Soil microbial community response to winter climate change is phylogenetically conserved and highly resilient in a cool-temperate forest

Abstract

The soil microbial community actively drives biogeochemical cycling even in the plant-dormant season of winter in temperate forests. The northern ecosystems are experiencing considerable winter climate change, which causes the snowpack to become thinner and the soil freeze-thaw cycles to occur more frequently in winter. These climatic and edaphic changes may affect the microbial community function. This study aimed to characterize the soil microbial community's response to winter climate change and its consequences in nitrogen (N) cycling. We conducted a large-scale snow removal experiment in a cool-temperate forest in northern Japan to simulate a winter climate change and assessed the abundance of total bacteria and fungi and ammonia oxidizers and the bacterial community composition throughout a year. This experiment indicated that snowpack decline prolonged the soil freeze-thaw period, which increased the carbon (C) availability to soil microbes in winter. The soil microbial community then sensitively responded by increasing in abundance and shifting the composition based on each taxon's absolute and relative abundances in the way that was phylogenetically patterned, which further activated microbial N cycling. However, the soil microbial community's high resilience driven by the C availability prevented the functional and compositional responses to winter climate change from persisting into the plant-growing season, which left no apparent cascading effect on the soil microbial community and N content during the plant-growing season. This study highlights the sensitive and phylogenetically patterned response of the soil microbial community to the change in soil nutrient availability and its high resilience under winter climate change in a forest.