Role of oaks in fisher habitat quality in the Sierra Nevada mountains at multiple spatial scales

Fishers (Pekania pennanti) occur in ponderosa pine， mixed conifer， and mixed hardwood conifer habitats in the southern Sierra Nevada at elevations from approximately 1400 to 2300 m. They are a candidate species for listing under both the Federal and California Endangered Species Acts. Since 2007， the U.S. Department of Agriculture， Forest Service (USDA FS) Pacific Southwest Research Station has been investigating fisher habitat selection in the mixed hardwood conifer landscape of the Sierra National Forest. California black oaks (Quercus kelloggii) occur in the forest types fishers occupy and are important habitat elements at multiple spatial scales. In the Kings River Fisher Project study area， black oaks were the most common species used for denning and the second most common species used for resting (52 percent and 24 percent respectively). At larger spatial scales， occupancy models indicate that hardwoods， in association with structural characteristics， such as stem diameter diversity and the presence of large snags， are important components of fisher habitat. Although little is known of fisher foraging habitat， black oaks are also associated with many important prey species of fishers. Shade-intolerant California black oaks are less abundant than they were historically; the creation of small openings to promote recruitment of young trees would therefore aid in the long-term maintenance of Sierra Nevada fisher habitat. Citation: Thompson， Craig M.; Purcell， Kathryn; Green， Rebecca; Sweitzer， Richard. 2015. Role of oaks in fisher habitat quality in the Sierra Nevada mountains at multiple spatial scales. In: Standiford， Richard B.; Purcell， Kathryn L.， tech. cords. Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world. Gen. Tech. Rep. PSW-GTR-251. Berkeley， CA: U.S. Department of Agriculture， Forest Service， Pacific Southwest Research Station， p.83-95