摘要:城市用地扩展对生态环境的负面效应日益显著。以呼和浩特市为研究区，在分析城市用地扩展时空特征的基础上，调整优化CA模型，对近景年城市用地扩展进行多情景模拟。从城市扩展、生态景观、粮食安全、生态退化等角度构建生态风险压力评价体系，对各情景下城市用地扩展所致的生态风险压力进行评估，得到的主要结论有：1990-2017年，呼和浩特市城市扩展强度指数不断下降，扩展速率经历了"上升-下降"的波动阶段，空间扩展阶段性特征明显；运用CA模型预测2025年、2030年城市用地扩展，只有耕地保护型、生态经济型方案下建设用地扩展速率处于下降态势，扩展强度指数进一步下降；研究时段内，研究区城市扩建压力上升2.2%，景观生态压力增加1.9%，粮食储备压力提高1.4%，生态退化压力抬高11%，生态风险压力提升15%，生态风险预警达到中警水平；到2030年，趋势外推和耕地保护情景下生态风险压力等级由Ⅲ过渡到Ⅳ，城市化发展情景下生态风险压力等级由Ⅲ跃升至Ⅴ，只有生态经济情景下生态风险压力等级由Ⅲ回落到Ⅱ。



Abstract:The negative effects of urban land expansion on ecological environment are increasingly becoming significant. Taking Hohhot City as the study area, this paper aims to adjust and optimize the Cellular model with multi-scenario simulation of urban land expansion based upon the analysis of the spatial and temporal characteristics of urban land expansion in recent years. In this paper, an evaluating system for ecological risk pressure is established to assess the ecological risk pressure resulted from urban land expansion under different circumstances. The evaluating system consists of four dimensions, namely, urban expansion, ecological landscape, grain security, and ecological degradation. Four conclusions are reported as follows. First of all, from 1990 to 2017, the urbanization expansion index of Hohhot was uninterrupted downward, and the expansion rate has seen a stage marked by an up-to-down fluctuation. We argue that the urban land expansion has manifested a strong periodical characteristic. Second, after making predictions for the expansion degree of urban land in 2025 and 2030 through the CA model, we conclude that only under the scenarios of agrarian protection and ecological economy, the expansion rate of construction land will manifest as a downward trend, and the index of expansion intensity will be in further decline. Third, during the study period, the pressures from urban expansion, landscape ecosystem, grain reserves, ecological degradation, and ecological risk have increased by 2.2%, 1.9%, 1.4%, 11% and 15%, respectively. These pressures lead to the intermediate level of the ecological risk forewarning. Last but not the least, by the end of 2030, the ecological risk pressure level, will upgrade from Ⅲ to IV under the scenarios of trend extrapolation and agrarian protection, and to V under the scenario of urbanization development. However, it will degrade from Ⅲ to Ⅱ under the scenario of ecological economy.





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb201912042638