Soil Microbial Community Patterns after a Large Forest Fire in Temperate Central Europe

Wildfires are a major ecological driver impacting terrestrial ecosystems, yet their belowground impacts remain poorly understood in Central European temperate forests. We investigated soil microbial responses during the first post-fire year following the large 2022 wildfire in the Bohemian and Saxon Switzerland National Parks (Czechia and Germany). We compared soil microbial communities across three forest types differing in fire sensitivity ( Fagus sylvatica , Pinus sylvestris, and Picea abies stands) and examined how forest type, aboveground burn severity, soil burn severity, and soil properties structured prokaryotic and fungal communities. Prokaryotic richness remained largely stable across burn severities, although the diversity of prokaryotes and gene copy numbers declined with soil burn severity. In contrast, fungal communities showed stronger responses. Fungal richness and diversity decreased with soil burn severity, while fungal gene copy numbers increased in stands of low aboveground severity. Microbial community composition shifted in response to fire, with pronounced turnover in fungal communities. Variation partitioning indicated that the composition was jointly influenced by forest type and aboveground burn severity, whereas soil properties explained little additional variation. Prokaryotic and fungal beta diversity did not correlate with plant beta diversity. Co-occurrence network analysis revealed fire-associated modules enriched in interkingdom links and a higher prevalence of positive associations in burned soils. Fire-associated taxa, including Actinomycetota and Ascomycota, dominated early post-fire communities. Our results demonstrate that early belowground recovery after wildfire in temperate Central European forests is shaped by strong environmental filtering imposed by burn severity and by legacy effects of forest type.