The Cerrado is the most diverse tropical savanna in the world. As a fire-prone ecosystem, natural fire in the Cerrado shapes plant communities and drives evolutionary processes. Human activities and landscape management can alter natural fire regimes and reshape Cerrado dynamics, making biodiversity conservation a challenge, particularly in densely populated areas. We reconstructed the historical fire regime of three protected areas (PA) and their buffer zones in São Paulo state to understand how current fire exclusion policies are affecting fire regimes and to measure how human-climate-fire relationships can change in areas under different land management. We used Landsat satellite imagery, from 1984 to 2017, with 30 m of spatial resolution and 16 days of temporal resolution. In total, we mapped 49,471 ha of burned area, and we detected variations in fire frequency and fire size among sites. PA dominated by open savanna in Itirapina concentrated 93 % of all observed fires, while PA dominated by forest-like formations in Assis represented only 2% of the fires. Annual rainfall showed a very weak relationship (R² = 0.04) with annual total burned area, while the rainfall split between dry and wet seasons showed a tendency to have a fuel moisture effect which determined the vegetation available to burn in the dry season (R² = 0.09). Fire regimes in PA were similar to those observed in buffer zones suggesting that fire-exclusion policies do not effectively prevent fires in PA that are surrounded by an anthropic matrix where fire is often used. When we included human factors in addition to rainfall, our models explained 44 % of variation of burned areas. We conclude that fire regimes in São Paulo Cerrado have been modified by humans and that fire exclusion is not a suitable policy for protected areas in this fire-prone ecosystem.

塞拉多（Cerrado）是世界上最多样化的热带稀树草原。作为易火的生态系统，塞拉多的自然火灾塑造了植物群落并推动了进化过程。人类活动和景观管理可以改变自然火灾状况，重塑塞拉多的动态，使生物多样性的保护面临挑战，尤其是在人口稠密地区。我们重建了圣保罗州三个保护区（PA）及其缓冲区的历史火情，以了解当前的防火政策如何影响火情，并衡量在不同土地管理下的地区人与火之间的关系如何发生变化。我们使用1984年至2017年的Landsat卫星图像，具有30 m的空间分辨率和16天的时间分辨率。我们总共绘制了49,471公顷的燃烧面积，我们发现了地点之间着火频率和火势的变化。在Itirapina中，以稀树草原为主的PA集中了所观察到的所有火灾的93％，而在Assis中以森林样地层为主的PA仅占了火灾的2％。年降雨量显示出非常弱的关系（R²  = 0.04），每年的总燃烧面积，而在干燥季节和潮湿季节之间的降雨分配则显示出具有燃油水分效应的趋势，这决定了干旱季节可燃烧的植被（R²= 0.09）。巴勒斯坦权力机构的火灾情况类似于在缓冲区观察到的情况，这表明防火政策不能有效地防止巴勒斯坦权力机构的火灾，该火灾被经常使用火源的人类基质包围。当我们除了降雨之外还包括人为因素时，我们的模型可以解释44％的燃烧面积变化。我们得出的结论是，圣保罗塞拉多的火灾状况已被人类修改，并且在这种易发火灾的生态系统中，排除火灾并非适用于保护区的适当政策。