Industrious beavers in England’s only wild colony have wowed scientists with their incredible dams

Industrious beavers in England’s first wild beaver colony have wowed scientists with their intricate 100-foot-long (30-metre) dams waving across Devon.

Across almost 100 acres of the Coombeshead Valley, a industrious group of two dozen or more animals have engineered a huge network of 14 pools and dams 13 years after they first ‘escaped’.

As Britain has scorched in the sun this summer and reservoirs across the country have run to record lows, this corner of the West Country has remained more fertile thanks to the beavers, experts claim.

People working on the reintroduction project say there has been no change in water level before the major drought struck nationwide at the end of May and the beginning of August.

A study from May found beavers are helping to reduce soil erosion and slow down the flow of rivers, which is in turn reducing flooding.

As Britain has baked in the sun this summers, with reservoirs running low, the beaver-ridden region has remained lush and full of life thanks to the beavers’ large dams

The beavers, which are thought to have escaped from captivity in 2005, built their dam at Percy’s Country Hotel, near Launceston, which is owned by Tony and Tina Bricknell-Webb.

They are believed to have got there by either unlicensed or accidental release and the Devon Wildlife Trust successfully applied for it to become a licensed trial reintroduction.

The aquatic engineers have already had a significant effect on the landscape.

Using branches from trees that they have felled, they have dammed lakes and created moat-like ponds of water.

On the body of water they have constructed islands out of timber, mud and rocks which they enter via water-filled tunnels. They have ‘coppiced’ trees like willow, hazel, rowan and aspen. 

Beaver families live in small lodges on the dams they construct and spend their days adding to and repairing the structures.

The mammals create these elaborate bodies of water to they can use their swimming skills to evade predators.

Typical Devonshire run-off streams, which usually leach nutrients from the landscape when they flood, have had their destructive flood flow stopped because of the amount of beaver activity, experts say.

Moisture from the pools has also provided green pasture in the valley when land around has yellowed.

Experts say that potentially harmful nitrogen run-off from fertilisers has been absorbed by plants the beavers encourage to grow in the mud.

Scientists from the University of Exeter, who are carefully monitoring the site, have described it as ‘quite possibly the heaviest engineered wild beaver site in England and amongst the most impacted of all sites in Britain’.

The beaver engineered dams and lagoons provide the perfect habitat for ducks, coots, moorhens, dragonflies, fish and much more. The fish provide a food source for birds such as heron and kingfisher

The beaver engineered dams and lagoons provide the perfect habitat for ducks, coots, moorhens, dragonflies, fish and much more. The fish provide a food source for birds such as heron and kingfisher

Scientists from the University of Exeter, who are carefully monitoring the site have described it as ‘quite possibly the heaviest engineered wild beaver site in England and amongst the most impacted of all sites in Britain’. Pictured is a beaver dam built in the county

Scientists from the University of Exeter, who are carefully monitoring the site have described it as ‘quite possibly the heaviest engineered wild beaver site in England and amongst the most impacted of all sites in Britain’. Pictured is a beaver dam built in the county

The beaver dams mean typical Devonshire run-off streams which usually leach nutrients from the landscape when they flood have had their destructive flood flow stopped

The beaver dams mean typical Devonshire run-off streams which usually leach nutrients from the landscape when they flood have had their destructive flood flow stopped

HOW AND WHY DO BEAVERS BUILD DAMS?

Beavers are found across the northern hemisphere and are among planet’s most skilled builders.

This reputation has earnt them the nickname ‘nature’s engineers’.

They fell trees by gnawing at their trunks and use the resulting sticks to construct dams to stop the movement of water in ponds, lakes, rivers and streams – creating a bodies of water with a low current.

The mammals then use sticks and mud to create a second structure – a large dome-shaped island that can reach as high as ten feet (3m) tall and up to 1,600ft (500m) long.

Each island includes two underwater entrances and a living chamber above water where the animals sleep and shelter.

Beavers often line the walls of this chamber with dry leaves and plants to insulate it during winter. 

It remains unclear exactly why beavers build dams, but scientists speculate the creatures use it for warmth and shelter in the winter and as protection from predators.

Beavers are strong swimmers, and creating a reservoir of water allows the animals to play to their strengths to escape those higher in the food chain.

The biggest beaver dam ever discovered measured 2,790ft (850m) – more than twice the length of the Hoover dam.

The woodland construction, found in the southern edge of Wood Buffalo National Park in Northern Alberta, Canada, was so expansive it could be seen from space.

Beavers are native to the UK and used to be widespread, but became extinct in the 16th century.

This was mainly because they were hunted for their fur, meat and a secretion that was widely used in perfumes, food and medicine.

According to the RSBP, the beaver is known as a ‘keystone species’ as it has a very positive influence on its environment.

Since 2016, scientists have installed meters above and below the dams to measure the effect of their presence on the flow and quality of the water.

Early results have been positive and those involved with the project hope the research could have significant implications for Britain as a whole.

The beavers are nocturnal animals. They do most of their dam building at night but can often be seen at dawn and dusk. They feed on vegetation surrounding their pools together with bark

The beavers are nocturnal animals. They do most of their dam building at night but can often be seen at dawn and dusk. They feed on vegetation surrounding their pools together with bark

Dr Alan Puttock, associate research fellow at the University of Exeter, said: “Beaver engineering at Combeshead, particularly the building of dams has transformed the environment, increasing water storage and creating diverse wetlands'

Dr Alan Puttock, associate research fellow at the University of Exeter, said: ‘Beaver engineering at Combeshead, particularly the building of dams has transformed the environment, increasing water storage and creating diverse wetlands’

‘Beaver engineering at Combeshead, particularly the building of dams has transformed the environment, increasing water storage and creating diverse wetlands’, said Dr Alan Puttock, associate research fellow at the University of Exeter.

‘Our research has shown that beaver activity can slow the flow of water following rain storms potentially providing a valuable component to future flood and land management strategies.

‘Additionally, beaver ponds store and slowly release water maintaining flow during dry drought periods such as those experienced this summer.

‘Our research has also shown that beaver dams can trap sediment and associated nutrients being lost from land upstream, with beneficial impacts for downstream water quality.’

The beavers are nocturnal animals and do most of their dam building at night but can often be seen at dawn and dusk. 

In November 2016 it was announced that beavers would remain in Scotland as a protected species. 

A colony of wild beavers in Devon is exciting scientists with their unique ability to build enormous dams

Some of the dams stretching as long as 100 feet (30 metres)

A colony of wild beavers in Devon is exciting scientists with their unique ability to build enormous dams, some stretching as long as 100 feet (30 metres). Image shows beaver at the Coombeshead estate near Percy’s Hotel in Devon

Across nearly 100 acres of Devon's Coombeshead Valley a group of two dozen or more animals have built a huge network of 14 pools and dams, some almost 30 metres in length. Pictured is a dam and pool created by the beaver family in the grounds of a country house hotel in the region

Across nearly 100 acres of Devon’s Coombeshead Valley a group of two dozen or more animals have built a huge network of 14 pools and dams, some almost 30 metres in length. Pictured is a dam and pool created by the beaver family in the grounds of a country house hotel in the region

In May, scientists from Exeter University, who have been studying a family of the mammals in Devon since 2011, found their 13 dams have also trapped more than 100 tons of sediment. Of this, 70 per cent was thought to be soil washing away from 'intensively managed grassland' fields upstream

In May, scientists from Exeter University, who have been studying a family of the mammals in Devon since 2011, found their 13 dams have also trapped more than 100 tons of sediment. Of this, 70 per cent was thought to be soil washing away from ‘intensively managed grassland’ fields upstream

According to Ms Bricknell-Webb, the beaver engineer dams and lagoons that provide the perfect habitat for ducks, coots, moorhens, dragonflies and fish

According to Ms Bricknell-Webb, the beaver engineer dams and lagoons that provide the perfect habitat for ducks, coots, moorhens, dragonflies and fish

Dr Puttock, who is carrying out the study with Professor Richard Brazier, said: ‘It is of critical importance to understand the impacts that beaver reintroduction will have in densely populated and managed countries such as the UK.

‘Studying the impacts of beavers at sites such as Combeshead allow us to gain understanding that will be invaluable to informing future environmental and land management policy.’

According to Ms Bricknell-Webb, the beaver engineer dams and lagoons that provide the perfect habitat for ducks, coots, moorhens, dragonflies and fish.

‘The fish provide a food source for birds such as heron and kingfisher. The insects which decompose the dead wood are in abundant supply and are available to woodpeckers’, she said.

‘Birds and bats nest in the holes they create. Rising populations of frogs feed a growing array of other predators. Reptiles hide in the burrows of the water voles returning to mow the plant sward, whilst the ground water locked in the soil changes the vegetation’, she said.

In May, scientists from Exeter University, who have been studying a family of the mammals in Devon since 2011, found their 13 dams have also trapped more than 100 tons of sediment.

Of this, 70 per cent was thought to be soil washing away from ‘intensively managed grassland’ fields upstream.

The ponds are also storing tons of carbon in the sediment, along with nitrogen and phosphorus, which can cause problems for wildlife and water quality in streams and rivers.

The team has also found that the water leaving the trial site had lower levels of sediment and nitrogen.

 

 

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