The uncontrolled invasion of moso bamboo (Phyllostachys pubescens) dramatically alters soil nitrogen cycling and destroys the natural habitat of Alsophila spinulosa. Nevertheless, no clear evidence points out the role of denitrifying bacteria in the invasion of bamboo into the habitat of A. spinulosa. In the present study, we found that low (importance value 0.0008), moderate (0.6551), and high (0.9326) bamboo invasions dramatically altered the underground root biomass of both P. pubescens and A. spinulosa. The root biomass of A. spinulosa was maximal at moderate invasion, indicating that intermediate disturbance might contribute to the growth and survival of the colonized plant. Successful bamboo invasion significantly increased rhizospheric soil available nitrogen content of A. spinulosa, coupled with elevated denitrifying bacterial abundance and diversity. Shewanella, Chitinophaga, and Achromobacter were the primary genera in the three invasions, whereas high bamboo invasion harbored more denitrifying bacteria and higher abundance than moderate and low invasions. Further correlation analysis found that most soil denitrifying bacteria were positively correlated with soil organic matter and available nitrogen but negatively correlated with pH and water content. In addition, our findings illustrated that two denitrifying bacteria, Chitinophaga and Sorangium, might be essential indicators for evaluating the effects of bamboo invasion on the growth of A. spinulosa. Collectively, this study found that moso bamboo invasion could change the nitrogen cycling of colonized habitats through alterations of denitrifying bacteria and provided valuable perspectives for profound recognizing the invasive impacts and mechanisms of bamboo expansion.

The water-level-fluctuation zone of a reservoir is an important connection between land and water; due to counter-seasonal rhythmic water level changes, this area is more sensitive and vulnerable, whereas the assessment and management of heavy metal pollution are still elusive. This study selected the water-level-fluctuation zone in the hinterland of the Three Gorges Reservoir. Through a quadrats investigation, the soil pollution status of seven heavy metals and the composition of herbaceous plants were identified, and the potential of the dominant species for phytoremediation was assessed. The results showed that the overall pollution was at the alert level (P_N = 0.97) and a low ecological risk level (RI = 123.12). And the study area was primarily contaminated by a mixed source of traffic, agriculture, and industry. A total of 17 dominant species were calculated using importance values. Most dominant species had better phytoremediation potential for Cd and Cu. None of the 17 dominant species were hyperaccumulators, but they could still play an important role in phytoremediation due to their high adaptability to specific environments. The results have guiding significance for the management and remediation of soil heavy metal pollution in global reservoir areas, further promoting global ecological security and sustainable development.