Residual forest structure influences behaviour of Pacific marten (

Abstract

Wildfires are broad-scale disturbances in North American forests, with impacts that persist for many decades. Further disturbance from post-fire salvage logging is extensively modifying burned landscapes. The removal of habitat structure by fire and salvage logging may affect the persistence of forest-specialist wildlife such as Pacific marten (Martes caurina). However, it is unclear which resources are important to marten on burned landscapes. We used snow tracking and habitat surveys to examine marten habitat selection after three large fires in north-central Washington, USA (10–13 years post-fire), and central British Columbia, Canada (1–2 and 6–9 years post-fire). We developed site-scale habitat models to explain marten foraging and scent-marking post-fire, and assessed further structural changes from salvage logging. Foraging marten chose sites with lower burn severity, greater canopy closure, more vertical structures (trees, snags, saplings, and shrubs), and greater moss/lichen cover than what was generally available. When scent-marking, marten selected structurally-complex sites with abundant deadfall or saplings. Marten moved more quickly when canopy cover was sparse, and rarely used salvage-logged areas. Our results suggest that marten rely on residual habitat structure within large burns, and that secondary disturbance from salvage logging is substantially more harmful to marten than the original fire.