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Research article - Peer-reviewed, 2022

Direct and indirect effects of fire on microbial communities in a pyrodiverse dry-sclerophyll forest

Bowd, Elle J.; Egidi, Eleonora; Lindenmayer, David B.; Wardle, David A.; Kardol, Paul; Cary, Geoffrey J.; Foster, Claire;


Fire is one of the predominant drivers of the structural and functional dynamics of forest ecosystems. In recent years, novel fire regimes have posed a major challenge to the management of pyrodiverse forests. While previous research efforts have focused on quantifying the impacts of fire on above-ground forest biodiversity, how microbial communities respond to fire is less understood, despite their functional significance. Here, we describe the effects of time since fire, fire frequency and their interaction on soil and leaf litter fungal and bacterial communities from the pyrodiverse, Eucalyptus pilularis forests of south-eastern Australia. Using structural equation models, we also elucidate how fire can influence these communities both directly and indirectly through biotic-abiotic interactions. Our results demonstrate that fire is a key driver of litter and soil bacterial and fungal communities, with effects most pronounced for soil fungal communities. Notably, recently burnt forest hosted lower abundances of symbiotic ectomycorrhizal fungi and Acidobacteria in the soil, and basidiomycetous fungi and Actinobacteriota in the litter. Compared with low fire frequencies, high fire frequency increased soil fungal plant pathogens, but reduced Actinobacteriota. The majority of fire effects on microbial communities were mediated by fire-induced changes in litter and soil abiotic properties. For instance, recent and more frequent fire was associated with reduced soil sulphur, which led to an increase in soil fungal plant pathogens and saprotrophic fungi in these sites. Pathogenic fungi also increased in recently burnt forests that had a low fire frequency, mediated by a decline in litter carbon and an increase in soil pH in these sites. Synthesis. Our findings indicate that predicted increases in the frequency of fire may select for specific microbial communities directly and indirectly through ecological interactions, which may have functional implications for plants (increase in pathogens, decrease in symbionts), decomposition rates (declines in Actinobacteriota and Acidobacteriota) and carbon storage (decrease in ectomycorrhizal fungi). In the face of predicted shifts in wildfire regimes, which may exacerbate fire-induced changes in microbial communities, adaptive fire management and monitoring is required to address the potential functional implications of fire-altered microbial communities.


bacteria; Eucalyptus pilularis; fire; fungi; pyrodiversity; SEM; soil

Published in

Journal of Ecology

2022, volume: 110, number: 7, pages: 1687-1703
Publisher: WILEY

Authors' information

Bowd, Elle J.
Australian National University
Egidi, Eleonora
Western Sydney University
Lindenmayer, David B.
Australian National University
Wardle, David A.
Nanyang Technological University and National Institute of Education (NIE) Singapore
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Cary, Geoffrey J.
Australian National University
Foster, Claire
Australian National University

Sustainable Development Goals

SDG15 Life on land

UKÄ Subject classification

Forest Science

Publication Identifiers


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