生态系统服务的可持续发展对区域生态安全起到不可忽视的作用。泾河流域作为黄河流域的一条重要支流，为关中地区的农业灌溉提供了重要的水源。多年来泾河流域的生态环境不断遭到破坏，水土流失严重，输沙量大，水体污染加剧，使得生态系统服务变得脆弱，同时，在人类活动频繁和气候变化的双重压力下，泾河流域的生态面临严重问题。为此，研究生态系统服务的演变机制、空间分布特征以及未来的发展趋势，并揭示服务之间的相互作用关系，对采取因地制宜的治理措施，来改善泾河流域的生态环境，达到人与自然的可持续性协调发展具有重要的科学意义。

本文基于土地利用/覆被与生态系统服务的紧密联系，以泾河流域土地利用/覆被变化为科学起点，利用InVEST模型结合土壤、气象和地形等基础数据，对泾河流域2005年、2010年、2015年和2020年的4项生态系统服务（产水量、碳储量、土壤保持、生境质量）进行定量评估，明晰其时空变化特征及空间异质性变化，并从统计学和空间分布角度分别探究服务间的权衡/协同关系，最后选取13个环境和社会经济因子作为土地变化的驱动因素，利用PLUS模型预测四种情景下泾河流域2030年土地利用/覆被情况，并研究生态系统服务和权衡/协同关系的变化，并对未来的泾河流域生态系统服务权衡/协同关系提出优化对策。本文的主要结果和结论如下：

（1）草地和耕地是泾河流域的两种主要土地利用类型，分别占流域总面积的45%和41%左右。15a间，草地呈逐年增加趋势，而耕地则不断减少，退耕还草工程的实施是产生这一变化的主要原因之一。建设用地变化幅度也较为显著，城镇化建设是建设用地增加和耕地减少的主要原因之一。土地类型变化具有转换频繁和转换量大的特征，最显著的变化发生在耕地与草地之间，且耕地向建设用地的转换也较为突出。尽管2005-2020年间各地类面积和分布产生不同程度改变，但从其整体组成结构来看，六种地类的占比结构始终处于稳定状态。

（2）2005-2020年泾河流域产水量、碳储量、土壤保持服务总体均呈增加趋势，而生境质量呈减少趋势。15a间，产水量、土壤保持和生境质量服务在空间上有较为明显的变化。产水量高值区域主要分布在流域的西南部，其面积先减少后增加，低值区主要分布在流域北部区域；2020年土壤保持服务高值区较2005年有所减少；生境质量高值区主要集中在流域东部和西南部，低值区集中分布在流域中下游和北部，且在北部呈扩大趋势；碳储量服务空间变化较小。综合来看，流域西南部产水量、碳储量、土壤保持和生境质量服务能力较为突出。各项生态系统服务的强弱与土地利用类型联系较为紧密，对地类的变化较为敏感，且具有明显空间异质性。2005-2020年产水量和土壤保持服务空间集聚特征变化明显，而碳储量和生境质量服务空间分异格局差异较小。

（3）从统计分析法来看，泾河流域4项生态系统服务间的关系在研究期内基本稳定。其关系主要为：生境质量与碳储量、土壤保持与生境质量、土壤保持与碳储量之间均为协同关系，产水量与碳储量、产水量与生境质量之间均为权衡关系。从空间分析法来看，4项服务冷热点空间分布具有异质性；4项服务供给能力均较高的区域面积占比很少，不足域总面积的7%，表明具有高协同度的区域较少，服务供给能力有待进一步加强。

（4）设置生产空间优先、生活空间优先、生态空间优先和综合空间优化4种未来土地利用模拟情景，并评估各情景下生态系统服务值。结果表明，生态空间优先和综合空间优化两种情景下的生态系统供给能力要优于生产空间优先和生活空间优先情景，更加适合未来的生态健康发展。不同情景下生态系统服务权衡/协同关系与2020年相比没有改变，但这一关系的强度发生不同程度变化。未来泾河流域应该进行合理分区，在不同生态分区实施不同情景策略和相应管控政策。

The sustainable development of ecosystem services plays an indispensable role in regional ecological security. As an important tributary of the Yellow River Basin, the Jinghe River Basin provides vital water resources for agricultural irrigation in the Guanzhong Plain. However, the ecological environment of the Jinghe River Basin has been continuously deteriorating over the years, with serious soil erosion, large sediment load, and aggravated water pollution, which has made the ecosystem services vulnerable. Meanwhile, under the dual pressures of frequent human activities and climate change, the ecology of the Jinghe River Basin is facing severe problems. Therefore, studying the evolution mechanism and spatial distribution characteristics of ecosystem services, as well as their future development trends and revealing the interactions among these services, has important scientific significance for taking targeted governance measures to improve the ecological environment of the Jinghe River Basin and achieve sustainable development between humans and nature in a coordinated manner.

Based on the close relationship between land use/land cover and ecosystem services, this paper takes the Jinghe River Basin as the scientific starting point to use the InVEST model combined with basic data such as soil, meteorology, and topography to quantitatively evaluate four ecosystem services (water yield, carbon storage, soil conservation, and habitat quality) in the Jinghe River Basin in 2005, 2010, 2015, and 2020, clarify their spatiotemporal characteristics and spatial heterogeneity changes, and explore the trade-offs and synergies between services from statistical and spatial distribution perspectives. Finally, 13 environmental and socio-economic factors were selected as driving factors for land use change, and the PLUS model was used to predict land use/land cover in the Jinghe River Basin in 2030 under four scenarios. The changes in ecosystem services and trade-offs and synergies were studied, and optimization measures were proposed for the future trade-offs and synergies of ecosystem services in the Jinghe River Basin. The main results and conclusions of this paper are as follows:

(1) Grassland and cultivated land are the two main land use types in the Jinghe River Basin, accounting for about 45 % and 41 % of the total area of the basin, respectively. Over the past 15 years, there has been a trend of increasing grassland while cultivated land has been decreasing, and the implementation of the "Grain for Green" project is one of the main reasons for this change. The changes in construction land use have also been significant, and urbanization is one of the main reasons for the increase in construction land and the decrease in cultivated land. Land use change is characterized by frequent and large-scale conversions, with the most significant changes occurring between cultivated land and grassland, and the conversion of cultivated land to construction land is also prominent. Although there have been changes in the area and distribution of various land types to varying degrees between 2005 and 2020, the overall composition of the six land types has remained stable.

(2) From 2005 to 2020, the overall trend of water yield, carbon storage, and soil conservation in the Jing River Basin showed an increase, while habitat quality showed a decrease. Over the 15-year period, water yield, soil conservation, and habitat quality showed relatively obvious spatial changes, while carbon storage showed less spatial variability. Overall, the southwest side of the basin exhibited prominent water yield, carbon storage, soil conservation, and habitat quality service capacity. The strength of each ecosystem service is closely related to land use types, sensitive to changes in land cover, and exhibits significant spatial heterogeneity. From 2005 to 2020, the spatial clustering characteristics of water yield and soil conservation changed significantly, while the spatial differentiation patterns of carbon storage and habitat quality showed relatively little difference.

(3) From a statistical analysis perspective, the relationships among the four ecosystem services in the Jing River Basin were basically stable during the study period. The relationships were mainly synergistic between habitat quality and carbon storage, habitat quality and soil conservation, and soil conservation and carbon storage, while there was a trade-off relationship between water yield and carbon storage, and water yield and habitat quality. From a spatial analysis perspective, the spatial distribution of the hotspots and coldspots of the four services showed heterogeneity, and the proportion of areas with high supply capacity for the four services was relatively low, accounting for less than 7% of the total watershed area, indicating that there are few areas with high synergy and the supply capacity of the services needs to be further strengthened.

(4) Four future land use simulation scenarios were set: production space priority, living space priority, ecological space priority, and comprehensive space optimization. Ecosystem service values were evaluated under each scenario. The results show that the ecological supply capacity under the ecological space priority and comprehensive space optimization scenarios is better than that under the production space priority and living space priority scenarios, which is more suitable for the future ecological and healthy development. The trade-offs and synergies of ecosystem services under different scenarios have not changed compared with those in 2020, but the strength of this relationship has changed to varying degrees. In the future, the Jinghe River Basin should be reasonably zoned, and different scenario strategies and corresponding control policies should be implemented in different ecological zones.