Predicting the impacts of forest management on woodland caribou habitat suitability in black spruce boreal forest

Abstract

Forest managers are under increasing pressure to conduct sustainable forestry while balancing multiple land use objectives. In the boreal forest, conflicts between forestry and conservation of woodland caribou Rangifer tarandus caribou (Gmelin) require that managers understand the effects of harvesting timber on the long-term viability of caribou. We hypothesized that large contiguous patches of suitable habitat are needed to ensure the long-term occurrence of caribou on managed forests. We developed a resource selection function describing the probability of caribou occurrence using satellite telemetry data from adult female woodland caribou. We used the Patchworks stochastic optimization model to predict the effects of three forest management strategies on caribou occurrence, harvest volume, and transportation cost for a 120-year planning period. The Patchworks model spatially allocates forest harvesting and generates a near-optimal solution to the constraints defining various management objectives. Management strategies that included caribou constraints produced greater probabilities of caribou occurrence than a strategy lacking explicit caribou objectives. No strategy predicted a substantial loss to forest harvest volume. The strategy with only aspatial habitat supply targets produced probabilities of caribou occurrence similar to, or greater than, the strategy containing spatial constraints relevant to caribou. The spatially constrained management strategy forecasted higher costs for building forest access roads. Our findings apply to seasonal range suitability for occupancy of caribou and further investigation is required to evaluate forest harvesting strategies in relation to annual range requirements. A combination of management targets that reflect the habitat needs and spatial requirements of woodland caribou should be used to guide conservation of caribou populations in boreal forests.