**5. Conclusions**

The present study highlighted the central role of soft-bottom macrozoobenthic assemblages and associated water and sediment variables in assessing the environmental status of the Yundang Lagoon following the massive restoration effort conducted over the past 30 years. We believe that the macrozoobenthos, which greatly contributed to the lagoon's recovery, will also have a future role in the evolution of the lagoon's biodiversity and functioning, especially considering the dominance of invasive alien species. In particular, the presence of *M. sallei* as a dominant species may be of concern for its possible role as a pest species, thus its spatiotemporal evolution should be carefully monitored. Our results provide valuable, data−based knowledge of the environmental quality, as well as early warning, detection, and prevention of any invasion process in the Yundang Lagoon, an area of special relevance for current legislation. Overall, the environmental and biological information gathered in the present study provides insights relevant to both the activities carried out within the long-term integrated managemen<sup>t</sup> program, and the forecast of possible future ecological scenarios for the lagoon. As such, these results can support the local administration as they strive towards proper managemen<sup>t</sup> of the lagoon and the restoration of the ecosystem services that this urban water body may provide.

**Author Contributions:** Supervision, data curation. and funding acquisition: P.M. and H.L.; investigation: P.M.; H.L., D.G. and C.L.; formal analysis: P.M., S.C. and M.F.G.; visualization: P.M. and M.F.G.; writing—original draft: P.M. and M.F.G.; writing—review and editing: P.M., S.C., M.F.G., D.G., C.L. and H.L.

**Funding:** The present study was carried out under the Executive Program of Scientific and Technological Cooperation between Italy and China (2010−2012) of the Ministry of Foreign Affairs of Italy granted to PM and LH, and the Short Term Mobility Program (STM−2015) of the National Research Council of Italy granted to PM and LH. The study was also partially funded by the National Key R and D Program of China (grant no. 2016YFC0502904).

**Acknowledgments:** We gratefully thank Shiqiang Zhou for help in macrozoobenthos identification, the staff of the Xiamen Yundang Lagoon Management Office for logistic and technical support, and Marcello Giorgi, University of Rome "Tor Vergata", for technical support in data analysis procedures. We gratefully acknowledge three anonymous reviewers whose comments greatly contributed to an improved version of the original manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.
