Alberta Grizzly Bear Populations Increasing

·5 min read

Grizzly Bears have been listed as a Species of Special Concern in Canada, but they do not have any federal protections under the Species at Risk Act.

In 2010 grizzly bears were designated as a Threatened species in Alberta based on their population size, human-caused mortality rates, and dubious habitat quality. The provincial grizzly population estimate at that time was between 700 and 800 bears.

The leading causes of Alberta's low grizzly bear population are habitat disturbance and human-caused mortality. The quality and quantity of suitable habitats are increasingly diminished by the ever-increasing incursion of linear features, such as trails, routes, and roads meant to facilitate human access to areas that had previously been inaccessible. One reason that habitat has such a profound impact on the grizzly population is that this species has one of the lowest reproductive rates of all North American land mammals. Females generally begin to reproduce at 5 – 8 years of age, after which they usually give birth to cubs every 3 – 5 years. Some research shows that females in the mountain parks only reproduce every 4 – 5 years on average.

The three main ways that humans cause grizzly mortality in Alberta are:

· Collisions with vehicles or trains.

· Conflicts or encounters between people and bears.

· Poaching.

Grizzly bears in search of food can be drawn to areas inhabited by people (including recreation areas, oilfield and industrial operations, and agricultural areas), increasing the chances of conflict between people and bears. When bears come into conflict with people, they are at greater risk of being killed or trapped and relocated. Unfortunately, relocating bears doesn't necessarily solve the problem. Adult grizzlies in Alberta have home ranges of between 165 km2 and 2,755 km2, depending on the sex of the bear and their location (the Rocky Mountains vs. boreal forest). The bear might return to the original area that it was removed from or continue the same problem behaviours in its new location. A relocated grizzly may wander into another bear's territory, which could lead to the relocated bear's death.

In some areas of the province, the annual rate of conflict between humans and grizzly bears has been increasing, possibly because the grizzly populations have been recovering.

The province's updated Grizzly Bear Recovery Plan takes increasing grizzly populations into account and includes strategies to reduce human-caused grizzly mortality, preserve access to suitable habitat, promote education about and awareness of bears, and assess grizzly bear populations. The updated plan also includes creating new Grizzly Bear Management Units to ensure that the province's management strategies and recovery work are focused where they are the most effective while also reducing conflict between wildlife and people.

fRI Research's Grizzly Bear Program recently released their findings from population surveys of two Bear Management Areas (BMAs) conducted in 2018 (in partnership with Alberta Environment and Parks, Millar Western, Spray Lakes Sawmills, Vanderwell Contractors, and West Fraser Mills). The surveys were conducted in BMA 4 (Clearwater, 7,252 km2 in the foothills east of Banff National Park) and BMA 7 (Swan Hills, 9,800 km2 between Whitecourt and Lesser Slave Lake). The Clearwater area had previously been surveyed in 2005, but the 2018 survey was the first population survey performed in the Swan Hills area.

The surveys were conducted by setting up scent lures at 173 sites in BMA 4 and 200 in BMA 7. A 50m barbed wire perimeter was built around each of the scent lures so that the bears drawn by the lure would have to climb under or over the barbed wire to get to it. Bear fur is so thick that the bears aren't actually injured by the barbed wire, but they will leave tufts of hair on the barbs. The sites were checked for hair samples every ten days, and the scent lures were refreshed.

DNA was extracted from the hair samples and then sequenced to identify each individual bear. Identifying the individual bears prevented the same bear from being counted multiple times if it visited more than one site. It also allowed for other information to be gathered, such as family relationships and the bear's sex. A statistical model known as Spatially Explicit Capture-Recapture was applied to the data to estimate how many bears were likely missed and how many of the detected bears were actually part of another population and just visiting the study area.

The main findings were that the Clearwater area had an estimated 88 grizzly bears in 2018, more than double the number of bears found in the area in 2005.

The Swan Hills area had an estimated 62 bears in 2018, but the precision of this estimate was considered to be low due to some sampling anomalies. A low proportion of grizzlies detected in more than one sampling session combined with a high proportion of new grizzly bears detected in the final sampling session was abnormal when compared to other grizzly bear DNA mark-recapture projects conducted in the province. To mitigate the scant data from this project, the researchers used a meta-analysis approach using data from the neighbouring BMA 2 (Grande Cache) survey completed in 2008. Due to these abnormalities, the researchers suggest that these estimates be interpreted cautiously.

With the up-to-date numbers from these population surveys, Alberta Environment and Parks estimates that the total number of grizzly bears in the province is between 856 and 973.

Dean LaBerge, Local Journalism Initiative Reporter, Grizzly Gazette