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magazine / nd07
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November/December 2007 issue |
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| IMAGE: GEOBASE |
In the zone
Just south of the Arctic Circle, taiga meets tundra,
creating a unique ecological mosaic
By Jennifer Ma
Surrounding the western reaches of Great Bear Lake in the
Northwest Territories, stunted white and black spruce and
lichen merge with patches of permafrost and ice, forming a
mosaic of vegetation in this false-colour satellite image (top).
At 31,150 square kilometres, Great Bear is the largest lake
entirely within Canada and the ninth largest freshwater lake in
the world. And it lies smack in the middle of the transition
zone between the lightly forested taiga to the south and the iceladen
tundra to the north.
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| CLICK MAP TO ENLARGE |
Swaths of pink highlight areas that are regenerating after
natural forest fires, which are common in the region, while pale
green indicates young forests and darker green pinpoints forests
in later stages of regeneration. The peninsula jutting into the
lake (top right), is part of the Grizzly Bear Mountain and
Scented Grass Hills National Historic Site which received
long-term protection funding in March. Its higher elevations
provide optimal growing conditions for conifers, which surround
treeless till and plateaus with polygonal peat formations
(in yellow) — characteristic of permafrost areas.
Capturing great amounts of sunlight, the lake is a huge heat
reservoir, typically not freezing over until November and thawing
in July. Scientists are closely monitoring such transitional ecozones
throughout the country to determine whether increasing
temperatures due to climate change will alter the mix of vegetation
and rich wildlife populations it supports.
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