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Ecosystem services are the benefits people obtain from ecosystems, and ecosystem services trade-offs have been widely applied to the development of land-use policy. Although previous studies have focused on trade-offs of ecosystem services, a scenario approach has been seldom used. The scenario approach can reveal the changes of ecosystem services for different land-use patterns in the future, and is of great significance for land-use decisions and ecosystem management. Based on the actual situation of deteriorating water quality and dwindling water supply in the Erhai Lake Basin of southwest China, this study put forward to convert paddy land to dry land (PLDL) in the basin, and simulated its potential impact on ecosystem services. Taking environmental pollution, social impact, economic benefit and residential participation into consideration, four scenarios of PLDL were designed. Then, four ecosystem services (water purification, water yield, soil conservation and rice production) were calculated for each scenario. The optimal scenario of PLDL in the Erhai Lake Basin was identified by trade-offs of the four ecosystem services. The results showed that the total nitrogen export could be reduced by 42.07% and water yield can be increased by 5.61% after converting 100% of paddy lands to dry land, thereby greatly improving the water quality and increasing the water yield of Erhai Lake. However, PLDL involving 100% of paddy lands also increased the sediment export by 17.22%, and eliminated rice production in the region. By comparing the four PLDL scenarios for converting just 50% of paddy lands, the residential participation scenario was identified to be the best choice for PLDL implementation because it achieved the best level of water purification and had the smallest negative effect on other ecosystem services. The optimal scenario for each township showed spatial differentiation, and there were conflicts between the optimal scenarios at basin scale and township scale, suggesting that the object and the spatial-temporal scale should be taken into consideration in land-use decisions using ecosystem services trade-offs. [ABSTRACT FROM AUTHOR]

As an information carrier and communication medium, indicators provide useful decision-making assistance in setting process goals and effectively reaching the goals. The main focus of this article is to investigate indicators' role in influencing planning through Strategic Environmental Assessment (SEA) especially related to Chinese experiences. From the perspective of planning and decision-making theory, the influence on planning is studied as influence of planning structure and influence of planning actors. Such a conceptual framework is applied in order to demonstrate how the use of indicators can influence planning through a SEA process. The study holds two empirical levels. On a general level, based on an online survey, this article investigates SEA practitioners' experiences in using indicators. On a case level, two urban plans are selected to provide more detailed experiences. The case level investigation is based on a documentary study and individual interviews with SEA practitioners/planners. By exploring how indicators influence planning through the structure of and the actors within SEA, this study tries to provide an overview of indicators' role in SEA. The results indicate that indicators are perceived as a useful tool in the Chinese SEA system. By improving and simplifying the procedures of SEA, the indicators exert more structural influence on SEA and on plan making. On the other hand, indicators are also shown to have more influence through political actors than found among technical actors. [ABSTRACT FROM AUTHOR]