维持城市生态系统服务供需平衡是建设宜居城市、提高城市居民福祉的基础,同时对区域经济与可持续发展具有重要意义。以西安市建成区为例,基于2018年遥感数据、统计数据和实地调研等多源数据,构建粮食需求、水资源需求、固碳释氧、空气净化、高温调节、减弱噪声和休闲娱乐服务需求测算模型,并应用ArcGIS等分析工具,对研究区城市绿色基础设施（Urban green infrastructure,UGI）服务供需空间匹配关系进行评估和分析,最后运用最小累积阻力模型识别生态源地和生态廊道,对西安市UGI空间格局进行优化。结果表明：（1） 西安市建成区UGI分布不均匀,破碎化程度高,连通性较差。UGI提供的生态系统服务总价值小于居民对服务需求总价值,在空间上表现为显著不匹配性。（2） 不同生态系统服务供需匹配状况存在差异,高温调节服务、空气净化服务和休闲娱乐服务供大于求,匹配状况较好;粮食供给、固碳释氧、水源涵养和减弱噪声服务供小于求,供需赤字。（3） 研究区生态系统服务供需具有显著空间异质性,随着人口集聚程度的提高,大部分生态系统服务（如高温调节、减弱噪声等）供需的空间匹配程度显著下降,在空间上表现为由城市中心的严重失调向边缘的良好匹配渐变。（4） 研究区生态源地斑块面积较小,破碎化程度高,连接度低,UGI网络缺乏主干生态廊道。通过构建由沿渭河、秦岭北麓2个生态走廊,沣河、潏河、灞河等7个生态保育区及沿道路绿化带等组成的UGI网络,可使生态系统服务供需空间关系更趋协调。

Urban green infrastructure (UGI) is a critical component of the urban natural ecosystem, which provides various ecosystem services for residents. It is of great significance to explore the spatial dependence of ecosystem service supply-demand relationships not only to reveal the relationship between ecology and economy but also for building a livable environment. However, better quantitative evaluation and spatial mapping of the demand of ecosystem services, and in particular analysis of the relationship between demand and supply of ecosystem services, are still missing. Taking the built-up area of Xi'an City in Shaanxi Province of China as an example, based on remote sensing, population and environmental monitoring data from 2018, several evaluation models for the demand of ecosystem services, such as high temperature regulation and noise reduction, were developed in this study, and the spatial relationships of supply and demand of different ecosystem services were analyzed on a pixel scale. Furthermore, in this study, we propose an optimized landscape pattern for a UGI in Xi'an by identifying ecological sources and ecological corridors based on the minimum cumulative resistance model. The results show that (1) the UGI in the built-up area of Xi'an is unevenly distributed, exhibiting a high degree of fragmentation and poor connectivity. The total value of residents' demand for ecosystem services can be reached with 224×10⁸ yuan, whereas the total value of UGI ecosystem service supply is just 28×10⁸ yuan, presenting a serious mismatch between supply and demand. (2) The degree of spatial matching between supply and demand of ecosystem services varies from one individual service to another. The supply of high temperature regulation, air purification, and leisure and entertainment services is greater than the residents' demand for these ecosystem services, so the matching situation between supply and demand is good in these cases; while the level of food supply, carbon sequestration and oxygen release, water conservation, and noise reduction services is less than the demand, the provisioning of these services are seriously lacking. (3) The matching of supply and demand of different kinds of ecosystem services has significant spatial heterogeneity. Overall, with the increase in population density, the spatial matching of supply and demand of most ecosystem services (such as high temperature regulation and noise reduction) decreases significantly, which shows a high matching degree in urban fringe areas and a serious imbalance in urban core areas. (4) In the overall study area, the ecological source patch is small, highly fragmented, and poorly connected, and the UGI network lacks a main ecological corridor. We propose constructing UGI networks composed of two ecological corridors (one ecological corridor along Wei River side and another along the north foot of the Qinling Mountains), seven ecological conservation areas (including the Ba River), and plentiful green belts along roads that will coordinate the spatial matching between supply and demand of ecosystem services and optimize the landscape pattern in Xi'an City. This work not only provides an enriched method for ecosystem services demand optimization but also will provide a guide for applying ecosystem service knowledge to ecological management, which will be an aid to the promotion of UGIs and sustainable development of ecosystems in Xi'an.