Assessment of the Ecological Value of Urban Wetlands and Optimization Strategies Based on Carbon Sink Benefits

Urban wetlands serve as vital spatial platforms for ecological restoration, carbon sequestration enhancement, and public environmental education; however, systematic research on their carbon sequestration benefits and the mechanisms linking these benefits to spatial design and public participation remains limited. Taking Nanjing Yuzui Wetland Park as a case study, this paper conducts a comprehensive assessment of plant community carbon sequestration benefits, spatial structural variations, and public ecological awareness by integrating official tree species data, field measurement data, the i-Tree Eco model, and questionnaire surveys. The results indicate that Yuzui Wetland Park already possesses a solid foundation for carbon sequestration, with a total carbon sequestration benefit of $48,777.38 and an average carbon sequestration benefit per tree of $24.63. Salix babylonica and Ulmus pumila L. are the primary contributors to current carbon sequestration, while Ginkgo biloba demonstrate strong long-term carbon storage potential, suggesting a clear division of labor among different tree species in short-term carbon fixation and long-term carbon storage. At the same time, significant differences exist between the native areas within the wetland and the peripheral roadside areas in terms of tree species composition, community structure, and carbon sequestration performance, indicating that spatial zoning is a key factor influencing the carbon sequestration benefits of urban wetlands. By integrating i-Tree Eco-based carbon assessment with questionnaire data, this study identifies a perceptual gap between the carbon-sink performance of Yuzui Wetland Park and public recognition of its ecological functions. The model results show measurable carbon-sequestration benefits and differentiated contribution patterns among tree species: Salix babylonica and Ulmus pumila L. contribute mainly to current carbon storage, while Ginkgo biloba shows long-term carbon-storage potential. The questionnaire results indicate that respondents recognized the wetland primarily through recreational and landscape functions, with lower recognition of carbon sequestration and water purification. These findings provide the basis for translating carbon-sink assessment into spatial visualization, environmental interpretation, and participatory landscape design. The study indicates that the optimization of urban wetlands should not be limited to plant selection and ecological calculations but should further integrate carbon sink assessment with spatial design and public participation to enhance the perceptibility, communicability, and practicability of wetland ecological value.