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Exclusive: Efforts to eradicate American mink help boost population of river-residing mammal in 11 areas of country
Water voles continue to decline in their distribution across Britain but there are signs of recovery in some regions, with populations bouncing back in 11 key areas, according to a report.
The river-residing mammal, which inspired Ratty in the Wind in the Willows, has revived in number in parts of Yorkshire, Oxfordshire, Hertfordshire and East Anglia thanks to targeted conservation work.
Reintroductions, habitat restoration and, crucially, the effective eradication of American mink – the non-native predator responsible for water vole population crashes – are helping the creature recover from historic lows, finds the National Water Vole Database Project report.
The Wildlife Trusts study found that in 2006 water voles occupied 1,071 10km squares across England, Scotland and Wales. In 2022, water voles were counted in just 652 10km squares, the lowest on record and a decline in range of 39%. These declines are on top of a catastrophic 94% estimated reduction in distribution between 1900 and 1998.
The study also reveals that the area occupied by American mink between 2013 and 2022 is 308 10km grid squares smaller than their total historic extent – suggesting that efforts to reduce the non-native predator are working.
The report also identified 11 new “regional key areas” for water voles – areas greater than 35 sq km where resilient water vole populations are found. A further 30 existing regional key areas expanded in size, while 12 retained their previous size.
Ali Morse, water policy manager at the Wildlife Trusts, said: “The data is giving us a very clear message. The overall national picture is one of decline due to the destruction of natural habitats and predation by the non-native American mink. However, water vole populations will thrive when the right conditions are created. It’s heartening to see that we can still rescue Ratty, if we all plan well and coordinate our efforts.
“Water voles are mini-ecosystem engineers, rather like beavers, and they contribute greatly to healthy river ecology. Reversing their historic loss needs to be a key focus of our conservation efforts.”
Water voles move seeds around, helping maintain lush and biodiverse riverbank vegetation, while themselves providing food for native predators including stoats, pike and birds of prey such as marsh harriers.
Although 17 regional key areas declined in size and in nine places the vole population was no longer widespread enough to qualify as a regional key area, the uplift in populations in 41 areas shows conservation efforts are working.
Yorkshire Wildlife Trust’s Skerne Wetlands, a former fish farm near Driffield turned into a wetland nature reserve 10 years ago, is the fulcrum of a new regional key area in the headwaters of the River Hull.
In Hertfordshire, water vole reintroductions by Herts and Middlesex Wildlife Trust on the River Stort in 2015 and River Beane in 2022, as well as restoration works on the River Ash, have resulted in water voles expanding their range.
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Water vole populations have also recovered west of Oxford thanks to American mink control efforts and habitat enhancements working with local landowners, with Berks, Bucks and Oxon Wildlife Trust managing what is the longest-running single species conservation project in Britain.
In January this year, the Waterlife Recovery Trust, which leads mink eradication in East Anglia, announced that mink had been removed from central and eastern Norfolk and Suffolk, an area representing almost 5% of England. The mink control effort has been made more effective with “smart” traps, which alert operators with text messages – reducing animal welfare concerns and enabling more traps to be set.
Boosted by recent funding from Natural England, the trust is expanding its work to cover an area from the Thames to mid-Lincolnshire – far beyond its original area of operation. This success raises hopes that a mink-free Britain may soon be within reach.
The Wildlife Trusts are calling for the rollout of a project to identify how nature restoration funds from housing developers can be better used to enhance water vole habitats, and priority for water vole habitats within the farm subsidies that support environmentally-friendly land management.
Morse added: “Bringing back resilient populations requires a coordinated approach. We need to help populations expand from remaining strongholds, by ensuring that developers, land managers, farmers and conservationists all work in tandem.”
Water voles bounce back in key areas but distribution across UK declines
