4 minute read
BRINGING BACK BEAVERS
Josh Harris 2009-2017 studied Natural Sciences at the University of Cambridge and is now working for the Beaver Trust, a charity focused on reintroducing beavers to the UK. An accomplished wildlife photographer, he also presents and produces his own wildlife and science communication films.
The Eurasian beaver is the second largest rodent in the world and superbly adapted to an aquatic lifestyle, with webbed hind feet, transparent eyelids and a flattened tail to steer when swimming. It is a herbivore and mainly eats leaves, bark and other vegetation, such as ferns and brambles. However, what is amazing about beavers is not the biology of the animals themselves but their impact on the ecosystem around them. By engineering their environment to suit their own needs, they inadvertently create a huge diversity of niches for other species.
The extent to which they do this really is incredible. When I first visited a beaver wetland in Devon, I did not see any beavers, but wading through the swamp was still one of the most fantastic wildlife experiences ever.
By felling trees, building dams and lodges, and digging canals, beavers create a mosaic of wetland habitats with a huge amount of structural diversity. Ponds are great for frogs and fish, which in turn support otters and kingfishers. Bats roost in the standing dead wood and hunt through the gaps between the trees. (The beavers’ thinning out of the tree cover makes it easier for bats to hunt.) Water rails and moorhens sneak through the rushes and wet willow scrub. Owls hunt the small mammals thriving in the tangled understorey of dead wood, brambles, sedges and regenerating willow.
In addition to these species which are known to live in beaver wetlands, there are others which we can speculate were there in the past and which could make a comeback if beavers were reintroduced. Abandoned beaver lodges may have been one of the original hibernation sites of hedgehogs, before gardens and wood piles were a thing. European tree frogs were found in Britain up until the 16th century and were probably associated with beaver wetlands. (They prefer low scrub rather than tall trees, so the coppiced wet willow woodlands which beavers create may have been perfect.) In Belgium, the comeback of beavers and the amphibian-rich ponds they create has attracted black storks, formerly not seen for hundreds of years.
By holding back water in the headwater streams and interrupting its flow downstream, their dams can reduce the severity of flooding in the lowlands – something which is becoming more severe as our climate becomes increasingly unpredictable. At the other end of the spectrum, they can retain water in droughts where streams would otherwise dry up. In some parts of North America, beaver wetlands can even act as refugia for animals to survive wildfires, because they remain lush and unburnt as the landscape around them is incinerated.
Beaver engineering can also substantially reduce the level of agricultural pollution in streams because the slow flows cause sediment to drop out, and the huge growth of vegetation and aquatic algae removes nitrates and phosphates from the water.
Many of these benefits can be substantially increased by setting aside unfarmed buffers along rivers and streams to give beavers the space and materials to work. These buffers can intercept some of the runoff from farmland and eliminate most of the problems that beavers can cause for farming. (Crop raiding by beavers seldom occurs when the crops are more than 20 metres from the water.) Across the landscape, a network of river buffers could form corridors for other wildlife to move along. River systems are a ready-made basis for a nature recovery network.
Ultimately, addressing the ecological crisis will require a dramatic shift in the way we use land to produce our food.
However, beavers are a great option for nature recovery because they can create huge environmental benefits whilst having only a relatively small impact on food production. (This is especially true for the valleys of the South West; the East Anglian fens would be a different question.) Most problems can be solved with simple management interventions such as protecting trees, removing dams and translocating problematic individuals.
The comeback of beavers to the UK’s rivers is, in my opinion, one of the most exciting things happening in the UK at the moment. As well as having a hugely important ecological function, beavers are also just amazing creatures by themselves. It won’t be too long before an early morning walk along the River Avon could involve a thrilling glimpse of this long-lost mammal.
For more information about the Beaver Trust, visit: www.beavertrust.org
To find out about Josh’s wildlife photography and filmmaking, see www.joshuaharriswildlife.co.uk and follow him at @joshharriswild.
