Post-fire dynamics of terrestrial lichens: Implications for the recovery of woodland caribou winter range

Abstract

Forest fires are the most dominant natural disturbance process influencing the habitat and distribution of woodland caribou (Rangifer tarandus caribou) in winter. This is a function of terrestrial lichens, the primary winter forage of caribou, taking decades to recover following fire. Working across the range of the Klaza caribou herd in the west-central Yukon, Canada, we used statistical count models to evaluate variation in lichen volume and percent cover among burns of different age classes. Burns of the same age had considerable variation in lichen abundance. Forage lichens were more abundant in coniferous stands with greater canopy openness, tree height, and basal area. Although not a significant parameter in models of volume or percent cover of lichen, time since burn improved model performance. Relative to thresholds in the published literature, most stands had sufficient lichen at 50 years post fire to be considered winter range for caribou. The relationship between caribou and burned landscapes is complex suggesting that wildlife and forest managers should look beyond burn age when accounting for the effects of fire on the availability and quality of winter habitat for woodland caribou.