A New Approach to Functional Zoning of Wetlands in Coastal Urban Agglomerations and Its Application in Two Coastal Urban Agglomerations, China

Wetlands offer important ecological functions and values. Wetland functional zoning provides a reference and basis for sustainable fulfilment and management. In this study, two coastal urban agglomerations in South China were taken as study areas, namely, the Guangxi Beibu Gulf (GBG) and Guangdong-Hong Kong-Macao Greater Bay Area (GBA). Based on multisource information data, a wetland functional zoning system was constructed with the four levels of zoning concept, zoning principle, zoning basis, and zoning scheme. The functional zoning and dynamic analysis of wetlands from 1990 to 2020 were carried out from multiple perspectives of wetland ecological functions, wetland management and conservation functions. The results showed that: 1) in terms of wetland ecological functions, the two coastal urban agglomerations were dominated by hydrological regulation and purification of environmental functional areas. The coastal region was largely characterized by the main functional areas of climate regulation and biodiversity maintenance. 2) Regarding wetland management and conservation functions, two coastal urban agglomerations exhibited similar trends in terms of the sizes of their conservation and buffer zones from 1990 to 2020. Prevention and control zones were mainly located in core cities in a concentrated manner. Conservation zones largely comprised mountainous woodlands and important wetlands. 3) The two coastal urban agglomerations could be divided into 21 wetland functional zones. The central river area has remained the main prevention and control zone for many years. Regarding conservation zones, ecological protection and restoration should be the main focus. Regarding buffer zones, the construction of wetlands and surrounding complex systems should be strengthened or enhanced. Regarding prevention and control zones, activities that do not affect wetland functions should be allowed, provided that they comply with existing laws and regulations. This study could provide technical support and practical application guidance for wetland regulation and management.