Background: Wildfires in Southern Europe arise from interacting climatic, ecological, and socio-ecological mechanisms. Drought enhances fuel desiccation, land cover change reshapes vegetation flammability, and the expansion of the wildland–urban interface (WUI) increases ignition pressure and exposure. Understanding how these drivers overlap spatially and temporally is essential to identify where reinforcing or decoupled processes shape wildfire dynamics. This study develops a spatially explicit framework integrating drought variability (Standardized Precipitation–Evapotranspiration Index, SPEI), Landscape Flammability Classes (LFC), and Wildland–Urban Interface (WUI) expansion to detect statistically supported hotspots and coldspots of wildfire occurrence across biogeographical regions. Methods: We analysed a 20-year dataset (2001–2020) at 12-km resolution, combining number of fire and fire size with long-term trends in three macro-drivers (SPEI, LFC, WUI). Temporal changes in wildfire parameters were estimated using generalized linear models with False Discovery Rate (FDR) correction. Trends in SPEI and WUI were assessed through Mann–Kendall and Kendall tau tests supported by Theil–Sen slope estimation, while LFC change was derived from land-cover transitions between 2000 and 2018. Finally, a spatial co-occurrence analysis classified each grid cell as a hotspot, coldspot, or mismatch area based on the degree of alignment between macro-driver trajectories and wildfire trends. Results: Significant and candidate hotspots were concentrated in the Anatolian, Continental, and Mediterranean bioregions, where over 30% of burned areas showed concurrent increases in drought intensity, landscape flammability, and WUI expansion. The Anatolian bioregion exhibited the strongest increases in WUI (+ 73.4%) and LFC (+ 67.2%), while the Continental region was dominated by widespread drying (90.5% of its area). Coldspots were mainly located in the Atlantic region, reflecting coherent declines in both wildfire parameters and macro-drivers. Mismatch zones, encompassing more than half of the burned area, revealed high spatial variability where fire dynamics diverged from macro-driver trends, indicating the influence of local-scale or non-mechanistic processes. Conclusions: The joint analysis of climate variability, fuel continuity and human pressures shows that wildfire patterns in Southern Europe depend on how the long-term trends of these macro-drivers align or decouple. Hotspots reveal regions where multiple drivers evolve in the same direction as wildfire activity, whereas mismatch areas highlight the role of local processes that interrupt large-scale relationships. The framework provides a quantitative basis for interpreting spatial heterogeneity in wildfire dynamics and supports integrated, multi-driver assessments for Mediterranean wildfire research.
Intertwining macro-drivers to explore hotspots of wildfire occurrence in Southern Europe
Ascoli, Davide;Oliveira, Sandra;
2026-01-01
Abstract
Background: Wildfires in Southern Europe arise from interacting climatic, ecological, and socio-ecological mechanisms. Drought enhances fuel desiccation, land cover change reshapes vegetation flammability, and the expansion of the wildland–urban interface (WUI) increases ignition pressure and exposure. Understanding how these drivers overlap spatially and temporally is essential to identify where reinforcing or decoupled processes shape wildfire dynamics. This study develops a spatially explicit framework integrating drought variability (Standardized Precipitation–Evapotranspiration Index, SPEI), Landscape Flammability Classes (LFC), and Wildland–Urban Interface (WUI) expansion to detect statistically supported hotspots and coldspots of wildfire occurrence across biogeographical regions. Methods: We analysed a 20-year dataset (2001–2020) at 12-km resolution, combining number of fire and fire size with long-term trends in three macro-drivers (SPEI, LFC, WUI). Temporal changes in wildfire parameters were estimated using generalized linear models with False Discovery Rate (FDR) correction. Trends in SPEI and WUI were assessed through Mann–Kendall and Kendall tau tests supported by Theil–Sen slope estimation, while LFC change was derived from land-cover transitions between 2000 and 2018. Finally, a spatial co-occurrence analysis classified each grid cell as a hotspot, coldspot, or mismatch area based on the degree of alignment between macro-driver trajectories and wildfire trends. Results: Significant and candidate hotspots were concentrated in the Anatolian, Continental, and Mediterranean bioregions, where over 30% of burned areas showed concurrent increases in drought intensity, landscape flammability, and WUI expansion. The Anatolian bioregion exhibited the strongest increases in WUI (+ 73.4%) and LFC (+ 67.2%), while the Continental region was dominated by widespread drying (90.5% of its area). Coldspots were mainly located in the Atlantic region, reflecting coherent declines in both wildfire parameters and macro-drivers. Mismatch zones, encompassing more than half of the burned area, revealed high spatial variability where fire dynamics diverged from macro-driver trends, indicating the influence of local-scale or non-mechanistic processes. Conclusions: The joint analysis of climate variability, fuel continuity and human pressures shows that wildfire patterns in Southern Europe depend on how the long-term trends of these macro-drivers align or decouple. Hotspots reveal regions where multiple drivers evolve in the same direction as wildfire activity, whereas mismatch areas highlight the role of local processes that interrupt large-scale relationships. The framework provides a quantitative basis for interpreting spatial heterogeneity in wildfire dynamics and supports integrated, multi-driver assessments for Mediterranean wildfire research.| File | Dimensione | Formato | |
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