Human land occupation regulates the effect of the climate on the burned area of the Brazilian Cerrado

Human activities and climate change are transforming fire regimes globally. The interaction between these two drivers is poorly understood, yet critical if we aim at predicting how biomes will respond to novel fire regimes. In the Brazilian Cerrado, altered fire regimes are threatening its unique biodiversity and ecosystem functioning. Here, using geospatial data for the period 1985-2020 and a causal inference framework to design Bayesian statistical models, we demonstrate that a larger human presence in the landscape (>= 40% land-use area) reduces the Cerrado's burned area and hinders its responsiveness to climate; while climatic effects only become apparent in landscapes with little human presence, where hotter and drier conditions increase burned area. Finally, we find spatially heterogeneous burned area trends over time, with increases associated to climate change in landscapes that have remained mostly intact, and decreases caused by anthropic expansion. Both diverging trends have important implications for the conservation of the Cerrado as land-use expansion and climate change continue to unfold. In landscapes with 40% or more human land-use area, humans decrease the Brazilian Cerrado's burned area and hinder its climate responsiveness, while climate effects are more noticeable in smaller human-influenced areas, according to a causal inference framework analysis.