Abstract: An evaluation index system was established to evaluate ecosystem services in wetlands surrounding Chongming Island. The total value of ecosystem services was 15.18 billion CNY in 2017. Among all the examined ecosystem services, the value of cultural service was the largest, being 10.42 billion CNY. Regulating and providing services were valued at 4.672 and 0.087 billion CNY respectively. Cultural service accounted for 69% of the total value, indicating a great potential of tourism service provided by the wetlands. Due to the limiting factors including data availability and choice of assessment techniques, there were uncertainties in our assessment outputs. Spatialtemporal heterogeneity and socioeconomic preference of willingness to pay would affect the valuation. We discussed the factors that may lead to assessment uncertainties, including service supply, willingness to pay, and evaluation methods. Our results from this study would provide improvement directions for future studies.

Key words: ecological network., nature reserve, minimum cumulative resistance model, gravity model