Richard Gleeson
Northern News Services

Yellowknife (Apr 26/02) - The wild and rugged Northern environment belies a vulnerability that will be sorely tested as new species disrupt its fine ecological balances.

The process is already well underway. White-tailed deer, magpies, cougars and coyotes are among the animals whose ranges have expanded to the NWT in recent decades.

Determining the impact new arrivals will have on native populations is as complex as predicting next year's weather.

First, we know fewer than half of the creatures and plants that make up northern ecosystems.

"So far 8,000 species have been identified and there are probably 30,000 species," said Suzanne Carriere, ecosystem management biologist for the Department of Resources, Wildlife and Economic Development. "I can tell you right now we will not identify them all."

The migration of species North is prompted by climate change. Scientists predict the average annual temperature in the North will climb by between 1.4 C and 5.8 C over the next century.

That may not sound like much of a change, but it is unprecedented in human history and enough to open up the North to a wide range of new species.

Some of the biggest effects will come not from migrating animals, but what they bring with them.

Yellowknife Mayor Gord Van Tighem recently gave an Ecology North presentation on the threat posed by parasites brought North by species such as white-tailed deer.

Predicting the incursion of new parasites is difficult, because some require intermediate hosts, such as snails, at different stages in their life. Both parasites and hosts are sensitive to temperature changes, their populations vulnerable to booms and busts.

The sensitivity of the North to change is a product of a biodiversity that is much smaller than Southern areas.

"When one species dies off there's not usually another one around to fill that niche, whereas in a jungle there will be five different species doing the same thing," said Ron Graf, manager of integrated resource management for RWED.

Graf said there little can be done to stop the introduction of new species. Scientific predictions can help policy-makers mitigate some of the negative effects, but it isn't easy.

"Ecosystems are not only more complex than we think, they are more complex than we can think," said Reed F. Noss, one of the world's leading conservation biologists, at a recent Yellowknife presentation on conserving Canada's boreal forest.