基于适应性循环的丹江口库区生态风险评价

库区是流域水系的重要组成部分,厘清库区经济社会发展过程中的生态环境效应和综合生态风险,对库区生态风险适应与缓解的决策制定具有重要意义。现有研究忽视了库区生态系统的自组织动态演化过程,有必要进一步考虑库区生态系统与社会系统的时空交互过程,对库区生态风险进行更为综合性和针对性的评价,弥补库区生态风险定量化评价研究空缺。基于此,以丹江口库区为例,综合考虑库区生态环境、景观结构及人类活动等要素,构建基于适应性循环理论框架的“潜力—连通度—韧性”三维综合评价指标体系,选取1990—2018年7个年份的数据,对研究区7个县(市、区)的生态风险适应性循环周期进行刻画。结果表明:(1)丹江口库区整体生态风险水平呈波动状下降趋势,生态风险变化趋势存在地域差异,淅川县、茅箭区、张湾区为生态风险上升地区;(2)适应性循环的阶段特征能够为判断库区生态风险现状提供依据,适应性循环释放阶段、重组阶段及僵化阶段表现出生态系统风险上升的趋势。修正后的适应性循环模型对系统僵化风险的指示作用更加明显,2015年以来,丹江口库区社会—生态系统处于重要的转折阶段,有效防止生态风险的进一步扩大是当前库区生态系统管理的关键所在,对于维持库区社会—生态系统的可持续性至关重要。

Assessment on Ecological Risk of Danjiangkou Reservoir Area Based on Adaptive Cycle

The reservoir area is an important part of the river basin and water system.It is of great significance for the decision making of ecological risk adaptation and mitigation to clarify the eco-environmental effects and comprehensive ecological risks in the process of socio-economic development of the reservoir area.The study of self-organization dynamic evolution process of the ecosystems in the reservoir areas has been ignored in the existing researches,it is therefore necessary to further consider the spatiotemporal interaction process between the ecosystem and the socio-economic system in the reservoir area,and to make a more comprehensive and targeted assessment on the ecological risk to make up for the lack of quantitative evaluation of ecological risk in reservoir area.To this end,this study attempted to take Danjiangkou Reservoir area as the study case to characterize the cycle of ecological risk adaptability in seven counties in the Danjiangkou Reservoir area based on the theoretical framework of potential-connectivity-resilience,which comprehensively considered factors such as the ecological environment,landscape structure and human activities in the reservoir area from 1990 to 2018.The results showed that:(1)the overall ecological risk level in Danjiangkou Reservoir showed a fluctuating downward trend,and there were regional differences in the variation trend of ecological risk;Xichuan County,Maojian District,and Zhangwan District were the regions with increasing ecological risk;(2)the stage of the adaptive cycle could provide basises for judging the current ecological risk situation in the reservoir area;the phases of release,reorganization,and fossilization of the adaptive cycle showed an increasing trend of ecological risk.The modified adaptive cycle model has a more obvious indicator effect on the risk of system fossilization.Since 2015,the socio-ecosystem of Danjiangkou Reservoir area has been at an important transition stage.Effective prevention of further aggravation of ecological risks is the key to the current ecosystem management of the reservoir area,which is crucial for maintaining the sustainability of the socio-ecosystem of the reservoir area.