Through the creation of a vast network of channels, pools, and dams, beavers have been found to drastically improve the quality of water, prevent floods, and mitigate soil erosion. As a result of these impressive and far-reaching benefits, experts are recommending that beavers should be reintroduced across England.
The researchers found that the water leaving a beaver wetland is around three times cleaner than the water entering it, that the pools they form store up to 16 tonnes (17.6 tons) of carbon and 1 tonne (1.1 ton) of nitrogen, and that they prevent the sedimentation in downriver catchments. The findings are the preliminary results of a study looking into the impact that a colony of beavers in Devon, in the southwest of England, have had on the surrounding environment.
The reintroduction of beavers in England is controversial, particularly following the unofficial release of beavers that has occurred in Scotland. Some claim that they cause flooding and damage, others that they maintain the environment. This has led researchers from Exeter University to study their impact on the ecosystem.
They found that in six years, the family of beavers created 16 pools of water along just a 183-meter (600 feet) stretch of stream. The dams caught the top soil that is washed off local fields, preventing the sediment from being washed downstream, while the pools caught the nitrogen and phosphorus that is being flushed off the land. They have also improved the vegetation and trees in the area, increasing the average height of plants.
It is not only the landscape that they are altering, though. The aquatic rodents are also having many positive impacts on the wildlife, too. Frogs were found to be more common in beaver ponds, and despite the concern of many fishermen in the region, brown trout populations are larger and healthier as a result of the newly created wetlands. There is also anecdotal evidence that the bird population has improved, no doubt as a result of the healthier prey base.
This, argue the researchers, proves the value of the animals. The government is already in the process of building leaky dams as well as adding trees to rivers to slow their flow, in a bid to prevent flooding of communities. But these are both things that beavers do for free. The researchers say that while they don’t solve all the issues of flooding, they should certainly be part of the solution.
Yet land owners and farmers are still largely against the reintroduction of the animals, and the government’s Environment Agency is reticent to sanction the release of beavers just yet.