DOI: 10.6084/m9.figshare.30427984.v1
title: Data for "Soil bacteria are more sensitive than fungi across different post-fire succession stages: Harnessing microbial sensitivity thresholds for recovery in warm temperate forests"

description: Soil microbial communities in forests are vulnerable to fire disturbances that are exacerbated by global climate change. However, the successional trajectories and underlying driving mechanisms of soil bacterial and fungal communities following wildfires remain poorly understood, particularly across different post-fire stages in warm temperate regions of East Asia. Using the "space-for-time substitution" approach, different post-fire stages in 0 years, 2 years, 5 years, 10 years, and 32 years were selected to explore changes in soil microbial community structure in the warm temperate broad-leaved forests of northern China. The results showed that by 10 years post-fire, both bacterial and fungal abundances in burned sites showed no statistical divergence from unburned controls (Bacteria: F/C ratio = 1.00, 95% CI [0.93–1.08], p = 0.895; Fungi: F/C ratio = 0.98, 95% CI [0.82–1.19], p = 0.858). During post-fire recovery timelines, bacterial communities demonstrated greater sensitivity than fungal communities to fire disturbance: Fire-induced declines in bacterial α-diversity were significantly larger than those observed in fungi, and β-diversity analysis revealed stronger community structure shifts in bacteria (Bray-Curtis dissimilarity, stress = 0.134) compared to fungi (stress = 0.212). The relationship between bacteria and fungi was predominantly symbiotic rather than competitive in fire-disturbed areas, mainly driven by bacterial activity, whereas in unburned areas, the interaction was more competitive than symbiotic. As the succession progressed, the α-diversity of bacteria reached its peak 5 years after the fire, and the diversity of fungi reached its peak 10 years after the fire. During post-fire succession, bacterial phyla such as Actinobacteria and Acidobacteriota exhibited significant increases in relative abundance. As for fungi, the main classes that changed were Agaricomycetes, Eurotiomycetes, and Wallemiomycetes. According to Mantel test results, soil organic carbon content (SOC; r = 0.196, p = 0.057) and total phosphorus (TP; r = 0.181, p = 0.051) exhibited the strongest correlations with bacterial community restoration, whereas fungal community reconstruction was primarily associated with TP (r = 0.145, p = 0.058) and pH (r = 0.126, p = 0.070). The nitrogen-to-phosphorus ratio (N/P; r = 0.102, p = 0.017) showed a secondary but significant influence on bacterial recovery. Major findings reveal that asynchronous recovery trajectories reconfigure microbial communities through distinct restoration phases governed by differential ecological sensitivities, decoupled resource allocation, and bifurcated environmental drivers. Our multi-temporal analysis establishes microbial interaction rewiring as a quantifiable indicator for monitoring post-fire ecosystem recovery. This study provides new insights into the succession trajectory and driving mechanism of bacteria and fungi communities after fire disturbances in forest ecosystems.