Canada’s arctic tundra is vanishing: researchers

ED STRUZIK
Postmedia News

Research from University of Alberta biologist Isla Myers-Smith and about 30 other researchers from 10 countries suggests that sizable chunks of the alpine/tundra world are being taken over by shrub cover that is increasingly crowding out those plants that many Arctic animals depend on.

“Climate warming may well be a reason why this is happening,” said Myers-Smith, who is the lead author of a paper published recently in the scientific journal Environmental Research Letters. “But snow cover, nutrient availability, and interactions with other plant species may also be important.”

It’s been common knowledge that snow cover, cold temperatures and high winds come early and often to regions such as the Yukon, which is why much of the Arctic and sub-arctic world is covered with lichens, mosses, and other small plants that tend to grow low or horizontally along the frozen ground.

It’s why these alpine and tundra environments traditionally favour caribou over deer and Arctic hares, Arctic fox, pikas, ground squirrels and marmots over other smaller mammals that can’t handle the extreme cold.

An increase in shrub growth may not sound serious when compared to the advance of trees such as spruce, which some scientists believe are moving higher up in the alpine country and closer to the Arctic coast as the climate warms.

But shrubs such as alder, willow, dwarf birch and creeping juniper grow a lot faster than trees do and they shade out sunshine that lichens, mosses and other alpine/tundra plants need to thrive during a growing season that is often measured in weeks rather than months.

“Shrubs also trap snow, which insulates soils in the winter, and shades soils in the summer,” said Myers-Smith.

“Research has shown that soil in shrub-free zones can be almost a cold as the air above it. But that same soil that lies beneath shrubs in winter can be up to 30 degrees warmer than the air temperature. This insulating and cooling can alter soil temperatures, nutrient cycling and permafrost thaw.”

“Shrubs also seem to do best in a landscape that is increasingly becoming more disturbed,” she said. “The darkening of the surface associated with shrubs growing above snow could also accelerate snowmelt and cause regional warming.”

Forest fire experts and climatologists such as Mike Flannigan of the University of Alberta are increasingly turning their attention to this world where there are no trees. The proliferation of woody shrubs could conceivably increase the potential for future tundra fires such as the one that burned 600 square kilometres of tundra in Alaska in 2007, putting as much carbon into the atmosphere as the entire tundra world can store in a year. Woody shrubs can produce a lot more fuel for wildfires than most tundra plants.

The research that Myers-Smith and her colleagues are doing can be painstakingly slow, often conducted over several years in a world that is not always welcoming to humans. Mosquitoes and wild weather make the fieldwork work extremely trying and occasionally dangerous.

While snow and wind storms are common, there are also grizzly bears, polar bears and even thunderstorms to worry about.

For some young Arctic scientists, fieldwork in remote areas can be overwhelming. More than one grad student from a Canadian university has had to be flown out from a remote camp, or given time off to deal with the stress that comes with the job.

As much as the climate change debate has fizzled in recent years, Myers-Smith is absolutely certain that investment in the kind of research she does will pay dividends.

“Climate change research in the North will help us to understand how our world is changing,” she says.

“It will also help us understand where the change is happening most rapidly. Ecologists can help us to identify when we can intervene to better manage a wildlife species or restore a disturbed area, and how ecosystems will change in the future so that we can adapt to the new conditions.

“Sometimes a small study at one location can identify an unconsidered factor that will go on to have big repercussions for our understanding of how ecosystems work.”