© J. Taillon, University of LavalThe Peary caribou are so scarce in Canada's high arctic that scientists want the creature listed as an endangered species.
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.