“I I hate beavers,” said a woman on a beaver hotline. Forty years ago, she planted an oak tree in a small town in the south of Zurich—now on the leading edge of beaver proliferation—and it had just been cut down, gnawed by large semi-aquatic rodents entering their seasonal home improvement regime.
The caller is one of 10 new people who get in touch every week at this time of year. Beavers, nature's great engineers, can wreak havoc in the winter by repairing their lodges and building dams. For people, this can mean flooding, sinkholes in roads and cutting down trees. Damage from one incident could amount to CHF 70,000 (£65,000).
To cope with the situation, the beaver-rich canton of Zurich has opened a hotline. Local Beaver Advisory Center staffed by environmentalists who provide advice, assess damage and evaluate potential compensation (A woman who has lost an oak tree is advised to wrap wire around the bases of other trees to prevent rodents from chewing).
Part of the job is to calm people angry at their beaver neighbors. “Some farmers are so angry you can barely understand them, but they calm down when you come see them,” says first responder Caroline Nienhuis, a biologist with Fornat, a consulting company that runs the hotline.
Switzerland is experiencing a beaver boom. When apex predators first repopulate a previous habitat, such as when wolves, bears and eagles return to the areas across Europe – the immediate reaction is often trepidation. However, as animals spread, this can often lead to conflict. Population growth usually occurs slowly when you first introduce a new species, and then it moves exponentially.
In 2008 there were 1,600, and in 2022 (when the last full monitoring was carried out) there were 4,900, and numbers have likely increased since then. What is striking about the example of Switzerland is the extent to which citizens agree to live near them. Unlike most European countries, not a single beaver has been legally killed. Switzerland since their reintroduction in 1956.
The Swiss approach is not a laissez-faire approach to its revival: its success lies in broad government guidance and support. Up to 1 million Swiss francs (£930,000) can be allocated each year to beaver damage and prevention efforts – the largest such fund in the world. Europe.
Peter Roos is a public works employee who maintains the waterways, roads, streets and paths in the municipality of Hettlingen, home to 3,200 people and now some beavers. Roos says he calls the hotline up to 20 times a year.
The latest move by local beavers is to increase the height of a dam, an undertaking that risks flooding the sewer system. Having discussed this on the site, Nienhuis and Roos agree that the dam needs to be lowered to solve the problem. The entire solution takes about 30 minutes.
“It’s about who has more patience: a human or a beaver?” says Roos. “Once you start manipulating their dams, they will become creative and build new dams.” His latest assignment is to investigate a crater created in a local parking lot, into which a truck wheel fell. “Keeping beaver activity under control is a huge amount of work,” Roos says.
Cull controversy
Some argue that this proves that large beaver populations not compatible with a large population. In Bavaria, about 2500 are shot every year, which is 10% of the population, but their number continues to grow. Poland issues culling permits about 6% beaver population annually (about 8300 individuals).
However, the effectiveness of culling in Switzerland has been questioned. If a stretch of river is favorable to one beaver, it will likely be favorable to others. “Shooting a beaver is effective, but only until the next beaver comes along,” Nienhuis says. “Then the same conflicts arise.”
Nienhuis says prevention and compensation are more effective. “It's important that people feel they can control the beavers and their activities so that they accept them. Once you lose local acceptance, it becomes a problem,” she says. The biologist believes that animals such as beavers, wolves and lynxes should not be returned to their habitat without a system for resolving the conflicts that inevitably arise. “If you say, ‘Deal with it yourself,’ then an illegal shooting will happen.”
Management costs are more than offset by the benefits beavers provide to wildlife and ecosystems. While they cause flooding in some areas, they reduce it in others because their dams slow the flow of water across the landscape, protecting downstream communities from flash floods. “We can't do what they do. We'll miss a huge opportunity if we go and shoot them all,” says Cecile Oberson, who works at the National Beaver Center (Nationale Biberfachstelle). They are, she says, “the most powerful force in river restoration.”
Boon for biodiversity
Marthalen is the largest beaver wetland in Switzerland, and environmentalists point to it as an illustration of why people should put up with them.
In 2011, a family of beavers moved onto the plantation and dammed the small creek that runs through it, turning four hectares into alluvial forest, flooding old oak trees and cutting down others.
This swampy area has seen an explosion of biodiversity. The calls of the black woodpecker and the tawny owl echo through the forest. This is a case study of how wild engineering by beavers can change ecosystems in a matter of years. “The impact on biodiversity is enormous. No human-led project will ever achieve these benefits,” Oberson says.
In habitats like Marthalen, researchers found up to six times more species of fish, amphibians, aquatic insects, aquatic plants and dragonflies and up to 60 times more abundance than in the same rivers without beaver activity. “It's amazing what a beaver can do and how it affects nature. It makes you realize how unnatural much of our nature is,” Nienhuis says.
Beavers are currently restoring, free of charge, 2,000 km of rivers in Switzerland that they have already colonized. “If we integrate them smartly, they can save us money and do it better than we can,” Oberson says.
“People think it’s a little exotic.”
Some regions are already managing their future of coexistence. Two years ago, beavers moved into a stream that runs through the village of Uwizen. In January 2024, after extensive excavation, a hole appeared in the road, and the following year another appeared. Beavers knocked down 20 trees, leaving the river bank bald. They had an appetite for farm sugar beets and Brussels sprouts. The water level has risen due to the construction of the dam. “I was worried about the tennis courts and people's houses flooding,” says Oliver Kuhn, who is responsible for local maintenance in Uwizen.
The damage was prevented by the construction of a beaver net fencing costing CHF 8,000, which was shared between the municipality and the canton.
Now most locals love their new neighbors. Kuhn, who named the beavers Justin and Hailey (pepperpronounced “bie-ber” (German for “beaver”), noticed that the kingfishers had returned since their arrival, as well as more dragonflies and bats.
“People think we have beavers here, it's a little exotic and unique. You can walk here with your dog and see beavers – it's special,” said Andie Pfenninger, who lives in Uwisen. “People see it as enriching where they live.”
Find more Age of Extinction coverage hereand follow biodiversity reporters Phoebe Weston And Patrick Greenfield in the Guardian app for more nature information
