Efforts by Aberdeen experts to save the water vole – one of the UK’s most critically endangered species - have taken a huge step forward after a successful eradication of alien American mink from high priority areas in the Cairngorms and North East of Scotland.
Water voles have now returned to certain areas where they had been decimated by American mink predation; the main reason for their massive declines across the UK.
The widespread presence of mink across the UK means that local eradication had been deemed impossible in the past and was usually only attempted on islands.
However, a four year project led by researchers from the University of Aberdeen has resulted in the complete removal of American mink from the Ythan catchment area in Aberdeenshire; showing that clearing entire river systems is possible.
They believe they have developed an effective approach to mink control that can now be applied over large areas.
The hope is that the continued success of the project could eventually lead to the eradication of mink across the entire North East of Scotland.
Listed in Scottish Natural Heritage's (SNH) Species Action Framework, the water vole is also a priority species in the UK Biodiversity Action Plan.
Once a common sight along our rivers and burns and the inspiration for "Ratty" in Wind in the Willows, following escapes and releases of mink from fur farms in the 1970's, they became confined to a few patches of habitat high in the uplands.
Researchers say the key to success has been a community based approach to mink control. Using local volunteers, supported by project officers, the initiative has successfully controlled American mink using monitoring rafts - floating structures containing a clay pad on which their paw prints can be easily seen.
Such an approach has been shown to have numerous advantages over traditional methods. Large areas can be monitored and recolonisation of controlled areas by mink quickly detected. The success of the project has been partly attributed to the fact volunteers are motivated by a desire to protect local biodiversity and feel they can make a difference.
The project, funded by conservation charity People's Trust for Endangered Species and Scottish Natural Heritage and part of the North East Scotland Biodiversity Action plan, shows that the war can also be won in three further catchment areas where similar work is currently ongoing; the Rivers Dee, Don and Spey in the Cairngorms.
Valuable populations of water voles exist in the headwaters of these rivers making them priority areas for mink control. Significant reductions in mink numbers have already been recorded and eradication from these catchments is achievable within the next three to five years.
Professor of Ecology at the University of Aberdeen Xavier Lambin, who has led the project said: "The results of the project have shown that is possible to turn back the tide of this invasive species of American mink over a very large geographical area, and thereby restore conditions for the survival and recovery of water voles.
"Plans are in place to merge the ongoing conservation work within the Cairngorms National Park and in the Ythan catchment area with the aim of eventually tackling the whole of the North East of Scotland. The approach to the issue is cost effective in that we are essentially using people power to manage the situation. With the strength of public support behind the project we believe there is no spatial limit as to what can be achieved in using this method."
Jamie Urquhart, North East Scotland Water Vole Conservation Officer based at the University of Aberdeen added: "The volunteers are essential to the continuation and expansion of the project. Without their support the project would be limited by the range of effective control offered by one individual - the Project Officer. The success of the project has been down to the fact people care about biodiversity in their local area and want to support moves to conserve the natural environment which surrounds them."
It is hoped that the development of the project across the North East will preclude any recolonisation of upper sections in the catchments which have already been fully or partly eradicated and also eliminate mink from adjacent catchments, maximising conservation benefits to native species.
Isla Martin area officer with Scottish Natural Heritage said: "This is not the end of the plight of the water vole, but it is the end of a very important first step. We will continue to fund the project until this phase is complete in 2010 and look forward to being part of this pioneering work in the future."