BEAVER-BUILT ponds are far more biodiverse than other wetlands, new research from the University of Stirling has revealed.

The study, published in Philosophical Transactions of the Royal Society B, surveyed aquatic plants and beetles in 20 wetlands in central and southern Sweden – 10 created by beavers, and 10 that were not.

The team, from Stirling’s Faculty of Natural Sciences, found 33 per cent more plant species and 26 per cent more beetles in the beaver-created wetlands.

Professor Nigel Willby, who worked on the research with Dr Alan Law, explained: “We found that the wetland types were very different to each other, with small-scale disturbances by the beavers – such as tree cutting and plant grazing – creating a complex, mosaic-like environment. This significantly benefits biodiversity – with a third more plant species and a quarter more beetles.

“These findings highlight the importance of pond creation by beavers in rewilding our landscapes, and for sustaining aquatic biodiversity – even in areas that are naturally rich in other wetlands.

“Put simply: anyone can build a pond – but if you want a really great pond, ask a beaver.”

Beavers are the only animals that can engineer the environment that they live in – using sticks to build dams, behind which ponds form. Beavers do this to raise water levels to avoid predators, such as wolves and bears: however, other animals also benefit from their work.

Professor Willby continued: “Many organisms benefit from the ponds that form behind beaver dams – including mammals, amphibians, ducks, insects and plants – and this has earned beavers the tag of ‘ecosystem engineers’.

“Partly to exploit this natural, free ecosystem, beavers have been widely reintroduced to their native range across the northern hemisphere – with the Eurasian beaver introduced to more than 25 countries throughout Europe.

“This research justifies the reasons why beavers have been reintroduced; they create unique habitats that massively benefits local wildlife. Humans are not capable of replicating this.

“We can say their reintroduction has been a qualified success. While we do not see beavers as a complete panacea, they do bring many benefits – including improving water quality, reducing the effects of floods and buffering the effects of droughts. These are all problems that society is going to face in the coming decades and beavers could help in providing a solution.”

The study, Rewilding wetlands: beaver as agents of within-habitat heterogeneity and the responses of contrasting biota, was a collaboration between Stirling, the Swedish University of Agricultural Sciences and the Aquatic Coleoptera Conservation Trust.

The research was funded by the Carnegie Trust, a University of Stirling Horizon studentship, and Swedish Research Council Formas.