Fire as a driver of fungal diversity — A synthesis of current knowledge

ABSTRACT

Fires occur in most terrestrial ecosystems where they drive changes in the traits, composition, and diversity of fungal communities. Fires range from rare, stand-replacing wildfires to frequent, prescribed fires used to mimic natural fire regimes. Fire regime factors, including burn severity, fire intensity, and timing, vary widely and likely determine how fungi respond to fires. Despite the importance of fungi to post-fire plant communities and ecosystem functioning, attempts to identify common fungal responses and their major drivers are lacking. This synthesis addresses this knowledge gap and ranges from fire adaptations of specific fungi to succession and assembly fungal communities as they respond to spatially heterogenous burning within the landscape. Fires impact fungi directly and indirectly through their effects on fungal survival, substrate and habitat modifications, changes in environmental conditions, and/or physiological responses of the hosts with which fungi interact. Some specific pyrophilous, or “fire-loving,” fungi often appear after fire. Our synthesis explores whether such taxa can be considered cosmopolitan, and whether they are truly fire-adapted or simply opportunists adapted to rapidly occupy substrates and habitats made available by fires. We also discuss the possible inoculum sources of post-fire fungi and explore existing conceptual models and ecological frameworks that may be useful in generalizing fungal fire responses. We conclude with identifying research gaps and areas that may best transform the current knowledge and understanding of fungal responses to fire.

KEYWORDS:

• Community dynamics
• endemism
• fire adaptations
• fire frameworks
• fire severity
• pyrophilous fungi

ACKNOWLEDGMENTS

We would like to gratefully acknowledge the Mycological Society of America for sponsoring a symposium on fire ecology where ideas that make up this contribution were laid out. We are grateful to Ellen Meyer for the conceptual model illustration. We also thank Tom Bruns, Jean Huffman, and Brandon Matheny for the use of their photos in FIG. 3. This material is based upon work supported by the National Science Foundation and United States Department of Agriculture (USDA) Forest Service. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funding agencies.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

SUPPLEMENTARY MATERIAL

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Additional information

Funding

Research by individual authors was supported by grants from various sources: United States Department of Agriculture (USDA) Forest Service co-operative agreement no. 15-CA-11330136–072 (to A.J.) supported Sam Fox; awards from the Center for Biodiversity Research at the University of Memphis and the Department of Biological Science at the University of Memphis (to S.P.B.), National Science Foundation awards no. 1733750 (to K.H.) and no. 1557000 (to B.A.S.), and National Park Service award no. 18-4606 (to K.H.). The Mycological Society of America (T.S.-N.) and Kansas Advancement for Women in Science and Engineering (S.F.) provided travel support that permitted participation in “Fungal Fire Ecology” symposium in the 95th annual meeting of the society that served as an impetus for this contribution.