Protecting water voles

Water voles are the UK’s fastest declining mammal, due to habitat loss and predation by the non-native American mink. In 2007, Essex Wildlife Trust launched the Essex Water Vole Recovery Project to ensure the water vole would not be lost in Essex.

Between the first Essex water vole survey in 1990 and 2007, water voles had declined from 80% of their historic sites, to just 17%. By 2004 no surviving colonies could be found on the main channels of the River Colne and by 2005 they had disappeared from the River Roding. By 2006, Essex’s water vole population was largely confined to the coast, with only a few fragmented colonies remaining in isolated headwaters and tributaries of its main rivers.

The Essex Water Vole Recovery Project was launched in 2007, starting with a mink control programme, which contributed to the subsequent re-colonisation of water voles in streams, brooks and ditches in north-east Essex.

To buffer this recovering population, water voles were reintroduced on the River Colne alongside a five year effort to control mink. The joint project between Essex Wildlife Trust and DP World translocated more than 500 displaced water voles from the Thames and another smaller colony from near Weald Brook to the Colne between 2010 and 2012. This is now the largest water vole translocation ever attempted in the Eastern Region, with over 600 voles released along 6 miles of river from Halstead to Fordham. Surveys in 2013 revealed that the population had dispersed widely throughout the catchment, contributing to the natural re-colonisation of over 500 km2 in north-east Essex.

In the south-west of the county, on the border between Essex and Hertfordshire, 188 water voles were released at Thorley Wash nature reserve on the River Stort in 2015. The joint project between Essex Wildlife Trust and Herts and Middlesex Wildlife Trust aims to kick-start a re-colonisation of the catchment after 8 years of successful mink control failed to result in a return of a natural water vole population. Habitat improvements and two nearby Essex Wildlife Trust nature reserves, Rushy Mead and Sawbridgeworth Marsh has allowed water voles to disperse into these areas and it is hoped this will result in a catchment scale re-colonisation, emulating the success of the River Colne project.

Elsewhere in the county however, water voles are still functionally extinct throughout whole catchments with only tiny fragmented colonies persisting in remote locations or upstream tributaries. Coastal populations still remain stable and if future conservation efforts can be maintained to secure a safe environment for water voles than these colonies may be able to repopulate other parts of Essex as they have in the current Essex Water Vole Recovery Project area.

You can help Essex Wildlife Trust monitor water voles as part of RIVERSEARCH, which has trained more than 250 volunteer surveyors to search for otters, water voles, water shrews and harvest mice. Courses are held each Spring, prior to the breeding season and are open to everyone, regardless of previous experience or knowledge. Essex Wildlife Trust are also looking for volunteers to adopt a monitoring raft which can alert us to the early signs of mink arriving. Full training and equipment will be provided.