BOW VALLEY – Off-highway vehicles such as dirt bikes and quads are forcing grizzly bears to alter their habitat choices and movements, according to new research.
A University of Alberta study found grizzly bears – males, solitary females and females with cubs – respond to recreational trail use to varying degrees, but were more likely to use habitat with non-motorized activity, like hiking.
Biologists say outdoor recreation on trail networks is a growing form of disturbance for wildlife, but few studies have examined how large carnivores respond to motorized and non-motorized recreation.
Mark Boyce, professor in the department of biological sciences at the U of A and co-author of the study, said he believes the research shows that ATVs and dirt bikes lead to grizzly bears avoiding areas and changing their movements, which could potentially affect their ability to forage on vegetation near these trails.
“Motorized activity is very disturbing to bears,” said Boyce, who also sat on the province’s grizzly bear recovery team.
“This has become a fairly hot topic because of the proposed wildland provincial park for the Bighorn and restricting quad use in the Castle.”
Grizzly bears were captured and fitted with GPS collars on the eastern slopes of the Rockies and foothills in west-central Alberta to track them, and motion-activated cameras were set up on trails to record what people were doing.
Previous research has shown that elevated stress and avoiding areas can be costly for individual grizzly bears and potentially could influence a bear’s fitness through changes in survival and reproduction.
This new study recently published in the Journal of Applied Ecology found that males and solitary female grizzly bears were more likely to avoid trails when there was motorized recreation, and tend to move faster when near these trails.
Females with cubs did not increase avoidance, however they had the largest response in terms of higher movement rates when close to trails with off-highway vehicles (OHVs).
“Females with cubs are often going to places that aren’t quite as good habitat and places where other bears might avoid,” said Boyce.
“They do move faster near a trail with quads. It’s not like they hang there, but they will spend more time near trails than the males.”
The Alberta government is phasing out OHVs in Castle Provincial Park and Castle Wildland Park over the next three years; however, some trails still remain dedicated to motorized recreational use.
This year, 137 kilometres of trails remained open to OHVs in the Castle, down from 350 kilometres.
In 2019, summer OHV trails will be down to 37 kilometres, and by 2020, only a one-kilometre section of trail on the park’s northwest will remain open to connect to a route outside its border.
Currently, there’s also a push from conservationists for creation of a wildland provincial park in a 6,717 square-kilometre area of the Bighorn backcountry, immediately adjacent to Banff and Jasper national parks.
While there are currently some restrictions on OHVs, a wildland provincial park designation would restrict quad and motorcycle access in certain areas considered critical to some wildlife.
“We had over-the-top excessive abuse of the landscape by quads in the Castle,” said Boyce, noting previous research had already shown bears there were sensitive to roads.
The issue of access management was front and centre during discussions to form the province’s grizzly bear management plan, given Alberta is riddled with a criss-cross of roads and trails severely eroding habitat security for grizzly bears.
With estimates of 43,000 kilometres of dirt and gravel roads in Alberta passing through grizzly bear habitat to access logging and industrial development like oil and gas, the group proposed a road density of 0.6 kilometres of road per square kilometre.
Higher road density leads to lower grizzly bear density, research has concluded. As well, industrial roads allow increased access for poachers.
“At 0.6 kms of road per square kilometre – that’s the cut off point. If you’ve got more than that, then the quality of areas for grizzly bears is substantially reduced,” said Boyce.
“We came to the conclusion that we needed to restrict highway vehicles from areas that were critical grizzly bear habitat and that by doing so, we would eliminate most of the problem,” he said, also noting poaching in these areas is not uncommon.
Grizzly bears were listed as a threatened species in Alberta in 2010 after DNA counts determined there were about 700 grizzlies remaining. Those numbers are being updated.
Research has shown the underlying cause of Alberta’s low grizzly bear population is habitat disturbance.
Some of the factors effecting grizzly bear conservation include human-caused mortality and unrestricted road access and use in grizzly bear habitats that can lead to habitat fragmentation and conflicts with people.
This latest study concludes grizzly bear reaction to recreational activity suggest management decisions to restrict human access, specifically for motorized recreation, could benefit grizzly bears.
They noted that further information is required to determine if human recreational activity is ultimately reducing grizzly bear survival or reproduction.
“Controlling recreational access, particularly motorized activity, on areas with high quality bear foods would be an important step in dampening potential negative consequences of human recreation,” the study concluded.
“Continued monitoring of the type and frequency of recreational access by both park and public land managers is required to fully understand the long-term influences of access management actions.”
Historically, Alberta is estimated to have had between 6,000 and 9,000 grizzly bears. Grizzlies ranged across the whole of Alberta, across Saskatchewan and into Manitoba.