The Slow Food Movement
In the vast tundra and boreal forests of the Northwest Territories, the survival of barren-ground caribou (Rangifer tarandus groenlandicus) depends on a patient relationship with their primary winter food: reindeer lichen. This is not a single organism; it is a composite lifeform—a symbiosis between a fungus and a photosynthetic alga. The dominant species, Cladonia rangiferina, grows at a glacial pace. Its hollow, branching structures, called podetia, increase in length by only 3 to 5 millimeters each year. This slow growth means that a patch of lichen grazed by caribou can take many decades to recover. It is this recovery time that dictates the caribou's own movements across the landscape.
The lichen provides carbohydrates, giving the caribou energy to survive the harsh winters. Caribou possess specialized microorganisms in their stomachs that allow them to digest the lichen's complex fibers, a feat few other animals can manage. Their broad, sharp hooves are perfectly adapted for digging through snow and ice to reach these lichen pastures, a behavior known as "cratering". This winter diet is so important that the migration patterns of entire herds, such as the Bathurst and Bluenose-East, are synchronized with the long-term availability of lichen fields.