Study On Coupling Research Of Physical And Human Process Based On Payments For Ecological Services

The coupling research of physical and human processes is a hot and difficult issue in geographical research. It is also a research priority in ecological economics. Research in Science and Social Science is separate from each other for a long time. The former often focuses on the location of phenomenon where it happens, but the latter focuses more on the reason why the phenomenon happens. Natural factors included in physical processes are mainly defined by their spatial and temporal scales, and are collected through natural units. Whereas human factors included in human processes are usually defined by their analysis scales such as function properties, and they are collected by administrative units including province, cities, counties and towns. Differences in research methods and data collecting and so on in the two aspects result in difficulties of coupling research. The society is now facing a series of environmental issues including global climate change, deforestation, water pollution, unsustainability of agriculture, biodiversity as well as other ecological services on the globe. These environmental issues not only take on interdisciplinary and multi-scale characteristics, but can also result in unpredictable and unforeseen outcomes. The single discipline can never solve these problems. The necessity and urgency of coupling research of physical and human processes has already been prominent. International succession of carried-out research programs reveals features of coupling research. These programs consist of International Geosphere-Biosphere Programme (IGBP), International Human Dimensions Programme on Global Environmental Change (IHDP), Global Land Project (GLP) and Integrated History and Future of People on Earth (IHOPE) and so on.Ecological Economics is an emerging discipline that addresses the relationship between ecosystem and economic system from a mostly broad perspective. It provides a good platform for coupling research of physical and human processes. When growth goes from an empty world into a full world, welfare that generated by economic services is increasing whereas welfare that generated by ecosystem services is decreasing. Decrease represents scarcity of resources, and scarcity means more valuable for these resources. Ecosystem services can be defined as the benefits humans obtain from nature. The Millennium Ecosystem Assessments classify ecosystem services into four categories: provision services, regulatory services, cultural services and supporting services needed for the production of all other services. The MEA also state that about60percent ecosystem services are being degraded. Payments for environmental services are an emerging research area in the discipline of Economic Ecologies. PES related theories and practices are developed in many countries and regions all over the world. PES have attracted increasing interest as a mechanism to translate external and non-market values of the environment into real financial incentives for local actors to provide ecological services. The notion of PES not only involves ecological services but decision mechanism of humans. Given the importance of ecosystem services, why are they not provided at the levels desired by society? Ecosystem services are produced or degraded through the interaction of physical process and the actions of individual decision-makers. It is necessary to understand physical process of ecosystem services and human process of decision-making by individuals.Heihe River Basin is a typical inland river basin. Water resources issue is always the key constraint in social and economic development. Continuing drought of climate, continued population and over-grazing of grassland together result in the degradation of grassland resources in upper stream of Heihe River Basin, making declination of water conservation function of grassland and other functions. The ecological environment get worsen. It is urgent to improve water resource services and to insure benefits for the people in upper stream of the watershed. Research on PES can solve the problem of incentive mechanism to supply of water resource services. So the upper stream of Heihe River Basin is chosen as research area. The physical process of generation of water conservation services is simulated by Soil and Water Assessment Tool. And the human decision process is derived by investigation opportunity cost of grazing prohibition. In the support of minimum-data approach, the impact of payments price on grazing prohibition and its provision of water conservation services is analyzed. Also the coupling research of human and physical processes is realized.Based on collecting various kinds of spatial data and meteorological and hydrological data for SWAT model in upper stream of Heihe River Basin, grazing prohibition scenario is designed. The physical process of water conservation services is simulated and the expected rate of ecosystem services is calculated. The opportunity costs of grazing prohibition obtained from household survey is analyzed. And the spatial distribution of opportunity costs as well as change of land use is conducted. The supply curve of water conservation services is simulated through probability model. The coupling research of physical and human processes is realized. A sensitivity analysis is conducted for probability model. Some policy suggestions are proposed. The conclusions and suggestions are as follows:(1) The physical processes are simulated by SWAT model. The spatial differences of water conservation services in each sub-basin are analyzed, providing guideline for payments for environmental services via actual ecological services. The average expected rate of water conservation services between grazing and grazing prohibition is25.27m3/hm2. The constructed SWAT model is calibrated and verified. The model shows well to simulate hydrology processes in the research area. Relative error of average annual discharges reaches16.3%and15.6, Ens respectively reaches0.81and0.88and the R2gets0.95and0.93during model calibration and verification period.(2) The selection mechanism of grazing prohibition for herdsmen under different payments prices is accessed by household survey, and the human processes are portrayed. Spatial heterogeneity of opportunity costs for grazing prohibition exists in each sub-basin due to grassland quality and access to grasslands. The average opportunity cost in grazing prohibition is289.99Yuan/hm2. Among these, the highest cost is580.80Yuan/hm2in sub basin9and the lowest opportunity cost is130.50Yuan/hm2in sub basin1. The household survey also reveals most herdsmen are not willing to grazing prohibition. They believe that subsides of Grazing land to grassland is relatively low. They live on grazing and after grazing prohibition their livelihood can't be sustained.(3) The supply curve of water conservation services can be derived through spatial distribution of opportunity costs for grazing prohibition under the minimum-data approach model. The site-specific land use decisions can be linked to the regional supply of ecosystem services. There exist differences in the ratio of grazing prohibition as well as the supply of water conservation services under various payments prices. Even if in the same sub-basin different payments prices can lead to different ratio of grazing prohibition and the supply of water conservation services. In sub basin1when payment price is8.26Yuan/m3the ratio of grazing prohibition is49.15%, and the total supply of water conservation services is8.6×104m3. When payment price rises to20Yuan/m3, almost all low quality grasslands shift from grazing to grazing prohibition and the total supply of water conservation services amounts to1.72×106m3. Also the total additional income change is analyzed. In sub basin1when payment price is8.26Yuan/m3, the additional income is6.96×105Yuan. When payment price rises to20Yuan/m3, the additional income can reach3.41×106Yuan.(4) A sensitivity analysis is conducted for the minimum-data approach. The results show that the expected rate of ecosystem services has a positive impact on the ratio of grazing prohibition and the supply of water conservation services. In sub basin1, when e is8.26Yuan/m3, the ratio of grazing prohibition and the supply of water conservation services is respectively49.63%and8.6×104m3. When e increases by30%and decreases by30%,76.08%and23.20%in grasslands converts to grazing prohibition. Also the supply of water conservation services is1.71×105m3and2.85×104m3respectively.