Differential responses of ecosystem functions and multifunctionality to wildfire and post-fire management across Mediterranean forest sites

Wildfires are major disturbances in Mediterranean forests, yet their effects on ecosystem functions and ecosystem multifunctionality (EMF) remain insufficiently quantified across contrasting environmental contexts. This multi-site study evaluates short and long-term responses of soil and vegetation functions, as well as overall multifunctionality, to wildfire and post-fire management (construction of log erosion barriers, straw mulching, reforestation, salvage logging and seeding) across four Mediterranean forest sites located in Castilla-La Mancha and Castilla y León, Central and Northern Spain. Eight ecosystem functions, including waste decomposition, microbial habitat, water regulation, plant production, soil fertility, climate regulation, ground surface composition, and soil physio-chemical properties, were assessed using a wide set of environmental indicators. Ecosystem multifunctionality was quantified using a recently developed EMF index based on PCA-derived weighting. Wildfire effects were function-dependent rather than uniform across sites. Several soil-related functions, such as waste decomposition, microbial habitat, and soil fertility, displayed relative resistance or rapid post-fire stabilization, while vegetation-related and hydrological functions showed stronger and more persistent alterations, especially in warmer and drier sites. EMF consistently declined in burned soils compared to unburned conditions, confirming its sensitivity to cumulative and asynchronous disturbances. Clear regional differences emerged, indicating that environmental context and time since fire strongly modulate recovery trajectories. Post-fire management effects were highly site-specific. Soil conservation measures produced limited improvements in multifunctionality, while salvage logging enhanced EMF under long-term semi-arid conditions. Seeding and reforestation provided only minor benefits to ecosystem multifunctionality. Overall, the study shows that wildfire impacts on ecosystem functioning are selective and context-dependent, that EMF is a robust integrative indicator for assessing post-fire ecosystem status, and that soil conservation treatments are generally more effective in supporting multifunctionality than disturbance-intense interventions.