基于层次分析法的阅海湖水生态承载力评价

Evaluation of Water Ecological Carrying Capacity of Yuehai Lake Based on Analytic Hierarchy Process

为了探明阅海湖水生态承载力状况与变化趋势,作者在2015-2017年冬(1月)、春(4月)、夏(7月)、秋(10月)采集阅海湖水样和水生生物样本,测定高锰酸盐指数等10个水质指标、水生生物密度指标,计算生物多样性指数,构建水生态承载力评价指标体系,采用层次分析法建立层次结构模型,从水生态支持力和水环境压力2个方面来综合评价阅海湖的水生态承载力。结果显示:(1)阅海湖压力指数、承载指数和水生态承载力指数变化规律相同,季节性变化显著,均为夏季最大,冬季最小;(2)阅海湖夏季为较高压、低承载状态,冬季为低压、弱承载状态;(3)2015-2017年阅海湖水生态承载力指数分别为:0.32、0.34、0.33。阅海湖水生态承载能力整体呈弱可承载状况,生态系统抗外界干扰能力和自我恢复能力有待提高,氮是影响阅海湖水生态承载力最重要的指标,应从源头上减少氮等营养盐进入湖泊。

The water ecological carrying capacity status and change trend of Yuehai Lake were studied,which would provide a basis for water quality improvement and self-repair ability.Water and aquatic biological samples were collected in winter(January),spring(April),summer(July),autumn(October)of 2015-2017 from the Lake.On the basis of 10 water quality indicators such as CODMn,aquatic organisms density and biodiversity index,the water ecological carrying capacity evaluation index system was constructed.By the method of analytic hierarchy process,the hierarchical structure model was established to evaluate the water ecological carrying capacity of the Lake from the perspectives of water ecological support and water environmental pressure.Results indicated that the variation rule of the pressure index,load index and water ecological carrying capacity index of the Lake were the same,with significant seasonal changes,which were the largest in summer and the smallest in winter.The Lake has a high pressure and low load state in summer and a low pressure and weak load state in winter.The ecological carrying capacity indexes of the Lake was 0.32,0.34 and 0.33 respectively from 2015 to 2017.The overall ecological carrying capacity of the Lake was weak,and the ability of the ecosystem to resist external interference and selfrecovery needed to be improved.Nitrogen was the most important index affecting the ecological carrying capacity,so nitrogen and other nutrients should be reduced from the source to enter the Lake.