Carbon to nitrogen ratios influence microbial diversity in the soil of interior Douglas-fir forests in British Columbia

Abstract

In British Columbia, clear-cut logging and subsequent reforestation is practiced, which has previously been shown to cease the flow of carbon and cause changes to the physical soil environment. After logging treatments, forests experience changes in the ratio of carbon to nitrogen levels which can in turn cause changes to soil microbial communities. These changes can ultimately lead to a change of the metabolic profile of the soil, which affects the entire forest soil ecosystem. Wilhelm et al. collected soil data from various North American forest sites over ten years after logging using different levels of organic matter removal to analyze the soil microbiomes with amplicon sequencing. Additionally, they collected information on carbon and nitrogen levels. Those data were used to investigate the changes in soil microbial communities that occur at different carbon to nitrogen (C:N) ratios. By investigating the microbial community diversity in the organic layer of interior Douglas-fir forest sites, phylogenetic distance was found to drive the differences in microbiota between low, medium, and high C:N ratio categories in interior Douglas-fir sites. Furthermore, low-abundance taxa unique to each C:N category, as well as bacterial families indicative of low and high C:N ratio soils were identified.