Historically, there were Southern Mountain caribou populations in the Monashee, Selkirk, and Purcell Mountain Ranges near Upper Arrow Lake and Kootenay Lake. Population declines have led to caribou only occupying the Selkirk Range near Nakusp (Upper Arrow Lake), Trout Lake, and Duncan Lake. This group of caribou is called the Central Selkirk subpopulation.
The Central Selkirk subpopulation are a mountain-dwelling herd that migrates seasonally to occupy habitat at different elevations. When there is a consolidated snowpack in winter, the caribou occupy mid- to high-elevation, sub-alpine fir forests where they can eat lichen out of the trees. As the snow melts in the spring, they migrate downslope to denser spruce, cedar, hemlock forests to forage on shrubs and vegetation. In the summer and early fall, the herd moves back up to high elevation alpine habitat until the snow becomes too deep, at which point they move into sub-alpine forests again.
These unique seasonal migrations allow caribou to avoid predators, reduce overlapping habitat use with other ungulates, and follow the seasonal availability of different forage types.
Caribou in the Central Selkirk subpopulation have been monitored since 1992, when biologists became concerned about the decreasing population. The census in 1997 showed there were 222 animals in the herd, which is the highest number recorded for the subpopulation. The 2021 census reported 28 animals, meaning there has been an 87% decrease in population since 1997. Only two of the 28 animals seen in the 2021 census were calves.
There has been no known adult caribou mortality over the last three years, but the overall population trend is still decreasing and there are not enough calves in the herd to support a healthy population.
Southern Mountain caribou throughout B.C. and Alberta have been declining due to direct and indirect impacts from human activity and climate change.
Industrial activity (e.g., forestry, mining) has led to habitat degradation and fragmentation which limits the caribou’s habitat use and abundance, alters food availability, and increases the risk of predation. Forestry operations create roads and cutblocks that fragment caribou habitat and limit foraging areas. Young, regenerating forests do not provide the appropriate habitat type or food for caribou. Mining leads to loss of habitat as well as habitat avoidance because of human activity in the area.
Industrial activity has made more young forests and habitat suited to other ungulates, such as deer, moose, and elk. These species are the primary prey of predators like wolves, cougars, and bears. When the other ungulates’ ranges start to overlap more with caribou, the predators follow and start to prey on the caribou herds as well. High predation rates in recent decades have resulted in low calf survival and are a major reason for population decline.
Recreational activity at any time of year will cause caribou to avoid the area and may disrupt their movement and foraging. Summer recreation is usually related to roads and trails, which can assist predator movement within caribou habitat. Winter activities (e.g., heli-skiing, snowmobiling, cat-skiing) are especially impactful because caribou have an extremely low energy budget in the winter. The lichen they rely on as food in the winter does not provide much nutritional value, so any unnecessary stress or extra energy spent avoiding humans causes a severe depletion to their minimal resources. Similar terrain is preferred by both winter recreationalists and caribou, which increases the risk of encounters and overlapping terrain use.
The Central Selkirk subpopulation has almost 300,000 hectares of core winter habitat protected from industrial activity. The caribou’s range also includes Lew Creek Ecological Reserve and Goat Range Provincial Park.
The Central Selkirk range is being used as a pilot project for a snowmobile management area. The Central Selkirk Snowmobile Management Area uses the GPS collars on caribou to create real-time, moving closures around the herd. This new adaptive management tool allows recreationalists to use terrain that is not occupied by caribou and gives caribou the space needed to minimize stress and disturbance.
Heli-skiing companies use similar collar data to give caribou a four-kilometre buffer to minimize impacts from helicopters and skiing.
Predator control has been ongoing in the Central Selkirks since 2019. The provincial government has hired crews to control wolf populations in caribou habitat across the province. The Central Selkirk range is one of two herd areas in the province where cougar populations are also being controlled. In 2021, the government renewed the predator control plan for another five years. Local hunters and trappers also hunt wolves, cougars, and bears in the Central Selkirk range.
The Arrow Lakes Caribou Society (ALCS), based in Nakusp, provides a local voice in land-use decision making regarding caribou recovery efforts for the Central Selkirk subpopulation. ALCS membership includes representation from outdoor recreational groups, local industry, and local and regional government.
ALCS started the Central Selkirk Caribou Maternity Pen project in 2019 as a way to increase calf survival. Female caribou will be captured in March 2022 and placed in the pen. They will be fed and cared for while they are pregnant and when their calves are young. This penning period provides females with high-protein feed, protection from predators, and veterinary assistance while pregnant and giving birth. It will protect young calves from predators when they are most vulnerable and increase their chance of survival when they are released with their mothers in July. The first year of maternity pen operations will be 2022 and the project is planned to continue for five years.