Wildfires Reduce Disease Risk in an Endangered Frog

Abstract Background The ongoing biodiversity loss crisis is increasingly driven by climate change and emerging infectious diseases. This crisis demands a deeper understanding of the synergistic impacts of multiple threats. Among vertebrates, amphibians are experiencing the steepest global declines, often driven by simultaneous threats. In this study, we examine the influence of wildfire severity on frog species richness, body condition, and chytrid Batrachochytrium dendrobatidis (Bd) fungal infection dynamics in the endangered Northern Stuttering Frog ( Mixophyes balbus ) in eastern Australia, where the 2019–2020 ‘Black Summer’ megafires burned large portions of the species’ range. Results We conducted over 230 nocturnal surveys across 20 stream transects spanning unburnt to high-severity burnt sites, collecting swabs from 210 captures over two post-fire breeding seasons. Overall frog species richness and diversity did not differ significantly across fire severities, nor did frog body condition, suggesting broader community resilience to fires. We captured a potential benefit of fires on a disease-affected species, as higher fire severity was associated with reduced Bd infection intensity, suggesting that fires may offer disease mitigation by creating warmer microhabitats on the forest floor. Body temperature was a significant predictor of Bd infection, with higher temperatures linked to lower infection prevalence and intensity. Seasonal variation further shaped infection patterns, with cooler months yielding higher infection prevalence. Conclusions Our findings provide novel evidence that wildfires may reduce disease risk for some frogs by altering microclimates. Additionally, we provide evidence that Australian frog communities may be more resilient to fire than previously assumed. This underscores the complex interplay between factors in disturbance ecology, highlighting the need for integrated strategies that consider disease outcomes in conservation planning and fire management.