A framework of freshwater services flow model into assessment on water security and quantification of transboundary flow: A case study in northeast China

Assessment of supply-demand relationships considering the interregional flow of ecosystem services

Accurate assessment of ecosystem service (ES) supply, demand, and flow is essential for identifying and enhancing the ES supply-demand relationship and promoting regional sustainable development. Based on the InVEST model, supply-demand ratio, coupling coordination analysis, breakpoint and field strength model, and GIS spatial analysis method, we evaluated the supply and demand of water yield, food supply, carbon storage, and soil conservation service in the Loess Plateau in 2000 and 2020 and analyzed the supply-demand relationship before and after considering the interregional ecosystem service flow (ESF). The results showed that (1) from 2000 to 2020, the supply and demand of the four types of ESs in the Loess Plateau increased. Before considering ESF, the surplus degree in water yield, food supply, and soil conservation increased, and carbon storage decreased. In most counties, the coupling coordination between the supply and demand of the soil conservation is mostly extreme incoordination and moderate incoordination, and other types of ESs are mostly reluctant coordination and moderate incoordination. The degree of incoordination in water yield and soil conservation have eased, while food supply and carbon storage have strengthened. For the comprehensive supply-demand relationship of ES, the degree of surplus and coordination increased, with most counties were in a state of surplus and coordination. (2) Water yield and soil conservation services flow primarily to the western and northwestern portions of the Loess Plateau, with a decrease in the number of flow paths but an increase in the total flow rate for the former and a decrease in flow paths and total flow rate for the latter. The food supply and carbon storage flow in all directions and the total flow rate increases, with a significant increase in the number of flow paths for carbon storage. (3) After considering ESF, the supply-demand relationship of each type of ES and the comprehensive ES supply-demand relationship are changed, in which the degree of surplus and coordination of deficit counties are significantly improved, and some counties even become surplus or improve the level of coordination. After considering ESF, the supply-demand ratio changes even more relative to the degree of coupling coordination. This study is of great significance for identifying the cross-regional transfer pattern of ES, understanding in-depth the dynamic supply-demand relationship of ES, and mitigating the mismatch between supply and demand of ES. It provides a scientific and objective theoretical basis for promoting regional sustainable development.

Water security assessment and driving mechanism in the ecosystem service flow condition

Water resources are the foundation of human survival and development. Thus, it is essential to quantify the relationship between water supply and demand and assess water security to ensure sustainable use of water resources. In this study, we quantified the relationship between water supply and demand in the Yiluo River Basin (YRB) using the InVEST model, constructed a spatial flow model of water provision service at the sub-watershed scale, and analyzed the water security index (WSI) under static and dynamic conditions. Subsequently, we used geographic detectors to identify the explanatory power of the main influencing factors of the WSI. The results showed that (1) from 2005 to 2018, the water supply decreased continuously and the water demand first increased and then decreased in the YRB; (2) the spatial pattern of WSI showed that it was high in the southwest and low in the northeast, wherein the highest and lowest WSI values occurred in 2005 and 2018, respectively. From 2005 to 2018, the mean values of the static and dynamic WSI decreased from 0.77 to 0.60 and 1.56 to 1.20, respectively. (3) The precipitation factor from the supply dimension and the gross domestic product (GDP) factor from the demand dimension had the strongest explanatory power for the static WSI. For the dynamic WSI, the flow quantity of the water provision service flow had the strongest explanatory power. This study provided a reference for governments to formulate sustainable water resource management.

Interactive influences of ecosystem services and socioeconomic factors on watershed eco-compensation standard "popularization" based on natural based solutions

Watershed eco-compensation is a policy tool to realize watershed environment improvement and regional economic development. It is important to eliminate the influence of economic differences between upstream & downstream regions and realize the fairness of regional social development based on Natural based Solutions (NbS). At present, lack of clarity in coupling and coordination analysis of ecosystem services & socioeconomic based on NbS could hamper watershed eco-compensation standards "popularization" and reduce the ability to successfully ecological governance. To meet the needs of economic development and ecological service value realization, dynamic equilibrium game research based on multidimensional relationship coordination and a multi-objective optimization solution of economic benefit distribution was carried out. To achieve the bargaining Bayesian/Nash equilibrium of the watershed eco-compensation standard in the game, the existence conditions of the equilibrium solution of the eco-compensation standard based on the mixed equilibrium game implementation process were studied. To carry out the complete information dynamic game, the equilibrium solution of the watershed eco-compensation standard based on the dynamic transfer payment was solved, and the rational analysis of the dynamic Bayesian equilibrium game of bargaining based on the incentive compatibility mechanism was also discussed. Water quantity and quality eco-compensation can ensure balanced development between ecological protection and the social economy in the Mihe River Basin. Combined with the variation law of socioeconomic water intake-utilization standards and the water use value, the city of Shouguang City & Qingzhou City should pay Linqu County 4.78 million US$ and 1.29 million US$ as watershed eco-compensation standards per year based on NbS, respectively. To verify the rationality of the results derived from the economically optimal model, two modes of "bargaining" & "perfect competition", were used to study the characteristics of the protocols generated by the equilibrium game, and the applicable conditions of the nonzero-sum game solution upstream and downstream of the watershed were also explored. Based on the nonzero-sum processing of the survey results, the current relationship between the input value of eco-compensation and the willingness to pay satisfies v ≥ c + 1 / 4 . Based on the dynamic game & Bayesian equilibrium solution of bargaining, the watershed eco-compensation quota of water quantity & quality is 6.07 million US$, the willingness to pay is 65.63 US$/month. These findings contribute to the quantifying process of bargaining & dynamic equilibrium by transforming "ambiguous" information to achieve sustainable ecosystem service management and develop socioeconomic strategies associated with different compensation features based on NbS, thus helping to inform watershed management.

Payments for Watershed Ecosystem Services in the Eyes of the Public, China

Recent decades have witnessed an increased development of schemes for payment for watershed ecosystem services (PWES). However, the public is usually excluded from PWES systems. Reliable and empirical research on PWES from the public perspective is scarce. Aiming to understand public perceptions, attitudes, participation, and responses to PWES, this paper investigated local residents living in the Yongding River watershed area through a face-to-face questionnaire survey. The results showed that the public had limited knowledge of PWES. The public was keen to be involved in PWES decision-making, but the current level of public participation was very low. Regarding willingness to pay (WTP) and willingness to accept (WTA), nearly 55% of the respondents supported paying the upstream residents for protecting the environment if they were beneficiaries in the downstream areas, while 85% of the respondents agreed to accept compensation if they were contributors to environmental improvement in the upstream areas. Although some of the respondents’ daily lives were affected by the watershed environment, they were reluctant to pay, reflecting a sign of “free-riding”. The regression analysis showed that public concerns, values, knowledge of PWES and the watershed environment, and demographic factors determined the WTP and WTA. The results of the contingent valuation method and opportunity costs method showed that the annual payment for headwater conservation areas (Huailai and Yanqing) ranged from CNY 245 to 718 million (USD 36 to 106 million). This study contributes to our limited knowledge and understanding of public sentiment and makes recommendations for improving public receptivity to PWES.

Simulation of Freshwater Ecosystem Service Flows under Land-Use Change: A Case Study of Lianshui River Basin, China

The service function of freshwater ecosystem is of great significance for ensuring the water security and the sustainable development of the social economy. However, it is vague how land-use change can influence freshwater ecosystem service flows. In this paper, we analyzed the land-use changes in the Lianshui River Basin from 2000 to 2018, built an ecosystem service flow model, and quantified the supply, demand, and flow of freshwater ecosystems under land-use change. The most intensified shifts of land-use change were the transfer of woodland to arable land and the transfer of arable land to built-up land. Urbanization and deforestation have increased water output by 0.06 billion m3, but water demand has increased by 2.42 billion m3, resulting in a 6% reduction in the flow of freshwater ecosystem services. Our study provides detailed information on freshwater ecosystem services flow from providers to beneficiaries within a watershed, showing how land-use change and ecosystem service flows can be integrated at the watershed scale to provide information for land-use management and the availability of freshwater ecosystems. Sustained development provides a scientific basis.