Declines in boreal caribou populations in the Hay River Lowlands and Cameron Hills may be linked to seismic lines cutting up their preferred habitat, said Allicia Kelly, biologist for the South Slave with GNWT’s department of Environment and Natural Resources (ENR).
Kelly, who presented at last week’s South Slave Regional Wildlife Workshop in Fort Smith, said data collected from over 100 collared caribou showed the animals actively avoiding seismic lines by at least 400 metres on each side and crossing seismic lines at a faster rate than they usually travel.
“This is a consistent pattern that is statistically significant,” she said. “We’ve interpreted it as another form of disturbance when they cross these lines.”
Kelly noted that caribou actively select open, old growth conifer forest as their habitat, while generally avoiding areas recently burnt by wildfires.
“What we’ve learned, which has largely confirmed what others have learned to the south in Alberta, is that caribou do well where there are large areas of secure habitat,” she said.
She said “secure habitat” means large, unbroken patches further than 400 m from linear features, such as seismic lines, roads and pipelines.
According to ENR data, roughly 52 per cent of the caribou’s region in the Hay River Lowlands is secure, with 15 per cent of that remaining in “big patches.” In the Cameron Hills the number was much lower, with just 16 per cent of the area labeled “secure.”
Boreal caribou populations are on the decline in both study areas. For the Hay River Lowlands, Kelly said the population has been at a slow decline but is “somewhat stable.” For those in the Cameron Hills, however, the outlook is more bleak. In February and March of this year, they counted an estimated 25 calves to 100 cows.
“The population trend is definitely downwards,” said Kelly. “The caribou in that area are not doing well.”
Blood and fecal samples taken from 149 collared caribou show nothing of concern in terms of parasites and disease. “Boreal caribou are healthy,” said Kelly.
While admitting that there are informational gaps in harvesting levels and predator numbers, she stated that seismic lines open up corridors for predators to travel.
Arthur Beck of Fort Resolution raised a concern that more needs to be done to fight forest fires in the NWT to protect the caribou’s preferred old growth food source – lichen.
“Lichen takes 50 years to ripen before caribou can digest it,” he said. “Let’s stop talking about monitoring and start doing more fire fighting to put out the fires when they’re small.”
The Canadian government recently drafted a recovery strategy for boreal caribou that is currently open to public comment. It defines 65 per cent of undisturbed habitat as “critical habitat” and recommends three per cent habitat restoration to bring the population back to “self-sustaining.”
Boreal caribou are protected under the federal Species at Risk Act. There are approximately 6,000 to 8,000 boreal caribou in the NWT.