Abstract
The relationship between soil microbiome stability and diversity remains a topic of debate. Our study aims to investigate the relationship between soil microbiome stability and diversity in different wetland types invaded by Spartina alterniflora and to reveal the mechanisms driving functional influences on this relationship during the later-stage development of the S. alterniflora invasion system. To investigated the structure, diversity, and functional traits of soil bacteria associated with S. alterniflora and their impact on bacteriome stability we conducted 16S rRNA sequencing of soils from two types of wetlands dominated by the invasive plant S. alterniflora at different growth stages, situated in temperate (salt marsh wetland) and subtropical (mangrove wetland) regions, and assessed bacteriome stability and its driving factors. Subsequently, we analyzed environmental and bacterial changes between the two sites and constructed co-occurrence networks among taxonomic groups and functional traits. The differences in the late-stage development of the two S. alterniflora-invaded wetland systems suggest that bacterial communities with higher diversity tend to exhibit greater stability. Keystone genera play both direct and indirect roles in regulating bacteriome stability, and all belong to dominant phyla. Furthermore, biological factors significantly outweigh nonbiological factors in driving stability. In contrast, core functions (broad functions) and specialized functions such as "nitrogen metabolism" and "sulfur metabolism" decrease bacteriome stability. Their enhancement of these metabolic processes correlates with reduced community stability, which is the key to the differences observed in the two invaded systems. This study advances our understanding of the relationship between soil microbial diversity and ecosystem stability, highlighting the importance of keystone taxa and functional traits for soil microbiome stability. It enhances our ability to predict microbial community transitions. It enhances a scientific basis for the management of S. alterniflora invasion.