THEY are notorious for gnawing down trees, destroying river banks and blocking streams with their impenetrable dams.

But it appears that beavers may, in fact, be key to turning the tide on the erosion of vital wetlands known as the "kidneys of the landscape".

Experts examining an area of Tayside over 12 years found the rodents provided an "innovative, hands-off" solution to the problem of wetland loss.

The study, by researchers at the University of Stirling, was carried out on a wetland in Tayside originally drained for farming

Over a period of 12 years local plant richness rose by 46 per cent and the total number of different plants recorded more than doubled.

Species which normally grow in areas with high nitrogen levels decreased, indicating a return to more natural soil conditions.

Professor Nigel Willby, of Stirling University, said: “Wetlands are tremendously important environments for biodiversity. They also serve to store water and improve its quality – they are the ‘kidneys of the landscape’.

“However, the world’s wetlands are disappearing at an alarming rate. The latest estimates suggest that almost two-thirds have been lost since 1900.

“Beavers are renowned for their engineering skills, like dam building, and are now being considered as tools for restoring wetlands.

“They have been reintroduced widely, including in Scotland, partly for this purpose and our findings demonstrate the surprisingly large benefits they can bring to biodiversity.”

The study, partly-funded by Scottish Natural Heritage (SNH) and published in the international journal Science of the Total Environment, is said to be the first to fully measure these environmental benefits over time.

Between 2003 and 2015, the beavers constructed 640ft of dams, 1640ft of canals and an acre of ponds, surrounded by a mosaic of vegetation which increased in complexity by 71 per cent.

Stirling co-author Dr. Alan Law said: “We know lots about the benefits of beavers in natural settings but until now we did not know the full extent of what they can achieve in present-day landscapes where restoration is most needed.

“Wetland restoration normally involves raising water levels, for example by ditch blocking, plus mowing or grazing to maintain diversity.

“Beavers offer an innovative, more hands-off, solution to the problem of wetland loss – provided their populations are suitably managed and protected.

“Seeing what beavers can do for our wetlands and countryside highlights the diverse landscape we have been missing for the last 400 years.”

Beavers were reintroduced to Scotland last year, 400 years after they were hunted to extinction in the UK.

SNH will use the findings of the study to inform discussions about how the animal can be integrated within the Scottish countryside.

The report states: “Our study illustrates that a well-known ecosystem engineer, the beaver, can with time transform agricultural land into a comparatively species-rich and heterogeneous wetland environment, thus meeting common restoration objectives.”

The latest findings follows the team’s earlier research which demonstrated how beaver dams can stabilise water flows, reducing downstream flood risk and water pollution.