Skin microbiome disturbance linked to drought-associated amphibian disease

Global climate change is triggering abnormal rainfall patterns, disrupting healthy associations between wildlife and their symbiotic microorganisms. We monitored a population of pumpkin toadlets in the Brazilian Atlantic Forest throughout a short-term drought. Amphibian skin bacteria are known to play an important role in inhibiting the widespread fungal pathogen Batrachochytrium dendrobatidis (Bd), thus we investigated links between skin microbiome health, pathogen susceptibility, and host mortality during a die-off event. Rainfall deficit indirectly predicted higher Bd loads through microbiome disruption, while its direct effect on Bd was weak. The microbiome exhibited reduced putative antifungal function and diversity following the drought, independent of infection status, and our findings pointed to a one-month lagged effect of drought on the microbiome that increased toadlet susceptibility to Bd. Our teleconnection analysis strengthened the notion that local- and continental-scale drivers of rainfall variability could impact complex host-microbiome interactions and disrupt wildlife disease dynamics across diverse ecosystems.