Soil organic carbon decline under bamboo invasion: The role of microbial carbon cycling

Moso bamboo (Phyllostachys edulis) invasion has increasingly threatened forest ecosystem stability by altering soil carbon cycling processes. However, the microbial mechanisms underlying the changes of soil organic carbon (SOC) during bamboo invasion remain poorly understood. In this study, we investigated the effects of bamboo invasion on microbial diversity, functions, and SOC content by collecting soil samples across a gradient of 0 %, 50 %, and 100 % bamboo invasion. The results showed that complete bamboo invasion significantly reduced bacterial α-diversity (P < 0.05) and promoted stochastic processes in shaping microbial communities, whereas fungal communities were more influenced by deterministic processes. Furthermore, bamboo invasion decreased the stability of bacterial interaction networks and significantly reduced SOC content (P < 0.05). To further validate this trend, we conducted a meta-analysis of 37 studies and 105 observations, which consistently indicated that bamboo invasion significantly reduced SOC. Our findings provide new insights, showing that the reduction in SOC is closely associated with a decrease in the abundance of microbial carbon cycling genes, suggesting that changes in these functional genes may be a key driver of SOC decline. These findings underscore the profound impact of bamboo invasion, which not only alters soil properties but also impedes microbial metabolism and carbon storage. The study highlights the urgent need to address plant invasions to preserve microbial ecosystem functions, which are crucial for maintaining global carbon cycles and ecosystem resilience.