Wildfire activity is projected to increase in boreal forests as a result of climate warming. The consequences of increased wildfire activity for soil carbon (C) storage in boreal forests may depend on the sensitivity of soil microbes to fire severity, but microbial responses to boreal forest fire severity are not well known. Here, we combine remote sensing of fire severity and field sampling to characterize the response of soil microbial biomass per g soil, microbial respiration of CO2 per g soil, and fungal groups to fire severity in a boreal forest ecosystem. We used remote sensing measurements of differenced normalized burn ratio from Landsat as a measure of fire severity. Our results demonstrate that fire severity controls soil microbial responses to boreal forest fires. In comparison to unburned stands, burned stands had a 52% and 56% reduction in soil microbial biomass and basal respiration, respectively. Within burned stands, we found that microbial biomass and basal respiration significantly declined with increasing fire severity. In addition, mycorrhizal taxa and basidiomycetes displayed particularly low tolerances for severe fire. Although wildfires result in the immediate loss of soil C, our study provides evidence that decreases in microbial biomass and respiration following high severity fires may reduce the capacity of the soil microbial community to decompose soil C over longer time scales. Therefore, models of C cycle responses to climate warming may need to represent the sensitivity of microbial biomass and fungal community composition to fire severity in boreal forests.
Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697-2525, USA;Department of Earth System Science, University of California, Irvine, Irvine, CA 92697-3100, USA;Woods Hole Research Center, Falmouth, MA 02540-1644, USA;Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697-2525, USA;Department of Earth System Science, University of California, Irvine, Irvine, CA 92697-3100, USA
Recommended Citation:
Sandra R Holden,Brendan M Rogers,Kathleen K Treseder,et al. Fire severity influences the response of soil microbes to a boreal forest fire[J]. Environmental Research Letters,2016-01-01,11(3)