Effects of Vegetation Restoration Type on Abundant and Scarce Soil Microbial Taxa in a Loess Plateau Mining Area

Vegetation restoration is critical for improving soil quality and microbial community dynamics in degraded mining areas. This study explored the effects of different vegetation types (grassland, shrubland, and mixed grass–shrub areas) on soil physicochemical properties, organic carbon fractions, and abundant versus scarce microbial taxa assemblies in a Loess Plateau coal mining area. Soil samples from four depths (0–100 cm) were analyzed using high-throughput sequencing for nutrient content; carbon components, soil organic carbon (SOC), particulate organic carbon (POC), mineral-associated organic carbon (MAOC), dissolved organic carbon (DOC), microbial biomass organic carbon (MBC), and readily oxidizable organic carbon (ROC); microbial diversity. Shrubland soils exhibited significantly higher total nitrogen (TN), total phosphorus (TP), and organic carbon components (SOC, MAOC, and POC) than other vegetation types (<i>p</i> < 0.05), with the greatest carbon accumulation noted in the surface layer depths (0–20 cm). Microbial communities displayed vegetation-specific patterns: abundant taxa (e.g., <i>Actinobacteria</i>, <i>Proteobacteria</i>) dominated nutrient cycling and exhibited resilience to environmental gradients, while rare taxa (e.g., <i>Methylomirabilota</i>, <i>Olpidiomycota</i>) correlated strongly with labile carbon fractions (DOC and POC) and demonstrated metabolic flexibility. Mantel tests identified soil pH, TN, and organic carbon components as key drivers of microbial community divergence (<i>p</i> < 0.01). Shrubland vegetation enhanced soil nutrient retention and carbon stabilization, whereas the mixed grass–shrub systems promoted niche partitioning among rare taxa. These findings highlight the roles of vegetation-mediated carbon inputs and environmental filtering in shaping microbial assembly, providing a scientific framework for optimizing restoration strategies in mining ecosystems.