快速城市化背景下广西典型城市景观空间格局动态比较研究

随着城市化的快速发展与城市规模日益扩张,城市景观空间结构不断地被人为改变着,不合理的景观空间格局既削弱了区域的经济和社会发展功能,影响着城市生态环境质量的不断提高,也进一步制约着城市的可持续发展进程。以广西3座典型中心城市——南宁、柳州和桂林市为研究对象,利用6景Landsat5 TM和Landsat8 OLI/TIRS影像数据,通过遥感影像分类技术提取研究区的土地利用景观信息,对典型城市1990—2015年的景观空间格局特征与生态过程进行对比分析,旨在揭示快速城市化阶段重点城市核心景观要素的时空演化规律。结果表明:(1)在城市化进程加快的背景下,广西各典型城市的景观空间格局均发生了剧烈的变化。受人为影响强烈的土地利用景观类型变动最为显著,建设用地景观的不断扩张与耕地、林地景观的缩减是城市化发展的基本特征。(2)在水平空间上,城市建筑景观逐渐由核心圈层向外围圈层扩展,外围区的自然景观受人工干扰强度加大,景观类型逐渐丰富,但破碎化程度加剧。(3)在垂直空间上,城市景观类型呈现较显著的海拔分异特征,中、低海拔区是城镇化最集中的地带,建设用地的景观优势度增长最为显著。高海拔区因但受城市扩张与农业开发活动的胁迫,自然景观的优势度与团聚性呈下降趋势。(4)从城市功能定位来看,南宁、柳州和桂林市作为广西3座不同功能类型的中心城市,它们在区域社会经济发展方面起到重要的辐射和引领作用。该研究为科学开展城市景观规划、实施城市生态环境管理和推进广西城市化健康有序发展提供参考依据。

Comparison of changing landscape patterns in the rapidly urbanizing cities of Guangxi

With the rapid urbanization and expansion of cities, the landscape structures of urban areas are artificially changing. This has led to reduced functions of urban eco-economic systems owing to the unsustainable ecological position of landscapes, which not only affects the quality of the environment, but also restricts the progress of sustainable urban development. For Nanning, Liuzhou, and Guilin, which are three typical cities of Guangxi, six Landsat5 TM and Landsat8 OLI&TIRS images were used as the data sources. The land use information was extracted by remote sensing techniques. Thereafter, the characteristics of landscape structure and landscape changing pattern of the three typical cities during the period 1990-2015 were analyzed to reveal the evolution of city landscape patterns during rapid urbanization. The results showed that (1) the landscape pattern of the three typical cities changed drastically with urbanization. Landscape changes under human disturbance were highly significant. The major characteristics of urbanization were the increase in construction land and decrease in cultivated land and woodland. (2) In the horizontal spaces, the construction land expanded rapidly from the center of the city outwards, with the natural landscape being dramatically affected by human activities in the outer areas. Landscape was heterogenous and fragmented. (3) In the vertical spaces, landscapes showed obvious vertical differences. Urbanization was mostly concentrated in the mid and low altitude regions. Clearly, landscape dominance by construction land increased. Because of urbanization and agricultural production, the dominance and abundance of natural landscapes declined. (4) From the perspective of function orientation, Nanning, Liuzhou, and Guilin, the three typical cities of Guangxi, have a strong attraction, radiation, and driving force to peripheral regions in terms of economic and social development. This paper provides reference for landscape planning, eco-environment management, and sustainable urbanization in Guangxi.