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Johnson DB, Woolet J, Yedinak KM, Whitman T. Experimentally determined traits shape bacterial community composition one and five years following wildfire. Nat Ecol Evol 2023; 7:1419-1431. [PMID: 37524797 PMCID: PMC10482699 DOI: 10.1038/s41559-023-02135-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 06/26/2023] [Indexed: 08/02/2023]
Abstract
Wildfires represent major ecological disturbances, burning 2-3% of Earth's terrestrial area each year with sometimes drastic effects above- and belowground. Soil bacteria offer an ideal, yet understudied system within which to explore fundamental principles of fire ecology. To understand how wildfires restructure soil bacterial communities and alter their functioning, we sought to translate aboveground fire ecology to belowground systems by determining which microbial traits are important post-fire and whether changes in bacterial communities affect carbon cycling. We employed an uncommon approach to assigning bacterial traits, by first running three laboratory experiments to directly determine which microbes survive fires, grow quickly post-fire and/or thrive in the post-fire environment, while tracking CO2 emissions. We then quantified the abundance of taxa assigned to each trait in a large field dataset of soils one and five years after wildfires in the boreal forest of northern Canada. We found that fast-growing bacteria rapidly dominate post-fire soils but return to pre-burn relative abundances by five years post-fire. Although both fire survival and affinity for the post-fire environment were statistically significant predictors of post-fire community composition, neither are particularly influential. Our results from the incubation trials indicate that soil carbon fluxes post-wildfire are not likely limited by microbial communities, suggesting strong functional resilience. From these findings, we offer a traits-based framework of bacterial responses to wildfire.
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Affiliation(s)
| | - Jamie Woolet
- University of Wisconsin-Madison, Madison, WI, USA
- Colorado State University, Fort Collins, CO, USA
| | - Kara M Yedinak
- Forest Products Laboratory, USDA Forest Service, Madison, WI, USA
| | - Thea Whitman
- University of Wisconsin-Madison, Madison, WI, USA.
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Woolet J, Whitman E, Parisien MA, Thompson DK, Flannigan MD, Whitman T. Effects of short-interval reburns in the boreal forest on soil bacterial communities compared to long-interval reburns. FEMS Microbiol Ecol 2022; 98:6603815. [PMID: 35671126 PMCID: PMC9303391 DOI: 10.1093/femsec/fiac069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 05/23/2022] [Accepted: 06/03/2022] [Indexed: 11/14/2022] Open
Abstract
Increasing fire frequency in some biomes is leading to fires burning in close succession, triggering rapid vegetation change and altering soil properties. We studied the effects of short-interval (SI) reburns on soil bacterial communities of the boreal forest of northwestern Canada using paired sites (n = 44). Both sites in each pair had burned in a recent fire; one site had burned within the previous 20 years before the recent fire (SI reburn) and the other had not. Paired sites were closely matched in prefire ecosite characteristics, prefire tree species composition, and stand structure. We hypothesized that there would be a significant effect of short vs. long fire-free intervals on community composition and that richness would not be consistently different between paired sites. We found that Blastococcus sp. was consistently enriched in SI reburns, indicating its role as a strongly ‘pyrophilous’ bacterium. Caballeronia sordidicola was consistently depleted in SI reburns. The depletion of this endophytic diazotroph raises questions about whether this is contributing to—or merely reflects—poor conifer seedling recolonization post-fire at SI reburns. While SI reburns had no significant effect on richness, dissimilarity between short- and long-interval pairs was significantly correlated with difference in soil pH, and there were small significant changes in overall community composition.
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Affiliation(s)
- Jamie Woolet
- Department of Soil Science, University of Wisconsin-Madison , 1525 Observatory Dr., Madison, WI, 53706 , USA
- Department of Forest and Rangeland Stewardship, Colorado State University , 1001 Amy VanDyken Way, Fort Collins, CO, 80521 , USA
| | - Ellen Whitman
- Northern Forestry Centre , Canadian Forest Service, Natural Resources Canada, 5320 122Street, Edmonton, AB, T6H 3S5 , Canada
- Great Lakes Forestry Centre , Canadian Forest Service, Natural Resources Canada, 1219 Queen St. E., Sault Ste. Marie, ON, P6A 2E5 , Canada
| | - Marc-André Parisien
- Northern Forestry Centre , Canadian Forest Service, Natural Resources Canada, 5320 122Street, Edmonton, AB, T6H 3S5 , Canada
| | - Dan K Thompson
- Northern Forestry Centre , Canadian Forest Service, Natural Resources Canada, 5320 122Street, Edmonton, AB, T6H 3S5 , Canada
- Great Lakes Forestry Centre , Canadian Forest Service, Natural Resources Canada, 1219 Queen St. E., Sault Ste. Marie, ON, P6A 2E5 , Canada
| | - Mike D Flannigan
- Department of Renewable Resources, University of Alberta , 751 General Services Building, Edmonton, AB, T6G 2H1 , Canada
- Faculty of Science, Thompson Rivers University , 805 TRU Way, Kamloops, BC, V2C 0C8 , Canada
| | - Thea Whitman
- Department of Soil Science, University of Wisconsin-Madison , 1525 Observatory Dr., Madison, WI, 53706 , USA
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