An increase in wildfires could make it harder for hunters to track the Porcupine caribou herd in northern Alaska and the Yukon.
That’s the conclusion of a study conducted by researchers at the University of Alaska Fairbanks and the U.S. Geological Survey, published last month in the journal PLOS ONE.
Researchers Dave Gustine and Todd Brinkman used computer models to simulate the effects of warming temperatures on spruce forests.
They projected that an increased amount of wildfires will burn 21 per cent of the herd’s winter habitat by the end of the century.
That means caribou are likely to seek out new areas for food and shelter, which may diminish access to hunters in remote communities such as Old Crow.
“Our results suggest that caribou herds wintering in boreal forests will undergo fire-driven reductions in lichen-producing habitats that will, at a minimum, alter their distribution,” the authors noted.
The simulation was carried out over an area of 570,112 square kilometres, encompassing the winter ranges of the Central Arctic and Porcupine caribou herds.
Using historic wildfire characteristics dating back to 1917 for Alaska and 1946 for the Yukon, the researchers found that the herd’s habitat is likely to decrease in size from 107,224 square kilometres to 84,353 by the year 2100.
The Central Arctic caribou herd is unlikely to experience a shift in migration, as it spends its winters on the tundra, where wildfires will have less of an impact.
However, the authors also note that the effects of fire-driven habitat changes to caribou population dynamics are uncertain.
“Projecting the influences of climate changes to wildlife populations is a necessary but daunting task fraught with numerous ecological, climactic and technical complexities, uncertainties and assumptions,” they write in their conclusion.
Stan Njootli Sr., a Porcupine caribou hunter from Old Crow, said it’s hard to project what may or may not happen within this century.
“I think another study is needed to see what grows after forest fires in a boreal forest,” he said.
“There are other factors at play that might cause a shift (in their migration). If you look at areas that are burnt, there are a lot of small trees growing. Caribou eat a lot of grass, and if there is a change in their diet it might mean healthier caribou, or less healthy caribou. At that point what would happen to their habitat and their migration is unknown.”
There is more rain this summer in Old Crow than before, Njootli said, which may also decrease the number of wildfires in the future.
He said previous computer models have proven inconclusive.
“They aren’t really credible to the general person on the street because they’re just models,” Njootli said.
The Porcupine caribou herd population was estimated at 197,000 after a 2013 survey.
The numbers weren’t always so healthy, however, according to the Porcupine Caribou Management Board.
When the first count was performed in 1972, the herd size was estimated at about 101,000 caribou.
Their size grew steadily until the late 1980s, until it reached 178,000 in 1989.
Then it saw a big drop, to 123,00 animals in 2001. Human activity and climate change were cited as possible causes for the decline.
When the latest numbers were revealed earlier this year, the board said it was unsure of the causes behind the steady increase in the past decade.
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