Ecological determinants of the spatiotemporal dynamics of wildfires in the Polissia and forest-steppe zones of Ukraine

This study investigates the ecological factors determining the spatiotemporal dynamics of wildfires in the Polissia and forest-steppe physiographic zones of Ukraine over the period 2001–2023. The relevance of the research stems from the increasing frequency and intensity of forest and steppe fires caused by climate change, particularly rising air temperatures and the growing incidence of extreme weather events. The present study utilised satellite-derived wildfire data from the Fire Information for Resource Management System (NASA MODIS/VIIRS) and climate data from the CRU TS 4.09 dataset in order to evaluate the monthly number of wildfire occurrences within administrative regions across the two physiographic zones. The modelling approach employed utilised generalized linear mixed models (GLMM) with autoregressive (AR(1)) structure, thereby facilitating a quantitative assessment of the effects of temperature, precipitation, and their interaction on fire intensity. The findings indicated a discernible nonlinear effect of temperature, with a notable escalation in fire risk beyond a threshold of approximately 18–20 °C, while fire activity remained minimal under moderate temperatures (10–15 °C). The findings indicated that precipitation had a statistically significant negative effect, particularly during the vegetation season. Seasonal analysis demonstrated that the majority of regions experience a spring peak in wildfire activity (March–April), with a secondary local maximum in August. The spatial variation between Polissia and the Forest-Steppe is indicative of distinct climatic regimes, land use patterns, and landscape structures. The study also examined changes in the fire dynamics after 2011, which may be attributed to both climatic trends and institutional reforms in environmental governance. A marked decline in the fire intensity was observed in several regions after 2014, possibly linked to changes in landscape accessibility, land use patterns, and reduced anthropogenic pressure. The overall ecosystem sensitivity to fire remains high, with an increased frequency and extent of fire outbreaks during drought years. The findings may contribute to the enhancement of wildfire monitoring and forecasting systems, particularly within the context of integrated natural risk management frameworks. The proposed approach to quantifying ecological determinants of fire activity can be applied to other regions of Ukraine and Central and Eastern Europe to support the development of adaptive conservation and land management strategies under climate change