Fire is a natural disturbance in California ecosystems and under normal conditions is beneficial to maintaining these systems. Over the last few decades, fires have become more frequent, more intense, and larger, due to climate change and human activities. I investigated the potential impacts to suitable habitat (CDFW models) for several common and at-risk species in California during fires over the last 30 years. At the state scale, a linear regression between 1991 and 2020 of annual burning of suitable habitat for mule deer, bobcat, black bear, ringtail, and porcupine indicated that annual impact increased significantly from 0.2% to 1.5%, 0.2% to 1%, 0.26% to 2.5%, 0.2% to 1.2%, and 0.2% to 2%, respectively. This masks that in 2020, impacts ranged from 4.5 to 6% of suitable habitat. At the scale of the San Diego County Multi-Species Conservation Plan, there was no significant change in annual rates of burning for Mountain Lion and American Badger habitat, but in individual years, the impact was as high as 33% (2007). These results suggest that mammal conservation planning at state and municipal scales include fire impacts as a potential source of loss and that fire planning include habitat protection as an important activity.

Fraser Shilling is a senior ecologist at Dudek, with the new Transportation Ecology program. He is also director of the Road Ecology Center, University of California, Davis. He gained his PhD from the University of Southern California in aquatic biology and has published extensively in the peer-reviewed literature.