基于AHP-PCA熵组合权重模型的三峡库区(重庆段)农业生态环境脆弱性评价

Evaluation for vulnerability of agroecological environment in Three Gorges Reservoir area(Chongqing section)based on AHP-PCA entropy combination weight mode

【目的】了解三峡库区蓄水后的农业生态环境状况,为提出有效的农业环境治理和保护措施提供参考。【方法】以三峡库区(重庆段)为研究区域,从气候条件、承载体、农业生产条件和社会经济4个方面建立农业生态环境评价指标体系,在用层次分析法(AHP)和主成分分析法(PCA)分别确定各指标主观权重和客观权重的基础上,以最小信息熵将权重组合为综合权重,在GIS支持下建立评价模型,对库区农业生态环境从结构性脆弱、胁迫性脆弱及综合性脆弱进行量化评价及等级评定。【结果】三峡库区(重庆段)农业生态环境脆弱性表现为(东)北部较高、中部较低、长江两岸较高,且以长江为分界线的长江北部在较高的胁迫性脆弱和结构性脆弱共同作用下较南部明显偏高,区域内70.00%以上的区(县)农业生态环境整体处于中强度等级以上,农业生态环境抗干扰能力不容乐观。三峡库区(重庆段)农业生态环境脆弱性的空间分布整体上与生态环境因子分布一致。【结论】以AHP-PCA熵组权重模型评价农业生态脆弱性具有可行性,可为生态环境脆弱性评价提供一种新的思路与方法。

[Objective]The agroecological environment of Three Gorges Reservoir area was investigated after water storage, in order to providing reference for effective management and protection measures of agroecological environment. [ Method ]With Three Gorges Reservoir area （Chongqing section） as research area, the evaluation index system of agroeco- logical environment was established based on climatic conditions, supporting body, agricultural production conditions and social economy. Meanwhile, the subjective weight and objective weight were determined by analytic hierarehy process （AHP） and principal component analysis（PCA） after indexes standardization and transpose, and the combination weight was synthesized according to minimum relative information entropy principle. Last, the evaluation model was established with the support of GIS, so as to evaluate quantitatively agroecological environment from aspects of structural vulnerabili- ty, stress vulnerability and comprehensive vulnerability. [Result]The results showed that, the agroecological environment vulnerability of Three Gorges Reservoir area was high in （east）north, low in the central region, and high on both sides of the Yangtze River. North of the Yangtze River was significantly higher in structural vulnerability and stress vulnerability than south of the Yangtze River. Furthermore, the agroecological environment of more than 70% counties were at medium, strong and extreme vulnerability grades, so the agroecological environment had poor ability to resist disturbance. [Conclusion]It is feasible to evaluate the vulnerability of agricultural ecosystem with the AHP-PCA entropy combination weight model, which provides a new method for evaluating ecological environment vulnerability.