Wildfire severity and time-since-fire drive biodiversity, ecosystem services and multifunctionality in Mediterranean forests

Wildfires are key ecological drivers in Mediterranean forests, yet their impacts on biodiversity and ecosystem services (ESs) vary widely depending on fire characteristics. In this study, we assessed how fire severity and time-since-fire shape biodiversity, ES provision, ES-multifunctionality and ES-uniqueness in Mediterranean oak forests across southern Italy. Drawing on 26 ecological indicators across 30 forest sites, we evaluated responses of above- and belowground biodiversity and five ESs: pollination, pest control, carbon storage, soil fertility, and water regulation. Our findings reveal that low-severity fires can enhance multiple ESs and aboveground multifunctionality, particularly in the short term, by promoting pollination and pest control functions. In contrast, high-severity fires tend to reduce multifunctionality, especially belowground, but significantly increase ecosystem uniqueness, fostering distinct combinations of biodiversity and service profiles. These divergent effects suggest that low-severity burns may support forest resilience and ecosystem functioning, while high-severity wildfires contribute to spatial heterogeneity and ecological novelty. Integrating both outcomes into wildfire management strategies can help balance conservation and multifunctionality goals in fire-prone Mediterranean landscapes. • Wildfire impacts depend on severity and time-since-fire. • Low-severity fires boost short-term aboveground multifunctionality. • High-severity fires reduce belowground functions but allow recovery over time. • Ecosystem uniqueness peaks after intense, recent wildfires.