While wildfire initially disrupts life below ground, healthy and diverse soil communities drive ecosystem restoration.

Researchers in China tracked the recovery of pine forests for nearly three decades after wildfires, finding that soil biodiversity and ecosystem function recover on different timelines. Although ecosystem functions remain impaired longer than biodiversity, wildfires highlight the link between the two, making diverse soil communities increasingly important for rebuilding resilient ecosystems in a warming world.

“Although our results indicate a general trend of biodiversity recovery over time, it remains unclear whether this reflects a return to pre-fire community composition or a shift towards functionally restructured assemblages,” write the researchers. “Long-term monitoring efforts extending beyond the 27-year post-fire window are needed to detect delayed responses, legacy effects or potential tipping points.”

Wildfires can both destroy and revitalize the ecosystem and soil biodiversity. The bacteria, fungi and other organisms inhabiting soil all contribute to ecosystem multifunctionality (EMF), whereby the ecosystem provides numerous services that allow nature to survive and thrive. These services include how carbon, nitrogen, water and other nutrients are supplied, cycled and stored as well as how biological material, such as leaf litter, is decomposed and recycled. With wildfires growing increasingly common, their impact on these critical ecological functions needs to be better understood.

Jianping Wu, a researcher at Yunnan University and colleagues sampled various sites from Yunnan pine forests in southwest China. Called wildfire chronosequences, these sites with similar starting ecologies had been burned in wildfires at different times—1, 5, 9 and 27 years ago—allowing the researchers to construct patterns of wildfire impact over time. The team compared these plots to others that remained unburned to understand how soil biodiversity and 38 ecosystem functions changed in the presence or absence of a wildfire. They sampled plant leaf litter and the soil at two different depths.

Wildfires impacted soil biodiversity and ecosystem functioning, with the consequences depending on soil depth and how much time had passed since the fire. For instance, in the top 10 cm of soil, bacteria, fungi, worms and other organisms all suffered significant losses immediately after the fire, with the largest hit happening some five years post-fire. The researchers suggest that temporary “fire-induced nutrient pulses” may explain the delay in the worst diversity losses. Roundworms suffered the most, likely due to their sensitivity to the loss of soil moisture and root-derived resources following a fire. With slow reproduction and longer life cycles, their recovery was much slower compared to microbes. With time, these organisms came back, matching or even surpassing their pre-fire levels after 27 years.

Deeper down, the effects of wildfires were slightly subdued, with some soil organisms experiencing a short-term diversity boost in the first year. Protected from immediate exposure, these organisms possibly benefited from nutrients washed deeper into the soil by seasonal rainfall, leading to the temporary upswing.

Looking at how ecosystem multifunctionality changed after wildfires, Wu’s team noticed similar patterns, but with more significant effects. Different soil functions, such as the cycling and storage of carbon and nitrogen as well as the presence of certain enzymes in the soil, suffered in various ways, taking longer to recover compared to the very soil communities that sustain them. While the subsurface layer was hard hit in the first five years, it began recovering around the nine-year mark. But on the surface, ecosystem multifunctionality remained depressed, and recovered only after 27 years.

Most crucially, the researchers found that fire bolstered the connection between soil communities and ecosystem multifunctionality. This relationship was essential to the recovery of ecosystem services after a wildfire. Fires burn unevenly, creating a patchwork of microhabitats that favor different organisms, and this very heterogeneity likely drives better ecosystem functioning.  

“As climate change intensifies fire regimes by increasing fire frequency, severity and duration, the temporal window for biodiversity recovery is reduced, increasing the risk of chronic diversity loss and functional instability. In fire-prone regions facing rising temperatures and prolonged droughts, multiple stressors could exacerbate biodiversity loss, delay EMF recovery or lead to novel soil communities with altered trait distributions,” write the researchers. “Such shifts challenge current assumptions of biodiversity–functional relationships under fire regimes. Integrating climate change projections into fire management and restoration frameworks will be critical for safeguarding soil biodiversity and the ecosystem services it supports.”

Reference: Juan Zhou et al., Wildfire strengthens the relationship between soil biodiversity and ecosystem multifunctionality in subtropical forests, Functional Ecology (2026). DOI: 10.1111/1365-2435.70304

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