Beavers ( Castor fiber ) became extinct across the island of Great Britain in the 16th Century because of overhunting for fur, meat and castoreum – a secretion in popular use for the perfumes and medicines of the day.
So sort after were the materials of the world’s second-biggest rodent that large numbers of European opportunists were drawn in search of its wealth during the settling of the New World. This is where the largest beaver populations still remain today as a species of Least Concern at approximately fifteen million.
In Britain, a beaver family of unknown origin colonised the River Otter in Devon in 2008. It is believed to be the first in the wild since their previous nationwide extinction ∼400 years ago. A pair was introduced into the colony in 2016 to improve genetic diversity.
Beavers are believed to now number ∼800 across England and Wales reaching perhaps as many as 1,000 in Scotland alone. In 2022 the British government awarded them nationally protected status “making it illegal to capture, kill, injure or disturb them.”
Given this legal status, widespread public support and positive influences on ecosystems, beavers are set to be a permanent fixture in British wildlife for many generations to come.
Beavers famously build dams – but why? The deep pools they form provide shelter and protection against predators (mainly foxes in Britain) for both adults and babies (kits). These ‘beaver lodges’ are only accessible underwater.
Beavers are a keystone species meaning they are a central influence in forming the ecosystems around them.
Dams, also known as impoundments, naturally create deep and slow-moving water which attracts insects, fish and amphibians. These species bring predatory birds and small mammals such as otters.
Adjacent areas are soaked with nutrients and are more likely to remain hydrated in times of severe drought such as the British summer of 2022. These surrounding areas often transform into fertile meadows inviting large herbivores including deer, wild horses, boar, cattle and bison. These mammals in turn bring about important large-scale ecological processes of their own.
The shift in water patterns drowns some surrounding trees providing perfect habitats for fungi and insects which bring birds such as woodpeckers, kingfishers and ospreys.
Where beaver fells many trees through gnawing, species such as willows have adapted to resist and regrow stems. This natural form of coppicing allows the tree to rejuvenate.
Dams also help to prevent the flooding of human settlements by breaking up heavy water flows during high precipitation weather events. Underground water tables are given a chance to refill.
Beavers are quickly reintegrating into British ecosystems and given the desperate need for ingenuity to fight climate change, the return of this native species working for free can only be a positive!