Water Vole Species Action Plan

The water vole was formerly common along the banks of rivers, streams, canals, ditches, dykes, lakes and ponds throughout mainland Britain. However since the 1980s there has been an accelerating loss of sites and this appears to have continued into the 1990s.  The water vole is one of twelve Priority Species of British terrestrial mammals identified in the Biodiversity Steering Group Report as needing conservation action.

Since 16th April 1998, the water vole has received limited legal protection through its inclusion on Schedule 5 of the Wildlife and Countryside Act 1981 (as amended) in respect of Section 9(4) only.  This section of the Act protects the water vole's places of shelter or protection, but not the animal itself.

This limited protection is in recognition that the mammal's significant decline has resulted from habitat loss and destruction rather than direct persecution.  It is an offence to:

• damage or destroy or obstruct access to any structure or place which water voles use for shelter or protection;
• disturb water voles while they are using such a place.

Licences are available from Scottish Natural Heritage (SNH) to allow the following:

• ringing or marking of the wild animals;
• conserving or re-introducing the wild animals to a particular area.

The Scottish Executive Environment and Rural Affairs Department (SEERAD) issues licences only to prevent the spread of disease or serious damage to any form of property or fisheries.  There is no provision for licensing the intentional destruction of water vole burrows for development or maintenance operations.

Ecology and Management

The water vole is the largest British member of the vole family, being frequently mistaken for a rat.  They are predominantly herbivorous, primarily feeding on lush waterside vegetation of grasses, sedges, rushes and reeds.  227 plant species have been identified at water vole feeding stations (Strachan and Jeffries 1993).  In the winter months, roots and bark of shrubs and trees form an important part of the diet together with rhizomes, bulbs and roots of herbaceous species.  They need to consume up to 80% of their body weight daily.  The best sites show layered bankside vegetation with tall grasses and stands of willowherb Epilobium spp., purple loosestrife Lythrum salicaria, meadowsweet Filipendula ulmaria and nettles Urtica spp., often fringed with thick stands of rushes Juncus spp., sedges Carex spp. or reeds Phragmites australis.

Water voles are found in most freshwater habitats in Scotland, ranging from slow flowing lowland ditches to head streams up to 620m altitude. Recent work has shown them to be more numerous in upland and peatland habitats than formerly thought.  They show no morphological adaptation for aquatic life and some communities may live a terrestrial life, burrowing in the soil, as occurs over much of their range in Europe and Russia.

In waterside populations each vole utilises a series of burrows dug into the riverbank where the soil permits; they do not normally use gravel beds or rock strata.  These comprise nest chambers, inter-connecting tunnels with many entrances, and bolt holes consisting of short tunnels ending in a single chamber.  Nest chambers occur at various levels in the steepest part of the bank and the nest consists of shredded grass.  Occasionally the animal will weave a nest into the bases of sedges and reeds.  Sites that suffer total submersion during protracted periods of winter flooding are untenable but populations may migrate seasonally to avoid flooding of burrow systems, to sites where this is not so severe.  The amount of bankside and emergent vegetation cover is very important, with the best sites offering a continuous swathe of tall and luxuriant riparian plants.  Sites excessively shaded by shrubs or trees are less favoured.

Breeding lasts from April to October and the females may produce 2 to 5 litters annually, each of 5 to 8 young.  Early-born young may breed that autumn, but most reach sexual maturity after their first winter. Exceptionally, water voles may survive three winters but mortality is thought to be very high among dispersing juveniles.

Water voles can be detected by the presence of runways up to 9cm wide at the edge of densely vegetated banks, and burrows and latrines containing cylindrical faeces with blunt ends.  At low population densities these signs may be difficult to find.

UK Biodiversity Context

The UK Action Plan has the following objectives:

• maintain the current distribution and abundance of the water vole in the UK.
• ensure that water voles are present throughout their 1970s range by the year 2010, considering habitat management and translocation of populations to areas from where they have been lost.

• insensitive river engineering, bank protection and maintenance works (e.g. de-silting operations) can damage habitats.
• urbanisation of floodplains has led to direct habitat loss and containment of the river channel.
• heavy grazing pressure from domestic livestock denudes riparian vegetation and may make sites untenable for water voles by poaching and trampling the banks.
• a substantial fringe of waterside vegetation is essential for water voles and this can be dramatically reduced through inappropriate management.  Bank mowing and vegetation clearance may also put the water vole at risk from predators.
• population fragmentation resulting from isolated habitats or local extinction may accelerate the rate of decline.
• fluctuations in water levels affect food, cover and burrows.
• predation by American Mink Mustela vison appears to be accelerated by poor riparian habitat.  The impact of the mink appears to be less where there is dense cover such as expansive wetlands or interconnecting waterways and ponds, or amongst reedbeds.  Locally, domestic/feral cats are predators of this animal.
• where water voles occur in urban situations they appear to be very tolerant of disturbance and may even occupy degraded habitats, survival chances increasing as there are few predators.
• poisoning by rodenticides, either directly or indirectly, when used for brown rat control, may be responsible for some localised extinctions, as may control operations for rabbits or moles in floodplains.
• changes in land-use and riparian habitat management have resulted in direct habitat loss or degradation, causing increased fragmentation and isolation of water vole populations.  These in turn have become susceptible to the effects of predation, especially by American Mink, which have been spreading in the absence of competitors.
• rats may pose a risk by either acting as a competitor or even as a predator of young voles.

Sympathetic management at existing sites and restoration and re-establishment of extensive areas of riparian vegetation (with perhaps selected periods of mink control) are suggested as the best mechanisms for arresting the water vole's decline and allowing recovery of the species over much of its former range.

• The Vincent Wildlife Trust is re-surveying the 2,970 sites that comprised the Water Vole survey of Britain over the period 1997-98 (survey report due in late 1999).
• In March 1997 the Wildlife Trusts launched Water Vole Watch, a national public participation survey.
• SNH are currently assessing the potential of carrying out water vole surveys in North Lanarkshire in 2000-2001, as part of a wider survey in Strathclyde and North Ayrshire.

• to arrest the decline in water vole, and to increase riparian habitats to encourage water vole population increase in North Lanarkshire (and Central Scotland).
• to restore water voles to their former widespread distribution (i.e. pre 1970's) by the year 2010.
• to ensure management of watercourses and wetland habitats which will maintain the restored population.

5. Proposals for action

Policy and legislation

• implement current protection measures and advise agencies to refer to the Water Vole Handbook (All).
• encourage recognition of all North Lanarkshire water vole sites in policy formulation for local plans and in flood appraisal or river management statements (NLC, SEPA).

Site safeguard and management

• recommend that all wetland areas and water courses are surveyed before any development or maintenance works, to minimise damage to habitats on sites both known and unknown. (NLC, SNH, SEPA)
• ensure all areas involved in flood alleviation or drainage works are surveyed before work starts and produce guidelines for contractors carrying out engineering works.  This will require recommended phasing of works (WoSW, NLC, private owners, SEPA, SNH).
• work with British Waterways to prevent destruction and disruption to habitats by canal dredging and to provide suitable banks or artificial burrow holes (NLC, BW, SWT, SNH).
• advise owners and seek to secure management agreements over water vole sites, including a systematic programme of control/trapping of American Mink, where required (NLC, private owners).

Species protection and management

• seek to reintroduce water vole to suitable (previously occupied) stretches of streams and ditches where mink are not known to occur and where access from existing population areas may be hindered by culverts or restricted by developments, as recommended by 2010 in UK Plan (SNH, private owners).

Advisory

• produce information for pest control agencies, to help prevent the use of rodenticides and herbicides in potential water vole habitat (NLC, CSCT, private firms).

Monitoring and research

• when water vole survey is published, utilise raw data to amalgamate with present records (SWT, NLC, SEPA, SNH).
• monitor what is undertaken by adjacent local authorities for the water vole in Glasgow City, East Dunbartonshire, Falkirk, South Lanarkshire and West Lothian (SWT, NLC).
• review survey of sites and assess progress in all the above actions. (SWT, SEPA).

Links with other action plans

• Habitats: Rivers and Streams and Floodplain Grazing Marsh.
• Species: Otter and Atlantic Salmon.

References

• Strachan, R. (1998) Water Vole Conservation Handbook, Wildlife Conservation Research Unit, University of Oxford.
• Strachan, R. & Jeffries, D.J. (1993). The Water Vole (Arvicola terrestris) in Britain 1989-90 - Vincent Wildlife Trust.
• Department of Environment (1995). Biodiversity: the UK Steering Group Report, Vol.2: Action Plans. HMSO.
• Plan written by Fiona Stewart Scottish Wildlife Trust. November 1999.

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