Bring Back Beavers!

Native American tribes held the humble North American beaver (castor canadensis) in high esteem, referring to them as ‘little people’. Alongside humans, no other animal is capable of such engineering feats as the beaver, adapting its environment perfectly to suit its own ends. It was believed that a great parallel beaver society existed alongside and in symbiosis with man. Then the Europeans came, and trappers fanned out across the great continent, 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 settlers arrived in their wake the beavers were long gone, wiped out across virtually the whole continent, and with them all trace of that parallel society.

Europe’s own indigenous beavers (castor fiber) had suffered a similar fate centuries earlier, killed not only for their fur, but also for the yellowish oil, castoreum, that beavers exude from sacs beneath their tail. This oil was in such high demand for use in cosmetics that the value of a single beaver in medieval Britain was equal to an entire year’s earnings for the average peasant. At the time of the First World War only tiny populations of European beavers remained in the remotest corners of Eastern Europe and Russia.

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

Beavers are highly territorial. They occupy in single pairs with their young (known as kits, born in late spring in litters of two or three), along with an assortment of adolescent offspring who tend to hang around until their second or third year. Beavers use water as a means of escape - so whilst their food is to be found on land – the twigs, leaves and soft inner bark of deciduous trees that they fell with ease (aspen, birch and willow are particular favourites), as well as shrubs, bracken, nettles, and all manner of plants – beavers never travel far from water. Life is therefore pretty straightforward for beavers living on prized territories along broad stretches of river, or on the edge of lakes or estuaries where, being tree-gardeners from whom we learnt the art of coppicing, the only effect they have is to open up the water’s edge to precious sunlight.

But when these high-quality areas are full, young beavers looking to establish a territory of their own must make their way upstream, into the tributaries and streams that flow down into the larger rivers. It is here that beavers really make an impact. Without deep water, they set about creating it, using rocks, branches, sticks and mud with almost unimaginable skill to construct first one and then a series of small dams along the stream, behind each of which they dig out a large pool that fills with water.

Soon after the arrival of a pair of beavers, a small seasonal stream begins to resemble the immaculately flooded steps of a terraced rice paddy. These new permanent pools quickly become havens for fish, aquatic insects, amphibians, kingfishers, ducks and wildfowl, storks and myriad other creatures that teem in a primeval beaver-made wetland in numbers that are unrecognisable to anyone used to a landscape without beavers. The range of plant species as habitats return to a wetland landscape - wildflowers, grasses and much needed scrub - are havens for nesting birds and small mammals.

The value of a single beaver in medieval Britain was equal to an entire year’s earnings for the average peasant. At the time of the First World War only tiny populations of European beavers remained in the remotest corners of Eastern Europe and Russia.

Streams braided from top to bottom by successions of beaver pools are not only of huge benefit to wildlife, they also protect us from both flooding and seasonal drought. In the absence of beavers, winter rainfall brings a torrent of water that flashes downstream all at once, bursting the banks of straightened and dredged waterways across the floodplain. 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 such as nitrates and phosphates from farming, 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 water table, swelling the size of aquifers in times of drought. Recent satellite imagery shows that the steady return of beavers to America’s arid Western states after an absence of centuries is greening the desert with wetland fire-breaks in a way that begins to explain the reverence Native Americans once felt for this innocuous semi-aquatic rodent.

In each territory a ‘lodge’ can be found in which a 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 so that the entrance can be found on the underside, safely beneath the water. These great lodges 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 have taken place across Europe, and in North America, and whilst numbers remain at a tiny fraction of their former level, 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 the South West of England. The growing realisation that beavers are the ultimate 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.

Of course, there are places in which beavers do present a problem - to man-made canals, power station cooling systems, and particularly low-lying, high-grade arable farmland. In those places beavers must be managed. 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 and gravel spawning beds 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 trimmed to perfection (at great expense), cleared of wild flowers and wild grasses. They 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 edge of the water is pure folly in any case, now prohibited in many countries.

The conservation movement has a tendency to flip that famous Martin Luther King line on its head telling us that it “has a nightmare” and can’t take it. But here’s a cause for celebration: the beaver is back, along with all of its magical effects on the landscape. If you don’t yet have beavers in your area it’s time to ask: Why not? ¬