Effect of Phyllostachys pubescens expansion and refelling on soil food web in a Cryptomeria japonica plantation, Lushan Mountain, subtropical China

Purpose This study aimed to explore the impact of the expansion and subsequent felling of Moso bamboo (Phyllostachys pubescens), a dominant species in China's bamboo cultivation history, on both above-ground and underground soil fauna communities and the soil food web within Japanese cedar (Cryptomeria japonica) forests in Lushan Mountain, subtropical China. Methods We identified three distinct areas where Moso bamboo had expanded into pure Japanese cedar forests. In each area, two experimental scenarios were created: a deforestation site (DF) where Moso bamboo had intruded and was later felled, and a control site (UF) with ongoing bamboo growth. Soil fauna communities were collected using pitfall traps (above-ground soil fauna) and the Tullgren dry funnel method (underground soil fauna), while stable isotope analyses were used to determine the trophic levels of these communities. Results Deforestation significantly reduced the abundance of Acari, the most populous taxon, as well as Collembola, Diptera, and Diptera larvae. Above-ground Hymenoptera populations declined in deforested plots, while underground numbers rose. Undeforested forests supported higher densities of Coleoptera, Hymenoptera, and Arachnida. Despite similar annual biomass trends across plots, deforested areas had a greater biomass, driven by larger soil fauna. Soil total nitrogen, total phosphorus, and organic matter content increased in deforested areas and showed a strong correlation with most soil fauna, especially Diptera larvae. Following deforestation, habitat alterations have affected soil fauna's food sources, resulting in a lower trophic level for groups like Diptera, Collembola, and Hymenoptera. Conclusion Our study underscores the significant impact of Moso bamboo expansion and subsequent felling on the soil fauna communities and food web in Cryptomeria japonica forests. These findings highlight the need for further research into the long-term effects and recovery patterns of these ecosystems.