Beavers as Natural Engineers
Beavers as Keystone Species
Imagine you lived in a former mill house in rural England, with a beautiful clear river snaking around the house, gracefully flowing downward to form a lake at the bottom of the valley.
Wouldn’t it be a delight to observe a family of beavers happily toiling all day to build superb lodges on the river banks and splash with their tails in the sun?
Beavers are fascinating species. They are engineering marvels, known for their exceptional engineering skills.
Beavers build dams, canals and lodges using sticks, branches, logs, mud and rocks as materials. Beavers are truly Olympic-level builders - some of their dams can be hundreds of feet long and several feet high. Remarkably, not only beavers build lodges - they also decorate them. Inside their lodges, beavers create living spaces with different chambers. They build sleeping platforms and even have a separate bathroom area.
Beavers are well suited to aquatic lifestyle, as they belong to the semiaquatic rodent family. They have webbed hind feet and a broad, flat tail that acts as a rudder for swimming. Their eyes and nostrils are also equipped with special membranes that allow them to see and breathe while submerged. Therefore, they are able to construct the entrance to their lodges underwater, to provide protection against predators. They also build underwater pantries near their lodges to store food. They anchor branches and logs in muddy areas to access them during winter when food is scarce.
Beavers are typically monogamous and form long-term pair bonds. They usually mate for life and work together to raise their offspring. After their first year, the young help their parents repair dams and lodges, older siblings may also help raise newly-born offspring. Beaver families often live in extended family groups called colonies.
These industrious animals are cleverly employing a variety of sophisticated tools at their disposal. Their teeth (which never stop growing), are used to gnaw through tree trunks and branches - helping them to build their dams and lodges. Beavers’ flat tails act as a versatile tools. They use them to carry mud and construction materials, balance while standing and even communicate - they slap their tails on the water’s surface to signal danger to other beavers in the area.
Beavers are exceptional swimmers - they can remain submerged for up to fifteen minutes and swim at five miles per hour. They are also phenomenal navigators. As nocturnal animals, they are equipped with excellent vision, which helps them to navigate and forage in darkness. These remarkable animals also have a built-in compass in their noses. They can detect the magnetic field of the Earth, helping navigate accurately.
It is hard not to admire these clever, talented and hard-working animals. In addition to all their talents, the beavers are also considered keystone species because their activities can dramatically transform landscapes and alter ecosystems by creating wetlands, that provide habitats for numerous other species, including fish, amphibians and waterfowl.
It was very sad to discover that beavers were almost hunted to extinction for their fur, meat and castoreum (a liquid substance excreted through the beavers’ castor sacs, to mark their territory). Castoreum has been used in medicine, perfume and food flavouring. Before protection began in the nineteenth and twentieth centuries, overhunting had nearly exterminated both the North American and the Eurasian beavers.
Due to the rise of anti-fur and animal right campaigns and collective conservation efforts - beaver populations globally have re-bounded since the nineteenth century.
The Revival of North American Beaver Across Canada and the US
In the early twentieth century, Archibald “Grey Owl” Belaney, who abandoned his trade as beaver trapper, has taken up the beavers’ cause to pioneer beaver conservation. Grey Owl wrote several books, and was the first to professionally film beavers in their environment. In 1931, he moved to a log cabin in Prince Albert National Park, where he was the “caretaker of park animals” and raised a beaver pair and their offspring. His passionate and eloquent writings soon drew international attention to the beavers’ plight.
Prince Albert National boom was part of a continent - wide resurgence that is still under way. At the start of the twentieth century, the number of North American beavers was as low as 100,000. Since then the population has climbed to an estimated 20 million and the species again generally thriving in every American state, as well as its historic Canadian range.
Conservation Programmes Across the UK to reintroduce the Eurasian Beaver
Across the UK and Europe there are a number of the Eurasian beaver reintroduction programmes currently in place. In May 2009, the Scottish Beaver Trial released the first beavers to live in Scotland in over four hundred years. This marked the first ever formal reintroduction of a native mammal species in Britain and launched a groundbreaking five year study to explore how beavers can enhance and restore natural environments. The successful trial led to a decision by the Scottish government to allow the beavers to remain in Scotland and in 2019 the government has granted beavers legal status as protected species.
There are many other successful beaver reintroduction programmes across the UK, including England and Wales, led by the Wildlife Trust and other organisations.
Why Should We Reintroduce Beavers?
Beavers along with sea otters, wolves, jaguars, honey-bees and sea-stars are keystone species. Their infrastructure creates wetlands used by many other species, and create a profound effect on other organisms in the ecosystem.
Beavers have a positive effect on their environment through their behaviour. By gnawing on stems, they 'coppice' trees like willow, hazel, rowan and aspen. The regrowth provides homes for a variety of insects and birds.
The wetlands in which beavers live are valuable for many other species too. They provide homes for animals like otters, water voles, common frogs, water shrews and birds such as woodcock and teal. Craneflies, water beetles and dragonflies in turn support breeding fish and insect-eating birds like spotted flycatchers and warblers. Woodpeckers, bats and a host of beetles use the standing dead wood.
Beavers can also offer a nature-based solution to improving the health and function of river catchments. Beaver-created wetlands can act as sponges, resulting in more constant flows and retaining water during droughts. A series of leaky beaver dams can reduce the speed of flow and help reduce the chance of flash flooding. Beaver dams can capture organic sediments, and reduce the effects of agricultural runoff and harmful chemicals such as pesticides, helping to improve water quality downstream.
There is a legal requirement to consider restoring beavers to their former range under the EU Habitats Directive and to protect them under the Bern Convention. There have been more than 200 formal beaver reintroduction projects (plus numerous unofficial releases) in more than 26 European countries and their ecology and management is well-studied.
We should all rally around supporting these vital reintroduction schemes so we can both enjoy seeing a family of beavers splashing by the river banks as well as knowing that by supporting just one newly introduced beaver family, we are also nurturing an entire ecosystem.
North American Beaver
