Biological invasions of three different alien tree species has comparable influence in soil mycobiome: increase the abundance of pathogens, and decomposers, but decrease root-associated endophytic symbionts

Invasive trees can significantly transform habitats, modify nutrient cycles, and change microbial community composition and assembly processes. Therefore, they pose significant threat to nature conservation and sustainable management. However, the impacts of invasive trees on the trophy and taxonomy of soil mycobiomes in forest ecosystems remain unclear. In this study, we investigated how the invasive tree species – Robinia pseudoacacia , Prunus serotina , and Quercus rubra – influence soil mycobiomes in forest ecosystems. We analysed soil samples taken from an invasive tree density gradient, using 81 study stands in Poland, Central Europe. The soil mycobiome was identified using Next-Generation Sequencing of the ITS2 rDNA barcode region for fungi. The three invasive tree species had a similar impact on the soil mycobiome. Each invasive tree reduced the relative abundance of root endophytes and increased the relative abundance of pathogens in soil. The response of saprotrophs varied, but they generally showed no negative response to invasive trees. The mycobial community composition and abundance of trophic guilds changed substantially, but taxa richness and diversity indices were weak predictors of disturbances. Robinia pseudoacacia had the most significant impact on the soil mycobiome, and Robinia -invaded stands had significantly higher N-NO3, potassium, and calcium content in soil. It is a major concern given that Robinia is probably the most common invasive tree in Europe. We recommend further investigation of the impact of R. pseudoacacia on soil microbiomes in various types of ecosystems to determine the habitats in which Robinia is most detrimental. This will inform targeted invasive species management. • Various invasive tree species have a similar effect on soil fungal trophic guilds • Biological invasions reduce shares of root endophytes and increase those for pathogens • Terrestrial and wood saprotrophs do not exhibit negative responses to invasions • Taxa richness and diversity indices are weak predictors of disturbances to mycobiomes • Robinia had the strongest impact on mycobiome taxonomy and soil chemical compounds