作 者 ：李中才,刘林德,孙玉峰,崔金荣
期 刊 ：生态学报 2010年 30卷 23期 页码：6495~6503
关键词：生态安全；压力-状态-响应模型；评价；生态足迹；能值分析；
Keywords:ecological security, pressure-status-response (PSR), evaluation, ecological footprint, emergy theory,
摘 要 ：生态安全是指一个社会的资源、环境系统能够满足经济、社会需要的同时，又不削弱其自然储量的状态。目前，广泛使用的“压力-状态-响应”（PSR）模型及层次分析法（AHP）存在一定的局限性，尚需要改进。以PSR模型为基础，选择北方针叶林、疏林、农田、荒漠灌丛、沙漠5类生态系统作为区域生态安全评价的参考系，提出了“主观能动响应力度”、“实效响应力度”的概念，综合应用了生态足迹、能值理论给出了计算生态状态指数、响应指数、压力指数的新方法，提出了计算区域生态安全指数的数学模型，增强了评价的客观性、可比性、通用性。以山东省长岛县为例，研究了生态状态、响应、压力之间的作用关系，绘制了生态安全指数的变化曲线，从时间尺度上（19902005年）评价生态安全的现状和发展趋势，推导出生态安全状况不断得到改善的必要条件。结果表明：虽然长岛县植被覆盖面积逐年增加，但是生态安全状况却没有得到明显改善，呈下降趋势。因此，植被存量，尤其森林植被的存量在增强生态安全等级上发挥着重要作用。从增加植被存量、加大生态恢复力度和减少生态压力方面提出了改善区域生态安全的建议与对策，为长岛县生态安全管理提供科学依据和指导。
Abstract:Ecological security is defined as the goal of stakeholder to create a condition where resources and environment of a region are provided for the needs of economy and social development without diminishing its resource stock. Although the Pressure-State-Response(PSR) framework together with Analytic Hierarchy Process(AHP) was widely adopted to assess ecological security at present, it has inherent limitations and need to be improved. Based on PSR model, the paper selected boreal forest, opening forest, cropland, desert shrubs and desert as reference system for evaluating regional ecological security, and made the per unit area amount of vegetation of tropical rainforest per year to be a standard unit, then gave the method of computing the ecological state index. The paper proposed the new conceptions of subjective response degree and objective response degree, and built up the method of calculating ecological response index. The paper established the method of calculating ecological pressure index through the junction of ecological footprint(EF) method and emergy theory. The paper proposed a new model of comprehensively evaluating the status of ecological security, which makes evaluation results more objective and more comparative. The paper analyzed the relation among ecological state, ecological pressure and ecological response: ecological rehabilitation from ecological system with the lower grade to ecological system with the higher grade needed to throw in the more ecological response. The index value of ecological response will be 1665, 18 and 4 if ecological state is changed from the critical state of ecological security, namely crises state, security state and relatively good state to ideal state. Taking Changdao county in Shandong province as an example, the paper researched the ecological security trend at time scale(19902005) by the improved model, and drew the curve in three dimensions to reflect the ecological security tendency, and then inquired into the requirement of continually enhancing ecological security status. The results show that Changdao′s area of plant is gradually increasing, but the amount of vegetation is decreasing from 1990 to 2005; the index value of ecological state has decreased by 0.266, 0.219, 0.176 and 0.152, respectively; the index value of ecological pressure has increased by 0 and 0.19; the index value of ecological response has been 0.266, 0.336, 0.330 and 0.304, respectively; the index value of ecological security has decreased by 0.070756, 0.067506, 0.057971 and 0038830, respectively. The current status of ecological security presents a declining trend. Even if the size of the forest area was added, ecosystem health status directly was not improved. So the amount of vegetation, especially forest area is an important factor for enhancing a regional ecological security. This suggests that further measures, such as reducing ecological pressure, adding ecological rehabilitation investment and increasing the mass of plant, must be adopted to reverse the current situation of Changdao′s ecological security. The improved models in this paper could make an important contribution to decision-making for Changdao′s governors and to the development of the island regional planning incorporation assessment and prediction of ecological security. This study demonstrates the potential of the improved model for assessing ecological security.
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