A long-term assessment of fire regimes in a Brazilian ecotone between seasonally dry tropical forests and savannah

•Fire regimes in the Caatinga-Cerrado ecotone are presented for the first time.•Temporal and spatial variation of fire occurrence was related to climatic variables.•Forty-eight percent of the Capivara-Confusões Mosaic burned over a 19-year period.•A multiple-year process could explain years with large burned areas.•Fire recurrence reached 10 and 47% of the burned area had some degree of recurrence. Fire is a recurrent phenomenon in semiarid seasonal ecosystems. The study of the relationship between fire and climate could provide new approaches for understanding fire dynamics in semiarid regions, which could be useful for strategically managing the loss and recovery of natural resources under threat. Here, we evaluated the patterns of fires occurrence in a semiarid Caatinga-Cerrado ecotone in the Northeast Region of Brazil by characterizing their spatiotemporal dynamics associated with climatic conditions. Using a temporal series of 306 Landsat images, we mapped a burned area database at a fine spatial resolution (30 m) from 1999 to 2017 in the Capivara-Confusões Mosaic of protected areas and their surroundings. Fire seasonality was analyzed through climatic seasons, distinguishing between the rainy season (RS), early dry season (EDS), middle dry season (MDS) and late dry season (LDS), by analysis of the daily precipitation of ground-based stations in the area. We created yearly, seasonal and recurrence maps of burned areas to assess fire regimes. The results showed that the 48% of the area was burned during the 19-year long period considered. Serra das Confusões National Park (SCoNP) had 302,644 ha burned, Serra da Capivara National Park (SCaNP) had 2056 ha burned and the ecological corridor had 215,718 ha burned. Most of the burned area was registered during the MDS (36% of the study area), there was almost no burned area in the EDS (