北方寒冷干旱地区内陆湖泊生态安全评价指标体系研究——以呼伦湖为例

呼伦湖作为我国北方寒冷干旱地区内陆湖泊的典型代表，在涵养水源、调节气候、防风固沙及维系呼伦贝尔草原生态系统平衡乃至我国北方生态安全屏障等方面发挥着不可替代的作用。准确识别呼伦湖流域主要生态安全问题、完善其生态安全评价指标体系对于科学研判呼伦湖生态环境状况、维持区域可持续发展及精准实施底线管控政策具有重要意义。在遥感影像、地面调查、实验模拟等多尺度数据分析基础上，结合历史资料收集、专家咨询、部门访谈等方式分析识别了呼伦湖区域生态安全问题及成因：（1）气候暖干化及超载放牧等因素使得草地退化显著，土地沙化、盐碱化面积扩大；（2）草原退化增加了干草入湖、大气干湿沉降及水土流失等水环境污染负荷；（3）气候暖干化造成湿地萎缩，加之长期的过度捕捞等人类活动使得渔业资源枯竭、鱼类小型化特征显著，水生生态系统稳定性下降，蓝藻水华频发。在全面诊断分析区域生态安全问题的基础上，以山水林田湖草系统方法论为理论指导，以改善呼伦湖流域生态环境质量为核心目标，依据评价指标的针对性、科学性、可操作性及系统性原则，采用压力-状态-响应（Pressure-State-Response，PSR）模型，以气象条件、人口、水资源、水环境压力及人类活动等5个一级指标构成的压力子系统，以水环境状况、水生态状况、陆域生态状况、生态系统服务功能和敏感性、景观格局及生态风险等6个指标构成的状态子系统，以生态治理措施及生态治理投入等2个指标构成的响应子系统，共同组成了一套包含13个一级指标38个二级指标的天空地一体、陆湖统筹的生态安全评价指标体系，以期为呼伦湖及北方寒冷干旱区类似湖泊的生态安全评价研究提供借鉴。

Index system of ecological security of inland lakes in cold arid region: a case study of Hulun Lake, China

Hulun Lake, as a typical representative of inland lakes in the cold and arid areas of northern China, plays an irreplaceable role in water conservation, climate regulation, windbreak, and sand fixation. This lake maintains balance in the Hulun Buir grassland ecosystem and even the ecological-security barrier of northern China. Thus, identifying the main ecological-security problems in Hulun Lake Basin and improving its ecological-security evaluation index system are highly significant. The obtained data can be used for the scientific research and assessment of the ecological environment status of Hulun Lake, the maintenance of regional sustainable development, and the accurate implementation of bottom-line management and control policy.Based on remote-sensing imagery, ground survey, experimental simulation, and other multi-scale data analyses, this paper aims to analyze and identify the ecological-security problems of Hulun Lake area and their causes by combining historical data collection, expert consultation, and department interview. The results are as follows:(1) warm and dry climate, overgrazing, and other factors induce significant grassland degeneration, so land desertification and salinization area expand. (2) grassland degradation increases water-pollution load, such as hay into lake, atmospheric dry and wet settlement, and soil erosion. (3) climate warming and drying cause wetland shrinkage. Long-term overfishing and other human activities lead to the depletion of fishery resources and significant fish miniaturization. Consequently, the stability of aquatic ecosystem is reduced, and blue-green algal blooms occur frequently. Based on the comprehensive diagnosis and analysis of regional ecological-security problems, together with theoretical guidance by the methodology of mountains, rivers, forests, fields, lakes, and grass-system methodology, and improving the ecological environment quality of Hulun Lake basin as the core goal, the pressure-state-response (PSR) model is adopted in the present study according to the principles of focalization, scientific nature, operability, and systematicness of evaluation indices. The pressure subsystem comprises five first-class indicators, namely, meteorological conditions, population, water resources, water environment pressure, and human activities. The state subsystem comprises six indicators, namely, water environment, water ecology, land ecosystem, ecosystem service function and sensitivity, landscape pattern, and ecological risk. The response subsystem comprises two indicators, namely, ecological-management measures and ecological-management investment. Then, they jointly form an ecological-security evaluation index system with the integration of sky and land and the overall planning of land and lake, which includes 13 first-class indicators and 38 second-class indicators, to serve as a reference for studying the ecological-security evaluation of Hulun Lake and similar lakes in cold and arid areas.