Wolf, Grizzly Bear, Black Bear, and Lynx, Photos courtesy of Corel Photograph Collection, David Blank, Phil Myers, and Corel Photograph Collection, respectively

Predation

The woodland caribou’s primary predator is the wolf. However, wolves also feed on moose (their most common prey), elk, mountain sheep, mountain goats, hare, deer, and beaver (Cumming, H.G., 1992; Edmonds, 1987). Predation is considered a major limiting factor for woodland caribou, especially when linked to habitat selection and disturbance of habitats by humans (Stuart-Smith et al, 1997; Wisheu, 2002). The predation rate of caribou is also related to prevalence of other prey though. Caribou tend to be most vulnerable to wolves since they depend on old-growth coniferous forests for their habitat.  When their habitat is destroyed by logging, mining, or other means of human disturbance, wolves have easier access to previously inaccessible areas. Caribou are less likely to be at risk of predation when their habitats and the surrounding areas remain untouched and inaccessible (Franke et al, 2004; Rasmussen).

Woodland caribou reduce their threat to predation in a couple of ways. First, they separate themselves from both predators and other prey by migrating to more isolated areas like islands.  They also distance themselves from conspecifics. Certain populations of woodland caribou separate themselves by swimming or traveling to smaller offshore islands without wolves, despite limited and poor quality of food resources on some islands (Bergerud et al, 1990; Cumming and Beange, 1987). One population of woodland caribou near Lake Nipigon, Ontario, traveled an average of 46km to reach island safe havens for the summer. These caribou travelled to the islands prior to the melting of the ice in the spring and returned to the mainland after reforming of the ice in the autumn. Their choice of island habitats were also influenced by the presence of moose on islands. Caribou preferred smaller islands when moose were not present and larger islands to distance themselves from the moose when they were present (Cumming and Beange, 1987). Woodland caribou seek out these more protected areas during the calving period and use dense forests, difficult mountain terrain, and areas of snowfall that would make preying difficult when islands are not used (Stuart-Smith et al, 1997).

Coniferous foothills of Alberta/British Columbia, Photo Courtesy of Scott and Ruth Bassett

Conservation

Increasing vulnerability to predation as a result of habitat loss is of continuing concern for the woodland caribou. While certain populations continue to grow and prosper (Parker, 1981), the majority of the woodland caribou populations are on the decline (Thomas and Gray, 2002). The large home ranges and old-growth coniferous habitat of caribou do not suit the idea of creating small caribou sanctuaries or reserves (Wisheu, 2002). Instead, provincial governments in Canada have taken different measures to protect their caribou populations. Only native hunting of woodland caribou is permitted in Alberta, Saskatchewan, and Ontario. This is a small step, however both native hunting and legal hunting in other provinces and territories of Canada must be carefully watched because of the limited reproductive abilities of the woodland caribou.

The woodland caribou are valued among hunters and others for their meat. Additionally, populations often elicit a controversy over the actual cause of their diminishing numbers: is it a result of increased predation (human hunting included) or inadequate habitats (Cumming, 1992). The correct answer may be masked by personal opinion and lost in the details of research. With that said, Cumming’s believes that the survival of the woodland caribou depends heavily on the importance of lichen and other food sources in winter ranges with few predators (1992). Research supporting this idea that caribou winter in areas of low predator prevalence seems to support Cumming’s stance (Bergerud et al, 1990; Stuart-Smith et al, 1997). Perhaps this is another avenue for which conservation agencies and the governments of northern North America can pursue to ensure the survival of the woodland caribou. Whichever strategy conservationalists and governments choose to employ, their choice should focus on maintaining both their habitat and preventing access to their habitat by both man and predator.