Wildfire alters the disturbance impacts of an emerging infectious disease via changes to host occurrence and demographic structure

1. Anthropogenic activities have altered historical disturbance regimes, and understanding the mechanisms by which these shifting perturbations interact is essential to predicting where they may erode ecosystem resilience. Emerging infectious plant diseases, caused by human translocation of nonnative pathogens, can generate ecologically-damaging forms of novel biotic disturbance. Further, abiotic disturbances, such as wildfire, may influence the severity and extent of disease-related perturbations via their effects on the occurrence of hosts, pathogens, and microclimates; however, these interactions have rarely been examined.

2. The disease “sudden oak death” (SOD), associated with the introduced pathogen Phytophthora ramorum, causes acute, landscape-scale tree mortality in California’s fire-prone coastal forests. Here, we examined interactions between wildfire and the biotic disturbance impacts of this emerging infectious disease. Leveraging long-term datasets that describe wildfire...