Forestry Opens Caribou Habitat to Wolves
Researchers plugging expert consensus about caribou ecology into a Bayesian network model have come up with a transparent decision-making tool to help maintain woodland caribou habitat. The model qualitatively shows the implications of different management options on the seasonal components of a caribou herd's range.
For instance, good early winter range for four herds in north-central British Columbia accumulates little snow and offers lichens that grow in pine forests of 70 to 140 years old. Habitat within 100 m of roads or with abundant shrubs that attract moose is rendered unsuitable because of the high risk of being frequented by wolves that prey on both moose and caribou.
These four herds have only wolves to worry about, as grizzly bears and cougars are scarce in this area. Nevertheless, the risk of encountering wolves reduces the size of seasonal ranges by 21 to 100 percent, with particularly heavy reductions in habitat used by caribou after the rut. The Takla herd of 125 animals currently has 12 ha of post-rut terrain that's of high to medium quality and safe from wolves.
The largest land management impacts on woodland caribou are those that influence predators: forest harvesting, stand age, road development and hunting regulation. Forecasting the effects of a conservative approach to timber harvesting on the 460-caribou Wolverine herd, finds that by 2075 its pine-lichen early winter range would decline to 350 ha of habitat with low exposure to wolves.
R. Scott McNay, Bruce G. Marcot, Viktor Brumovsky and Rick Ellis. 2006. A Bayesian approach to evaluating habitat for woodland caribou in north-central British Columbia. Canadian Journal of Forest Research. 36(12): 3117-3133.