V i v i a n  S o n g
Freelance writer
Freelance writer
Alien invasion

Toronto Sun, Sun Media papers, October, 2007.

There are potentially hundreds of sleeper cells living among us.

They live discreetly, waiting patiently for conditions to be ripe before they strike and terrorize the very nature of Canadiana.

These sleeper cells hitchhike rides into the "virtually borderless" country via planes and ships, undetected by authorities until it's too late.

They are invasive species, described in the most dramatic of terms by Anthony Ricciardi, a professor of environmental science at McGill University, whose tone is laden with a sense of urgency.

"The world will suffer more ecological explosions and surprises" as alien species invade new habitats and compete with domestic organisms for survival, he warns.

"There is no mass extinction event that compares to what's happening now," he says.

And climate change is only accelerating the situation.

"Suddenly, with global warming, barriers that kept things out, like thermal barriers, are being reduced. Winters are less harsh and summers are longer," Ricciardi explains.

That means organisms like sea squirts are quickly making themselves at home in habitats that were previously unwelcoming.

Sea squirts are soft-bodied globular masses that have become meddlesome pests in Atlantic Canada, latching onto lines of cultured mussels and often killing their hosts.

Though some species are native to tropical and subtropical waters, they're quickly establishing colonies that blanket a hundred square kilometres of sea floor like "pancake batter" in sensitive areas like Georges Bank, an important scallop fishing ground off Nova Scotia, Ricciardi says.

"It's become a blob, an amorphous, continuous colony of sea squirts that doesn't seem to be limited by much."

Meanwhile, mutinous domestic species are also rising up in frenzied chomping sprees thanks to warmer winters.

"The mountain pine beetle is the best example in Canada of a species that appears to be benefiting from climate change," says Hugh MacIsaac, a University of Windsor biologist.

The pine beetle has historically been regulated by predators and cold winters. But they're surviving through warmer winters, and they're projected they'll kill off 78% of B.C.'s marketable pine forests by 2015.

Though MacIsaac "doesn't subscribe" to the theory that the Asian long-horned beetle and emerald ash borer are thriving in Canada because of climate change, he acknowledges the invasive insects could become more devastating with a modest rise in winter temperatures.

From 2003, when it was first discovered in the Toronto area, to 2004, the Asian long-horned beetle killed 17,000 healthy broadleaf trees.

The emerald ash borer also "bulldozed" its way through ash trees in southwestern Ontario, MacIsaac says.

While most of Canada's invasive species traditionally hail from Europe, increased global trade with Asia is bringing aliens into the country at an unprecedented pace.

MacIsaac and Ricciardi describe ships as "syringes inoculating the system with new species" in a hub and spoke structure.

So aquatic species that move out of the Black Sea and into port areas like Antwerp, Belgium, for instance, are picked up by European ships and brought into the Great Lakes in a leapfrog effect.

Meanwhile, Canadian biologists are watching other species like the disease-carrying Asian tiger mosquito closely. It first appeared in the southern U.S., but has climbed as high as Ohio, thanks to rising temperatures. The Asian tiger mosquito transmits viruses like West Nile and, in its native range, dengue fever.

"With most invasions that's it," Ricciardi says. "Once they're in, they're in. They're a devastating form of pollution."

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EMERALD ASH BORER

·  Probably came from Asia in the 1990s

·  First discovered in Michigan in 2002

·  Attacks only ash trees

·  Adult beetles are metallic green, about 20 mm long

SEA SQUIRTS

·  Native to the northwest Pacific.

·  The body of an adult tunicate is essentially a sack with two siphons through which water enters and exits. Water is filtered inside the sack-shaped body.

·  Mature length: 5 cm; grey-green colour.

·  Competes for space and food with native aquaculture species (e.g., mussels, oysters).

MOUNTAIN PINE BEETLES

·  Inhabit pines, particularly the ponderosa pine, lodgepole pine, scots pine and limber pine.

·  Less than a centimetre long.

·  Kill trees by boring through the bark and feeding on the phloem layer.

·  Caused massive damage to lodgepole pine forests in Canada. A recent reduction in the severity of winters in B.C. has allowed the population to explode.

·  Infestations have been reported in northern B.C., Jasper National Park and northwestern Alberta.

WEST NILE VIRUS

·  Carried and spread by mosquitoes.

·  Can cause encephalitis or meningitis in humans.

·  Was discovered in the West Nile area of Uganda in 1937, then spread to Mediterranean and Europe.

·  In 1960, it was observed in horses in Egypt and France.

·  Between the 1950s and 1999, there were sporadic epidemics in Israel, South Africa,Romania and Russia.

·  West Nile first appeared in Canada in Ontario birds in 2001. Human cases first appeared in the same province in 2002.

·  Was assumed we were facing a strain that exists in Africa. Other evidence points to the strain from Israel, which can cause more dangerous results.

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