关键词: 关键词　生态系统服务, 供给, 需求, 供需匹配, 城市河流

Abstract: As an important green infrastructure and public open space in cities, urban rivers are rich in natural factors and processes. However, due to the implementation of the rapid urbanization process, urban river ecosystem services decreased, rendering it difficult to meet the growing diverse needs of urban residents. Compared with the respective urban rivers in Southern China, the urban river ecosystem in Northern China is more significantly affected by seasonal water volume, physical structure characteristics of rivers, and water conservancy projects. It has the comparative characteristics of insufficient water volume, obvious seasonality, and habitat sensitivity.
　　In this work, an evaluation system of urban river ecosystem service supply and demands in Northern China was built, and an ecosystem service evaluation method including comprehensive considerations of supply-demand characteristics and supply-demand matching degree was tested. The Xingji River in Jinan City, which is a typical urban river in Northern China, was chosen and was divided into six sections according to the types of cross sections. The ecosystem service supply and demand characteristics of the Xingji River were systematically evaluated based on the utilization of a field survey, remote-sensing images and questionnaire survey data. The supply-demand matching degree was also analyzed by the supply-demand ratio. Based on the above-mentioned analysis results of the supply characteristics and supply-demand matching degree, a supply-demand matching-supply level distribution model was introduced and four quadrants were divided including supply surplus, high-efficiency matching, low-efficiency matching and weak services. On this basis, the practical efficiency of the ecosystem services in the Xingji River was further evaluated. 
　　From the acquired research results, it was demonstrated that the supply level and supply-matching efficiency of the Xingji River were relatively low. The Xinglong Reservoir-Second Ring South Road, Second Ring South Road-Shungeng Road, and Jingshi Road—Xiaoqinghe had the greatest negative influences on the whole ecosystem services of the river and are regarded as the key units for landscape reconstruction in the future. With respect to the different service types, three service types had low supply-demand matching efficiency. Improving cultural services is also considered an important link to enhance the ecosystem service supplies in the Xingji River. As far as the service dimensions are concerned, water purification, building healthy habitat, increasing recreation opportunities, and weak waterborne opportunity services are four types of service dimensions that have to be urgently improved. In addition, three optimization strategies were proposed to realize supply-demand matching of ecosystem services, from perspectives of improving adjustment, support and cultural services. (1) Improving water purification ability and increasing adjustment services of the river by maintaining healthy water volume and building a wetland system. (2) Forming healthy river habitat and increasing supporting services by reconstructing river morphologies, and building diversified habitats. (3) The public demands for diversified waterborne recreation spaces and expectation for close interaction with water should be satisfied and cultural services should be improved by using the abundant waterborne spaces and creating elastic landscapes.
　　In this work, an ecosystem service supply-demand evaluation system was built based on the ecological characteristics of the urban rivers in Northern China. The ecosystem system service supply-demand characteristics and matching degree were effectively combined by the supply-demand matching and supply level distribution model to evaluate the practical service efficiency. A method for a comprehensive understanding of ecosystem service efficiency is provided in this work, whereas from the evaluation results more specific guidance to optimization strategies can be provided. Our work provides theoretical support and scientific references for urban river landscape planning and design in Northern China under the orientation of ecosystem services.

Key words: ecosystem services, supply, demands, supply-demand matching, urban rivers