Scientists use hair samples, collected after a bear rubs against a tree like the one pictured here, for DNA analysis. Photo courtesy of Ryan Peruniak.
A new study by University of Alberta biologists show that black bear populations are lowest on Crown land, contrary to popular belief among biologists. Instead, black bear populations are most dense on national park land, followed by private lands, highlighting issues for management and conservation.
"We might have thought that Crown land would host more black bears," said Mark Boyce, professor in the Department of Biological Sciences. "However, many bears appear to have been displaced onto private lands, likely due to excessive recreational use of Crown land for recreation, like quadding, camping and motorbiking."
The study provides the first comprehensive analysis of the black bear population in Alberta in more than 30 years, using bear hair samples from rub objects to identify individuals by DNA and then to estimate population size.
"There are a number of possible reasons why density differs by land tenure, such as mortality risk from humans and the availability of foods. Private lands in our study are mainly agricultural lands, which also can be attractive to black bears, especially stored and standing grain," said Annie Loosen, who recently graduated after completing her MSc under the supervision of Boyce. "In Alberta, this is particularly problematic because landowners can hunt or give other hunters permission to shoot a black bear on their land at any time of year without restriction."
Supporting policy
The findings support recent decisions limiting off-highway vehicle use in Castle Provincial Park and Castle Wildland Provincial Park, explained Boyce. "Our results reinforce the decision to protect core habitats in provincial parks. We are keen to learn the response by both grizzly bears and black bears to increased protection on Crown land."
The researchers also recommend ongoing monitoring of black bear populations to document the outcomes of policy changes.
The paper, "Land tenure shapes black bear density and abundance on a multi‐use landscape," was published in Ecology and Evolution(doi: 0.1002/ece3.4617).