Seasonal and density effects of submerged vegetation restoration on microbial communities in the semi‐constructed wetland

Ecological restoration through the use of submerged vegetation has been widely implemented both domestically and internationally, yielding significant results. The relationship between submerged vegetation and microbial communities has become a key focus in current research. Despite this, the regulation of submerged vegetation density post‐restoration remains a topic of debate, and the impact of submerged vegetation density and seasonal variations on microbial communities requires further investigation. A comprehensive study was conducted on different densities of submerged vegetation communities, water physicochemical properties, sediment nutrients, and bacterial communities following a semi‐constructed wetland ecological restoration project. The results indicated that the submerged vegetation density of around 50% of the water led to the highest dissolved oxygen (DO) content and a greater number of unique operational taxonomic units. Furthermore, both submerged vegetation density and seasonal changes were found to significantly influence microbial α‐ and β‐diversity. Redundancy analyses indicated that environmental factors explained the variability in bacterial α‐diversity, accounting for 74.63% of the variation. Particularly, the CODCr content in water was identified as a key environmental factor affecting bacterial α‐diversity, while DO, pH, turbidity, and total organic carbon in sediment had a significant impact on bacterial α‐diversity in water. This study advances our understanding of the ecological importance of submerged vegetation restoration and its effects on microbial communities, providing valuable insights for the management of submerged vegetation in wetland ecological restoration processes.