生态系统健康是区域可持续发展与生态系统管理的重要内容，受人类活动影响强烈的干旱区可持续发展问题是国内外研究的热点。土地利用与覆被变化（LUCC）作为人类活动影响陆地生态系统的最直接方式，在生态系统健康和可持续发展研究中占有重要地位。然而当前的相关研究对于揭示干旱区绿洲开发引起的流域土地利用结构变化与社会经济结构变化同流域生态系统健康状态间的作用关系与影响机制以及流域可持续管理路径仍有待更加深入地探索。碳、水流动过程是链接自然生态系统与社会经济系统的关键纽带，碳、水流动过程研究有利于阐明与揭示区域生态环境问题和社会经济活动之间的内在联系，尤其对于水资源紧缺，生态脆弱的西北地区。本文以我国西北典型干旱区玛纳斯河流域为例，研究以农业开发与城镇化发展为主要驱动的流域土地利用结构与社会经济结构变化对流域碳、水流动格局的重塑，以及流域自然生态系统服务功能与城镇生产、生活功能对碳、水流动过程变化的响应；并对流域自然生态系统功能与城镇功能变化引发的效应、效率进行整合，诊断流域健康状态；最后在流域健康、可持续发展目标下，基于系统动力学模型，以水土资源优化配置为手段，模拟实现流域复合生态系统社会、经济、生态综合效益最大化的发展路径。即以“结构—过程—功能—效应/效率—状态—管理”为研究主线，以阐明流域系统运行机制为重点，以揭示流域系统运行状态为核心，以实现流域系统可持续管理为落脚点，对玛纳斯河流域生态系统健康问题进行系统性分析。对于以玛纳斯河流域为代表的干旱脆弱区健康、可持续发展具有一定的理论与实践指导意义。

所得主要结果如下:

      （1）玛纳斯河流域土地利用与景观格局变化研究表明：2000-2020年间，流域农业的开垦与城镇经济建设使土地利用结构发生了很大变化，土地利用变化表现为耕地、建设用地增加，林地、草地、未利用地减少，水域、冰川基本保持平衡。随着草地和未利用地向耕地与建设用地的大量转入，耕地面积由4602km2增长到6710km2，建设用地面积由392km2增长到662km2，面积增长幅度分别达到45.61%、68.88%。林地、草地、未利用地面积分别减少290.50km2、776.32km2、1182.61km2。水域、冰川面积变化不大。耕地、建设用地面积的增长同时伴随着土地利用强度由0.476增长到0.527。二者面积变化由加速扩张到降速增加，最后趋于稳定，耕地动态度也由不平衡趋于平衡，建设用地总体处于准平衡阶段。生态用地动态度表现为负值，处于转出状态，综合土地利用动态度由不平衡状态趋于平衡。流域景观格局变化表现出阶段性特征：2000-2010年以破碎化、多样化、异质性、景观形状复杂性增强为主要特征；2010-2020年，随着耕地、建设用地优势度的提高、团聚性的持续增强，流域整体景观格局向集约化、均衡化、规整化演变。

      （2）玛纳斯河流域农业开发对水文过程的影响及效应研究结果显示：节水技术、种植结构改变了耕地面积与农业用水间的关系；农业用水过程主导了流域自然与社会经济系统间水资源利用格局，引发资源环境问题。农业开发过程促使耕地面积持续增长，农业用水常年占用水总量的90%以上，但并没有与耕地面积表现出一致性增长，而呈现周期性波动变化。农业水循环逐渐占据流域水循环主导地位，农田水利建设、农业结构改变及农田灌溉面积增加改变了地表径流流向及水系结构、地表水通量分配、蒸发及下渗过程，从循环路径、参数、结构方面改变了流域水循环过程。水资源生产生活功能逐渐取代生态功能，使流域生态环境发生正负双向改变。借助3S技术对部分生态水文效应进行了量化，生态环境变化具体表现为局地小气候有所改善，土壤盐碱化、荒漠化面积显著下降，同时农业面源污染、地下水超采、生物多样性减少等问题越发严重。

       （3）基于以碳排量量化的城镇化水平、以固碳量量化的生态系统服务水平、以碳储量量化的功能、人类福祉水平评估结果表明：玛纳斯河流域城镇化过程增强了城镇生产生活功能，但使自然生态系统服务间呈现差异性变化，导致人类福祉发展的不均衡。2000-2015年流域城镇化各层面均实现了稳步增长，整体城镇化过程碳排量增长10.34倍。流域生态系统服务功能呈波状下降趋势，较2000年降低12.31%。其中供给服务呈现增长趋势，固碳量是原来的3.06倍，与支持、调节、文化服务表现出权衡关系，后三者表现为协同下降，固碳量分别降低46.97%、21.65%、16.45%。除供给服务外，支持、调节、文化生态系统服务水平与各城镇化水平空间布局大体相反，受到城镇发展的约束作用。人类福祉在研究时段内取得显著提高，2015年福祉总碳储量增长量是2000年的1.92倍，其中社会福祉增长0.57倍，经济福祉增长2.69倍，生态福祉减少23.24%。随城镇化发展，社会结构、经济结构、土地利用结构的变化增强了城镇生产生活功能以及自然生态系统供给服务功能，促进了人类经济福祉、社会福祉的提高，但降低了自然生态系统支持、调节、文化服务功能，生态福祉下降。城镇生产功能与自然生态系统供给服务功能与人类福祉关联性最强，是流域人类社会、经济福祉增加的主要促进因素。

       （4）玛纳斯河流域生态系统健康评价结果表明：流域社会经济的快速发展使流域复合生态系统健康状态整体呈现波状上升趋势，但水、土资源及生态环境质量的下降导致流域可持续发展潜力降低。2000-2015年，健康综合指数由0.41上升到0.62。在子系统健康状态层面上，资源子系统中地下水资源、生态土地资源减少，气候条件转好，植被活力增强，使其健康状态总体呈现波动上升；环境子系统中大气、水环境质量下降，土地盐碱化、荒漠化减轻，环境子系统总体呈现波动下降；生态子系统中供给服务增长，支持、调节、文化服务降低，使其健康状态总体呈现波动下降；社会子系统与经济子系统各层面均呈直线上升。表明研究期内，流域的开发建设虽然卓有成效，但由于没有处理好开发与保护的关系，致使重要生态资源与环境对社会经济发展的支撑力降低，影响流域可持续发展潜力。在县市尺度上，各县市综合健康状态呈现先降后升，总体增长趋势。平均健康指数石河子、沙湾县、玛纳斯县分别为0.479、0.476、0.443，石河子与沙湾县健康状态较优于玛纳斯县。相较于2000年，各2015年健康综合指数分别提升52.44%、45.08%、21.69%。

       不同研究阶段各指标对生态系统健康变化的贡献度不尽相同，贡献度高的指标总体可归纳为自然生态系统服务指标（支持、调节服务）、系统耦合效率指标（单位GDP用水、城镇发展效益指数、单位生产用水碳排放量）、生产指标（工业产品供给量、能源消耗）、环境指标（土地盐碱化面积、水体等标污染负荷）。在子系统水平上，从平均水平看，在对流域生态系统健康影响力的表现上，生态子系统>系统耦合效率>经济子系统>资源子系统>环境子系统>社会子系统。

      （5）基于自然生态系统健康目标、经济增长目标、资源最大人口承载目标、低碳目标以及代际公平目标五大目标，构建流域健康、可持续发展系统动力学模型。模拟研究表明：方案2（社会经济发展型）、方案3（社会经济优先兼顾生态型）、方案5（统筹兼顾型）情景下，社会经济高速发展，至2035年可实现约4倍的GDP增长，总人口达到92-95万人，城镇化率达到86.5%-88%。但建设用地增长65%，使土地碳效益降低60%以上。方案4（生态保护优先兼顾社会经济型）、方案5（统筹兼顾型）采取高强度生态系统保护措施，增加了60%以上的水资源人口承载力，但由于执行退耕计划，使土地人口承载力降低10-20%。生态用地显著增长，生态系统服务能力提升6%以上。方案1（现状延续型）、方案2（社会经济发展型）发展情景下未加强对自然生态系统的保护，生态系统服务未被有效提升，草地、水域面积仍呈减少趋势，水资源人口承载力最低，使自然生态系统健康受到威胁。各发展方案均使经济结构更加优化且实现农业用水占比85%以下，但均未能实现水资源的区域自给自足，年均需外调4-7亿m3水资源。综合效益方案5>方案2>方案3>方案4>方案1。

       Ecosystem health is an important part of regional sustainable development and ecosystem management. The sustainable development of arid regions strongly affected by human activities is a hot research topic at home and abroad. Land use and cover change (LUCC), as the most direct way that human activities affect terrestrial ecosystems, occupies an important position in the study of ecosystem health and sustainable development. However, the current relevant research still needs to be further explored to reveal the relationship and impact mechanism between the changes of land use structure and socio-economic structure and the health state of watershed ecosystem caused by oasis development in arid areas, as well as the path of watershed sustainable management. The carbon and water flow process is the key link linking the natural ecosystem and the socio-economic system. The study of the carbon and water flow process is conducive to clarifying and revealing the internal relationship between regional ecological and environmental problems and social and economic activities, especially for the northwest region where water resources are scarce and the ecology is fragile. Taking Manas River Basin, a typical arid area in Northwest China, as an example, this paper studied the reshaping of carbon and water flow pattern by the change of land use structure and socio-economic structure driven by agricultural expansion and urbanization, and the response of natural ecosystem service function and urban production and living function to the change of carbon and water flow process; And integrate the effect and efficiency caused by the change of natural ecosystem function and urban function in the basin, so as to diagnose the health state of the basin; Finally, under the goal of healthy and sustainable development of the basin, based on the system dynamics model, the development path of maximizing the comprehensive social, economic and ecological benefits of the basin composite system is simulated by means of the optimal allocation of water and soil resources. That is, taking "structure-process-function-effect/ efficiency-state-management" as the research main line, clarifying the operation mechanism of the basin system as a key point, revealing the operation state of the basin system as the core, and realizing the sustainable management of the basin system as the foothold, this paper made a systematic analysis on the health problems of the ecosystem in Manas River Basin. It has certain theoretical and practical guiding significance for the healthy and sustainable development of the arid and fragile areas represented by the Manas River Basin.

The main results obtained were as follows:

      (1)The research on the change of land use and landscape pattern in the Manas River Basin showed that: From 2000 to 2020, agricultural reclamation and urban economic construction in the basin had greatly changed the land use structure. The land use change was reflected in the increase of cultivated land and construction land, the decrease of forest land, grassland and unused land, and the basic balance of water area and glacier. With the large transfer of grassland and unused land to cultivated land and construction land, the area of cultivated land had increased from 4602km2 to 6710km2, and the area of construction land had increased from 392km2 to 662km2, with an area growth rate of 45.61% and 68.88% respectively. The area of forest land, grassland and unused land decreased by 290.50km2, 776.32km2 and 1182.61km2 respectively. The water area and glacier area changed little. The increase of cultivated land and construction land area was accompanied by the increase of land use intensity from 0.476 to 0.527. The area change of the two was from accelerating expansion to decreasing increase, and finally tended to be stable. The dynamic degree of cultivated land also tended to be balanced from imbalance, and the construction land was generally in the quasi-equilibrium stage. The overall dynamic degree of the ecological land use was negative, in a state of transfer out, and the dynamic degree of comprehensive land use tended to be balanced from an unbalanced state. The changes of landscape pattern in the basin were characterized by stages: from 2000 to 2010, it was mainly characterized by fragmentation, diversification, heterogeneity and increased complexity of landscape shape; From 2010 to 2020, with the improvement of the dominance of cultivated land and construction land and the continuous enhancement of agglomeration, the overall landscape pattern of the basin was evolving toward intensification, balance and regularization.

      (2)The research results of the influence and effect of the agricultural development on the hydrological process in the Manas River Basin showed that water-saving technology and planting structure changed the relationship between cultivated land area and agricultural water use; The process of agricultural water use dominated the utilization pattern of water resources between the natural and socio-economic systems of the basin, causing resource and environmental problems. The agricultural development process promoted the continuous growth of the cultivated land area. Agricultural water occupied more than 90% of the total water all year round, but it did not show a consistent growth with the cultivated land area, but showed periodic fluctuations. The agricultural water cycle gradually occupied the dominant position of the water cycle in the basin. The construction of farmland water conservancy, the change of agricultural structure and the increase of farmland irrigation area had changed the surface runoff flow direction and water system structure, surface water flux distribution, evaporation and infiltration process, and changed the basin water cycle process from the aspects of cycle path, parameters and structure. The production and living functions of water resources gradually replaced the ecological functions, resulting in positive and negative changes in the ecological environment of the basin. With the help of 3S technology, some ecological and hydrological effects had been quantified. The changes in the ecological environment were embodied in the improvement of the local microclimate, the significant decrease in the area of soil salinization and desertification, and at the same time the problems of agricultural non-point source pollution, groundwater over exploitation and biodiversity reduction had become more and more serious.

       (3)The evaluation results based on the urbanization level quantified by carbon emissions, the ecosystem service level quantified by carbon sequestration, the urban function and human well-being level quantified by carbon storage, showed that: The urbanization process of the Manas River Basin had enhanced the production and living functions of the counties and cities, but had caused differential changes in natural ecosystem services, resulting in unbalanced development of human well-being. From 2000 to 2015, all levels of urbanization in the basin achieved steady growth, and the overall urbanization process carbon emissions increased by 10.34 times. Ecosystem services in the basin showed a wavy downward trend, 12.31% lower than that in 2000. Among them, the supply of services showed an increasing trend, and the amount of carbon sequestration was 3.06 times that of the original, showing a trade-off relationship with support, regulation and cultural services. The latter three showed a synergistic decline, and the amount of carbon sequestration decreased by 46.97%, 21.65% and 16.45% respectively. In addition to supply services, the levels of support, regulation, and cultural ecosystem services were generally opposite to the spatial distribution of various urbanization levels, and were constrained by urban development. Human well-being had been significantly improved during the study period. In 2015, the total carbon storage of well-being increased by 1.92 times that of 2000, of which social well-being increased by 0.57 times, economic well-being increased by 2.69 times, and ecological well-being decreased by 23.24%. With the development of urbanization, the changes of social structure, economic structure and land use structure had enhanced the production and living functions of cities and towns and the supply service functions of the natural ecosystems, promoted the improvement of human economic and social well-being, but reduced the support, regulation and cultural service functions of natural ecosystems, and reduced ecological well-being. Urban production function and natural ecosystem supply service function were most closely related to human well-being, and were the main promoting factor for the increase of human social and economic well-being in the basin.

       (4) The results of ecosystem health assessment in the Manas River Basin showed that the rapid development of social economy made the overall health state of composite ecosystem show a wavy upward trend, but the decline of water, soil resources and ecological environment quality leaded to the decrease of sustainable development potential of the basin. From 2000 to 2015, the comprehensive health index increased from 0.41 to 0.62. At the level of subsystem health status, in the resource subsystem, groundwater resources and ecological land resources decreased, while climate conditions were improved and vegetation vitality was enhanced, so that the overall health status fluctuated upward; In the environmental subsystem, the quality of the atmosphere and water environment had declined, the area of land salinization and desertification had been reduced, and the overall  health status of the environmental subsystem had shown a fluctuating decline; The supply of services in the ecological subsystem had increased, while the support, regulation, and cultural services had decreased, so that the overall health status had fluctuated and declined. It showed that although the development and construction of the river basin was very effective during the study period, the lack of proper handling of the relationship between development and protection had reduced the support of important ecological resources and the environment for social and economic development, affecting the sustainable development potential of the river basin. At the county and city scale, the comprehensive health status of each county and city showed a trend of first decline and then increase, with an overall growth trend. The average health index of Shihezi, Shawan, and Manas counties were 0.479, 0.476, and 0.443, respectively. The health status of Shihezi city and Shawan county is better than that of Manas County. Compared with 2000, the comprehensive health index of each city in 2015 increased by 52.44%, 45.08% and 21.69% respectively.  

       The main indicators causing health changes in each research stage are different. Which can generally be summarized as natural ecosystem service indicators (support and regulation services), system coupling efficiency indicators (water consumption per unit of GDP, urban development benefits, carbon emission per unit of production water use), urban production indicators (supply of industrial products, energy consumption), and environmental indicators (land salinization, water pollution load). At the subsystem level, from the average level, the impact on watershed health was: ecological subsystem > system operating efficiency > economic subsystem > resource subsystem > environmental subsystem > social subsystem.

       (5) Based on the five goals of natural ecosystem health goal, economic growth goal, resource maximum population carrying goal, low-carbon goal and intergenerational equity goal, this paper constructed the system dynamics model of the basin ecosystem healthy and sustainable development. The simulation study showed that: Under the scenarios of scheme 2 (socio-economic development type), scheme 3 (socio-economic priority taking into account ecological type), and scheme 5 (overall planning type), the socio-economic development was rapid, and by 2035, a GDP growth of about 4 times can be achieved, and the total population will reach 920,000 to 950,000 people, with an urbanization rate of 86.5%-88%. However, a 65% increase in construction land reduced land carbon benefits by more than 60%. scheme 4 (ecological protection prioritizing taking into account social and economic type) and scheme 5 (overall planning type) adopted high-intensity ecosystem protection measures, increasing the population carrying capacity of water resources by more than 60%, but the land population carrying capacity was reduced by 10-20%. The ecological land had grown significantly, and the ecosystem service capacity had increased by more than 6%. Under the development scenarios of scheme 1 (status quo continuation type) and scheme 2 (socio-economic development type), the protection of natural ecosystems had not been strengthened, the ecosystem services had not been effectively improved, the grassland and water areas were still decreasing, and the population carrying capacity of water resources was the lowest, putting natural ecosystem health at risk. Each development plan optimized the economic structure and achieved the proportion of agricultural water use below 85%, but failed to achieve regional self-sufficiency in water resources, and 400-700 million m3 of water resources need to be transferred in every year. Comprehensive benefit scheme 5> scheme 2> scheme 3> scheme 4> scheme 1.