基于系统水平的湖泊流域生态风险评估

Ecological Risk Assessment in a Lake Watershed Based on Ecosystem Level

为实现流域范围内的生态环境管理和生态风险控制,在生态风险评估框架基础上,基于相对风险模型构建了系统水平的湖泊流域生态风险评估模型.模型分析了社会经济系统与生态系统的耦合方式,将生态系统整体作为风险受体、生态系统服务作为评估终点,通过风险组分及其关系的分析量化实现了区域相对生态风险水平的表征,并以太湖流域上游区域为例进行了试算.结果表明：研究区内无锡-江阴区域（沿江水系）生态风险最高,溧阳-宜兴、常州-金坛、湖州-德清和长兴-安吉区域风险值分别为无锡-江阴区域的73.2%、78.8%、74.4%和59.9%;长兴-安吉区域（西苕溪水系）生态风险最低.不同区域风险主要来源不同,湖州-德清区域主要受水利设施影响,长兴-安吉区域各风险源贡献率较为均衡,其他区域主要风险源为工业、种植业和水产养殖业,其风险贡献率分别为13%~18%、12%~19%和8%~15%;研究区域内,水产品、水质净化等生态系统服务的产出受到较大影响.

In order to perform ecological environment management and control of ecological risk in a basin,an ecological risk assessment（ ERA） model of a lake basin was built on the basis of ERA frameworks and relative risk model（ RRM）. By analyzing mutual coupling effects between the socio-economic and ecological systems,and regarding ecological services as the endpoints and ecosystem as the risk receptor,the regional relative ecological risk was characterized by describing and quantifying the risk components and their relationships.This model was applied in the upstream Taihu Lake Watershed. The results showed that Wuxi-Jiangyin and Changxing-Anji regions exhibited the highest and the lowest ecological risks,respectively. Liyang-Yixing,Changzhou-Jintan,Huzhou-Deqing,and ChangxingAnji regions yielded 73. 2%,78. 8%,74. 4% and 59. 9% of the highest ecological risk,respectively. The main risk sources of each region were different. Huzhou-Deqing area was mainly affected by water conservancy establishment,while the contribution rate of every risk source was relatively balanced in the Anji-Changxing area. In other areas,the effects of industries,agriculture and aquaculture as risk sources were severe,with risk contribution rates being 13%-18%,12%-19% and 8%-15% respectively. Thus,ecological services of aquatic products biomass and water purification ability were mainly affected.