侵蚀环境小流域生态经济系统健康定量评价

生态经济系统健康是黄土丘陵区侵蚀环境下水土保持与生态建设的目标.在分析侵蚀环境下生态系统健康特征和诊断指标筛选原则的基础上,从资源环境支持、社会经济人文影响和生态综合功能3个方面,选择17个因素作为参评因子,建立了一套适合于侵蚀环境小流域生态经济系统健康诊断的指标体系.以均方差决策法确定各指标的权重,运用递阶多层次综合法、线性加权函数法分别建立二级层次和综合指标健康诊断模型——健康指数.分析研究侵蚀环境小流域生态经济系统健康动态,结果表明,该环境系统健康状况相对稳定,健康指数呈逐年波动式上升趋势（由1985年的0.370增大到2003年的0.573）,具有较强的可持续发展能力.同时,以现实生态经济最佳水平为目标,引入障碍度、优势度等概念,运用通经分析对该环境小流域系统健康进行障碍和优势诊断,并据此提出了建设对策和建议,为该环境小流域生态环境建设提供科学依据.

Health diagnoses of eco-economy system in Zhifanggou small watershed on typical erosion environment

To reach the ecosystem health from both ecological and economic points is the objective of water conservation and ecological building in the loess hilly area under erosion environment.On the principle of ecosystem healthy quantitative assessment and diagnosis index selecting,17 factors were selected and evaluation index system was established to make ecosystem health assessment from the following three aspects: resource and environmental capacity,social and economic impact,and ecological services in a small watershed under erosion environment.The mean-square deviation decision method was employed to determine the weight of each factor and then the step-up multilayer synthesis with liner weighting function method was used to build two-level hierarchy and collecting index health consultation model-health index.The health dynamics of eco-economy system in the small watershed under erosion environment was analyzed.It was shown that the watershed ecosystem is relatively stable and the health index has an increasing trend from annual fluctuation(0.370 in 1985 to 0.573 in 2003).This indicates that it has a quite strong ability on sustainable development.At the same time,the obstacle and advantage to the watershed ecosystem health were studied by introducing the concepts of obstacle degree and advantage,and path analysis method,with considering the real eco-economic optimal level as the uppermost goal.Finally,suggestions on ecological building were provided which give a scientific basis to the ecosystem rehabilitation in the small watershed.