经济快速增长区城市用地空间扩展对生态安全的影响

目前我国正处于经济快速发展、城市化进程加快阶段,承受着生态环境恶化的巨大压力,大多数城市已为环境污染、空间拥挤、绿化率低、秩序混乱等严重的城市问题所困扰.昆山市作为我国经济发展最为活跃的地区之一,其城市化过程与生态环境安全之间的矛盾更为突出.在总结国内外生态安全和城市生态研究的基础上,分析城市用地扩展对城市生态安全产生的影响.昆山市城市用地空间扩张经历了缓慢发展期(1949～1977年)、老城区改造期(1977～1985年)、新区开发期(1985～1999年)和快速扩展期(1999年至今)4个阶段,针对城市土地利用变化特征及其城市土地利用存在的问题,对昆山市城市用地空间扩展进程和模式及扩展的主要特征方面进行剖析.从城市废水、废气和固废排放量几个方面分析了昆山城市用地空间扩展过程中生态环境变化情况,指出高速工业化、城市化过程,快速增长的经济可能威胁到昆山城市的生态安全.同时建立城市生态安全评价模式,构建城市生态安全评价的指标体系,探讨城市生态安全评价的方法,评价了昆山市1985～2004年的城市生态安全,最后对昆山市未来城市生态安全进行预警.为维护昆山市的生态安全,实现可持续发展提供科学依据.

The effects of urban land use extension on ecological security in fast-growing economic zone

China is experiencing a period in fast economic development and swift urbanization at present and meanwhile bearing enormous pressure from environment deterioration. Most of the cities have been suffering from such serious urban problems as environmental pollution, crowded space, low greening ratio and chaotic order. As the one of most vibrant economic-developing areas in China, the contradiction between urbanization and ecological security in Kunshan is more outstanding. Based on the summary of domestic and international ecological security and urban ecological study, this paper makes an analysis of the effects of urban land use extension on urban ecological security. Urban land use extension of Kunshan has undergone four stages, namely slow development stage (1949-1977), old town alteration stage (1977-1985), new area developing stage (1985-1999) and fast extension stage (1999 till present). From the aspects of urban waste water, waste gas and solid wastes, the paper makes an analysis of the eco-environmental change during the process of urban land use extension in Kunshan and points out that fast industrialization and urbanization process as well as fast economic development may threaten the urban ecological security in Kunshan. Meanwhile, the paper sets up an evaluation mode for urban ecological security, constructs the indexes system of urban ecological security evaluation, discusses the method of urban ecological security evaluation and evaluates the urban ecological security from 1985 to 2004 in Kunshan. At last the paper makes an alerting research on the future urban ecological security in Kunshan. In order to improve the ecological security of Kunshan and the economic sustainable development, some beneficial suggestions and countermeasures were put forward.