The term “ecosystem services” was formally proposed in the early 1970s (Holdren and Ehrlich, 1974), and the Millennium Ecosystem Assessment (MA 2005) defined it as the benefits people obtain from the ecosystem (Zhao et al., 2007). Many studies on ecosystem services have been conducted since then, and preliminary research results have been documented (Li et al., 2022). Monetisation and quantification of ecosystem services have gradually garnered attention to assess the contribution of ecosystems to human welfare and guide the application of ecology in economic decision-making (Bayon, 2004; EC, 2008; Peterson et al., 2010; Roces-Díaz et al., 2015). However, because of the complex transfer process of ecosystem services from natural ecosystems to social and economic systems, the same terms have often been understood and applied differently, resulting in ambiguity in the concepts. For one example, the concept of ecosystem services proposed by Villamagna et al. (2013) distinguishes supply (ability to provide services) from use (depending on supply and demand). In contrast, the System of Environmental-economic Accounting—Ecosystem Accounting (SEEA EA) manual equates the supply of an ecosystem with its use (United Nations, 2021). Another example is Crossman et al. (2013) who have mixed-use and demand in the same term (often referred to as “demand”). Nevertheless, in mapping and assessing ecosystems and their services (MAES) action, the European Union distinguishes between use and demand for ecosystem services (European Union, 2020). Because the definitions in these studies do not correspond, we have synthesised these concepts into three categories: supply, demand, and use ( Figure 1 ). We define the supply of ecosystem services as the ability of the ecosystem to provide services sustainably under existing ecosystem status and management conditions, regardless of human needs (Gómez-Baggethun et al., 2010; Haines-Young and Potschin, 2010; Burkhard et al., 2012; van Oudenhoven et al., 2012; Maes et al., 2016), such as the ability of the ecosystem to provide water retention services. Demand refers to the number of services that society requires or expects (Fisher et al., 2009; Villamagna et al., 2013; Maes et al., 2016; Goldenberg et al., 2017; Chaplin-Kramer et al., 2019), such as the number of water retention services. Use was determined based on the spatial relationship between supply and demand (Maes et al., 2016; European Commission et al., 2020; European Union, 2020: Vallecillo et al., 2019), which refers to the number of services obtained and utilised by human society from the ecosystem, such as the total amount of water used in personal or economic activities. The supply of ecosystem services directly depends on regional ecological integrity, which is influenced by human actions and decisions such as land cover change, land use, and technological progress. Similarly, the use of ecosystem services is influenced by policies, population dynamics, economic factors, cultural norms, and governance influence. Therefore, the supply and use of ecosystem services must be distinguished and accounted for to guide the formulation of relevant policies for ecological restoration and protection (Curran and de Sherbinin, 2004). Nevertheless, in previous assessments of ecosystem services, most did not distinguish between supply and use, instead choosing only one or the other in ecological studies or economic statistics applications (van Jaarsveld et al., 2005; McDonald, 2009; García-Llamas et al., 2018; European Union, 2020). For example, Song and Ouyang (2020) took Qinghai Province as an example to research the potential gross ecosystem product (GEP), accounting for an ecological benefit assessment. The United Nations Cooperation Project (NCAVES) calculated the actual gross ecosystem product of Guangxi and Guizhou in China based on the SEEA framework in 2016 (NBS China UNSD and UNEP, 2021), while the EU MAES report accounted for ecosystem services ‘ supply and use (European Union, 2020). However, in its accounting, the functional quantity index cannot be compared horizontally but only vertically. The supply and use of ecosystem services are interconnected and interact with each other, just like ecosystems and socioeconomic systems. These concepts must be connected for horizontal comparison to reflect the local ecosystem background and human utilisation of ecosystem services and formulate reasonable management policies.

The value quantity of ecosystem services is more widely used than the functional quantity because it converts different types of services into common weights before measuring them to facilitate horizontal comparison and comprehensive evaluation (Costanza et al., 1997; Boyd and Banzhaf, 2007). In 2013, Ouyang et al. (2013) from the Chinese Academy of Sciences proposed the concept of gross ecosystem product. In 2021, the United Nations released the first international standard, the SEEA-EA manual, which cited the concept of gross ecosystem product at an international level (United Nations, 2021). The following year, the National Bureau of Statistics of China and the National Development and Reform Commission jointly issued the Standard for Accounting of the Total Value of Ecosystem Products (Trial) by referring to the SEEA-EA manual, emphasising the accounting of ecosystem services used by human beings (National Development and Reform Commission, 2022). The 2013 concept emphasises the supply capacity of ecosystem services, while the 2021 concept emphasises the actual utilisation of ecosystem services by humans. The different emphasis of gross ecosystem product concepts also reflects the different focus of people in different fields: supply and use.

In summary, this study selected value indicators to calculate the supply and use of ecosystem services, namely potential and actual gross ecosystem product, to evaluate and compare the supply capacity and actual use of ecosystem services in Miyun County horizontally. In this study, we aimed to comprehensively understand the interdependence between the ecosystem and human society in Miyun County and provide decision-making support and policy guidance for ecological protection and sustainable development. Potential gross ecosystem product reflected the functional status of the ecosystem, which provided data support for its ecological protection benefit assessment, performance appraisal and outgoing audit of local leading cadres. Actual gross ecosystem product reflected the actual benefits of human society, which could be included in the system of national accounts(SNA), and as a standard for ecological compensation and criteria for ecological trading. Both together provided management basis and policy-making support for guiding regional ecological protection and sustainable development.

The potential gross ecosystem product for Miyun County was 254.32 billion yuan in 2020 ( Table 2 ). Among all the ecosystem services, the water retention service contributed the most (119.5 billion yuan), accounting for 47% of the potential gross ecosystem product in Miyun County, followed by the natural landscape (52.16 billion yuan). Wetland ecosystems were the main contributors to water retention services. The value of ecosystem services provided by wetlands was almost 4.5 times that provided by the other areas (per unit area) combined ( Figures 4 , 5A ).

The actual gross ecosystem product in Miyun County was 53.28 billion yuan. Among all kinds of ecosystem services, the contribution of climate regulation service was the highest (17.46 billion yuan), accounting for 32.8% of the actual gross ecosystem product in Miyun County, followed by the water retention service (11.86 billion yuan). Forest ecosystems contributed the most to climate regulation. The value of ecosystem services contributed by wetlands per unit area was the highest at 96 yuan/m² ( Figure 5B ).

Among all types of ecosystems in Miyun County, wetlands contributed the most to the potential gross ecosystem product (141.92 billion yuan), followed by forests (61.19 billion yuan) and urban ecosystems (0.4 million yuan). Forests contributed the most to the actual gross ecosystem product (20.49 billion yuan), followed by wetlands (14.47 billion yuan). The contribution of urban ecosystems to the actual gross ecosystem product were the same as its contribution to the potential gross ecosystem product (0.4 billion yuan). Although the demand in urban ecosystems was theoretically high, owing to its low supply capacity, the ecosystem services provided by urban ecosystems were utilised by residents and contributed to the actual gross ecosystem product ( Figure 6 ).

The spatial distribution patterns of potential gross ecosystem product In Miyun exhibited apparent spatial heterogeneity. The potential gross ecosystem product was high in the Northwestern region and the surrounding areas of the Miyun Reservoir. Areas with high values of ecosystem services were affected mainly by the Miyun Reservoir and Chaobai River systems, with rich vegetation, high water retention and climate regulation service values, and relatively complete ecological functions. Therefore, the supply potential was high. The potential gross ecosystem product was low in the southwestern region, mainly distributed around the economic centre of Miyun County. Water and vegetation areas were small because of the extensive distribution of construction land. Therefore, the supply potential of ecosystem services was low ( Figure 7 ).

The distribution pattern of the actual gross ecosystem product In the Miyun area also exhibited obvious spatial heterogeneity. High actual gross ecosystem product was primarily associated with the southwestern region. This is due to the rapid economic and social development, high levels of regional economic development, dense populations, and high intensities of ecosystem service use. Areas with low actual gross ecosystem product were mainly distributed in the northeast. Owing to their low degree of development and utilisation, poor regional accessibility, and low population, the intensity of the use of ecosystem services was low.

The difference between the potential and actual gross ecosystem product in Miyun tended to be lower in the southern region and higher in the central and northern regions. With regards to the spatial distribution, gross ecosystem product surplus areas were mainly distributed in the northwestern regions with an excellent ecological environment and relatively low population density. In the southwestern regions, the regional economic development speed is fast, the construction land area is large, and the ecological resource utilisation intensity is high. Consequently, the potential supply of ecosystem services could not meet the needs of residents, as reflected in the gross ecosystem product deficit ( Figure 8 ).

For natural ecosystems (forests, shrubs, grasslands, and wetlands), the potential gross ecosystem product was positively correlated with the actual gross ecosystem product (R² = 0.61). It follows that, within natural ecosystems, the greater the supply intensity of ecosystem services, the higher the use intensity. However, due to the intensity of human interference, farmlands, towns, and bare land did not show correlations between actual and potential gross ecosystem product. Correlation analysis between the driving factors and the potential and actual gross ecosystem product showed that the natural ecosystem area (R² = 0.88) and vegetation coverage (R² = 0.73) were the main factors affecting potential gross ecosystem product in Miyun County. The GDP (R² = 0.84) and population (R² = 0.82) were the main factors affecting actual gross ecosystem product in Miyun County ( Figure 9 ).

In 2020, the potential gross ecosystem product of Miyun County was 254.32 billion yuan, and the actual gross ecosystem product was 53.28 billion yuan, approximately 21% of the potential gross ecosystem product. Water retention services had a higher supply capacity among all the ecosystem services, whereas climate regulation services were more useful to people. Among all types of ecosystems, wetlands had the highest supply capacity for ecosystem services, which reflects the importance of wetland ecosystems in Miyun County. This is especially true for reservoirs in the supply of ecosystem services. The areas centred around and close to the Miyun Reservoir are rich in water resources and fishery products, and have strong climate regulation ability, which brings high tourism and cultural value. As a result, the potential gross ecosystem product of the reservoir around the bank and the supply potential were high, differing substantially from the high-deficit areas outside the bank. The actual gross ecosystem product accounted for only 21% of the potential gross ecosystem product, indicating that the overall intensity of the local use of ecosystem services is relatively low compared with the potential service supply. The difference between the potential and actual gross ecosystem product show the scope of vast exploitable space for water retention and natural landscape services in Miyun County. Therefore, local governments should consider further rational development and utilisation of ecological resources such as promoting local water resource utilisation and tourism development under a sustainable model and achieve a “win-win situation” between the social economy and the ecological environment. The potential gross ecosystem product in the Miyun area positively correlated with the actual gross ecosystem product of natural ecosystems, which means that the greater the supply intensity of ecosystem services, the higher the use intensity. This correlation also suggested that the availability of ecosystem services was one of the factors promoting their use. Thus, increasing the supply of ecosystem services through increased investment in protecting and maintaining ecosystems will directly benefit people, which was consistent with a study done by Aziz (2023).

When the use of an area exceeded its local supply (actual gross ecosystem product > potential gross ecosystem product), it indicated that the utilisation of the ecosystem by the local human society exceeded the threshold of its ability to provide ecosystem services, and when the utilisation of ecosystem services by human beings increased, it often comes at the cost of the ecosystem service potential, which could result in ecosystems being unable to continue to meet human demand for services, reducing the ecosystem’s contribution to human well-being (EC, 2008). Therefore, when formulating policies, local governments should focus on strengthening the protection of the wetland ecological environment and maintaining its advantages. In regions with medium to high surplus, the government can encourage ecotourism and the development of ecological products to boost local economic growth, raise awareness about ecosystem services, and promote their utilisation. By introducing ecotourism initiatives and supporting local ecological products, residents can be encouraged to actively safeguard and utilise ecosystem services. For areas with general or low surplus, the government should focus on ecological restoration and protection, enhancing ecosystem stability and capacity through activities such as vegetation restoration, wetland conservation, and water source protection. Additionally, promoting ecological agriculture and forestry, adopting eco-friendly practices, and enhancing ecosystem service supply in farmlands and forests are essential. In deficit areas where natural ecosystems are scarce, the government can invest in building ecological infrastructure like wetland parks, green spaces, and nature reserves to boost ecosystem service supply. These efforts not only enhance ecosystem services but also improve environmental quality and residents’ quality of life. Implementing resource taxation and fees in deficit areas can curb overuse, encouraging more efficient resource utilisation. Establishing strict land development controls can limit damage to ecosystems and prevent overuse of services. It is crucial for the government to institute ecological compensation and incentive mechanisms across Miyun County to reward effective ecosystem management. By economically rewarding major ecosystem service providers, excessive consumers can be motivated to preserve and enhance ecosystem services effectively.

Potential gross ecosystem product could be used as the basis for ecological protection benefit assessment and government performance assessment. Actual gross ecosystem product could be included in the system of national accounts (SNA), and also could be used as a standard for ecological compensation and criteria for ecological trading. In our study, the supply and use of ecosystem services were distinguished and compared to fully understand the interdependence between the ecosystem and economic society in Miyun County. Simultaneously, value indicators were selected to compare potential and actual gross ecosystem product horizontally to understand the overall supply potential of ecosystem services and the relative situation of human use in the study area, providing a reference for decision-making.

This study has some limitations. From the perspective of ecosystem service flow, three components — supply, flow path, and demand — must be considered. Research on the framework of ecosystem services is still in its initial and conceptual stages, and the feedback mechanism between spatial attribute characteristics and location, such as the spatial flow path, flow, and degree of ecosystem service use, is still poorly understood. Although the total value of the supply and use of ecosystem services in Miyun County was calculated in this study, the spatial flow path of ecosystem services has not been determined. Therefore, we could not determine the flow direction of their supply and use and, thus, could not establish their spatial distribution or connection. Future studies could further explore the flow paths and ranges of ecosystem services between regions. Emphasis should be placed on applied research regarding ecosystem service flow, exploring the coupled relationship between ecosystems and human welfare, and promoting the continuous improvement of human welfare.

The original contributions presented in the study are included in the article/Supplementary Material. Further inquiries can be directed to the corresponding author.

Y-qS: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources, Visualization, Writing – original draft, Writing – review & editing. XY: Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Supervision, Validation, Writing – review & editing. MC: Data curation, Investigation, Resources, Writing – original draft. Z-yO: Conceptualization, Investigation, Project administration, Supervision, Writing – review & editing.