Understanding Picoides articus (Black-backed Woodpecker) occupancy in fire-suppressed forests of the northern Blue Mountains, USA

Abstract Fire is a significant disturbance agent, impacting forest structure and composition. In fire-adapted forests, fire can foster biodiversity by resetting successional processes and increasing habitat heterogeneity. However, fire suppression practices have altered historical fire regimes and left fire-adapted ecosystems largely unburned and the use of unburned forests by post-fire habitat specialists is understudied. Picoides arcticus (Black-backed Woodpecker) is a post-fire specialist that thrives in recently burned coniferous forests by exploiting heterogeneous patches of live and dead trees. Despite being a regional species of conservation concern, its occurrence and habitat use remains poorly understood in the managed forests of the northern Blue Mountains of Washington and Oregon, USA. Here, we combine passive acoustic monitoring and Bayesian occupancy modeling to understand P. arcticus occurrence across two National Forests during the breeding season. We examined how the prevalence of prominent tree species, attributes of forest structure, and fire history relate to occurrence. We found the odds of P. arcticus occupancy was 3.67 times larger for every 2.88 m2 ha−1 increase in lodgepole pine (Pinus contorta) basal area and 2.16 times higher with every 5.04 m2 ha−1 increase in ponderosa pine (P. ponderosa) basal area. The small number of survey stations classified as burned limited our ability to identify an effect of fire history. Our findings provide insight into how a fire-adapted species is using largely unburned forest. We also fill important knowledge gaps for a priority species of conservation concern by creating a species distribution map. Collectively, this information can inform active forest management and conservation decisions.