Wildfire and Drought Alter the Ecology of Jaguars and Co-Occurring Mammals in the World's Largest Wetland.

Climate change-driven disturbances are reshaping ecosystems worldwide with profound implications for biodiversity. We leveraged a long-term dataset and a natural before-after-control-impact experimental framework to evaluate the impacts of wildfire and concurrent drought on jaguars and the terrestrial mammal community in northern Pantanal. Using camera traps and jaguar scats collected before, during, and after a large wildfire, we (1) assessed the immediate and short-term impacts of fire on jaguar demography, abundance, activity, space use, and diet; (2) determined whether changes in mammal species richness and relative abundance occurred; (3) assessed whether these changes were driven by fire, drought, or both; and (4) tested competing hypotheses regarding community structure. We hypothesized that abundant aquatic prey either allow jaguars to suppress terrestrial herbivores through apparent competition, or alternatively, terrestrial mammals are released from predation and instead regulated by bottom-up resources. We found that jaguar activity initially declined post-fire but rebounded over time, with a significant increase in abundance and recruitment 1 year post-fire. Annual recapture rates of individual jaguars remained similar after fire, indicating that resident jaguars survived the fires and maintained their home ranges, whereas a large number of immigrants arrived from other areas. Mammal species richness and relative abundance increased across the study period and were more strongly correlated with drought-induced changes than with fire-related impacts. Jaguars maintained their specialization on aquatic prey, supporting the hypothesis that consumption of aquatic prey reduces predation pressure on terrestrial mammals. Our findings suggest this area may serve as a climate refuge for jaguars and other wildlife, providing stability amid extreme climatic events. We emphasize the importance of maintaining such refugia and implementing proactive fire management to mitigate future disturbances.