Effects of thinning and ground cover plants on soil bacterial community composition and diversity in Picea asperata plantations within giant panda habitats

Forest thinning and ground cover plant management play crucial roles in habitat enhancement, yet their effects on soil microbiota remain poorly understood. This study examines their impact on soil properties and bacterial communities in artificial spruce forests (Picea asperata) within China's Huangtuliang ecological corridor, a crucial habitat for giant pandas. Thinning significantly alters soil pH and total phosphorus (TP) levels, with minimal changes observed in total nitrogen (TN), microbial biomass carbon (MBC) and nitrogen (MBN). The combined effect of thinning and ground cover presence increases soil organic carbon (SOC) to 65.47 g/kg, contrasting with its absence. Thinning enhances the abundance of Proteobacteria, Acidobacteria and Chloroflexi while reducing Actinobacteria. Conversely, ground cover removal decreases Proteobacteria and Bacteroidetes but increases Chloroflexi, Verrucomicrobia and Rokubacteria. These changes lead to reduced bacterial community diversity, as indicated by a lower Shannon diversity index and distinct community composition differences demonstrated through beta-diversity analysis. Soil pH, TP and MBN are crucial in maintaining bacterial community structure, with pH and TP exhibiting the strongest correlations. Network analysis confirms the significant influence of TP and pH on bacterial genera across various phyla. This study reveals the role of stochastic processes in high-elevation, low-temperature ecological corridors (R-2 = 0.817), with thinning's impact varying depending on the ground cover presence, thus enhancing effects post-removal by reducing dispersal limitation (migration rate, m = 0.96). These findings highlight the ecological implications of habitat management in sensitive ecosystems and advance our understanding of microbial dynamics in critical habitats.