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Water Vole

What action is going on for this species?

The following will give you information on what work has been taking place through the Species Action Framework:

Species background

Why is this on the Species Action List?

The water vole satisfies criterion 1a of the Species Action Framework as a species for conservation action. 

It has suffered a significant decline, especially in the 1990s.  Management action is needed to address threats from habitat loss and, in particular, from predation by American mink, an invasive non-native species.  The water vole is a relatively high profile species and can be used as a means of highlighting the damaging effects of invasive non-native species.  Management targeted at water voles, such as mink eradication projects, benefits the wider ecosystem in which the vole lives (American mink is also on the Species Action List and actions relating to this species cross-link to the water vole).

It is a UKBAP Priority Species and is included on the Scottish Biodiversity List. The places of shelter or protection of the water vole are protected under the Wildlife and Countryside Act 1981, as amended, but not the animals themselves. This level of protection is under review and may be extended in future.

Habitat, distribution and abundance

In lowland areas, water voles occur in small slow-flowing or static burns, small backwaters, canals, ditch systems and overgrown field drains, and sometimes in intensively-farmed and urban areas.  Such watercourses are typically less than 3m wide and 1m deep and do not show extreme fluctuations in water level.  Water voles prefer sites with easily excavated soil and a steeply sloping bank profile into which they can burrow.  The best sites support a continuous swathe of tall herbaceous riparian vegetation.  Sites excessively shaded by shrubs or trees are avoided.

In the uplands, water voles are restricted to narrow moorland burns and barren peat hags on flat or gently sloping ground.  Areas with a thick layer of peat are preferred. 

The species is widely distributed elsewhere in Britain, but is now very localised due to numerous local extinctions and largely restricted to smaller watercourses and headwaters. It is also widespread in continental Europe where it commonly occurs underground well away from open water.

General ecology

Recent studies have demonstrated that Scottish water voles are genetically distinct from those further south.  The voles that colonized England and Wales following the last Ice Age originated from south-east Europe, whereas Scotland's voles are descended from migrants from northern Iberia.

Water voles live in loose colonies within a 'metapopulation'.  Each vole defends a linear territory of 30-200m during the breeding season.  The males occupy territories that are roughly twice the size of the females', often overlapping those of adjacent females.  Both sexes use their droppings in conjunction with their scent glands to mark these areas.

History of decline, contributory factors and current threats

The water vole is widely acknowledged to be one of our most threatened native mammals, having undergone a dramatic decline, particularly during the latter part of the 20th century.  The total UK population was reduced by 88% during the period between 1989 and 1996.  Factors causing loss or decline include habitat degradation and fragmentation, combined with predation by American mink.  The decline is correlated with the spread of mink across the country.

The 'Species Lead' at Scottish Natural Heritage

Robert.Raynor@snh.gov.uk Tel 01463 725000