Aboveground organic matter removal reshapes soil microbial functional group balance in temperate forests

The growing demand for renewable materials and energy leads to intensified forest management practices. Therefore, combining high forest productivity and soil carbon storage capacity with lower quantities of organic matter (OM) left on the ground to decompose represents a major challenge. Although microbial communities drive processes responsible for organic carbon stabilization in soil, we have limited knowledge of how the inputs of superficial OM affect the richness and composition of soil microbial communities. This study determined the impacts of OM removal on soil bacteria and fungi at six sites across French temperate forests using high-throughput amplicon sequencing. After three years of OM manipulation, we measured an alteration of the bacterial copiotrophic and fungal saprotrophic abundance and richness. Furthermore, aboveground OM removal reshaped microbial communities toward bacterial oligotrophic and fungal ectomycorrhizal-dominated populations, which are less efficient for OM decomposition. Finally, we proposed that understanding the response of soil microbial communities to variations in OM inputs should help anticipate future functional changes in forest ecosystems submitted to the intensification of silvicultural practices.