In fire‐prone regions such as the Mediterranean biome, fire seasons are becoming longer, and fires are becoming more frequent and severe. Post‐fire recovery dynamics is a key component of ecosystem resilience and stability. Even though Mediterranean ecosystems can tolerate high exposure to extreme temperatures and recover from fire, changes in climate conditions and fire intensity or frequency might contribute to loss of ecosystem resilience and increase the potential for irreversible changes in vegetation communities. In this study, we assess the recovery rates of burned vegetation after recurrent fires across Mediterranean regions globally, based on remotely sensed Enhanced Vegetation Index (EVI) data, a proxy for vegetation status, from 2001 to 2022. Recovery rates are quantified through a statistical model of EVI time‐series. This approach allows resolving recovery dynamics in time and space, overcoming the limitations of space‐for‐time approaches typically used to study recovery dynamics through remote sensing. We focus on pixels burning repeatedly over the study period and evaluate how fire severity, pre‐fire vegetation greenness, and post‐fire climate conditions modulate vegetation recovery rates of different vegetation types. We detect large contrasts between recovery rates, mostly explained by regional differences in vegetation type. Particularly, needle‐leaved forests tend to recover faster following the second event, contrasting with shrublands that tend to recover faster from the first event. Our results also show that fire severity can promote a faster recovery across forested ecosystems. An important modulating role of pre‐fire fuel conditions on fire severity is also detected, with pixels with higher EVI before the fire resulting in stronger relative greenness loss. In addition, post‐fire climate conditions, particularly air temperature and precipitation, were found to modulate recovery speed across all regions, highlighting how direct impacts of fire can compound with impacts from climate anomalies in time and likely destabilise ecosystems under changing climate conditions.

Mediterranean European countries, including Portugal, are considered fire-prone regions, being affected by fire events every summer. Nonetheless, Portugal has been recording large burned areas over the last 20 years, which are not only strongly associated with hot and dry conditions, but also with high fuel availability in the ecosystems. Due to recent catastrophic fire seasons, Portugal has been implementing preventive policies during the pre-fire season, which, in turn, can optimize combat strategies during the fire season. In this context, our study contributes to fire prevention by identifying the regions with the highest potential to burn. The application of a Principal Component Analysis (PCA) to a range of climatological, ecological, and biophysical variables, either provided by remote sensing or reanalysis products, and known to be linked with diverse fire-vulnerability factors, allows the objective identification of the regions with the highest susceptibility to burn. The central and southernmost areas of Portugal present a stronger signal in the PCA, suggesting a likely high exposure to future fire events. The fuel accumulation over several months, in conjunction with elevation and fire weather conditions, are the terms out of the retained PCs that can explain most of the variability. The quality assessment performed for the burned areas in 2022 showed that they occurred in highly susceptible areas, highlighting the usefulness of the proposed methodology.

Persistent hot and dry conditions play an important role in vegetation dynamics, being generally associated with reduced activity. In the Mediterranean region, ecosystems are adapted to such conditions. However, prolonged and intense heat and drought or the occurrence of compound hot and dry events may still have a negative impact on vegetation activity. This work aims to study how the productivity of Mediterranean vegetation is affected by hot and dry events, examining a set of severe episodes that occurred in three different regions (Iberian Peninsula, Eastern Mediterranean and Western Europe) between 2001 and 2019. The analysis relies on remote sensing products, namely Gross Primary Production from MODIS to detect and monitor vegetative stress and LST from MODIS and SM from ESA CCI to evaluate the influence of temperature and soil water availability on stressed vegetation. Of all events, the 2005 episode in the Iberian Peninsula was the most significant, affecting large sectors of low tree cover areas and crops and leading to reductions of annual plant productivity in affected vegetation of ~47 TgC/year. The obtained results highlight the influence of land-atmosphere coupling on vegetation productivity and clarified the role of warm springs on vegetation activity and soil moisture that may amplify summer temperatures. The functional recovery of affected vegetation productivity after these episodes varied across events, ranging from months to years. This work highlights the influence of hot and dry events on vegetation productivity in the Mediterranean basin and the usefulness of remote-sensing products to assess the response of different land covers to such episodes.

Wildfires are a serious threat to ecosystems and human. In Portugal, during 2017, a catastrophic fire season burned more than 500 000 hectares and caused the death of more than 100 people. Previous studies have shown that hot and dry fuel conditions promoted widespread propagation of wildfires. However, burned area (BA) and mega-fires, such as the 2017 ones, depend not just on favourable meteorological conditions, but also on fuel accumulation and dryness. In this study, we will assess the influence of spring meteorological conditions on fire season BA, through their effects on fuel accumulation and dryness. Using satellite-based data, we show that the association of higher temperatures and water availability in spring can increase the risk of summer wildfires propagation, flammability and intensity through their influence on vegetation gross productivity. This study highlights the important role of fuel accumulation during the growing season in fire-prone regions like Portugal. Our results imply that fuel management may be an effective way to mitigate extreme fire seasons associated with warmer and drier conditions in the future.

Southern Europe is considered a fire-prone region, and fire events occur here every summer. In this context, large fires have hit Portugal over the last 20 years, due to frequent hot and dry summer conditions, and also to high fuel availability in ecosystems. Moreover, climate change in the Mediterranean basin is expected to increase the severity of fire weather conditions and therefore to increase the occurrence of extreme fire seasons. Recent catastrophic fire seasons have led to the implementation of a set of policies during the months before the fire-season, aiming at fire prevention and suppression, which can in turn increase the combat efficiency of fires during the fire season. Therefore, this work intends to contribute to fire prevention by identifying regions with a high likelihood to burn. A Principal Components Analysis (PCA) was applied to several climatological, ecological, and biophysical variables, related to fire weather, fuel availability, and elevation covering the period from 2001 to 2021. Results allowed to assess the areas where large fires were more likely to occur in 2022. The central and southernmost regions of Portugal showed a stronger signal in the PCA, indicating a likely high susceptibility to future fire events. The association of fuel accumulation since the last fire event with elevation and favourable fire weather conditions explains most of the variability of the first six PCs. These results were compared with the fires that occurred in 2022, and a match between larger burned areas and high signals in the PCA was found, highlighting the usefulness of this methodology. This study was supported by FCT (Fundação para a Ciência e Tecnologia, Portugal) through national funds (PIDDAC) – UIDB/50019/2020, and under the projects FlorestaLimpa (PCIF/MOG/0161/2019).

Rural fires are recurrent in Southern Europe due to climate conditions, land use change, or a combination of both. Wet and mild winters and dry and warm summers favour the growth of vegetation and its subsequent low moisture content, increasing fuel availability. In Portugal, between 15 and 20 September 2024, severe wildfires burned more than 145,000 hectares and caused the death of more than 9 people. In Greece a major fire, stated as the largest recorded in the EU, started near the city of Alexandroupolis on August 21, with around 80.000 hectares burnt, mainly affecting the Dadia Forest and causing the death of almost two tens of migrants. Despite the crucial role played by dry fuel conditions fostering the propagation of wildfires, favourable meteorological conditions and fuel accumulation are related to the recorded fire activity and burned area. The influence of spring meteorological conditions on fire season burned area through their effect on fuel accumulation and dryness is assessed. The link between hot temperature and water availability in spring and the increased risk of summer flammability and fire spread through their influence on vegetation gross productivity is evaluated using satellite-derived data. The important role of fuel accumulation during the early growing season in fire-prone regions is highlighted in the case of Portugal in 2024 and Greece in 2023 and reinforces the crucial importance of fuel management for the definition of effective fire prevention measures in the context of warmer and drier conditions forecasted for southern European Countries.Acknowledgements: This work is supported by the Portuguese Fundação para a Ciência e Tecnologia, FCT, I.P./MCTES through national funds (PIDDAC): UID/50019/2025 and LA/P/0068/2020 https://doi.org/10.54499/LA/P/0068/2020 and also on behalf of DHEFEUS -2022.09185.PTDC and the project FAIR- 2022.01660.PTDC).