The Eurasian beaver (Castor fiber) went extinct in the UK about 400 years ago. They were hunted to extinction for their meat, fur, and scent glands. Famous for creating lodges to live in and gnawing trees, you would think that this would be a good thing for the environment.
However, beavers play a crucial role in maintaining wetland. Since Roman times, over 90% of UK wetland environments and habitats have disappeared.
Why are beavers important?
Preventing flood risk
Between 2015 and 2021, the British government spent £2.6 billion on flood defences. This is to double over the next six years. However, beavers could be able to reduce this cost. The ponds and watercourses that they create can hold a vast amount of water. They act like sponges and slowly release the water, reducing the risk of flash floods after storms.
Redistributing water through these beaver-created watercourses lessens the flow rate of rivers as it moves to lowlands. By gradually releasing water, less top soil is washed away during heavy rainfall.
Reducing drought risk
In the UK, ‘drought’ means below average rainfall. This is when the water reserves are not replenished over several months, which can have serious financial impact. Farmers in particular can be affected by drought, as their crops and livestock depend on water.
However, 160% more water is available during a drought period when beavers are present. As the wetlands created by beavers releases water slowly into the ground, water stays present. A Canadian study on river catchment found that there was 60% more open water during drought where beavers were present.
Improving water quality
In the UK, only 14% of rivers are in good ecological condition. Some are polluted with nitrate, 70% of which comes from agricultural run-off. Beavers are crucial in limiting the amount of pollution in our watercourses.
Several studies have found that beaver-created watercourses reduce the amount of nitrogen pollution. The dams that beavers make act as giant sieves that trap sediment, which can develop algal blooms that are harmful to wildlife, livestock, and people. The ponds also contain bacteria that devour nitrates.
Researchers in Devon have show that beaver watercourses have prevents sediment from flowing downstream. Water that started in these watercourses contained 150 mg of sediment; however, only 40 g remained when the water left.
Creating habitats
Beavers play an important role in building and maintaining habitats where they are present. However, these wetlands have disappeared from the UK, including the habitats that beavers created. Reintroducing beavers to the UK would also reintroduce a lost ecosystem.
Often referred to as ‘ecosystem engineers’, beavers coppice trees, dam small water courses, and dig their own canals. These changes create wetlands that benefit various species, including otters and water voles, and can sequester carbon. The environment around beaver-created watercourses can increase the number of herbaceous plant by over 33%, which feeds surrounding wildlife.
The Devon Beaver Trial has shown that beavers have created a mix of wetlands, ponds, open grassland, trees, and areas of sphagnum moss in just a few years. This has supports numerous species, including species of fish, dragonflies, butterflies, reptiles, birds, and bats.
Reducing fire risk
The number of wildfires are increasing, and are becoming more intense. However, the environments that beavers can create can provide sanctuary for numerous plants, animals, and people.
Why do people dislike beavers?
Anglers are concerned about fish stocks, particularly salmon, which is a reason why some people dislike the idea of reintroducing beavers to the UK. This is in fact a myth: beavers are vegetarians.1 At present, there is limited research on whether beaver dams block migrating salmon.
Farmers are often unhappy with reintroducing beavers. While beavers can reduce the risk of flooding, they can also increase it. They can flood areas to create ponds and watercourses, which benefit various species.2
In general, people do not mind when they are by nature conservation sites or next to farmland; however, when they flood flat and fertile land or roads, we determine that beavers must be eradicated.2 Farmers in Germany were incensed by beavers, which created dams out of maize stalks. This led to farmland becoming swampy and farmers getting their tractors stuck.2
Conclusion
While beavers are notorious for cutting down trees to create lodges, there are numerous benefits. There are some downsides, but beavers create watercourses what can decrease flooding and drought risks, improve water quality, and create environments for plants and other animals.
Read more:
- Gow, D. ‘Prologue’, Bringing Back the Beaver (2020) London, White River Junction, Vermont: Chelsea Green Publishing, p.6-9.
- Gow, D. ‘If you look now at her face’, Bringing Back the Beaver (2020) London, White River Junction, Vermont: Chelsea Green Publishing, pp.89–107.