An Assessment of Lichen Ecology, Distribution, and their Importance to Caribou

The study addresses the decline of boreal caribou (Rangifer tarandus caribou) in northern Alberta and Canada’s boreal forest, which may be linked to habitat loss, human disturbance, climate change, and reduced lichen availability. Its purpose is to examine lichen distribution and caribou winter diet in relation to stress indicators and habitat selection. Key objectives include identifying winter diet composition, assessing impacts of diet and proximity to roads on stress, mapping lichen-rich areas, analyzing how lichen and road distance influence resource use, and recommending future research on caribou-lichen dynamics.

The study found that lichen-rich habitats are rare within the Egg-Pony and Algar caribou ranges, and their distribution is strongly influenced by wildfire history, with areas burned 50–80 years ago showing the greatest lichen cover. Caribou winter diets are dominated by terrestrial and arboreal lichens, and nutritional condition improves when lichens are more abundant, as indicated by elevated T3 and reduced GC hormone levels. Caribou tend to select sites rich in lichens and farther from winter roads, but lichen-rich areas near roads may still pose stress due to high GC levels. Based on these findings, the study recommends long-term monitoring of caribou diet and physiology, conserving and restoring lichen-rich habitats, improving mapping of these areas using high-resolution imagery or LiDAR, and sampling caribou nutrition across seasons to better understand limiting factors and support population recovery.