Boreal woodland caribou (Rangifer tarandus caribou) are designated as threatened under Canada’s Species at Risk Act. A Recovery Strategy for the boreal population of caribou identified critical habitat for all but 1 of 51 caribou ranges – Saskatchewan’s Boreal Shield (SK1). The strategy identified 65% undisturbed habitat as the threshold below which a local population was not likely to be self-sustaining. Disturbance was measured as the combined effects of fires <40 years and anthropogenic land use. The fire component of the total disturbance model used fire polygons that were delineated using traditional mapping methods. Our study maps fire from 1988–2013 using the differenced Normalized Burn Ratio analysis of Landsat Thematic mapper and Operational Land Imager. Annual burned areas based on fire perimeters were similar between traditionally and Landsat-derived inventory approaches, but the traditional methods overestimated within-burn areas by 31.8%, as a result of including post-fire residuals and water bodies as burned. The federal recovery model assumes that all lands within provincial fire polygons (<40 years) are inadequate as caribou habitat, and ignores the potential value of post-fire residuals and water bodies as habitat. For some Boreal Shield ranges including SKI, where fire comprises the majority of the total disturbance and residual patches are abundant, total disturbance calculations, critical habitat designation and range planning decisions should take into account residuals, including water bodies.

Environment and Climate Change Canada (ECCC) calculated that 55% of Saskatchewan’s Boreal Shield has been disturbed by wildfire in the last 40 years. The 2012 Canadian Federal Recovery Strategy for woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) states that these large-scale natural disturbances can cause caribou to cease use of portions of their range. This assumption neglects the potential habitat value of postfire residuals. We tested this assumption using 2 years of GPS data obtained from 56 female caribou to identify calving site selection. Seventy-nine calving events were identified from 91 individual calving seasons. For both calving and postcalving periods, woodland caribou preferred nonburned (>40 years) over burned habitats (≤40 years). Within burned areas, residual patches dominated by bogs–fens were preferred, indicating that burns with residuals are important woodland caribou calving habitat. The residuals may act as island refuges providing food–security, while surrounding burns provide reduced visual obstruction from which caribou can detect approaching predators. Although more data are necessary to make robust conclusions, this study provides novel insight into the ecological interactions of forest fires with woodland caribou in northern Saskatchewan, and offers important considerations regarding critical habitat identification and range-level planning to ensure all suitable caribou habitats are identified.

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