Soil fungal communities perform many functions (e.g., decomposition, mycorrhizal symbiosis) that help plants meet their nutrient demands. While these functions may be especially critical in a post-fire context, overall trends for fungal response to fire have been difficult to elucidate. We used meta-analytical techniques to investigate fungal response to fire across studies, ecosystems, and fire types. Change in fungal species richness and mycorrhizal colonization were used as the effect size metrics in random effects models.
Results/Conclusions
On average, there was a 31% reduction in fungal species richness post-fire and a 13% decrease in mycorrhizal colonization. Additionally, there was a 42% reduction in fungal richness post-fire when assessed by sporocarp surveys, but fungal species richness was not significantly affected through detection using molecular methods. Fire reduced mycorrhizal colonization measured in situ by an average of 27%, yet, on average, showed no measurable effect when assessed by ex situ bioassays. These findings suggest that the putative magnitude of fire effects on soil fungal communities may be somewhat dependent on the approach and assessment method used. Furthermore, because we found that biome but not fire type was a significant moderator of our models, we conclude that biome might be a more useful predictor of fungal species richness response to fire than fire type. Reductions in fungal species richness and mycorrhizal colonization post fire declined logarithmically and approached zero (i.e., no effect) at 22 and 10 years, respectively. We conclude that fire reduces fungal species richness and mycorrhizal colonization, but if conditions allow communities to recover (e.g., without subsequent disturbance, favorable growing conditions), soil fungi are resilient on decadal time scales, which likely contributes to overall ecosystem recovery.