Caribou migration patterns shrinking along with habitat: UBCO study

New research from UBC Okanagan shows the migration areas of endangered caribou have decreased significantly, and resource extraction may be to blame.

Dr. Clayton Lamb is a researcher with UBC Okanagan’s Irving K. Barber Faculty of Science. He led a team who studied migration patterns in threatened caribou herds over a span of 35 years.

After collecting decades of data, the research team recently published a paper revealing a significant decline in migration areas.

Lamb says migration is critical to sustaining wildlife populations, “yet these movements are increasingly disrupted by human activity worldwide.”

“The data shows that most of these subpopulations remain migratory to some degree, but seasonal migrations appear to be shrinking in both duration and extent,” says Lamb.

The study indicates caribou are exposed to high levels of human-caused landscape disturbance, and this impacts migration.

Southern caribou traditionally has migrated vertically, up and down mountains, and horizontally between mountainous areas and lowland forests, in search of food. But that is changing.

“Due to their southern distribution, these caribou are exposed to higher levels of human-caused landscape disturbance and associated habitat change and loss," Lamb said.

"Observations from Indigenous communities, local people, scientists and government biologists indicate that southern mountain caribou migrations are changing or not happening at all.”

Dr. Adam Ford, director of UBC’s Wildlife Restoration Ecology Lab and UBCO’s Institute for Biodiversity, Resilience and Ecosystem Services, is a part of the research team.

He says caribou habitat loss is a serious threat to the survival of the species, and there has been a significant decline in southern mountain caribou migration over the past 40 years.

“We believe these changes are correlated with human-caused disturbances, including change and loss to habitat,” says Ford.

Over the course of their investigation, the southern mountain caribou population declined by more than 50 per cent. In 1983, the typical landscape disturbed by human causes, including logging, reservoirs and oil and gas drilling activity, was about five per cent, while natural disturbance from fire and pests was 0.3 per cent.

By 2020, however, more than 30 per cent of that landscape was disturbed by human behaviour.

“Sustaining caribou populations and their migratory behaviour into the future will require a rapid change in managing the landscape that facilitates extensive habitat conservation, restoration and a reduction in ongoing human-caused disturbance,” said Lamb.