Beaver wetlands become biodiversity hotspots for pollinators

Across quiet streams and forest edges, beavers work without an audience. Their dams slow rivers, flood fields, and turn farmland into pools of new life. These changes do more than shape the land.

According to new research from the University of Stirling, beavers also create some of the best habitats for pollinators. Where humans dig ponds, beavers build wetlands that buzz with energy.

Beavers build better wetlands

Researchers compared beaver-made wetlands with man-made ponds in rural Scotland. The difference was clear.

Beaver wetlands had 29 percent more hoverfly species, 119 percent more individual hoverflies, and 45 percent more butterflies. Human ponds, though still valuable, couldn’t compete.

Patrick Cook, the study’s lead author, said that most funding still goes to human pond creation.

“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,” noted Cook.

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

The research revealed that beaver wetlands support fast-growing flowering plants. These plants recover quickly after disturbance and produce more blooms, drawing in hoverflies, bees, and butterflies.

Human ponds, on the other hand, were dominated by tougher, slow-growing species that offered fewer flowers.

Why pollinators need help

Pollinators are in crisis. In the United Kingdom, 80 percent of butterfly species are shrinking in number or range. Hoverflies and bees face similar threats from pesticides, habitat loss, and climate change.

“Pollinators, such as bees and butterflies, are undergoing widespread and dramatic declines in the size of their populations,” said Cook.

“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.”

The study offers a hopeful path. Beavers, by simply living their lives, build places that help these insects survive. Their wetlands give hoverflies standing water rich in decaying plants – perfect for breeding.

For butterflies, the open, sunny clearings near dams provide nectar-rich flowers almost all summer.

Studying beaver-made wetlands

The team worked in six wetlands in Perthshire. Three had been shaped by beavers, and three were human-built. Each site was visited six times between May and August 2023.

The researchers counted bees, hoverflies, butterflies, and day-flying moths. They also recorded every flower visited.

Beaver wetlands had hundreds more flower interactions. Hoverflies made most of the visits – over 60 percent. Butterflies followed, feeding on plants like Cirsium arvense and Ranunculus lingua.

At the human ponds, bees dominated instead. This showed how habitat type shapes who comes to feed and how often.

Cook noted that hoverflies are often overlooked. They visit flowers frequently, travel long distances, and even help control pests as larvae.

Hoverfly abundance in beaver wetlands suggests that these areas could boost pollination and pest management at the same time.

How beavers shape nature

Beaver activity constantly changes its surroundings. Water levels rise and fall, trees fall into pools, and fresh vegetation takes root.

These shifts create an ever-changing patchwork of plants and open space. Pollinators thrive on that variety. Where people see mess, insects find opportunity.

Cook noted that the research adds further important evidence of the beneficial effects of beaver wetlands for wildlife, in this instance pollinators.

“If we want to realize 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,” said Cook.

“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,” added Professor Nigel Willby.

Wetlands thrive with beavers

The study proved that beaver wetlands match or exceed the biodiversity value of artificial ponds. They create food, shelter, and breeding sites for multiple pollinator species without human effort.

Sophie Ramsay, manager for Bamff Wildland, where part of the research took place, called the results encouraging.

“This brilliant new research shows once again that beavers are vital to the agricultural landscape as well as to biodiversity in general,” noted Ramsay.

The findings highlight the need to rethink how conservation funding is spent. Beavers don’t just build dams. They build resilience. By shaping natural wetlands, they restore habitats that farming and drainage once erased.

The study is published in the Journal of Applied Ecology.

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