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Smooth cordgrass (Spartina alterniflora) was introduced to China in December 1979 to buffer against tides and to accelerate coastal wetland accretion. Since then, its propagation and natural dispersal have allowed this exotic plant to rapidly expand throughout coastal China with generally negative ecological effects. In 2003 S. alterniflora was labeled as an invasive plant in China, and it now covers ~50,000 ha. In this review, we first summarize the mechanisms of spread and spatial distribution of S. alterniflora, and how its physiological characteristics and strong adaptability to the available niche space in China's wetlands have enabled its spread and competition with native plants. Then we review the effects of S. alterniflora on ecosystem function in terms of habitat conversion and the alteration of biodiversity, soil carbon flux and sequestration, and various processes of nutrient regulation. We conclude that we need a long-term and context-dependent perspective, in order to maximize the benefits and minimize the costs of S. alterniflora within each of China's unique provinces.

Although much research has focused upon the negative impacts of invasive Spartina alterniflora upon salt marshes dominated by other Spartina spp., little is known about its impacts upon native Scirpus mariqueter marshes. In 1997, S. alterniflora was introduced to the Jiuduansha Shoals, Yangtze Estuary, China, to accelerate the formation of marsh habitat via accretionary processes, with the larger goal of drawing waterfowl away from wetlands near the Pudong International Airport, Shanghai, China. In 2000, a nature reserve was established on the Jiuduansha Shoals, making the impact upon the native S. mariqueter community a high priority for research. Our objective was to quantify the impacts of introduced S. alterniflora and Phragmites australis to the native S. mariqueter -dominated community at this site in four elevation zones, as compared with a nearby natural shoal. We found that species diversity was greater in the lower elevations with the engineering, through elimination of the natural dominance of S. mariqueter . We also found that diversity was lessened in the higher elevations, due to rapid growth and exclusion by the planted S. alterniflora in conjunction with the native P. australis . Moreover, we found that the growth of the native S. mariqueter was stimulated when S. alterniflora was planted nearby. It is quite likely that the net effect of these ecological processes will be to accelerate further accretion, leading to an eventual replacement of the S. mariqueter -dominated community in the long-term. Future management approaches should focus upon harvesting, grazing, and perimeter-ditching the S. alterniflora to avoid this situation.

Over the course of a year, we conducted a study on future restoration work in the Sanyang wetland, a degraded permanent river wetland that is close to the center of Wenzhou city, China. Our main objective was to plan the restoration by using both structural indices and a valuation of the wetland's ecosystem services, thereby linking the science to human welfare. Based on field surveys and research into the history of the study area, we calculated both the potential and current values of the main ecosystem services. The results showed that the potential value at the Sanyang wetland was 55,332 yuan ha −1 yr −1 , while the current value was only 5807 yuan ha −1 yr −1 . In other words, 89.5% of the service value needs to be restored for the wetland to reach its potential value. We recommend that the service provided by the wetland's ability to purify the environment needs to be the top priority in restoration. In addition, water and sediment quality should also be greatly improved.