The effects of fire severity on California spotted owl habitat use patterns

Fire is a dynamic ecosystem process in mixed-conifer forests of the Sierra Nevada, however there is limited scientific information addressing wildlife habitat use in burned landscapes. Recent studies suggest stand-replacing wildfires may be a major source of habitat loss for spotted owls (Strix occidentalis). While fire promotes heterogeneous forest patches, high severity fire may create large canopy gaps that can fragment closed-canopy habitat preferred by spotted owls. Large areas of high severity fire may eliminate protective cover or perch sites for spotted owls, while unburned or low to moderate severity fire containing intact forest canopy may provide protective cover or high prey availability. I used radio telemetry to determine whether foraging California spotted owls in Yosemite National Park showed selection for particular types of fire severity. My results suggest that spotted owls exhibited habitat selection for lower fire severities, edge sites, and locations near the roost within their home range. Although owls selected high contrast edges with greater relative probabilities than low contrast edges, I did not detect a statistical difference in these edge types. Protecting the remaining forests from stand-replacing fires via mechanical thinning or prescribed fire is a priority for management agencies, and my results suggest that fires of low to moderate severity can create habitat conditions suitable for California spotted owls.