辽河中下游流域生态安全评价

Ecological Security in the Middle and Lower Reaches of the Liaohe River

生态安全是指能够维持和保障人类社会可持续发展,同时不损害和威胁生态系统本身健康和完整性的生态系统状态,是人与自然生态环境达到高度和谐状态。生态安全评价的根本目的是为区域可持续发展的资源保护和生态环境建设提供决策参考。本文从辽河中下游流域的实际情况出发,建立了辽河中下游流域生态安全评价指标体系,采用专家打分法确定评价指标的权重,运用生态安全综合评价模型对研究区1986年、2000年2个时段的生态安全状况进行了评价和比较分析。结果表明:虽然近几年的退耕还林等生态环境建设活动,使得辽河中下游流域的生态安全状况有所好转,2000年流域整体生态安全指数比1986年增加0.08,但是目前流域的生态安全状况还是不容乐观,生态较安全区面积大幅度减少,减少面积占流域总面积的22.15%,生态预警区面积大幅度增加,增加面积占流域总面积的17.85%。影响辽河中下游流域生态安全的因素有自然因素和人为因素两种,但主要受人为因素的影响,自然因素的变化相对稳定。

Ecological security is defined as the undamaged and unthreatened conditions of living space and ecological environment which support regional sustainable development. The major aim of evaluating ecological security is to provide a reference for decision-making on resource protection and regional sustainable development. The middle and lower reaches of the Liaohe River are an old industrial base in China＇s northeast, and are important in terms of heavy industry, energy and marketable grain. Recently, with increasing population and continuous expansion of agricultural land, large areas of forest, grassland and wetland have been converted to other uses, leading to serious environmental problems such as soil erosion, water shortages, and declining water quality. In order to understand the effect of environmental problems on ecological security, it is important to evaluate the ecological security conditions in the study region. This paper established an indicator system for evaluation of ecological security, determined the weight of indicators using expert scoring, evaluated the ecological security of the study area, and compared findings for 1986 and 2000. The results showed that the ecological security index for the middle and lower reaches of the Liaohe River was 5.86 in 1986, which was at the level of ＇pre-warning＇. The total area of the region considered to have ＇ relative security＇ was more extensive than the other categories, totaling 4.0 million hm^2 or 62. 8% of the study region. By 2000, environmental activities were strengthened and ecological security conditions had improved, with an increase in the ecological security index of 0.08. The area classified as ＇secure＇ also increased to 751 424 hm^2, or 11.7% of the study area. However, the overall conditions of ecological security were not satisfactory. The area considered ＇relatively secure＇ decreased substantially, by 22.15% of the entire study area, while the area classified as ＇pre-warning＇ increased greatly, to 17.85% of the whole area. Natural and human factors both affect the ecological security of the Liaohe River, but human factors are dominant. Compared with human factors, the changes in natural factors are relatively stable.