Is this why some northern caribou numbers have drastically dropped?

A researcher studying barren-ground caribou says his work supports the idea that herds naturally cycle over time in response to changes in habitat and food availability.

Why the populations of some caribou herds have steeply declined has troubled governments and Indigenous communities for years. The Bathurst herd, for example, has gone from nearly 500,000 animals in the 1980s to fewer than 4,000 now.

Approaches used to try to halt this decline include wolf management programs, where wolves are killed in a bid to reduce the stressors on caribou herds. Not all experts agree that those programs help.

Eric Bongelli’s presentation at this month’s North American Caribou Workshop, hosted in Yellowknife, focused on the Bathurst, Qamanirjuaq and George River herds.

According to Bongelli, his latest research – which he said is a continuation of earlier work – suggests caribou populations are closely tied to the condition of their range, with herd numbers increasing as vegetation recovers and declining after prolonged grazing reduces available forage.

He said the decline phase is not necessarily unusual, but part of a natural process tied to how the ecosystem regenerates.

“When caribou decline to low numbers, that’s a natural life history response. They do, in a way, need to decline to low numbers to allow for range recovery to begin, to allow for lichen and other forage to regrow on the range before their populations can recover again,” he said.

Bongelli said the issue is particularly important in the North because caribou are a keystone species with deep cultural significance and history for many communities. He said a significant amount of time, effort, and research goes into caribou monitoring and recovery programs. As a result, changes in herd size have direct implications for wildlife management decisions.

He said the effectiveness of programs like wolf management depends on how they are measured, but his team’s conclusion is that those programs are “probably not necessarily needed.”

“Our research speaks to the idea that the decline phase of caribou populations or subpopulations is going to happen regardless,” he said.

“They need to decline to a number that allows grazing or the range to recover. Any sort of program that may slow down that rate of recovery, there could be short-term benefits for that, but also long-term implications.”

Looking ahead, he said there aren’t many ways to actively accelerate range recovery on a broad scale.

Instead, he suggested minimizing habitat disturbance and maintaining access to undisturbed range may be more important than direct intervention.

Land scars

Micheline Manseau, a research scientist at Environment and Climate Change Canada, said the work Bongelli presented helps to set out how population size and habitat limits can shape whether a herd declines or recovers.

Drawing on her own experience, Manseau linked the discussion to her work on the George River caribou herd in northern Quebec, where she documented severe summer range impacts when the herd reached high numbers.

She said damage to the landscape was not only from grazing but also trampling during dry summers, when large herds moving across fragile tundra caused visible degradation of lichen-rich areas.

“When you have 800,000 animals on a summer range and it’s a dry summer, the impact of them moving across the range is quite significant and that’s what we documented at the time,” she said, adding that her research was conducted in partnership with Inuit communities in northern Quebec, who shared their own observations about the relationship between heavy grazing and caribou declines.

“They would talk about the range conditions in a way that the land was covered in scars – but they all knew and they always said that when the scars disappears, when the lichen grows back, and then when you actually start seeing fewer tracks, then the caribou will come back and they will come back from different areas.”

Manseau said a key takeaway from the conference was that maintaining habitat connectivity is essential, allowing caribou to move freely, preserve genetic diversity and remain resilient to environmental change.

Support for wolf programs

Stephanie Behrens, manager of lands protection and renewable resources for the Tłı̨chǫ Government, said that government’s main focus is monitoring barren-ground caribou across their seasonal ranges to better understand ongoing population decline.

Behrens said crews monitor caribou along migration routes and in key summer areas such as Point Lake, Contwoyto Lake and Lac de Gras. In winter, monitoring focuses on harvest levels and caribou movements near the Tibbitt to Contwoyto Winter Road and MacKay Lake.

“With the decline of the Bathurst herd, a lot of our Elders and harvesters were concerned with the drastic decline and so [we are] just really trying to understand what’s going on with them,” she said.

According to Behrens, monitoring has revealed shifts in caribou distribution in recent years. She said the Bluenose- East herd, once commonly found near Délı̨nę and Great Bear Lake, is now seen more often around Point Lake.

Meanwhile, she said, the Bathurst herd’s range has contracted as its population has declined and the Beverly herd has moved farther west than its historical range. “Because of their shift in distribution, we’re able to harvest from that herd,” she noted.

Behrens said the Tłı̨chǫ Government has worked closely with the GNWT on a wolf reduction program aimed at supporting caribou recovery. Although a formal joint management agreement expired in March 2024, the Tłı̨chǫ Government has continued implementing related measures.

She said community members across the region remain concerned about wolf numbers and have encouraged the government to continue the program.

Behrens believes the health of the herd cannot be attributed to a single factor.

“I think climate change is a big thing. Every year, environmental conditions are changing. Each year, we’re seeing more drought conditions and more wildfires, more intense wildfires, and habitat fragmentation is occurring because of that,” she explained.

“If the caribou don’t have areas that they typically travel to, then they’re going to stay away from those areas. Then they don’t have the vegetation that they can feed on.

“Development, anthropogenic factors can attribute to that as well. There’s a lot of disturbance, especially around the mine sites, and the winter road that is causing a lot of stress to the animals. With climate change there are new diseases and parasites that are arising.”