Differences in organic matter removal treatments do not influence soil microbial diversity in British Columbia managed forests

Abstract

Microbial diversity is essential to the wellbeing of a given soil ecosystem, correlating to higher primary productivity levels. Microbial composition between different layers of soil, or soil heterogeneity, has been linked to microbial diversity and a healthy soil ecosystem. Organic matter removal treatments are logging practices that involve removing organic matter such as trees, branches and leaves, from a certain harvested area. It is well known that organic matter removal treatments have an effect in soil physical properties and the soil microbiome. However, the effects of organic matter removal treatments on soil microbial diversity and soil heterogeneity have not been extensively explored. We hypothesized that harsher organic matter removal treatments would result in a reduction of soil heterogeneity, and by extension, microbial diversity. Using the QIIME2 pipeline, we analysed 16s rRNA gene sequencing data collected from British Columbia managed forest sites that had undergone various organic matter removal treatments. Alpha and Beta diversity analyses were performed to evaluate microbial diversity between different organic matter removal treatment sites and compare the diversity between soil layers within each site, respectively. We found that changes in microbial diversity were not correlated to changes in organic matter removal treatments or soil heterogeneity, even when confounding variables were controlled for with a logistic regression model. Nevertheless, organic matter removal treatments seem to have an effect in the abundance of certain microbial taxa. These results show that organic matter removal treatments do not appear to play a role in microbial diversity. However, other abiotic factors potentially influence soil microbial diversity and more research should be conducted to further investigate this conclusion.