基于稳定映射分析的深圳绿色景观时空演化及启示

绿色景观是城市开发建设所必需的空间资源,也是城市生态功能维续的基础和载体, 其动态演变过程关乎人类福祉与城市可持续发展。本文应用1986-2005年多时序的Landsat TM/ETM+遥感数据,采用改进型稳定映射变化轨迹分析、景观格局指数和系统聚类方法,综 合分析城市化以来深圳市绿色景观的时空动态演变过程,探讨其空间发生机制。结果表明： 研究期内深圳市绿色景观面积和类型组成变化显著,且均在1995年前后出现变幅拐点,具明 显的阶段性特征；全市绿色景观动态变化轨迹包括4大类、2中类和13小类,以类内转化过程 比例最高 (30.5%),由此引发的潜在生态环境影响应成为今后城市景观演变与生态环境效应研 究的一大重点；各类绿色景观变化轨迹形成集聚型、相对集聚型和分散型空间布局,长期保 持过程集中分布于高海拔地区,与低海拔区域分布的波动、消失过程构成空间共轭关系,地 形条件成为深圳市57%以上绿色景观的天然庇护。而在地形平坦的城市中,如何在快速城市化 过程中有效保留充足、高质量的绿色景观资源,是值得进一步深入探讨的问题。

Green Landscape Evolution and Its Diving Factors in Shenzhen

Green landscape is not only the basis of urban development, but also the carrier of urban ecosystem services. Its dynamic evolution is related to human well-being and urban sustainability. Taking Shenzhen City as a case study, this paper explored the spatial trajectory of green landscape through the urbanization and its evolution mechanism based on TM/ETM + remote sensing data from 1986 to 2005. An improved trajectory analysis of stability mapping, landscape metrics and systematical clustering method were synthetically applied in this study. The results showed that the total area and composition of green landscape in Shenzhen had changed significantly since 1986, and the inflection point occurred around the year of 1995. This indicates that the green landscape change is well consistent with the urbanization process of Shenzhen City. The trajectory of green landscape change involved four process categories, two classes and 13 sub-classes. Quantitatively, the proportion of the transformation process within classes was the highest (30.5%), followed by the stable process (26.97% ), the process of shrinkage & disappearance (22.64%) and the fluctuation process (17.90%), and that of the recovery process is the lowest. So the frequent conversion among green landscape types and the following ecological effects should be a major concern in studies on urban landscape evolution and its effect in the future. Configurationally, the stable forest process and the process of shrinkage and disappearance presented a centralized pattern, two of which formed a conjugate spatial relationship;and the other stable processes and the recovery process presented a relatively centralized or decentralized pattern. After three decades of rapid urbanization, more than 57% of terrestrial areas is covered by green landscape in Shenzhen at present, which is attributed to the topographic conditions and more concrete protection measures such as the basic ecological control line policy, but there are still large amounts of risks for green landscapes. So it is critical to study how to keep sufficient high-quality green landscape for cities in the plains, where the urbanization might extend to a larger extent.