This helps explain why caribou need so much room to roam. After all, the food they eat today will not grow back for many years. In the arctic, life is strong and fragile at the same time. Caribou are one of the few animals that can eat this abundant plant because of the acid it contains. Lichens are high in carbohydrates and have the most food value of any plant available to the caribou.
Lichens are very, very slow growing.
As a rule of thumb, it can take 50-100 years for lichens to grow back. So if an area is overgrazed or burned the caribou won't be able to use that habitat for many years. In fact, there have been fires in northern Manitoba within this herd's winter range and we're concerned how this might affect their use of the area. In the wintertime, caribou obtain the lichens by 'cratering' through the snow. When we go out for field studies in late March we've seen instances where they've cratered through snow as much as 2 feet deep.