Vegetation succession enhances microbial diversity, network complexity, and stability in coastal wetlands, underscoring the pivotal role of soil salinity and key microbial species

In coastal wetlands, vegetation succession is primarily driven by changes in hydrology, sedimentation, and soil salinity. This ecological process is known to significantly influence microbial communities. However, its specific effect on microbial interactions and network dynamics in coastal wetlands remains insufficiently understood. This study adopted a spatial ecological sequence approach instead of a temporal succession method to comprehensively analyze the effects of vegetation succession on microbial communities in the Yellow River Delta. The results demonstrated that soil salinity, rather than nutrient levels, was the primary driver of microbial community shifts during succession. Succession increased the relative abundance of dominant phyla, such as Acidobacteria, Actinobacteria, Chloroflexi, and Planctomycetota, whereas key taxa, including salt-tolerant species, functioned as pivotal nodes regulating community interactions. Co-occurrence network analysis revealed that vegetation succession significantly enhanced the complexity and stability of microbial networks by reducing soil salinity and thereby altering the composition of key microbial taxa. These findings reveal the salinity-mediated mechanisms underlying microbial network assembly during vegetation succession in coastal wetlands and identify environmentally responsive microbial taxa that act as critical connectors within microbial communities, providing a mechanistic basis for the ecological restoration and sustainable management of salinized coastal ecosystems.