流域生态系统健康评价研究

Assessment of Watershed Ecosystem Health

以流域为单元,评价生态系统健康状况,将为流域的规划、管理和保护以及流域综合治理提供决策依据。总结了国内外关于流域生态系统健康评价的方法,对流域生态系统健康评价体系的理论基础、基本框架、指标选择、指标的评价函数、权重分配、体系建构步骤等关键性问题进行了研究。以“自然条件限制因子-流域生态健康指示因子-人类活动影响因子”评价体系为基础,选择了水质、植被、水土保持、生物多样性、湿地、土地利用、人口、点源污染、面源污染、水资源开发利用率、河流自然化、人均GDP、土壤、水文和生物第一性潜在生产率等20项指标,构建每个评价指标的评价函数,利用层次分析法对滦河山区流域和北四河平原流域进行生态系统健康评价。综合评价结果表明,滦河山区流域和北四河平原流域生态系统健康得分为76和46,年降雨量、点源污染、面源污染、水资源开发利用率是我国北方半湿润/半干旱地带小流域生态系统健康状况的主要控制因子。

The healthy situation of watershed ecosystem is decided by multiple ingredients. The author treated watershed as a basic unit for study, put emphasis on the systematism and integrality of watershed and chose ＂natural constraint factor-watershed health indicator factor- anthropogenic disturbance factor＂ as the base of assessment system. The ＂natural constraint factor＂ included physical category, chemical category and ecological category. Physical and chemical category included indicators of river water quality, lake water quality, vegetation coverage, soil erosion and change rate of wetland area. Ecological category included indicators of biodiversity index, evenness index and exotic species-indigenous species ratio. The ＂watershed health indicator factor＂ included three aspects ： natural endowment of land resources was expressed by indicators of soil thickness and soil organic matter. Natural endowment of water resources was expressed by annual rainfall. Natural endowment of biology resources was expressed by net primary productivity（NPP） of terrestrial vegetation. The ＂anthropogenic disturbance factor＂ included three aspects：The disturbance to underlying surface of watershed was expressed by anthropogenic indicators of urbanization area and ratio of arable land area. The anthropogenic disturbance to quality, quantity and distribute of water resources was expressed by indicators of point source pollution, non-point source pollution, degree of development and utilization of water resources. The social economical disturbance to the health of ecological environment of watershed was expressed by indicators of population and per capita GDP. The author created 20 indicators for quantitative expression and assessed the health of ecological environment in watersheds of Luanhe Mountainous area and Beisihe Plain by method of AHP （Analytic Hierarchy Process）. The grades of the two watersheds are respectively 76 and 46. Annual runoff, point source pollution, non-point source pollution and water resources exploitation ratio are the main manipulative indicators of watershed health in semi-humid to semi-arid sectors in north China.