless and is unlikely to return naturally once lost from a site. It is a distinctive species, so the marked decline in distribution is likely to be real. However, its ability to persist in modified water bodies (e.g. Fenland drains) makes it less vulnerable than other relict-fen species. Actions should therefore focus more on monitoring than on specific interventions at this stage. The isolated sites in Herefordshire and the City of York are inherently more vulnerable than those in the Fens and East Anglia and require regular monitoring, which may identify appropriate habitat management measures (the York population appears to have increased significantly in response to a reduction in shade, for example). |
| 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: | A. undulatus can survive in IDB ditches and may benefit from improved management for biodiversity but its very localised distribution means that any management needs to be precisely targeted. This species is likely to benefit from landscape-scale wetland restoration projects in the Fens (e.g. Great Fen Project, Wicken Fen expansion). |
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: | Agabus undulatus can be readily identified in the field (thus avoiding the need to remove large samples of beetles) and can be detected by hand-netting. Its also likely to have some capacity for dispersal into connected habitats (e.g. via ditch systems). This makes it a useful indicator (or flagship) species to monitor the success of wetland re-creation projects within its current range. Ad hoc recording as part of GB water beetle recording scheme (Balfour-Browne Club/Aquatic Coleoptera Conservation Trust). Several surveys of Fenland drains have been completed recently under the aegis of Cambridgeshire Acre and Cambridge University. These have added to and updated records of A. undulatus. The sole northern population, the last of several in the Vale of York, was reduced to very small numbers at one site. Loss of that population would have led to a severe contraction in the species' English range. Habitat management has greatly increased the population, making it more resilient. |
Key Actions
Key Action 1
Proposed Action: Survey aquatic macroinvertebrates of ponds and ditches on restored/re-created wetlands in the Fens, using Agabus undulatus as a flagship species.
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Status survey/review
Duration: 1 year
Scale of Implementation: Unknown
High priority sites: Great Fen, Wicken Fen extension areas, Willow Tree Fen Lincs WT reserve, RSPB Ouse Fen reserve
Comments: Appropriate wetland re-creation sites in Lincolnshire, Cambridgeshire, Norfolk and Suffolk.
Key Action 2
Proposed Action: Monitor York and Herefordshire populations at 5 year intervals to ensure species remains present and habitat is in favourable condition. Make recommendations for habitat management where appropriate.
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Status survey/review
Duration: >10 years
Scale of Implementation: ≤ 5 sites
High priority sites: Naburn Marsh SSSI (York), Hereford site tbc
Comments: Relevant to 2 sites. These two outlying populations are important to maintaining the range of this species in Great Britain. Both are amenable to monitoring. Repeat at 5 year intervals.
Key Action 3
Proposed Action: For all protected sites with post-2000 records, advise site managers on the presence and requirements of this species in consideration of SSSI and nature reserve management, especially pond restoration and water level control. Consider opportunities for listing this species as a site 'feature' (e.g. review of SSSI citations).
Action targets: 5. Remedial action identified
Action type: Advice & support
Duration: 2 years
Scale of Implementation: National
High priority sites: All known 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.