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Caribou bones tell tale of volcanic activity in Canadian North: Researchers
By Randy Boswell, Canwest News ServiceFebruary 23, 2010
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The Peary caribou are so scarce in Canada's high arctic that scientists want the creature listed as an endangered species.
Photograph by: J. Taillon, University of Laval
Scientists studying ancient caribou bones recovered from melting ice patches in the Yukon have shed new light on the ecological impact of a massive volcanic eruption that blanketed much of northwest Canada with ash 1,000 years ago.
The ancient explosion at Mount Churchill, a U.S. peak just west of the Yukon-Alaska border, left a layer of debris up to 30 centimetres thick across a fallout zone that extended into parts of British Columbia, the Northwest Territories and Alberta.
Already known to have affected the First Nations cultures of the time, the blast is shown in the new Canadian-led study to have been the likely cause of major changes in Yukon caribou populations that are still seen today ? and which, according to the researchers, must be factored into efforts to save the "iconic" species pictured on Canada's quarter from further endangerment or extinction.
"In North America, the outlook for caribou is grim, in particular for the forest-dwelling woodland caribou . . . almost exclusively found in Canada," the team of Canadian, British and American researchers, led by Simon Fraser University biologist Tyler Kuhn, write in the latest issue of the journal Molecular Ecology.
They argue that the "cataclysmic event" a millennium ago appears to have had "a noticeable effect on the distribution of caribou populations living within the region at the time."
Environmental changes caused by the eruption, possibly in combination with a period of climate warming around the same time, led to the replacement of existing caribou populations in the fallout zone by genetically distinct herds that arrived post-eruption and are still represented in the region today, the study states.
The "surprise" discovery was made after the researchers found that "bones older than 1,000 years in the Whitehorse area did not match with the local caribou grazing nearby," according to a summary of their research.
The findings are described as "the first to identify a possible link between changes in local wildlife and the volcanic eruption."
DNA profiles of present-day populations and the ancient icefield bones ? some of which had been frozen in place for 6,000 years ? should help wildlife officials devise caribou conservation strategies that maximize genetic diversity, the team concludes.
"Most woodland caribou herds in Canada are threatened, and their survival will likely depend on our ability to act in the best interest of these herds," Kuhn says in a summary of the team's study.
"Understanding the relationships among herds is important, but understanding how herds react to environmental changes through time is equally necessary for us to manage caribou properly."
The researchers also note that the eruption of the Mount Churchill volcano marked an important transition in the hunting culture of the northwest's prehistoric humans from throwing-dart to bow-and-arrow technology.
http://www.windsorstar.com/technolo...Canadian+North+Researchers/2602926/story.html
By Randy Boswell, Canwest News ServiceFebruary 23, 2010
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The Peary caribou are so scarce in Canada's high arctic that scientists want the creature listed as an endangered species.
Photograph by: J. Taillon, University of Laval
Scientists studying ancient caribou bones recovered from melting ice patches in the Yukon have shed new light on the ecological impact of a massive volcanic eruption that blanketed much of northwest Canada with ash 1,000 years ago.
The ancient explosion at Mount Churchill, a U.S. peak just west of the Yukon-Alaska border, left a layer of debris up to 30 centimetres thick across a fallout zone that extended into parts of British Columbia, the Northwest Territories and Alberta.
Already known to have affected the First Nations cultures of the time, the blast is shown in the new Canadian-led study to have been the likely cause of major changes in Yukon caribou populations that are still seen today ? and which, according to the researchers, must be factored into efforts to save the "iconic" species pictured on Canada's quarter from further endangerment or extinction.
"In North America, the outlook for caribou is grim, in particular for the forest-dwelling woodland caribou . . . almost exclusively found in Canada," the team of Canadian, British and American researchers, led by Simon Fraser University biologist Tyler Kuhn, write in the latest issue of the journal Molecular Ecology.
They argue that the "cataclysmic event" a millennium ago appears to have had "a noticeable effect on the distribution of caribou populations living within the region at the time."
Environmental changes caused by the eruption, possibly in combination with a period of climate warming around the same time, led to the replacement of existing caribou populations in the fallout zone by genetically distinct herds that arrived post-eruption and are still represented in the region today, the study states.
The "surprise" discovery was made after the researchers found that "bones older than 1,000 years in the Whitehorse area did not match with the local caribou grazing nearby," according to a summary of their research.
The findings are described as "the first to identify a possible link between changes in local wildlife and the volcanic eruption."
DNA profiles of present-day populations and the ancient icefield bones ? some of which had been frozen in place for 6,000 years ? should help wildlife officials devise caribou conservation strategies that maximize genetic diversity, the team concludes.
"Most woodland caribou herds in Canada are threatened, and their survival will likely depend on our ability to act in the best interest of these herds," Kuhn says in a summary of the team's study.
"Understanding the relationships among herds is important, but understanding how herds react to environmental changes through time is equally necessary for us to manage caribou properly."
The researchers also note that the eruption of the Mount Churchill volcano marked an important transition in the hunting culture of the northwest's prehistoric humans from throwing-dart to bow-and-arrow technology.
http://www.windsorstar.com/technolo...Canadian+North+Researchers/2602926/story.html