Absent from the Scottish landscape for 400 years, the Eurasian beaver (Castor fiber) is again resident on Scotland?s west coast, following its reintroduction to the Knapdale Peninsula in Argyll, in May 2009.

With the full backing of the Scottish Government, this five-year scientific trial, costing £2million, is being run by the Scottish Wildlife Trust and the Royal Zoological Society of Scotland. It is hosted by Forestry Commission Scotland and monitored by Scottish Natural Heritage and Oxford University.

The trial has been instigated because the Eurasian beaver is one of the species listed on Annex IV of the EC Habitats Directive adopted in 1992. This directive requires EU member states to study the desirability of reintroducing such species where they have become extinct.

To this end, 16 beavers were imported from Telemark in Norway and released on to Loch Coille-Bharr and Dubh Loch in the remote 44km2 Knapdale Forest trial site. According to the Scottish Wildlife Trust, Knapdale provides an ideal environment for the beavers, being rich in willow, birch, rowan and alder ? trees that make up a large part of their diet. In addition, the remote area suffers minimal disturbance from man.

Though not solely dependent on native hardwoods for food, beavers do consume their leaves, twigs, bark and shoots throughout the autumn and winter. In addition, they fell trees for creating dams and lodges. This fact has caused anxiety among those involved in forestry, who fear that reintroduced beavers would lay waste to large tracts of native woodland.

However, it has been proven that instead of denuding areas of young hardwoods, beavers in fact help tree regeneration. The rodent?s felling activity acts as a natural form of pollarding, resulting in new and vigorous growth springing from the original tree stumps. In addition, during the spring and summer months, much of this vegetarian mammal?s diet is made up of aquatic weeds, and 128 other plant species. Furthermore, it is rare for the beaver to venture more than 50m from the safety of water, so it is impossible for large areas of forestry to be destroyed.

To witness first hand the effect beavers have had on the Scottish environment, I visited the Aigas Field Centre, near Beauly, in Inverness-shire. This Highland paradise sits above the river Glass, and has been created by writer and lecturer Sir John Lister-Kaye OBE, one of Scotland?s foremost naturalists.

Keen to show that beavers could bring environmental benefits to Scotland, Sir John and his team of rangers commenced the Aigas Beaver Demonstration Project in 2006. They released a pair of Eurasian beavers on to an eight-acre loch, within a 200-acre wooded enclosure, at Aigas.

Sir John led me around the shores of the loch, which is now home to six beavers. As we walked, he pointed out tree stumps gnawed by beavers, which had already begun to sprout healthy new growth, and showed me small ponds created by the animals where, in summer, insects abound, and amphibians and fingerling trout find sanctuary.

There are two active beaver lodges at the Aigas loch site, comprising large mounds of tree limbs and branches on the bank. They are south-facing, and with their entrances beneath the water, so the beavers can safely enter and exit, hidden from the eyes of potential predators. During the year there is only a 2°C variation in the core temperature of the lodge.

As we threaded our way along the lochside, I could see that far from creating a scene of beaver devastation, I was in fact witnessing a scene of regeneration. The animals had opened up dense, dark, waterside thickets, where life-giving sunlight had penetrated for the first time in decades, causing new growth that benefits many creatures, not least roe deer.

Nature finds a way

The Knapdale trial is a successful managed project, but indomitable as ever, nature seems to have struck out on its own where the Scottish beaver is concerned. Early in 2001, to the great surprise of all living along its banks, confirmed reports of beaver sightings began to come from the river Tay and its tributaries. This included a sighting by a party of canoeists on the river Earn in May of the same year.

In the ensuing decade there were further reports of beaver sightings on the Earn, Tay, Isla, Ericht and Dean Water, as well as physical evidence in the form of gnawed trees and lodge construction. The estimated population of wild beavers now living within the Tay catchment area is between 50 and 1000.

Whether or not the Tay beavers were escapees from wildlife collections or deliberately released, they are now breeding and so pose a conundrum for Scottish Natural Heritage (SNH) and the Scottish Government.

Caught on the back foot, SNH decided to trap the creatures to return them to captivity. They worked on the premise that any beavers living in the Tay catchment area were there illegally, as their release had not been sanctioned by the Scottish Government. Trapping was also justified on the grounds that it was not clear whether the beavers were European or North American Castor canadensis. If they were American, cross-breeding with legally released beavers could lead to genetic complications.

Having instigated a programme of recapture, SNH trapped a live beaver along the river Ericht in December 2010. The animal was transferred to Edinburgh Zoo, where it died in captivity. DNA analysis of the creature (along with a small number of other beavers found dead) concluded that the Tay animals were not American but of both western and eastern European origin, descending from a robust hybrid used for reintroduction to Bavaria.

Complicated matters

The Tay beaver situation has now entered a legal morass. The Scottish Wild Beaver Group was formed to liaise with Government, local communities and landowners to promote the positive effects wild beavers could have on the river Tay. The group is calling for legal protection for the Tay beaver, and it is here that matters start to become rather complicated. As well as being protected by Annex IV of the EC Habitats Directive, the beaver is also listed in Annex II, which requires protected areas for it to live in. However, as the beaver became extinct in Britain over 400 years ago, it is no longer listed is indigenous and is not, therefore, protected under Schedule 5 of the 1981 Wildlife and Countryside Act, nor under Schedule 2 of The Conservation of Habitats and Species Regulations 2010.

This raises questions as to whether Scotland?s wild beavers are protected by law. Are landowners within their rights to kill an animal they consider to be a pest? Stewart Stevenson MSP, who is also Scotland?s environment minister, is due to make a decision on the fate of the Tay beavers later this year, but until that happens, the status of the Scottish beaver seems shrouded in a fog of uncertainty.

Just as the Eurasian beaver has its supporters, so there are those who view its return with trepidation. When I interviewed Dr David Summers of the Tay District Salmon Fisheries Board, he said that the damming of feeder burns and tributaries by beavers might present a considerable obstacle to migrating salmon and sea trout, as fish attempted to reach their spawning grounds.Dr Summers explained that this could be particularly significant on slow-flowing rivers with a shallow catchment, where tree-lined riverbanks would make for ideal beaver habitat.

In addition, he voiced concern that excavating beavers could cause considerable damage to riverbanks and flood valuable agricultural land by dam building. He emphasised that the wide-scale reintroduction of beavers to Scotland must only be allowed if legislation is put in place for the removal of problem animals and their dams by those landowners and fishery managers who are detrimentally affected by the animal?s activities.

It is ironic that unlike the official £2million Scottish Beaver Trial at Knapdale, Argyll, beavers have cost the British taxpayer not a penny. Indeed, the errant Tay beavers may well prove to be an unexpected asset to the Scottish economy, as already, tourists have expressed an interest in beaver- watching around the Blairgowrie area.

In addition, as beaver numbers increase, there will be a need for licensed control. In Scandinavian countries this is carried out by stalking the animals at dawn and dusk, and shooting them with small calibre centrefire rifles, as both the pelt and meat of the beaver are highly prized. Is there not the possibility that the income generated by beaver hunting, and beaver tourism, far outweigh any negative aspects caused by the Eurasian beaver?s return to Scotland?

This shy, non-aggressive vegetarian has stirred powerful emotions in Scotland. Whatever the outcome of the Scottish Government?s decision this year, it is bound to have its critics. Is it better perhaps to accept that a native species has returned by an unexpected route, and to make the most of any benefits presented by the Eurasian beaver in Scotland?