Beavers should be embraced as key allies in the fight against biodiversity loss according to scientists at the University of Stirling, after new research revealed the significant ecological benefits the animals bring to wetland habitats.

Beaver populations across Europe and North America are recovering from historically low levels after being hunted to near extinction.

Across Britain, the species are being reintroduced because of their positive impact on biodiversity and their role in managing river flows. However, these efforts are often met with opposition from landowners.

Now a new study led by Dr Alan Law of the University of Stirling's Faculty of Natural Sciences has shown that, on average, beaver-created wetlands had 19% more species than other types of wetland.

The research team now believe that their findings could hint at the scale of past biodiversity loss associated with a lack of beaver-dependent wetlands, while offering a glimpse of what could now be gained from their widespread reintroduction.

Study lead Dr Alan Law, a Lecturer in Nature-Based Solutions, said: “Biodiversity is good for humans as we depend on it, whether directly or indirectly, for essential resources such as food and clean water. A species such as beaver that improves biodiversity via restoring our environments for free should be welcomed with open arms.

“We need to learn to live alongside beavers again, accept that parts of our environment are under new hydrological management by an experienced engineer, and provide time and space to fully realise the wider benefits that come from this.”

The study took place at 18 different wetland sites in Evo, Finland, nine of which were created by beavers.

Using eDNA technology which detects organisms by capturing and sequencing tiny traces of genetic material they shed into their environment, the team were able to establish the number of invertebrates (including true flies, river flies, worms and crustaceans) and vertebrates (amphibians, fish, birds and mammals) by analysing water samples from the locations.

In-situ surveys were also used to study aquatic plant and water beetle species.

A total of 380 different species were detected across the two wetland types, with 105 species being restricted to beaver wetlands and 65 to those without beavers, the rest being shared.

The increase was most notable for plants, beetles and true flies, while plant functional diversity - the way plants grow, reproduce and use resources - was 55% higher in beaver wetlands compared with control sites.

Study co-author Professor Nigel Willby added: “The planet is experiencing a biodiversity crisis. To stop biodiversity loss, it’s not enough to just protect and conserve land - we also urgently need to restore the natural processes that create and maintain habitat, and this includes the ecosystem engineering activities of beavers.

“Beavers physically reshape landscapes by selectively felling trees, digging canals, grazing plants and building dams on small streams. The unique combination of shallow water, dead or fallen trees, woody dams and grazing or digging by beavers themselves makes their wetlands ultra-biodiverse, but also impossible to mimic.”

Wetland landscape transformation by beavers: responses of biodiversity and functional indicators at multiple scale was published in Landscape Ecology.
Work was led by the University of Stirling in partnership with the University of Helsinki, University of Hull, Aquatic Coleoptera Conservation Trust and UK Centre for Ecology and Hydrology.

Fieldwork in Finland was funded by the Carnegie Trust for the Universities of Scotland. Funding from Biotechnology and Biological Sciences Research Council (BBSRC) allowed a follow-up workshop in Finland for all authors to complete the first manuscript draft. Natural England and Scotland’s Hydro Nation Scholars programme provided further support.