Habitat selection by Pacific marten (Martes caurina) and other carnivores after wildfire and post-fire salvage logging

Wildfire and post-fire salvage logging are altering North American forests at an unprecedented rate. These disturbances affect key resources for wildlife across a range of spatial scales, from individual trees to entire landscapes. Habitat losses from fire threaten forest-specialist carnivores, such as Pacific marten (Martes caurina), that require closed, connected, and highly structured habitats. Salvage-logging, as a secondary disturbance, may amplify these impacts. Although marten use burned forests, the pattern and severity of landscape change strongly influence where these animals persist. In addition, fire-driven shifts in habitat structure and prey abundance may alter carnivore communities, restricting regionally-threatened specialist species like Canada lynx (Lynx canadensis) while benefitting generalists like coyotes (Canis latrans). I used a multi-scale approach to examine habitat selection by marten and other carnivores in north-central Washington, USA (burned in 2006) and central British Columbia, Canada (burned in 2010 and 2017). I also assessed these species’ responses to salvage-logging after the 2010 burn. I used snow tracking and forestry surveys to identify habitat features associated with marten foraging and scent-marking, and deployed GPS collars to characterize marten home ranges. Finally, I used winter track and camera surveys to explore the distribution of carnivores across these landscapes. Marten consistently relied on residual forest structure and avoided salvage-logged areas. Foraging marten selected sites with lower burn severity, greater canopy closure, more vertical structures (trees and snags), more saplings and shrubs, and greater moss/lichen cover than was generally available post-fire. When scent-marking, marten chose structurally complex sites with abundant deadfall or shrubs. Marten home ranges were closely associated with residual forest cover. More broadly, carnivore detection rates differed by burn severity: lynx selected unburned areas and marten selected lightly-burned areas, while coyotes and weasels (Mustela spp.) dominated in severely-burned and salvage-logged areas. My work indicates that burned forests with sufficient residual structure can support rich carnivore communities. However, it is also clear that salvage logging poses a major challenge to wildlife conservation. Lightly-burned areas provide critical post-fire habitat for marten in both Washington and British Columbia, and the retention of residual trees after wildfire should be a top management priority.Science, Irving K. Barber Faculty of (Okanagan)Biology, Department of (Okanagan)Graduat