One of the signs of spring in Moscow is flooding on the outskirts of the city as warmer temperatures melt the winter snowfall. Winter this year was mild and the snowfall unusually light, but the floods had a familiar pattern: frequent and heavy. That has alarmed Moscow regional officials and they blame some of the worst flooding on industrious, dam-building beavers. Canadian beavers at that. One Russian TV channel aired a story on the furry rodents that began with an animated graphic. It showed a ring of beavers encircling the city as they noisily chewed their way toward the Kremlin. Said Alexei Panteleyev, the regional vice-governor: “The building of beaver dams has caused a number of floods in past years in the district and we need to make serious efforts to address this issue.”
So — one of Canada’s national symbols is frequently described in Russia as a pest and an invasive alien species. The Canadian arrival is thriving, muscling aside its less energetic Russian cousin. Castor canadensis, which can top 32 kg on the scales, has been throwing its weight around for over 50 years, ever since Finnish biologists released a few pairs into the wild in 1937. They did so in the hope that the Canadian beavers would replace native populations that hunters and trappers had driven to extinction. From that beachhead, Canadian beavers gnawed their way across Finland before waddling across the Russian border and beginning a southward march, taking over territory from the slightly different European species as they advanced.
Not only do the Canadian interlopers have sharper teeth and more energy, those eager beavers have better engineering skills than the Russian rodents they are displacing. They build bigger, higher dams — some as long as 100 m — reproduce more quickly than the locals, and have few natural predators to keep their numbers in check. Disgruntled officials grumble that beaver dams drown forested areas, killing commercially valuable trees, and complain that the animals’ tree-felling activities often leave adjacent farmland vulnerable to erosion. As well, say the officials, the 20,000 Canuck beavers in northwestern Russia are a health hazard as their water-borne feces contains such diseases as giardiasis, or beaver fever, an intestinal illness spread by a microscopic parasite.
For such regional representatives as Panteleyev, tired of dealing with complaints each year about washed-out roads, railways and flooded culverts, getting rid of those unwanted foreigners could mean catching the animals, then shipping them to sparsely settled areas for release. But even in Russia, with a booming economy floating on high oil and gas revenues, that’s time-consuming and expensive, and many cash-strapped local governments simply can’t afford it. The beavers could also be trapped for their fur — an untreated beaver skin can fetch $100 in a cold country with few qualms about keeping warm with animal pelts — or simply shot to shrink their numbers.
“Shoot them?” said Vladimir Krever, the World Wildlife Fund’s biodiversity program coordinator in Russia. “That’s really an unprofessional point of view. This is a local problem but it’s not necessary to shoot the beavers to solve it.” He, like other environmentalists, noted that beavers play an important role in conservation, by preserving wetlands, stabilizing stream flows and creating habitats for trout and other species. The size of the ponds behind beaver dams, he suggested, could be adjusted through the insertion of a simple flow-control pipe.
Many Russians, though, see an uncomfortable parallel between the Canuck invasion and the dismal experience of Argentina in 1946. There, 25 breeding pairs of Canadian beavers were imported to help start the country’s new fur industry. When that enterprise failed, the beasts were set free on an island in the Tierra del Fuego archipelago. In contrast to their native habitat in Canada, the transplants didn’t have to worry about wolves, bears or other traditional predators. They thrived and spread throughout the islands — where there could now be as many as 200,000 of the animals. Their dam-building has flooded farmland and roads as well as bringing devastation to slow-growth forests that take hundreds of years to grow back. Argentines, who worry that the beavers will one day make it across the Magellan Strait and start chewing their way through mainland forests, gloomily regard them as an unstoppable plague.
Canadian beavers don’t pose that kind of threat in Russia. Just as clearly, however, they are now as much a part of the Russian landscape as the spring floods that they make worse each year.