重庆市生态风险预警等级划分及演化趋势模拟

生态风险预警等级评估和演化趋势模拟,可为生态风险管理提供可靠的辅助决策。以重庆市为研究对象,基于驱动力-压力-状态-影响-响应模型,构建重庆市生态风险预警指标体系,采用正态云模型和集对分析法,定量分析重庆市生态风险时空分异特征和演化趋势。研究结果表明：（1）2013-2019年,重庆市生态风险值呈"上升-下降"的波动趋势,综合生态风险隶属于重警等级,生态风险综合值从0.295下降到0.278,生态环境逐年好转;（2）重庆市生态风险有下降、不变、先上升后降低、先降低后上升以及一直升高5种演化趋势,分别占比39%、16%、5%、21%、24%;（3）重庆市生态风险转移分为两个方向,2013-2016年生态风险空间分异性增大,中警、轻警和无警风险等级不断向东北、东南和西部四周分散转移;2016-2019年生态风险分布格局变化较小,重警风险区在东部聚集;（4）演化趋势模拟结果表明,未来重庆市生态风险降低的区县有13个,占比34%,生态环境有向好发展的趋势;生态风险上升的区县有25个,占比66%,生态环境会有所恶化,但是恶化程度较低。将生态风险等级划分与预警演化趋势相结合,能为城市生态风险管理提供科学依据。

Classification of ecological risk warning levels and simulation of evolutionary trends in Chongqing Municipality

The level assessment on the ecological risk early warning and the simulation on evolutionary trend can provide reliable auxiliary decision making for the ecological risk management. Taking into account the Driving-Pressure-State-Impact-Response model, this paper establishes an index system for ecological risk early warning to quantitatively analyze the temporal and spatial differentiation characteristics and evolution trend of ecological risk in Chongqing Municipality, using the normal cloud model and the set-pair analysis method. The results demonstrate that:(1) from 2013 to 2019, the ecological risk value of Chongqing presented a "rise-decline" fluctuation trend, and the comprehensively ecological risk was ranked as heavy warning level, while the comprehensive ecological risk value decreased from 0.295 to 0.278, denoting that the ecological environment had been improved. (2) There were five evolutionary trends of ecological risk in Chongqing:decreasing, unchanged, increasing-decreasing, decreasing-increasing and always increasing, accounting for 39%, 16%, 5%, 21% and 24% of all regions, respectively. (3) The ecological risk transferred to ward two orientations in Chongqing. From 2013 to 2016, the medium-alert, light-alert and no-alert risk areas continued to spread to the northeast, southeast and west of Chongqing, which intensified the spatial differentiation of ecological risks; whereas from 2016 to 2019, the high-alert risk areas were concentrated in the east, suggesting the little change in the ecological risk distribution pattern. (4) The simulation results of evolution trend revealed that 13 counties, accounting for 34% of all areas, would experience the declining ecological risk and subsequently improving ecological environment in Chongqing in the future; additionally 25 counties, accounting for 66%, would maintain the deterioration of ecological environment to small extent. The combination of ecological risk classification with early warning evolutionary trend can contribute a scientific basis to urban ecological risk management.