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What is Threatening Woodland Caribou?

June 30, 2021
Stew Coles
Woodland caribou in the boreal forest

By Caitlyn Anhorn

Like most other species in the wilderness today, the fate of boreal Woodland caribou relies on the actions that we humans take. While Woodland caribou have been listed as threatened on the Species at Risk Act since 2003, their population in Saskatchewan has still not stabilized. We are at the point where we need to take significant action in hopes that the caribou will remain here. Below are some of the threats that largely impact caribou and their habitat in Saskatchewan. 

Habitat Disturbance

Human activities and forest fires lead to increased clearings and linear disturbances. This is troublesome because Woodland caribou rely on large intact old-growth forest to access food (mainly slow-growing lichen), to avoid predation, and for calving needs. Disruption to the forest impacts both the immediate and surrounding areas and makes it harder for caribou to travel within and between habitats.

Activities like logging, roadbuilding, mining, and oil and gas development fragment the caribous’ boreal forest habitat. Though forest fires are essential to the health of the boreal, they are now more severe because of climate change and fire suppression, and they reset the forest’s cycle making the area unsuitable for caribou habitat. Typically, this would be okay because caribou can return to the area after a few decades of growth; however, compounded with other human disruption, finding suitable habitat is becoming more difficult. 

Caribou rely on old-growth forest that harbors lichen, their main food source. As picture here, new growth after a fire makes the area unsuitable for caribou.
Caribou rely on old-growth forest that harbors lichen, their main food source. As picture here, new growth after a fire makes the area unsuitable for caribou.

Predator and Other Ungulate Presence Because of Habitat Disturbance

As the boreal forest is disturbed, there are increased clearances and linear disturbances which also make it easier for predators like wolves and black bears to access caribou. Wolves effectively use anthropogenic disturbances to chase prey at high speeds without barriers such as trees or fallen logs. 

The clearances and resulting new growth also attract other ungulates like moose, deer, and elk which simultaneously increase predator presence.  

As other ungulates move into the area, they may transport disease that can threaten caribou. Chronic Wasting Disease (CWD) primarily infects moose, elk, and deer, but transmission to caribou is likely possible. The disease spreads between individuals through bodily fluids, infected animals, and contaminated areas. It is fatal as it infects the central nervous system; abnormal proteins gather in the brain and tissues and eventually severely impact regular activity. 

Climate Change

It is unsure how climate change may threaten Woodland caribou in the long-term, but it will inevitably have an impact. Be it a change in weather patterns in the winter or summer, changes in forest make-up, and/or changes in food availability. 

With climate change, the seasons may shift or change durations and there may be more freeze-thaw cycles, changes in precipitation events, colder winters and/or hotter summers. Increased forest fires or changes to the forest may continue to increase the presence of other ungulates and therefore predators. 

Keep reading here:

Recovery Strategy for the Woodland Caribou (Rangifer tarandus caribou), Boreal population, in Canada

Population and habitat ecology of boreal caribou and their predators in the Saskatchewan Boreal Shield