Beaver-created wetlands increase pollinator numbers, boosting biodiversity, according to new research by the University of Stirling.

The study compared the pollinators found around wetlands made by beavers to those found around human-created ponds.

It shows, for the first time, that beaver-created wetlands are home to greater numbers of hoverflies and butterflies than human-created equivalents.

The research found that beaver-created wetlands showed a 29% increase in hoverfly species, 119% more hoverfly individuals and 45% more butterflies than those that were artificially created.

Hoverflies play a vital role in pollination, while butterfly populations are suffering from an ongoing decline - with 80% of species showing either a drop in population, or decrease in the number of areas where they are found.

Study lead Patrick Cook, PhD researcher at the University of Stirling’s Faculty of Natural Sciences and Senior Ecologist at Butterfly Conservation, hopes that beaver wetlands will now be viewed as a scalable nature recovery strategy to reverse the decline of pollinators - but has warned that landowners need to be incentivised.

He said: “Pollinators, such as bees and butterflies, are undergoing widespread and dramatic declines in the size of their populations. This has negative effects on the delivery of pollination, but it is also leading to the loss of some of our most charismatic species from the countryside.

“We urgently need methods to reverse these declines.

“Currently, in the United Kingdom, most agri-environment subsidy schemes support human pond creation, with little financial incentive for landowners to accommodate beaver wetlands - despite the potential boost in pollination services.

“This position needs to change if we are to benefit from the buzz, flutter and hum of pollinators that beaver wetlands promote.”

The study also showed that beaver wetlands diversify the flower foraging opportunities for pollinators, illustrating the important role they can play in boosting pollinator numbers within agricultural landscapes.

Reintroducing beavers is a well-known and increasingly popular way of creating habitat for wildlife, as beavers make wetlands by building dams and felling trees.

Beavers have well-documented benefits for aquatic wildlife but understanding of the impacts they have on land-based wildlife, such as pollinators, remains limited.

Researchers surveyed land around the edges of beaver wetlands and human created ponds in 2023, counting species and individuals of bees, butterflies, hoverflies and day-flying moths.

They also recorded any interactions between these groups and flowers, with the pollinator surveys repeated six times from May to August at Bamff Wildland, a rewilding estate in Perthshire, and two neighbouring private farms.

Researcher Cook, who also led a recently published Butterfly Conservation study into the response of moths to woodland expansion, added: “Our work adds further important evidence of the beneficial effects of beaver wetlands for wildlife, in this instance pollinators.

“If we want to realise these benefits, we need to go beyond removing dams and incorporate these wetlands fully into agri-environment schemes to support landowners with beavers on their land.”

Professor Nigel Willby, Professor of Freshwater Science at the University of Stirling, said: “On occasion there may be valid reasons to remove a beaver dam. But we should remember that for every beaver dam removed a beaver wetland dies, along with a multitude of attached benefits, including for pollinators."

Sophie Ramsay, manager for Bamff Wildland, commented: “This brilliant new research shows once again that beavers are vital to the agricultural landscape as well as to biodiversity in general.”

The study, Beaver wetlands create a buzz and a flutter for pollinators, was published in the Journal of Applied Ecology, and was funded by the NERC Iapetus programme - a Doctoral Training Partnership funded by the Natural Environment Research Council (NERC) that is focused on environmental sciences.

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