Abstract: Ecological restoration is an efficient method to reduce the degradation of natural coastal wetlands. Restoration age has important effects on soil chemical properties and plant community characteristics. However, long-term monitoring on the effects of wetland restoration projects and their underlying mechanism is still limited. Here, we examined the effects of different restoration ages (0, 3, 7, 10, and 19 years) of wetlands on soil properties, plant species diversity, and community stability in the Yellow River Delta. The results showed that soil electric conductivity, available phosphorus concentration, and available potassium concentration decreased with increasing restoration age. However, soil available nitrogen concentration increased during the restoration process. Shannon index, Pielou evenness index, and species richness index of plant communities increased continuously with increasing restoration age, while plant diversity indices were mainly driven by the changes in soil electrical conductivity. In addition, restoration age also promoted plant community stability, which was significantly and negatively related to soil electric conductivity, available phosphorus and available potassium, and positively related to available nitrogen concentration. With the proceeding of restoration, soil environment and plant community structure improved continuously. Therefore, restoration projects can stimulate positive succession of community and improve the stability of coastal wetland ecosystems.

Key words: coastal wetland, restoration age, species diversity, community stability, soil chemical property.