Rapid changes in major nutrients and fungal community during early decomposition of Betula platyphylla litter on volcanic lava plateau

Volcanic eruptions deposit lava that covers the original soil and alters biogeochemical cycles, leading to the formation of unique ecological characteristics. Litter decomposition is an important part of the nutrient cycling in volcanic forest ecosystems. This study aimed to investigate the dynamic coupling between litter nutrient release and fungal community succession during the decomposition of pioneer <i>Betula platyphylla</i> in a volcanic forest. We conducted an <i>in situ</i> decomposition experiment combined with Illumina MiSeq high-throughput sequencing and fungal functional prediction. We found that, on the lava plateau, after 18 months of decomposition, <i>Betula platyphylla</i> litter remains in the early stages of decomposition, with rapid changes occurring in its nutrient composition and fungal community structure. (<i>p</i> < 0.05). The diversity and composition of fungal communities in <i>Betula platyphylla</i> litter differed significantly among the four sampling periods. The succession of fungal communities, dominated by Ascomycota and Basidiomycota, was primarily driven by changes in litter mass remaining and key nutrient concentrations (C, N and P). Our results offer valuable insights for further investigations into the dynamics of fungal communities during litter decomposition in volcanic forest ecosystems.