Grizzly Bear Population Increased Slightly, But Density Fell Sharply Near Roads

The grizzly bear population across a large section of the central Canadian Rockies appears to have increased slightly over a 12-year period.

But the growth was not evenly distributed.

A study using thousands of remote-camera detections found the estimated density of grizzly bear activity centres fell by 56 percent within four kilometres of paved roads between 2012 and 2023. Farther from paved roads, density increased by 37 percent.

The results point to a complicated conservation picture: the broader population may be growing, while bears become less concentrated in the places most heavily shaped and used by people.

“The grizzly bear population in our study area increased slightly over 12 years, yet the density of activity centers declined sharply near paved roads,” the researchers wrote.

Twelve Years of Cameras and Collars

The peer-reviewed study was first published in April 2025 and examined grizzly bears across a 15,512-square-kilometre region encompassing Banff, Kootenay and Yoho national parks and the Ya Ha Tinda area east of Banff National Park.

The broader research landscape also included communities and transportation corridors along or near its boundaries. A map published with the study identifies Canmore, Banff, Lake Louise, Field, Golden and Radium Hot Springs.

Researchers combined GPS information from 25 radio-collared bears with images collected by 711 remote cameras between 2012 and 2023.

The cameras recorded 11,974 grizzly bear detections, an average of nearly 1,000 per year. Researchers also recorded 367 detections of females travelling with cubs of the year.

Using those records, they developed a statistical model to estimate how bear abundance and density changed across the landscape over time.

A Slight Overall Increase

The researchers estimated an average density of 9.1 grizzly bears per 1,000 square kilometres across the study period.

By 2023, the estimated density had reached 10.4 bears per 1,000 square kilometres.

The statistical model indicated a slight overall increase, with an average annual growth estimate of approximately two percent. However, the study’s credible interval included the possibility of little or no growth, meaning the result should be interpreted as a modest positive trend rather than a precise annual increase.

The estimated density of reproductive females also rose, although those results varied considerably from year to year and carried much more uncertainty because relatively few females with cubs were detected.

Bears Became Less Concentrated Near Roads

The most striking finding was not the overall population estimate, but where bear density changed.

The estimated density of grizzly bear activity centres declined sharply close to paved roads while increasing in more remote areas.

An activity centre is a statistical estimate of the central area around which an animal’s movements and home range are organized. A decline in activity-centre density does not mean bears stopped using roadsides entirely. It suggests fewer bears centred their home ranges near those corridors as the study progressed.

The researchers found activity-center density fell by 56 percent within four kilometers of paved roads and increased by 37 percent farther away.

Why the Roadside Decline Happened Is Less Certain

The study identifies two possible explanations for the decline near paved roads.

Some bears may have died as a result of human activity, including transportation-related mortality or other human-caused incidents.

Others may have shifted the centres of their home ranges farther from roads to reduce encounters with people.

The researchers could not determine precisely how much of the decline was caused by mortality and how much reflected bears relocating.

“Mechanisms of decline may have included direct mortality and shifting activity centers to avoid human activity,” the study states.

Visitation across the national parks in the study area increased by about 30 percent during the research period, rising from approximately 3.3 million visits in 2012 to 4.3 million in 2023.

Most visitors were concentrated near communities, roads and accessible trail systems. The researchers used proximity to paved roads partly as a measure of that concentrated human activity.

The study found bear density increased in remote areas even as it declined closer to those roads.

Roads Can Attract Bears and Displace Them

The findings add another layer to recent research about how grizzly bears respond to development in the Canadian Rockies.

A separate study previously covered by Bow Valley Insider found highways, communities and other forms of development can restrict bear movement across the southern Rockies.

That research also identified a potentially dangerous contradiction. Roadside areas can produce attractive vegetation because disturbed ground receives more sunlight. Bears may be drawn toward those food sources even though roads expose them to traffic and human conflict.

Recent incidents along Banff National Park’s railway corridor have demonstrated that danger.

In May, a grizzly cub travelling with Bear 142 was struck and killed by a train near Protection Mountain. Weeks later, video captured a mother and cub leaving the tracks shortly before another train passed.

The population study did not specifically analyze railway mortality as a separate variable. However, the railway runs beside the Trans-Canada Highway through much of the central study area, making roads, railways, communities and human activity closely connected features of the same valley-bottom landscape.

Protected Areas Supported Higher Bear Density

The study found grizzly bear density was highest in good-quality habitat, close to protected areas and farther from paved roads.

Density declined as the distance from federal or provincial protected areas increased.

That finding supports the importance of national and provincial parks for large carnivores. But the researchers also caution that roads and human activity can reduce the effectiveness of protected areas from within or along their boundaries.

Much of the study took place inside national parks, yet localized density still declined near paved roads.

“Human activity and associated infrastructure can reduce the effectiveness of protected areas through mortality or habitat degradation and loss,” the researchers wrote.

The paper also points to the importance of cooperation across jurisdictional boundaries. Bears regularly move between national parks, provincial lands and other areas where rules, development pressures and mortality risks can differ.

Results for Females Were Less Certain

Researchers separately estimated trends among reproductive females, defined as adult females travelling with cubs born that year.

Their estimated density increased over the study, but annual results fluctuated widely.

The researchers found slightly lower reproductive-female density near roads, but emphasized that the estimate had a high level of uncertainty. The study could not establish a strong roadside trend for these females comparable to the trend found for the overall population.

The authors said the uncertainty may reflect the relatively small number of reproductive females or differences in how individual females balance human disturbance against threats from adult male bears.

The results should therefore not be interpreted as proof that all females with cubs consistently avoid roads more than other bears.

What the Researchers Say Could Help

The study discusses several measures that could reduce the effects of roads and growing visitation.

Wildlife overpasses and underpasses can reduce collision risk and help animals cross transportation corridors. Seasonal or nighttime closures can give wildlife access to important habitat when human use is limited.

The authors also point to visitor-management systems, including timed-entry approaches used elsewhere, as one possible way to reduce concentrated disturbance during busy periods.

These are presented as potential management tools, not as guarantees that roadside bear density will recover.

The researchers also recommend periodically fitting more bears with GPS collars. Most of the collared-bear data came from the earlier years of the project, limiting the researchers’ ability to measure how home-range sizes and camera-detection rates may have changed over time.

A More Complicated Measure of Success

The study offers cautious evidence that the grizzly population across the research area increased slightly between 2012 and 2023.

That is an encouraging regional result.

But it also shows why population totals alone do not tell the full story.

Bears were increasingly concentrated in remote areas and less concentrated near paved roads. Around transportation corridors and communities, the pattern moved in the opposite direction from the wider population.

The study does not show grizzly bears disappearing from the Bow Valley, nor does it provide a population estimate specifically for Canmore, Banff or Lake Louise.

What it shows is a gradual redistribution across a heavily visited mountain landscape.

There may be slightly more bears across the region than there were at the beginning of the study. But fewer are centring their lives near the roads and communities where people are most likely to encounter them.