Soil Water and Nutrient Availability Drive Increased Bacterial Diversity and Metabolic Strategy Shifts Along a Desertification Reversal Sequence

ABSTRACT Vegetation restoration is a primary strategy for reversing desertification in drylands, with its long‐term effectiveness heavily dependent on the recovery of soil microbial functions. However, how soil bacterial communities and their metabolic functions respond to continuous restoration gradients remains poorly understood. Here, we examined soil bacterial diversity, community composition, and predicted metabolic functions along a continuous restoration sequence (ranging from mobile dunes through natural shrublands and plantations to oasis farmland) in the Minqin desert‐oasis ecotone, northwest China. We found that bacterial α‐diversity increased significantly from mobile dunes to oasis farmland, and β‐diversity revealed pronounced shifts in community composition among restoration stages. Actinobacteriota , Proteobacteria , and Chloroflexi dominated all stages and soil depths, whereas Acidobacteriota were significantly enriched in oasis farmland. Predicted metabolic functions also differed markedly among restoration stages: basal maintenance metabolism dominated in mobile dunes, whereas energy metabolism, metabolism of cofactors and vitamins, and genetic information processing all showed significantly higher relative abundance in oasis farmland. These shifts indicate a transition in bacterial metabolism from survival‐oriented maintenance to more complex, cooperative modes. Soil water content and nutrient availability, especially nitrogen, were the primary environmental drivers of variation in bacterial diversity and predicted metabolic functions. Together, this study highlights the critical role of soil bacterial community dynamics and associated metabolic shifts along desertification‐reversal sequences, thereby providing key microbial insights for guiding sustainable vegetation restoration and land‐use management in desert‐oasis ecotones.