PS 22-50 - Assessing Recent Spatiotemporal Changes in Critical Forest Cover for Caribou in Eastern Canada Using Landsat Imagery

Abstract: Caribou is of great cultural value to many Indigenous communities in Canada. Moreover, the boreal population of woodland caribou is an umbrella species for old-growth forest specialists in the forests of eastern Canada. As a result of anthropogenic disturbances, boreal populations of caribou have declined significantly in recent decades, leading to its designation in 2003 as threatened under the Canadian Species At Risk Act. Indeed, human activities such as logging and mining have led to significant alterations of forest covers, and they have been proven to have severe impacts on boreal caribou habitat. As such, it is important to identify how and where these alterations were most important and at which pace they occurred in recent decades in order to better understand their historical impacts on boreal caribou habitat alteration. In this study, we evaluated spatiotemporal changes in forest covers in eastern Canada between 1985 and 2020 using a recent nationwide Landsat-derived product, i.e., the Spatialized Canadian Forest Inventory (SCANFI), and interpreted these changes using a habitat suitability model developed for boreal caribou. The results indicate that substantial changes took place between 1985 and 2020: forests have become younger and more fragmented, with higher deciduous content, which together have led to a decline in caribou habitat quality. The loss of mature and old-growth forests, an important habitat component for caribou, has been especially pronounced within caribou ranges, with clear-cut logging being the primary driver of these changes. These findings confirm that forest management strategies in recent decades, through the continuous development of the forest road network and associated logging, have greatly contributed to the alteration of the critical habitat of caribou, even after its designation as a threatened species. Our study stresses the urgent need to modify forest management strategies by prioritizing the protection and restoration of mature forests and decommissioning portions of the road network, particularly in areas that are important to caribou. The results of this study also underscore the importance of the fine-scale monitoring of the changes in forest cover to assess their historical impacts on wildlife habitat.