Tom Buckley was overjoyed. Earlier this year the retired environmental scientist proudly documented the first family of beavers living wild in England since the species was hunted to near extinction in Britain several hundred years ago—a discovery that came almost by accident.

He first noticed a few tree stumps gnawed to pencil-like points on the River Otter, a shallow watercourse near his home in the town of Ottery St. Mary. The find prompted him to place a night-vision camera on the riverbank that soon produced a grainy, black-and-white video of three beavers happily frolicking in the water. "It was marvelous to see," said Buckley, whose images made international headlines.

But if it sounds curious that beavers should suddenly reappear on an island like Britain after a centuries-long absence (in a river and in a town named after otters, no less), the British government certainly isn't pleased. Following those initial news reports, it announced plans to trap and remove the beavers.

While one theory suggests they escaped from a nearby nature reserve, it's far more likely they were released illegally by what's known in the trade as "beaver bombers"—in other words, wildlife vigilantes who operate under the cover of night. And with animals of such questionable origins, Britain's environment department cites the risk of a tapeworm sometimes found in beavers in continental Europe.

That is, assuming they're Eurasian beavers (Castor fiber) and not the North American variety (Castor canadensis), a separate species that, like many things American, can grow larger than its European counterparts.

Environmental Change

More important, however, beavers cut down trees, build dams, and flood waterways. Apart from humans, no other species alters its environment more. And in its decision, the British government raises a much broader question about the animal's place and potential impact in modern Britain.

"Beavers have not been an established part of our wildlife for the past 500 years," said a department spokesman. "Our landscape and habitats have changed since then."

In truth, no one's sure exactly when the beaver went extinct in Britain. The rodent was highly valued for its fur and medicinal glands. The last written record is a bounty paid for a beaver head in Yorkshire in 1789, although the species would have vanished from other regions of the country long before then. What is certain is that the beaver is native to Britain and the River Otter is just the latest front in a contentious, decades-old battle over whether to reintroduce the species, with a cadre of ecologists on one side that touts the beaver's environmental benefits, and farmers, landowners, and fishermen on the other who fear the animal could disrupt a way of life to which the British have grown accustomed.

View Images The beaver seen here, at night along the River Otter, is thought to be the only one of its kind living wild in England. Photograph by Tom Buckley/Rex Features via Associated Press

In Ottery St. Mary, Jenny Hill, a local resident, wiped crumbs from a tablecloth after a church social event. "I think it's awful," she said of the government's intent to capture the beavers. "I really just hope they leave them alone." To rally support, Buckley has plastered shop windows around town with signs that read "Save Our Beavers," urging people to sign a petition.

Instead of killing the animals, the government hopes to find them a new home in captivity. But even then, the decision has infuriated Buckley. "I can't think of anything more horrifying," he said as he gazed out on the River Otter. "I've spent so much time with these beavers, probably more than anyone else."

Since his initial sighting, the 61-year-old has diligently chronicled the beavers. He can identify each one by the markings on its tail, and earlier this summer, he filmed three brand-new, baby kits. If the adult beavers weren't born wild on the river, Buckley asserts, their offspring most definitely were.

On the opposite side of the debate is Mark Owen of Angling Trust, an organization that represents the interests of anglers in England. It has lobbied ministers in London to remove the beavers, concerned their dams will block the migration of salmon and sea trout. "All fish species need to move around the river system in order to properly complete their life cycles," Owen said.

A Country Transformed

Although beaver and fish would have coexisted in Britain for tens of thousands of years, and continue to do so in other countries, he believes the British countryside has been transformed beyond recognition since the last beaver disappeared.

"The majority of our rivers have been impacted by man, either by dredging, straightening, or widening. We also presumably, at that point, had very good and high fish stocks. Now we don't," Owen argued.

"Not enough scrutiny has been given to the effects of beaver reintroduction."

However, most pro-beaver folks will tell you the case in favor of beavers is already well established. Britain lags far behind the rest of Europe, where the beaver's comeback is widely regarded as an environmental success story. Reintroductions on the Continent began in the early 20th century, after the population sank to a mere 1,200 survivors. It now stands well above 300,000.

View Images NG STAFF; JOEY FENING. SOURCES: SCOTTISH BEAVER TRIAL; NORWEGIAN INSTITUTE FOR NATURE RESEARCH

Likewise in North America, where the fur trade decimated the species, millions of beavers are now thriving across Canada and the United States. Under European Union law, an onus is placed on member states like Britain to consider reintroducing lost species, but Scotland is the only territory to have made any real strides on behalf of the beaver (the Scottish government makes its own decisions on such matters).

Wildlife conservationists there have just completed a five-year reintroduction trial, and a public poll found 60 percent of Scots support reestablishing the beaver as a native species.

Beavers Easy to Reintroduce

"Beavers are one of the easiest extinct animals to reintroduce," said Derek Gow, an ecologist who operates a farm a short drive from the River Otter. "It's something we should have done a very long time ago."

In conservation circles, Gow is often referred to as "The Beaver Man." And with his large frame and round, bearded face, the man very much resembles the creature. He sees the beaver as an essential keystone species that's vital for creating the kind of complex wetlands that support greater biodiversity and, in response to the Angling Trust, healthier fish stocks.

To demonstrate, Gow has released dozens of beavers into large, open enclosures on his land. We made our way down into a wooded ravine where the animals have been reengineering an ordinary stream into a cascade of small dams and shallow pools filled with amphibian eggs.

"Before we put the beavers in, there were no clumps of amphibian eggs at all," Gow said. "By the time the beavers finish manipulating this site, there will be thousands and thousands. If there are no beavers building dams, then things like amphibians simply can't exist. And of course, these amphibians are, in their own right, a very important prey base for a host of other species."

It's a habitat Gow says Britain has been missing for the past few centuries.

If Adrian Lloyd Jones had his way, beavers would already be hard at work in the Welsh countryside. For nearly a decade the 45-year-old has run the Welsh Beaver Project on a shoestring budget, working to bring the species back to Wales, which like Scotland has its own say on reintroductions. When we met, he was showing off a taxidermied beaver named Hanc to a group of children at a summer funfair on the Afon Rheidol, a small river that winds through a bucolic valley full of sheep and spindly hedgerows.

Jones plans to release beavers nearby and needs as much local support as he can get, so he had made the trip down in a beat-up old van, sleeping in the back next to Hanc to save money. He smiled as the kids prodded the stuffed animal and their parents politely asked questions.

"I haven't had one person against," he said.

Welsh Government Opposition

Elsewhere, though, Jones has run into fierce resistance, including heated town hall meetings, and his experience proves just how fraught species reintroduction can be. The Welsh Beaver Project was supposed to have released its first batch of beavers this summer, but as Jones claims, the Welsh government scuppered those plans.

The minister for natural resources in Wales, John Griffiths, who oversees such decisions, declined a request for an interview. That's perhaps because beavers can be a political minefield in Britain. While polls like the one in Scotland reveal general support for beaver reintroduction, farmers often abhor the idea, and they're an important voting block, particularly in Wales where agriculture remains a key component of the economy.

"Over 90 percent of the farmers and landowners have signed a petition against having any beavers on the river," said Gareth Daniels, a tall, 62-year-old sheep and cattle farmer who owns 190 acres along the Rheidol. His family goes back several generations in the river valley, which saw intense flooding in 2012, and he worries beaver dams would only exacerbate the problem.

Daniels drove his pickup truck across the Rheidol's shallow gravel bed as his cows watched from the riverbank. "I call the beaver a vermin," said the Welshman, using the term applied to a number of species hunted to extinction, or very near it, under England's so-called Vermin Acts of the 16th century. "I'm not really interested in bringing species that have been extinct back. I would rather it not happen."

Dafydd Jarrett of the National Farmers' Union in Wales agrees. While Jones argues that beaver-created wetlands would actually retain water and minimize flooding, Jarrett isn't convinced farmers will have the liberty to remove problematic dams or even kill particularly troublesome beavers.

"The public outcry ... could potentially put any control program at risk," said Jarrett, who fears beavers in Britain could earn European legal protection just as they enjoy in other countries.

He points to places like Bavaria in Germany, where farmers frequently come into conflict with beavers whose underground burrows can erode farmland next to riverbanks.

"Epidemic" Destruction

And in the U.S., growing beaver populations have been known to cause what the U.S. Department of Agriculture called "epidemic" destruction to crops and other property.

In response to such complaints, Jones has moved his proposed reintroduction off the main trunk of the Rheidol, away from farmland. He hopes the Welsh government will finally give him the go-ahead next spring.

On the River Otter, Tom Buckley says he's seen wildlife agents scouting for a place to set their beaver traps, although the environment department declined to confirm this. Rumors abound of other beaver families living up and down the river, and a local wildlife trust is pleading with the government to let the beavers stay so it can study their environmental impact.

George Eustace, the British undersecretary who announced the planned capture, did not respond to an interview request. Yet even if the British government removes the animals, or if Wales never grants permission for a release, many proponents believe beavers will recolonize Britain, whether farmers and anglers like it or not.

"If we don't do an official reintroduction, it'll happen anyway," said Jones as he strapped Hanc into the back of his van with a bungee tie. He points to the Tay in Scotland, currently home to an estimated 200 to 300 beavers living wild on its banks and tributaries.

Beaver advocates claim their numbers have grown out of a handful of escapees from nearby enclosures over a decade ago. But privately, other beaver experts admit a population of that size would have to be the result of illegal releases, and the future of the Tay beavers is uncertain. Scottish ministers are expected to decide next year whether they can stay.

"There's no doubt that beaver bombers are putting pressure on the government," Jones said. "If they don't do it properly, it's going to happen by the back door, and happening by the back door wouldn't be a good thing. It's far better to do it in a planned, coordinated, and organized way."