洞庭湖区农业生态安全评价

生态安全是一定时间尺度内，不同层次、不同类型的生态系统保持其自身正常结构与功能和满足人类持续发展需要的状态。它是农业可持续发展的核心和基础。在分析农业生态安全面临的问题、构建农业生态安全评价指标体系的基础上，运用层次分析法和GIS技术，采用“农业生态不安全指数”对洞庭湖区各县（市）的农业生态安全状况进行了综合评价。结果表明，湖泊调蓄功能衰退，洪涝灾害威胁加剧，水土流失严重，环境蒋染加重是洞庭湖区农业生态安全面临的主要问题。洞庭湖农业生态安全表现出明显的地域分异特征，生态农业生态不安全指数由湖边向丘陵、山地区递减。本研究成果可直接为洞庭湖区生态环境保护及建设提供科学依据，其研究方法可为区域农业生态安全评价借鉴。

Evaluation on Agricultural Eco-Security in Dongting Lake Area

Ecological security is the needed state that different hierarchy or type of ecological systems to keep its normal configuration and function and gratify sustainable development for human in some period of time.It's the key part and base for agricultural sustainable development.The danger of environmental retrogression is kept on guard highly in China.The study of ecological security is becoming the major foreland and task in geography,ecology,and resource and environment science.Taking counties as basic unit,under the technique of AHP and GIS,based on the analyses of the compressive stress of the agricultural eco-security system and the set eco-security evaluation index system through pressure and quality of resource-environment and protection and renovation of resource-environment,integrative evaluating on the agricultural eco-security of counties in Dongting Lake area is made by "agricultural eco-insecurity exponent".The result indicates,agricultural eco-security of Dongting Lake area has been confronted with a series of problems and challenges,such as the descending of the accommodation function of the lake,the more and more serious of water loss and soil erosion and flood disaster,three wastes of small and medium sized cities,agriculture and heavy metals generating pollution and so on.And the regional heterogeneity of the security degree is distinct.The agricultural eco-insecurity exponent is getting smaller from near the lake to far away from it.The research achievements can be used as science-dependencies for maintaining the agricultural eco-security in Hunan province directly,and its research technique can be used for reference in regional agricultural eco-security evaluation.