Devegetation is a widespread driver of fire in the Brazilian Cerrado

The Cerrado is the largest tropical savanna in the world, featuring a wide range of vegetation types with different sensitivity to fire. The structure, functioning and rich biodiversity of the non-forest formations is intimately associated with the presence of fire, which historically has acted both as a natural disturbance and as a tool used by Indigenous communities. Currently, the Brazilian Cerrado is threatened by substantial devegetation (i.e., conversion of native vegetation to human land uses) and alterations in the fire regime (e.g., frequency, seasonality), negatively impacting biodiversity, local communities, and global climate regulation. Although it is known that land conversion can lead to fires in the Cerrado, the extent and proportion of burned area attributable to this process remain unclear. This study, covering the period 2003-2020, quantifies both the surface of native vegetation lost through land conversion (devegetation) and the area burned by fires ignited in converted areas, focusing on the portion of the Cerrado included in the state of Mato Grosso and the MATOPIBA region. Using geospatial data on devegetation (PRODES Cerrado), fires (Global Fire Atlas), and land use (MapBiomas), we classified individual fires into Devegetation Related Fires (DRF) or devegetation Independent Fires (IF). DRF were those ignited within or in close proximity to devegetated patches up to two years following the conversion, while IF included all other fires. We further examined differences in seasonality and size distribution between DRF and IF, and analysed DRF prevalence across different land tenures, including Indigenous Territories, Protected Areas, and private lands. Over the 18-year study period, DRF burned, with distinctive seasonality and reduced average fire size, approximately 20 million hectares within the study area, which represents about a quarter of the total native vegetation area. This accounts for approximately 12 % of the total burned area in the study region and is comparable to the size of the devegetated area during the same period (around 15 million hectares). Although governance systems like strictly Protected Areas and Indigenous Territories limited devegetation, they could not prevent impacts from DRF, which burned 12 % and 16 % of their total native vegetation area, respectively. These findings highlight the urgent need to halt devegetation and regulate fire use in the Cerrado through integrated fire management policies.