Roadside slopes restoration enhanced fungal diversity and microbial network complexity but reduced bacterial diversity and microbial network modularity in a subtropical region, Southwest China Raw sequence reads

To restore the degraded roadsides ecosystems, conventional methods such as plant revegetation and soil amendments are commonly employed. However, our understanding of the effects of these restoration approaches on the long-term impact on soil microbial diversity and network complexity across different vegetation types remains poor, resulting in less sustainable restoration. In this study, we investigated the impact of roadside restoration on microbial communities in various vegetation types in restorations that varied in age. Our results showed that restoration age had a more pronounced impact on microbial diversity than the specific vegetation type. As restoration progressed, microbial network complexity increased, as did fungal diversity, while bacterial diversity declined. This suggests a potential contribution of keystone taxa to network complexity. However, this increased complexity was accompanied by a decrease in modularity, which may compromise system stability. Distinct vegetation types were associated with restoration-sensitive microbial communities at different stages of restoration. Legume plants and nitrogen-fixing, such as, Albiziak alkora, Ginkgo biloba, and Rhus chinensis, Rhapis excels, Rubia cordifolia exhibited such associations after 5 years of restoration. These keystone taxa included Proteobacteria, Actinobacteria, Chloroflexi, Gemmatimonadota, and Myxococcota. We further found that bacterial alpha diversity was significantly correlated with restoration time, soil pH, moisture, available phosphate, nitrate nitrogen, and plant height, while fungal diversity was primarily shaped by restoration time. Together, our findings suggest that manipulating soil properties, environmental factors, vegetation type, and dominant species could guide the trajectory of ecological recovery by promoting certain microbial taxa.