基于改进SPA的乐山市耕地生态安全评价

Evaluation on Cultivated Land Ecological Security of Leshan City Based on Improved Set Pair Analysis

耕地生态安全评价是对农田生态复合系统的全面诊断,也是测度区域可持续发展的重要内容.本文以四川省乐山市为例,在界定耕地生态安全内涵的基础上,构建基于PSR模型的评价指标体系,并采用改进的SPA法分别对乐山市及各区县2007,2009,2012年耕地生态安全进行评价,并对其变化因素进行了分析.结果表明:1)乐山市耕地生态安全水平整体上呈上升趋势,安全等级由"临界安全"逐渐演变为"较安全",区域上呈现出北高南低的现象;2)耕地资源数量和质量、生态环境的优劣、经济发展水平是导致南北耕地生态安全差异的主要因素;3)改进的SPA法能够揭示耕地生态安全评价指标体系的分异程度,提取综合评价结果的中间信息,在耕地生态安全评价中具有一定实用价值.

Evaluation of cultivated land ecological security is comprehensive diagnosis for complex system of farmland ecosystem,and it is an important content to measure regional sustainable development.This paper takes Leshan City of Sichuan province for example,on the basis of defining the connotation of cultivated land ecological security,constructing an evaluation index system base on the Pressure-State-Response（PSR）model.With the improved SPA the cultivated land ecological security in Leshan City and its districts in 2007,2009,and 2012 has been evaluated.Then the change factors are discussed and conclusions are summarized as follows：1）The level of cultivated land ecological security in Leshan City is increasing on the whole,safe level is gradually improved from ＂critically safe＂to＂safe＂,the level of cultivated land ecological security in each district is improved in varying degree.2）The quality and quantity of cultivated land resources,the good points and bad points of ecological environment,and the level of economy are the main factors which lead to the differences of cultivated land ecological security between the south and the north.3）The improved SPA method can reveal the degree of differentiation of evaluation index system for cultivated land ecological security,and extract the intermediate information of comprehensive evaluation results,which has some practical value in the evaluation of cultivated land ecological security.