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作 者 ：孙洪波,杨桂山*,苏伟忠,朱天明,万荣荣

期 刊 ：生态学报 2010年 30卷 20期 页码：5616~5625

关键词：沿江地区；土地利用；子流域；生态风险评价；空间分异；

Keywords:area along Changjiang River, land use, sub-watershed, ecological risk assessment, spatial differentiation,

摘 要 ：基于改进的相对生态风险模型，从风险源强度、受体暴露度以及风险效应三方面构建土地利用生态风险评价指标体系，以子流域为单元分析南京地区土地利用生态风险空间分异及影响因素，结果表明：综合生态风险值总体分布较分散，高风险区位于江北八百河流域、老山北坡及南坡河系、石臼湖流域，风险源强和受体暴露度较高，风险效应值较低，潜在生态风险很高，应重点实施环境治理，强化土地生态环境建设；较高风险区位于一干河、二干河、句容河、秦淮中游、江宁河、向阳河、固城湖、境外常州太湖流域，风险源强和受体暴露度中等，应加强环境治理，强化土地利用规划引导与集约利用；较低和低风险区包括境外沿江八卦洲、沿江靖安板块、沿江秦淮河、沿江汤水河、沿江滁河、横溪河、牛首河、前进河、马鞍山长江流域，风险源强和受体暴露度较低，风险效应值低，主要分布于沿江以及山地丘陵河流上游地区，沿江流域近年排污治理力度较大有效保证了低风险源强值，而山地丘陵河流上游植被覆盖度一般较高，人为影响相对较弱，应注重生态环境维护和土地集约利用；其他流域综合生态风险中等，应加强生态环境监测，防止生态环境恶化。

Abstract:The ecology risk assessment is currently the advanced concept and method to study the relationship between regional development and eco-environment. The theoretical research on ecology risk assessment is still in its initial phase at present, and the method of ecology risk assessment has not made an important breakthrough. Also, the quantitative expressions of risk sources, risk receptor, assessment endpoint and risk effect are still the key problems in the theoretical system of ecology risk assessment. The previous research of ecology risk assessment mostly focused on biological toxicology and the effect of single chemical pollutant on environment and human health in the 1980s. In the 1990s the effect of contaminants on the ecology system has been the study focus. But since the 21st century, the human activities, such as the land use, urbanization process have become the hot spots of the ecology risk assessment research, and the study scale of risk assessment was enlarged and developed from single population to regional and landscape scale. Both the change of research contents and the extending of research scale reflected the change of thinking and research framework of ecology risk assessment. This view point change from micro to macro scale raised a higher demand to the research idea and method of ecology risk assessment, under this background the comprehensive assessment way is necessary. Based on the improved model of relative ecological risk assessment, the index system of land use ecological risk assessment was built according to the strength of risk sources, the exposure degree of risk receptor and the risk effect. The spatial unit for assessment was the sub-watershed. The paper described and analyzed spatial differentiations of land use ecological risk and impact factors in Nanjing. The results presented a dispersed pattern of the risk value in summary. Firstly, the sub-watersheds with the higher value including Babai River, North slope and south slope rivers of Laoshan and the Shijiu Lake and had higher values both of risk resource strength and risk receptor exposure, but didn′t show high risk effect value. These regions bore high potential ecological risk and we should put the environmental management into practice with emphasis on ecological construction during the process of land use. Secondly, the sub-watersheds of Changzhou Tai lake,Yigan River, Ergan river,Jurong River, middle reaches of Qinhuai River, Jiangning River, Xiangyang River and Gucheng lake with a high risk value possessed middle values of risk resource strength and risk receptor exposure. For these regions we should strengthen the environment management and realize the scientific and intensified land use plan. The sub-watersheds with the low and lower risk value included Maanshan Changjiang river, Baguazhou, Jingan,Qinhuai river,Tangshui river, Chu river, Hengxi river, Niushou river and Qianjin river, which had lower risk resource strength value and risk receptor exposure value and lowest risk effect value. These sub-watersheds mainly were along Changjiang River and at the up reaches of hill rivers. For the areas along Changjiang River in Nanjing the ecology environment quality were effectively guaranteed in recent years. The up reaches of Hill Rivers had high vegetation coverage and weak human impact. For these regions, we should reinforce the maintain of the ecological environment and the intensive use of land. Thirdly, the other sub-watersheds showed middle risk value and we should strengthen the monitoring of ecological environment and prevent the ecological environment from degeneration.

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