Using Landsat imagery to backcast fire and post-fire residuals in the Boreal Shield of Saskatchewan – Implications for woodland caribou management.

Abstract

Kansas, J.L, Vargas, J., Skatter, H.G., Balicki, B., and McCullum, K.

Woodland caribou are ‘threatened’ under Canada’s Species at Risk Act.  The 2012  Recovery Strategy identified critical habitat for all but one of 51 boreal caribou ranges – Saskatchewan’s Boreal Shield (SK1).  The strategy identified 65% undisturbed habitat as the threshold below which a local population was not likely self-sustaining.  Disturbance was measured as the combined effects of fires <40 years and anthropogenic land use.  The fire component of the total disturbance calculation used fire polygons that were mapped using traditional methods.  Our study maps fire from 1988 to 2013 using dNBR analysis of Landsat-TM and OLI imagery.  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 Boreal Shield ranges 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 consider residuals, including water bodies.

International Journal of Wildland Fire. 25(5): 597-607.

Manuscript can be downloaded here.