Tree species determine soil microbial diversity: variation in fungal and bacterial communities in temperate forests

This study investigates the influence of three deciduous tree species: small-leaved linden (Tilia cordata), common beech (Fagus sylvatica), and sessile oak (Quercus petraea) on soil microbial diversity in temperate forest ecosystems. Conducted on loess soils in southern Poland, the research clarifies species-specific effects on soil microbiota and chemical properties, providing insights into tree-microbe-soil interactions in forest environments. Soil samples were collected from monospecific stands and analysed using next-generation sequencing (NGS). Fungal and bacterial DNA was extracted, and libraries targeting the ITS1 (fungi) and 16 S rRNA V3-V4 (bacteria) regions were sequenced using the Illumina MiSeq platform. Microbial communities were evaluated in relation to soil pH, nutrient content, and exchangeable cations. Linden soils had the highest pH (5.1-7.0) and calcium content (18.9 cmol(+)·kg⁻¹), while beech soils were the most acidic (pH 3.8-5.7) with the lowest calcium (8.0 cmol(+)·kg⁻¹). Fungal communities were dominated by Basidiomycota, Ascomycota, and Mortierellomycota, with varying proportions across species. Bacterial diversity was highest in linden and oak stands. Dominant bacterial phyla included Actinobacteriota, Proteobacteria, and Acidobacteriota. Each tree species hosted a distinct microbial community, reflecting its impact on soil properties and microbial structure. Tree species significantly shape soil microbial diversity and chemistry. Incorporating microbial data into forest management may enhance soil function, biodiversity conservation, and ecosystem resilience. Broader spatial sampling is recommended to generalize findings.