Tools for managing invasive species: Aerobiological and spatial analysis of Acacia dealbata in the context of wildfires near urban areas

The expansion of invasive alien plant species, such as Acacia dealbata , represents a growing threat to biodiversity and ecosystem stability. This species has become widely naturalized in Southern Europe Galicia (Spain), particularly in low- and mid-altitude areas, where its high adaptability and rapid vegetative regeneration after disturbances such as wildfires or infrastructure development have promoted the replacement of native vegetation. This study proposes a new methodology to identify and prioritize areas invaded by A. dealbata that present high ecological, fire-related and socio-economic risk, integrating aerobiological, climatic and spatial data. Long-term aerobiological records (1993–2024), used as an indicator of changes in the area occupied by A. dealbata, historical wildfire data (1986–2024), multi-scalar drought indices (SPEI), and spatial analyses based on remote sensing and GIS are combined for a 5-km radius study area located in the province of Ourense, Galicia. We evaluate relationships between drought, burned areas and interannual variability in pollen production. A spatial prioritization framework is also developed using an Analytic Hierarchy Process (AHP) combining proximity to infrastructure, wildland–urban interfaces, historical wildfire recurrence and contact with other forest types. Interannual variation in Acacia pollen load was strongly associated with wildfire activity in the previous year (ρ = –0.72). The SPEI indicates that the June–September period is the most prone to dry biomass accumulation. The resulting spatial prioritization identified critical areas where A. dealbata overlaps with high fire potential and exposure of infrastructure and urban areas. These priority areas account for 90% of the total invaded surface, with more than 60% classified as high priority.