Water Vole (Arvicola terrestris)

Species Description

 

The water vole is a small semi-aquatic mammal that uses a wide range of fresh-water habitats. Important habitats for water voles within Northamptonshire include rivers, streams, ditches, ponds, canals, marshes, reedbeds, fens, gravel pits, lakes and reservoirs. The water vole is mainly herbivorous, feeding on grasses, sedges and rushes, with the predominant food being the common reed. Water voles excavate burrows in the riparian zone, with entrances usually being just above or below the water level, and sometimes on the top of the bank.

The water vole has suffered a serious decline across Britain in recent years, and although the decline in Northamptonshire has been lower than the national average, this species is of critical concern.

Water Voles are thought to remain in only a few isolated pockets in Northamptonshire. The only remaining colony that could be described as a stronghold exists on the northern edge of Wellingborough, but the persistence of this requires more recent confirmation. Other sporadic sightings have occurred in the past 5 years, which suggests that a few scattered individuals may still be surviving elsewhere.

Current UK Status and Trends

On average 11.21% of sites across Britain were positive in 1996-98, representing a loss of 69.63% occupied sites since 1989/90.

Estimated Current Northants Resource

26% of surveyed sites in the Anglian region contained water voles in 1996-98, representing a loss of 58.82% over 8 years. Occasional new records occur, but old records become unreliable.

Progress Towards BAP Targets 2002-2007

Swanspool Brook designated as a County Wildlife Site because of the presence of water voles.

Lead Partner

The Wildlife Trust

Main Issues and Threats

  • Predation by American mink (Mustela vison).
  • Destruction of burrows and bank-side habitat by insensitive dredging and re-profiling methods.
  • Reduction in suitable bank-side habitat caused by inappropriate management (poaching by stock, overgrazing, intensive mowing etc) or loss to development.
  • Non-specific pest control procedures accidentally affecting water voles or misidentification of water voles as brown rats resulting in targeted pest control.
  • Isolation of small populations causing reduced mobility and low genetic diversity.

General Strategy

  • Promote suitable management of riparian habitat, funded primarily through the Countryside Stewardship Scheme (Advice can be provided by The Wildlife Trust, RNRP or FWAG).
  • Suitable management involves retaining a patchwork of vegetation along banks, with cut and uncut sections. Vegetation should only be cut on one bank per year, and only between October and March. Riparian buffer strips should be created, with no grazing, cultivation or spraying within 6 m of the watercourse.
  • Refer to best management practices when undertaking any engineering or habitat work.
  • Habitat restoration across farmland at the catchment scale to include wetland creation, sympathetic ditch management, and use of riparian buffer strips.
  • Creation of corridors of suitable habitat adjacent to existing colonies to enable populations to increase in size and range.
  • Strategic mink control based on key site conservation.
  • The specific target areas are Swanspool Brook between Wellingborough and Mears Ashby, Barnwell Brook through Barnwell, and RAF Croughton near Brackley.

Associated BAP Habitats

  • Eutrophic Standing Waters
  • Ponds
  • Reedbed
  • Rivers and Streams

Specific Management Required for Associated Habitats

Species

Management Prescriptions

Key Sites

Eutrophic Standing Waters

Retain a patchwork of vegetation along banks, with cut and uncut sections. Vegetation should only be cut on one bank per year, and only between October and March. Riparian buffer strips should be created, with no grazing, cultivation or spraying within 6 m of the water.

Canals and fishing lakes.

Ponds

As for Eutrophic Standing Waters.

Unknown

Reedbed

Establish high edge/reed ratios and healthy fish populations.

Nene Valley reedbeds.

Rivers and Streams

As for Eutrophic Standing Waters.

Small, slow flowing streams and ditches.

Targets

Target Code

Target Type

Target Description

Target Units

Northants Baseline Resource

Target

By

Unit Cost £

Total Cost £

NOR_WAV_T1

Maintain Extent (Range)

Maintain the current range (2 occupied 10km squares) of water vole in Northamptonshire.

Occupied 10 km Squares

2

No Net Loss

2015

   

NOR_WAV_T2

Expansion (Range)

Achieve an increase in range by 1 new occupied 10km square in the county by 2015.

Occupied 10 km Squares

2

3

2015

   

Actions

Action Code

Action Description

Lead Partner

Support Partner(s)

Related Target

NOR_WAV_SU_A1

Carry out annual surveys on the last known water vole positive sites.

The Wildlife Trust

 

NOR_WAV_T1

NOR_WAV_SU_A2

Collate incidental records and plan extended surveys for 2008/9 based on these.

The Wildlife Trust

Environment Agency

NOR_WAV_T1

NOR_WAV_SU_A3

Encourage the formation of a water vole conservation group to take forward the survey program.

The Wildlife Trust

Environment Agency

NOR_WAV_T1

NOR_WAV_SP_A4

Designate all water vole positive sites as LWS.

The Wildlife Trust

Environment Agency

NOR_WAV_T1

NOR_WAV_CA_A5

Produce management plans for all known water vole sites by 2009, and update if new sites are identified.

Environment Agency, British Waterways

The Wildlife Trust

NOR_WAV_T1

NOR_WAV_CA_A6

Produce, publicise and distribute a best practice management leaflet by 2009 for landowners who have water voles on their land.

Environment Agency

 

NOR_WAV_T1

NOR_WAV_CA_A7

Produce, publicise and distribute a best practice leaflet for engineering works on watercourses by 2009.

Environment Agency

 

NOR_WAV_T1

NOR_WAV_SM_A8

Carry out natural mink control by encouraging the spread of otters into areas where water voles are still found.

All

 

NOR_WAV_T1&2

NOR_WAV_HS_A9

Retain and improve bank side habitat adjacent to known and historical water vole sites, through agri-environment and other schemes where appropriate, to provide protection and encourage spread.

FWAG, RNRP, British Waterways (canals)

Environment Agency, The Wildlife Trust

NOR_WAV_T2