Study shows caribou herds in British Columbia and Alberta grow from wolf culls

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New research suggests the once dwindling number of Western Canada’s caribou is finally growing.

But the same article concludes that the main reason for the spike is the killing of hundreds of wolves, a policy that will likely have to continue for decades.

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“If we don’t kill the wolves, given the state of habitat that industry and government have allowed, we will lose caribou,” said Clayton Lamb, one of 34 co-authors of a study recently published in the journal Ecological Applications.

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“It’s not the wolves’ fault.”

Caribou conservation is considered one of the most difficult wildlife management problems on the continent.

The animals, printed on the back of Canadian currency since 1937, require quiet stretches of hard-to-reach ancient boreal forest. Those same forests tend to be logged or gouged, creating paths and cut lines that invite deer and elk, along with wolves that eat anything with hooves.

Between 1991 and 2023, caribou populations fell by half. More than a third of the herds disappeared.

Governments, scientists and First Nations have been trying for years to find ways to bring them back. Lamb and his colleagues looked at 40 herds in British Columbia and Alberta to see if anything had worked.

The document suggests caribou numbers have increased by 52 percent since about 2020 compared to what would have happened if nothing had been done. Currently there are 4,500 in the two provinces, about 1,500 more than there would have been.

“There could be some real good news,” Lamb said. “It was surprising, in a good way.”

The ranges of some herds are almost 90 percent disturbed by industry, and habitat restoration is the preferred solution. But it takes decades for a clearcut or cut line to return to anything resembling an old-growth state, so several stopgap measures have been used.

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Because different measures were used in different herds, the researchers were able to link population trends to interventions.

Sterilizing wolves didn’t work because it couldn’t be done on enough predators.

The same goes for declining moose and deer populations that attract wolves to caribou habitat. Almost all of those populations would have to be killed, an unpopular move in rural and First Nations communities where hunting is both a pastime and a necessity.

“Moose thinning is incredibly controversial,” Lamb said.

Moving animals from large herds to small herds only helped for one or two seasons.

What worked was killing wolves.

“Wolf reductions alone increased the growth rate of southern mountain caribou subpopulations by (approximately) 11 percent,” the report states.

That growth rate increased when wolf culls were combined with other measures such as feeding, penning and protecting pregnant cows.

“Wolf reduction was the only recovery action that consistently increased population growth when applied in isolation,” the report says. “Combinations of wolf reductions with maternal pens or supplemental feeding provided rapid growth.”

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The find puts wildlife managers in a difficult situation, Lamb said.

“Shooting wolves to save another species is an incredibly difficult decision.”

In 2020 and 2021, Alberta euthanized 824 wolves.

Some caribou ranges have been protected. In British Columbia, an agreement between the province and a First Nation has conserved 8,000 square kilometers, an area larger than Banff National Park.

Alberta has protected some habitat, but undisturbed ranges continue to shrink under pressure from the forestry and energy industries.

A recent study found that human disturbance increased in 23 of Alberta’s 28 caribou subranges between 2018 and 2021. Development permits were approved for 700 square kilometers of caribou range.

Until those trends are reversed, heavy-handed tactics like wolf culls will be the price for caribou herds, Lamb said.

“Every year we delay tree growth is one more year of having to implement these interventions. “I think we’re talking about many years of support for caribou.”

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