Fishers (Pekania pennanti) are a medium-sized carnivore of conservation concern in portions of the western United States. Fishers in the southern Sierra Nevada of California are federally endangered and other populations in the western United States have been evaluated for federal listing. Small and isolated populations are the most immediate and challenging threat to fisher persistence in Washington, Oregon and California. Species distribution, habitat associations, and population size are critical information needs for species recovery. Distribution patterns and habitat associations have been evaluated using presence-only and expert opinion models. These models, however, frequently fail to meet assumptions, increasing calls for analyses in detection-non detection frameworks. We modeled the distribution, abundance, and habitat relationships of fisher across Washington, Oregon, and California. We developed a hierarchical model of detection-non detection data using occupancy and integrated modeling. We found that the use of bait and surveying in the winter had positive influence on the detection of fishers. We also found that canopy cover, the standard deviation of canopy cover, and stand age influenced patterns in fisher abundance. Our results will be a useful decision-support tool to promote species recovery in the face of stochastic events and a changing climate.

Sean Matthews, Ph.D. is the Conservation Biology Program Manager with the Institute for Natural Resources at Oregon State University. Sean is dedicated to the conservation of iconic and vulnerable species and ecosystems through applied field research, science communication and education, and policy intervention. He engages with federal and state agencies, indigenous leaders, academic partners, private industry representatives, rural communities, and urban populations to address shared conservation challenges. Some of Sean’s recent research includes investigating the response of forest carnivores to landscape changes brought by wildfire, evaluating the feasibility of reintroducing fishers to Oregon, and developing survey techniques for porcupines.