After a 400-year absence, beavers were re-introduced to the Cairngorms National Park in December 2023 through a partnership led by the Cairngorms National Park Authority, working closely with partners, land managers and local communities. Supported by Cairngorms Connect, the first families quickly settled at RSPB Scotland Insh Marshes and Wildland Kinrara. Two years later, we spoke with Estate Operations Manager Thijs Claes to hear how one family built a dam in a location once earmarked for restoration, sparking changes the team had long hoped to see.
Soon after their release at Insh Marshes, a family of beavers built a dam in a spot already familiar to the restoration team. It was the same place they had once considered blocking to help restore natural water flow across the floodplain.
“One of the considered options we had in the past was to block the main drain because we thought it could have positive impacts,” said Thijs Claes, Estate Operations Manager at RSPB Insh Marshes. The main drain is a channel that carries a lot of the water off the floodplain and into Loch Insh. Slowing or holding water in this system could help keep parts of the marsh wet during dry summers, improving conditions for wetland birds and plants, and encouraging transition habitats to form in gradual transition zones between woodland and floodplain.
“But it’s a complex thing to do,” he explained. “It would require a lot of financial resources, hard labour, technical knowhow and licence applications, so we hadn’t been able to take this option to restore the floodplain forward yet.”
In 2024, the beavers did it themselves. And in doing so, they triggered many of the same changes the team had hoped for.
The dam’s early impact
The results came quickly. During the spring drought of 2024, the dam made a noticeable difference. “We measured it once. It was almost 60 centimetres that the water was kept higher,” said Thijs. “It didn’t raise the water level beyond what we’d normally see in winter. It just kept it there for longer, which is an important nuance.”
He explained that if people were told the water level had increased by 60 centimetres, they might rightly be concerned about impacts on infrastructure or land. But what the beavers had done was hold back the natural winter flows, buffering the effects of drought at a local scale.
“Even during the drought, that part of the reserve remained really nice and wet,” he said. “That’s good for the birds that want muddy ground to feed on and for the ducks to have some water to play around in.”
That localised change has transformed part of the floodplain. Drone photos show that what used to be a narrow, drained-out ditch now holds a long, shallow pool that extends into the marshes. “You can clearly see that it increases the diversity of habitats,” Thijs said. “We’ve not got only narrow streams anymore that drain the marshes, but we’ve got this long shallow pond with irregular edges, extruding a little bit more onto the floodplain, which is really nice.”
Reshaping woodland edges
The dam’s presence, combined with the beavers’ tree-felling, is starting to reshape the woodland edge. Instead of a sharp divide between trees and floodplain, there is now a gradually shifting zone where shrubs, flowering plants and wetter ground meet. And thanks to the beavers’ browsing, the outer edge of the woods is becoming more open, with scrubby growth and flowers filling in the gaps. “Instead of having woodlands that immediately kind of cut off and become a floodplain, they’re impacting the first ten metres or so from the woodland and creating a bit more bushy, flowery edge,” explains Thijs.
This shift is partly caused by higher sustained water levels, but also by the beavers’ habit of felling and gnawing trees. As they open the canopy and let more light in, a dense mix of shrubs, herbs and flowers begins to take over, softening the boundary between woodland and wetland. It is not an engineered edge, but a dynamic one shaped by instinctive behaviour. Over time, it may expand and retreat, depending on where the beavers focus their activity.
He explained that this kind of transition zone can support more wildlife. “That gradient from one habitat into another, that transition zone, that’s where you’ll find especially high levels of biodiversity in terms of birds, and insects like butterflies.”
While some people might see beavers felling trees and worry about woodland loss, Thijs sees it differently. He pointed out that beaver browsing often acts like coppicing. “There’s a misconception that beavers kill trees. They don’t,” he said. “Most trees survive after being gnawed. Out of 200 trees I looked at, I might have seen one that died. The rest were regenerating like crazy and growing back bushier.”
That kind of disturbance, he explained, isn’t new. “It’s something we as humans used to do – coppice woodlands and go back into a woodland every five to ten years and harvest firewood from it,” he said. “It’s a minimal disturbance that you create, which usually translates into an increase in biodiversity. That’s exactly what the beaver does.”
He also pointed out that beaver families do not keep growing endlessly. “Once you’ve got a nice settled family of, let’s say, five or six beavers, then that’s it,” he said. “The impact is not going to keep increasing because the territory is protected by that beaver family.”
Monitoring and early results
Thijs has been involved in the beaver work from the start, supporting preparation, engagement and ongoing monitoring. “We surveyed the whole reserve to see where they eventually settled, which allowed us to find the lodges and the dams,” he said. “Now we’ve put the cameras on, and we monitor them every day.”
The beavers have already had kits again this year, and there is hope that new dams will appear elsewhere on the reserve, further supporting the wetland ecosystem. “There are some locations where I hope they’re going to build a dam,” he said. “They’ll definitely have positive impacts on the hydrology that we’re trying to improve on the reserve.”
A shift in how people see beavers
While ecological changes are becoming visible, social change is more complex. Thijs has spent time speaking with crofters and farmers, and said views vary widely.
“A lot of people still aren’t fully aware of the beavers, or they’re just starting to hear about them and are quite positive,” he said. “There’s a small group promoting them. But there’s also still a strong voice of concern from crofters and farmers who are understandably wary about the changes they will make to the landscape.”
Some of those who were initially cautious are starting to change their views. “Some crofters have got beavers on their farm and are starting to embrace it,” he said. “It’s a very complicated mix of people, each under different pressures and circumstances.”
He sees the arrival of beavers as a starting point for conversations that hadn’t happened before. “They’ve definitely been a catalyst for working together with other land managers,” Thijs said. “I’m in contact more with other land managers than I used to be because there are beavers around, which is great.”
Hope for wider acceptance
Thijs hopes that as beavers spread naturally into new areas, people will begin to see that their presence does not always bring problems. “I hope more beavers pop up in the landscape, and that where people were worried about them, they see it’s actually fine,” he said. “There’s already been examples of that – where all they did was make the news. I hope more of that will happen.”
At the same time, he recognises that problems will arise in some places. “I’m also sure that in some places where they pop up, they will be a cause for concern,” he said. Burrowing for example could restrict safe access and localised flooding could cause significant financial costs to an individual landowner or interfere with the workings of a water treatment plant. “And we need to make sure that our communities and the national mitigation framework are strong, and balanced and flexible enough to deal with it pragmatically. This is crucial to keep growing wider support for these amazing animals.”
He is careful not to downplay the concerns of land managers. Many farmers and crofters, he said, are already under economic pressure, and any new complication can feel like the final straw. “The problem is not with nature, because they love nature. They wish they could welcome nature on their farms as much as possible – and they do. Some might even say that a part of the local culture is lost, because they are not farming side by side with beavers anymore,” he said. “It’s just that their businesses are not often economically viable by doing it, and that’s the problem.”
He believes that wider change is needed to support those trying to make a living while coexisting with wildlife. “As a society, we need to build a system that supports local crofters and farmers who actively support nature on their farm and produce food locally,” he said. “There are some amazing examples nearby, but they are not supported enough at the moment.”
Letting nature lead
Back at Insh Marshes, the beaver dam continues to quietly hold water on the floodplain. It wasn’t built through a grant or a restoration tender. It was built by instinct, in a place that was once part of a plan.
“If we didn’t have beavers, we’d be trying to do this ourselves,” said Thijs. “So yeah – it’s just brilliant.”
This article was written by Iona Haines, ELSP Communications Coordinator. Work on bringing Beavers back to the Cairngorms National Park has been led by the Park Authority, working closely with partners, land managers and local communities.
