Bring Back The Beavers

Beavers are ecosystem engineers that help to mitigate floods and droughts, reduce forest fires, and create wild habitats

Words by Ben Goldsmith

I know a West country woodland which has an immediately identifiable magic about it. A stream meanders through the great oaks along which there are a series of sunlit, neatly dammed pools that quite hum with life; dragon- and mayflies, swallows, swifts, kingfishers, ducks, amphibians, small fish and creatures of all kinds teem here in numbers that I’ve never seen anywhere else in Britain. The birdsong is cacophonous, year-round. The water’s edge is lined with the fresh growth of willow, hazel and alder artfully coppiced as if by skilful human gardeners. This wood happens to be home to a family of beavers (castor fiber).

Native American tribes held the humble North American beaver (castor canadensis) in high esteem, referring to them as ‘little people’. Alongside man, no other animal is capable of such engineering feats as the beaver, adapting its environment perfectly to suit its own ends. It was believed across America that a great parallel beaver society lived and worked alongside and in symbiosis with man.

Then the Europeans came, and trappers fanned out across the great continent, nearly always the first to arrive in each place, working their way along rivers, streams, across wetlands, swamps and estuaries, searching for every last beaver, such was the value of their fur. And so by the time the documenters, cartographers, photographers and hordes of settlers arrived in their footsteps the beavers were long gone, wiped out across virtually every state, and with them their dwellings and dams and canals and all trace.

Europe’s own indigenous beavers (castor fiber, very similar to their North American cousins) had suffered a similar fate, albeit centuries earlier, not only for their fur, but also for the yellowish oil, castoreum, that beavers exude from glands beneath their tail. This oil was so fantastically valuable for use in early cosmetics that the value of a single beaver in medieval Britain, where the last few disappeared during the reign of Henry VIII, was equal to an entire year’s earnings for the average peasant. By the First World War only tiny remnant populations of European beavers remained on the mainland, in the remotest corners of Eastern Europe and Russia.

Only now are scientists beginning to grasp the immense scale of the impact that the wholesale removal of beavers must have had across the temperate northern hemisphere, to the extent that our very conception of how our landscapes once might have been, and how they should be, turns out to have been wrong.

Beavers are highly territorial, living in small family groups comprising a single pair and their young (known as kits), along with an assortment of adolescent offspring who tend to hang around until their second or third year. They use water as a means of escape, so whilst their food – in the winter the twigs, leaves and soft inner bark of deciduous trees that they fell with ease, and in the summer the fresh shoots of bracken, nettles, and all manner of plants – is to be found on land, beavers never travel far from water. Life is therefore straightforward for beavers with prized territories along broad stretches of water where the only visible effect they have is to open up the water’s edge to precious sunlight. But when these choice areas are fully occupied young beavers looking to establish a territory of their own must make their way up the catchment into the streams and tributaries. It is here that they really make an impact. For without adequate deep water, beavers set about creating it themselves, using stones, branches, and mud with almost unimaginable skill to construct first one and then a series of small dams, behind each of which they dig out a large pool that fills with water, such that before long a small seasonal stream begins to resemble the flooded steps of an immaculately terraced rice paddy. These primeval beaver-made wetlands soon abound with life in a way that is simply unrecognisable to anyone accustomed to a landscape without beavers. Streams braided from top to bottom by successions of beaver pools in this way are not only of tremendous benefit to wildlife, but they also protect us from flooding and from seasonal drought – both of which are occurring with ever greater frequency and force not just here in Britain but everywhere. In the absence of beavers, winter rainfall brings a torrent of water that rushes downstream all at once, causing flash flooding. That in turn gives way to dry, lifeless gullies through the summer once the water has gone. Beaver dams dramatically slow and regulate the flow of water, holding it back in great volume, giving nature time to cleanse it of sediment and impurities, and releasing it, clean, down the catchment through the year. The water passing slowly through these pools makes its way into the groundwater too, which raises the whole the water table. Recent satellite imagery shows that the steady return of beavers to America’s arid Western states after an absence of centuries is quite literally greening the desert in a way that begins to explain the reverence Native Americans once had for this seemingly innocuous, nocturnal, semi-aquatic rodent.

In each territory can be found a ‘lodge’ in which the beaver family finds refuge during the daytime: a large shield-shaped dome made of sticks, plastered with mud, and comprising a series of warm, dry inner chambers, built such that the entrance can be found on the underside, safely beneath the water. These great lodges, some of which can be centuries old, provide a home for countless other species. Nesting birds, hibernating reptiles and amphibians, hedgehogs and small rodents all use beaver lodges for cover in this way.

Since the beginning of the last century beavers have been granted legal protection in a growing list of places, whilst the value of their fur has diminished. Beavers are therefore staging a remarkable comeback. Carefully planned reintroductions, sometimes Government-sanctioned, sometimes not, have taken place across Europe, and in North America, and whilst numbers remain at a tiny fraction of their former level on both continents, there now exist perhaps a million in Europe and fifteen million in North America. In Britain, where the last beavers were extirpated before the reign of Henry VIII, there are small but viable and growing populations in Scotland and dotted across the South of England. The growing realisation that beavers are the most key of all keystone species, critical for the healthy functioning of the hydrological system, for mitigating flooding and drought, for rebuilding broken, depleted ecosystems, has led to calls for the return and protection of beavers right across their former range. Scotland is the latest country to grant beavers full legal protection, following several years of campaigning by conservationists.

Of course there are places in which beavers do present a problem, such as man-made canals, or particularly low-lying, high-grade arable farmland that is at risk of inundation. In those places beavers must be managed, preferably (but not necessarily) non-lethally, as is now routine in places where beavers have already made a comeback. But for the most part opposition to the return of beavers arises from a lack of understanding. Many salmon fishers for example, presumably fans of the Chronicles of Narnia in which Mr and Mrs Beaver eat all the fish, don’t realise that beavers are entirely herbivorous. Others worry that migratory fish such as salmon and trout will be unable to make it across beaver dams, forgetting that these fish co-evolved over millions of years with beavers, and whose young may even depend on the cool, stable pools created by beavers. Indeed new lawsuits in Oregon and California contend that the killing of beavers and the removal of their dams represents the destruction of critical salmon habitat, illegal therefore under the Endangered Species Act. Then there are the tidy-obsessives, the same people who demand that our road verges are regularly strimmed to perfection (at great expense), cleared of wild flowers and wild grasses. These people object to the perceived untidiness created by beavers along the water’s edge. But nature loves heterogeneity, otherwise known as untidiness, and considering that the vast majority of our land is cultivated, tidied and managed by us humans, surely we can allow nature a modicum of free rein along our watercourses. Farming right to the water’s edge is pure folly in any case, for a whole host of reasons, and is now prohibited in many countries.

The return of beavers to Britain, along with all of the magical effects they have on our landscape, is truly a marvel, and absolutely something to celebrate. So be happy, and if you don’t yet have beavers in your area, ask why not.

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