The impact of wildfire smoke on local avian biodiversity

Land use alterations and climate change are shifting natural fire regimes, leading to prolonged and intensified fire seasons accompanied by widespread air pollution, with potentially important consequences for local wildlife. Combining data from the North American Breeding Bird Survey with high-resolution satellite imagery, we estimate the impact of wildfire-specific smoke pollution (PM2.5) on avian biodiversity in the contiguous United States (US) from 2008 to 2022. The panel fixed effects instrumental variable estimation results indicate a short-term adverse effect of PM2.5 on taxonomic and phylogenetic diversity metrics. More specifically, a standard deviation (sd) increase in wildfire-specific PM2.5 pollution reduces species richness, abundance, and phylogenetic diversity by about 0.1 sd. For the most polluted transects the effect is up to 2–3 standard deviations. The adverse impacts on biodiversity vary across ecosystems, with particularly pronounced effects in the North American Deserts and Eastern Temperate Forests. These findings underscore that fire management and conservation strategies should consider biodiversity impacts among the many factors guiding resource allocation, particularly as wildfire intensity and smoke exposure are projected to increase in many regions worldwide.