The combination of historical fire suppression and ongoing climate change is a recipe for megafires in the seasonally dry forests of western North America. Reducing the risk of large, stand-replacing fires can be partly achieved through fuels reduction and forest restoration activities, but these actions can alter the habitat of wildlife species. Understanding the short- and longer-term impacts of megafires on sensitive old forest-dependent wildlife like the spotted owl (Strix occidentalis) is a key element to understanding forest restoration trade-offs. For example, if megafires are detrimental to the spotted owl, fuels reduction and forest restoration that reduce the likelihood that such fires occur are likely to provide benefits to this and other old-forest species.
We have studied a population of spotted owls in the central Sierra Nevada, CA since the 1980s – tracking owl survival, reproduction, and territory occupancy on an annual basis. Then, 25 years after we began the study, a large, severe fire (the King Fire) burned through approximately half of our long-term study area in 2014, creating a rare and powerful opportunity to study the effects of fire on spotted owls via a natural experiment (i.e., a ‘before-after control-impact’ study design). In other words, with half of our study area having burned and the other half remaining unburned, along with a quarter-century of pre-fire data, we could directly evaluate the effects of the fire on our population of owls by comparing the status of owls in burned and unburned areas. We tracked the trajectory of owl populations and drivers of territory occupancy for 6-years post-fire.