COS 188-2 - Resilience to Megafire in California Oak Woodland Mammal Communities

Background/Question/Methods

Global change continues to exacerbate the frequency and severity of megafires around the world, with catastrophic consequences for both wildlife and humans. Despite this, there remains a considerable gap in our understanding of how wildlife species respond to megafire. Megafires may dramatically alter critical wildlife habitat and potentially threaten the conservation of local animal populations. The 2018 Mendocino Complex fire, now the third largest fire in California’s recorded history, is a striking example of this phenomenon as it burned over 3,000 acres of the Hopland Research and Extension Center in Northern California. We take advantage of a rare scientific opportunity to leverage camera trap data collected before, during, and after this fire to examine how mammal species respond to megafire. In this study, we combine a systematic grid of camera traps with an occupancy modeling framework to observe the impacts of megafire on species occupancy and activity across an assemblage of twelve mammal species in an oak woodland savannah.

Results/Conclusions

Using single-species occupancy models we found that responses to megafire across mammal species are species-specific. Large carnivores (mountain lion and black bear) decrease their activity in recently burned areas while many mesopredators (coyote and gray fox) increased their occupancy and activity in burned areas. We found that the occupancy and activity of most species by the end of this study (two years post-fire) were comparable to occupancy and activity levels pre-fire, suggesting most species were resilient to megafire. Using a multi-species occupancy model, we found that species richness was concentrated in areas with remaining canopy cover immediately following megafire. Taken together, these results may indicate the importance of habitat refugia following megafire in providing important resources in the short-term and for facilitating recolonization of burned areas in the longer-term. Megafire may also prompt short-term changes in mammal species composition and alter certain interspecies interactions, like predation. Fire and land management that can limit the size and severity of wildfire and encourage future fires to be “patchier” may help enhance the resilience of wildlife communities to future megafire.