Beavers create thriving ecosystems helping us to put nature firmly back on the road to recovery. And they do all this for free!
The Eurasian beaver (Castor fiber) is a large herbivore, a mammal that was formerly native to these shores and once played an important part in our landscape from prehistoric times until it was hunted to extinction in the 16th century for its fur, meat and scent glands. The loss of this charismatic species also led to loss of the mosaic of lakes, meres, mires, tarns and boggy places that it so brilliantly built.
The Wildlife Trusts are working hard to bring these fantastic mammals back to Britain.
As large as a Labrador dog, but with shorter legs, the European beaver is robust and heavily built. Two distinctive features are a broad, flat tail, covered with scales, and webbed feet. It has small eyes and ears, and light brown fur. They are mainly nocturnal, emerging just before sunset, but can be active by daylight in quiet areas.
They live in family groups of three to five, comprising an adult pair, kits, yearlings and one or more sub-adults. Females normally reach reproductive age at three years, and can produce one litter each year of two to three kits. Longevity is typically seven or eight years but specimens of up to 25 years have been recorded.
Their diet is entirely herbivorous. In late spring and summer it eats mainly aquatic plants, grasses, ferns and shrubs. At other times, woody species form the major part of its diet.
A Nature Based Solution
Beavers are often referred to as ecosystem engineers
They influence stream flows and flood risk
Beaver dams slow the flow of water. Dams hold water, push water sideways and release water slowly, re-wetting surrounding areas and creating complex wetland environments. During flash floods, these dams and associated 'storage' pools in the upper catchment have the capacity to hold water back, reducing the amount of water heading downstream.
Although dams are sometimes washed away, research shows that beavers also restore riverbanks, creating natural meanders which also help slow the flow.
Beaver dams and pools are also beneficial during periods of drought. They are leaky, providing a constant flow of water. Low flows cause serious environmental problems as oxygen levels are depleted and any pollutants are concentrated.
Beavers rarely build dams in main rivers downstream.
They improve water quality
By slowing and filtering the water, beaver dams cause sediment and nutrients to be deposited in ponds, improving the quality of water flowing downstream. These pollutants include run off from managed farmland (manure, fertilizer), phosphorous, nitrogen and soil.
These create problems for wildlife in rivers and streams and also need to be removed from human water supplies to meet drinking-quality standards.
They capture carbon
Beaver wetlands capture carbon, locked up in dams, and boggy vegetation and wet woodlands which are restored, helping to tackle climate change.
They create diverse habitats
Beavers make changes to their habitats, such as digging canal systems, damming water courses, and coppicing tree and shrub species, which create diverse wetlands. In turn these wetlands can bring enormous benefits to other species, such as otters, water shrews, water voles, birds, invertebrates (especially dragonflies) and breeding fish.
In low lying floodplains where agricultural activities depend on land drains and deep ditches, beaver dams can have more significant impacts. They can obstruct culverts and “restore wetlands” in places that are not compatible with the existing land-uses.
Evidence from elsewhere in Europe shows that instances of beaver dams creating undesirable flooding are uncommon, localised and usually small-scale. Management techniques include the removal of dams, the introduction of overflow piping, or the installation of fencing. The removal and translocation of beavers could be considered. Some countries with sustainable beaver populations permit seasonal hunting and/or lethal control as legitimate management strategies.
Many other Wildlife Trusts have been carrying out beaver reintroduction trials working alongside communities and landowners to put beavers into managed and contained sites. It has been a huge success, maximising the benefits that beavers provide. The Wildlife Trusts now have a range of carefully honed techniques, which help avoid or minimise any localised negative impacts which might occur. To read more about these trials:
For further information, watch this online talk by Welsh Beaver Officer Alicia Leow-Dyke