Sunday, April 15, 2007

The Superbeaver: Elk Island Vs Tierra del Fuego

Elk Island, Alberta, Canada

Busy beavers
The beaver tends to live on the extreme edges of our consciousness: Canadian icon on the one hand, the world's largest rodent on the other. But in Elk Island National Park beavers have been quietly going about their work for over 60 years and are now finally getting recognition for their role in protecting the park's watersheds during a drought.

Park Warden Glynnis Hood is writing her doctoral thesis on beavers. Through studying years worth of aerial photos before and after beavers were re-introduced to the area she has seen first-hand the role the beavers and their dams play in maximizing what little water is available during a drought to protect watersheds and the animals who depend on those waters for survival.

Beavers were re-introduced to the park in 1941 after reaching near-extinction due to hunting the animals for their pelts. To study their impact on the land, Hood compared two drought years—one with beavers and one without. She studied aerial photos taken in a section of the park in 1950 where beavers had not yet returned, and compared her findings with the 2002 drought.

She found evidence of 67 percent more water during the 2002 drought season, despite the fact that 1950 saw 40 percent more precipitation.

"The stats are showing that the only thing accounting for that is active beaver lodges," Hood says.

Tierra del Fuego, Argentina
Argentina's great beaver plague
By Elliott Gotkine
BBC correspondent in Tierra del Fuego, Argentina

Beavers have created a landscape of dead trees
At the end of the world, a sky-blue stream sweeps down from an ice-glazed mountain on its way to the Beagle Channel.
Wild horses chomp nonchalantly on lush, green bushes. Tourists gawp at a submerged forest as a beaver glides gracefully among the trees.
This is the Argentine part of the island of Tierra del Fuego, which is shared with Chile. It looks like an ecological paradise.
But on closer inspection you realise that something isn't quite right.
"All those trees you see," says Bismark, our tour guide, as he points towards a dammed river that is now a lake, "they're all dead. And this is because of the beaver."
Inside the beaver-built body of water there are hundreds of petrified-looking trees. They are dried-out, grey and naked.

Environmental havoc
Each lake is usually formed by just two beavers. They chop down trees with their razor-sharp teeth and use them to dam rivers.
They do this to protect themselves from possible predators - even if there aren't any - and to give them easier access to food, primarily tree bark and other vegetation.
Now, if you consider that there are estimated to be up to 250,000 beavers on the island, you begin to get an idea of the environmental havoc being wreaked here by the world's second-largest rodent (the capybara is number one).
Yet beavers are not native to South America. Around 50 of them were introduced here from Canada in the 1940s. Argentina's then military rulers hoped that they would multiply and create a fur industry - in earlier centuries beaver pelts were among the most valuable in the world.
The beavers certainly multiplied. But their fur was out of fashion.
With no natural predators and an abundance of food, these tree-eating herbivores thrived - so much so, that beavers are now officially considered a plague.

Loggers fear for livelihood
Local loggers have borne the brunt of the beaver plague.
The day will come when they're going to be the only ones left here
Manuel Berbel
Manuel Berbel owns a timber-yard just outside the island town Tolhuin. Dressed in a red lumberjack shirt and speaking through his handlebar moustache, he told me he had been logging here for 20 years.
During that time, he has seen large chunks of his livelihood ravaged by beavers. They also pollute the water, he told me, and make roads impassable. The situation, he says, is getting worse every day.
"The number of beavers keeps growing and growing," he said, as he pointed to the land he rents from the government.
"The day's going to come when they're going to be the only ones left here and we're all going to have to leave. It will become the island of the beavers." He chuckled stoically at the thought, before continuing his anti-rodent rant.
"And I want to tell people in other countries, who say what a cute animal the beaver is, to think before introducing it. Its only natural predator is the bear. So they should have brought the bear too."

Beaver bounty
To control the population, local hunters used to be paid a beaver bounty of $1.50 for every dead rodent.
There were claims that 20,000 were killed, but little proof. So the payments were suspended last year, and the beavers are now multiplying at an annual rate of 20%.
Tourists pay to see them
"We've decided to launch a controlled killing campaign in some specific beaver colonies and to find possible uses for the animal's skin and meat," says Sergio Luppo, the island's top environmental official. "We want a controlled management of the population." \

For some, though, beavers have been a boon.
The tourists being led by Bismark through the labyrinth of desiccated trees have paid a local travel agency more than $30 a head in the hope of snatching a glimpse of a wild beaver. In the National Park, they have a "beaver trail", and there are plans to build a second one.
There are even improbable sounding plans to harness the pent-up energy in beaver dams to extract hydro-electric power.

Most of the people here have over the years resigned themselves to sharing the island with the beavers. But there could be worse to come.
The rodents have multiplied so prodigiously that they're running out of space.
It is feared they could soon swim cross the Straits of Magellan and colonise the mainland. And if that happens, Argentina's Great Beaver Plague could go continental.

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