With increased temperatures on the rise and shorter fire cycles becoming more prominent, food availability for caribou in the future will be scarcer, a recent study from UNBC suggests. The study, published in the Journal of Vegetation Science, highlights the dynamics of fire, caribou and lichens in the High Boreal and Subarctic regions of the Northwest Territories, Canada.
The researchers focused on the Bathurst caribou herd, which has suffered a dramatic loss of 98% in population over the last 30 years. Today, only about 8,200 caribou from this herd remain.
Barren-ground caribou select winter range sites with high abundance of lichens.
However, it takes many years for lichens to regrow after fire and in some areas it takes more than 120 years post-fire. Lichens are also complex organisms and their growth is favoured in particular forest types.
Why does fire frequency impact lichen for caribou? Shouldn’t the lichen be resilient to fire?
More research is suggesting that boreal forest is on the brink of a potential loss of resilience with climate change. With these changes come shorter fire cycles, which shrink recovery time of lichens that are slow growing.
With increasing fire frequency, the ecosystem resilience of the caribou’s habitat is threatened. It’s affecting the ability for an ecosystem to rebound its forest structure and function. The researchers found that though burn severity did not influence lichen recovery, frequency does. Future fire cycles could be shorter in the winter range of the Bathhurst herd. As a result, this would cut the time for recovery of lichens and result in a reduction in food availability during a critical point in their life cycle.
Lack of food resources, coupled with illegal killing of the caribou, pose a real threat to the survivorship of these caribou. In the last two weeks alone, 80 Bathurst caribou were illegally killed in N.W.T from the already dwindling populations. As of 2015, Bathhurst herd has been completely protected from any hunting. Unfortunately, this has sparked a movement of illegal hunts. In response, a Mobile Core Bathurst Conservation Area has been established north of Yellowknife, between North Slave and the Sahtu lands.
Caribou in Canada are canaries in a coal mine. We are seeing drastic loss from climate change and human pressure and it is more critical now than ever to fight these drivers of caribou population loss by protecting habitat.