Fungal-mediated home-field advantage in litter decomposition of Solidago canadensis across soil depths

Invasive plant litter decomposition generally exhibits a home-field advantage (HFA), enhancing invasion success. However, the mechanisms underlying this advantage have not been clarified. We evaluated the impact of adding Solidago canadensis litter on the soil physicochemical properties and microbial communities (fungi and bacteria) of different soil types (SS: invaded soil, NS: non-invaded soil) and at different depths (0, 5, 10, and 20 cm). Notably, the decomposition rate was significantly higher in SS than in NS soil, thus supporting the HFA phenomenon. Litter decomposition increased the soil organic carbon, total nitrogen, total phosphorus, dissolved organic carbon, and dissolved organic nitrogen over the short term and led to a gradual decrease in the pH of SS, and increase of pH in NS. Although litter addition did not significantly alter the overall relative abundance of bacterial communities in either soil type, it led to a marked increase in the relative abundance of the fungal phylum Ascomycota. Moreover, litter decomposition significantly reduced the Shannon diversity index of both bacteria and fungi in NS, particularly at the 5 cm and 10 cm depths. Fungal diversity (Shannon, Chao1, and Ace indices) was significantly higher in SS than in NS, whereas the opposite pattern was observed for bacterial diversity. Random forest analysis indicated that soil fungi drove the HFA of S . canadensis litter decomposition, which was likely due to physicochemical changes that favored fungi. In conclusion, S . canadensis litter decomposition exhibited a distinct HFA effect driven by the soil fungal community that promoted nutrient cycling. • Home-field advantage was more significant at a depth of 5–10 cm. • S. canadensis litter decomposition alters soil physicochemical properties. • Greater soil fungal diversity occurred in the home field than the away field. • Fungal communities dominated the home-field advantage phenomenon.