近35a来广州城市绿色空间及破碎化时空分异

伴随城市化进程的加快,绿色空间作为城市基础性要素之一,其稀缺性和作用日益凸显。论文以1979—2014年为研究时段,基于覆盖广州市域的7个时相Landsat影像获取城市绿色空间的信息,首先分析城市绿色空间数量变化与强度,再从研究区整体、境内各行政区单元和自中心城区向外人为划定的梯度景观等不同尺度对绿色空间破碎化的时空分异进行量化研究。得到以下主要结论:城市空间自中心向外扩展蔓延;城市绿色空间总量在研究始末变化不大,但随不同的时段呈起伏变化,其中1979—1990、2000—2005年间增幅较大,分别为2.3%和5.3%,1990—2000年则降幅较大,为-2.7%。绿色空间破碎化的时空差异明显,研究区绿色空间破碎化波动变化,呈减少(1990—2000年)—增加(2000—2005年)—减少(2005—2014年)之态势;而行政区的尺度上,与中心区毗邻的番禺、白云和花都区的阶段性特点突出,破碎化程度较大;在自中心区向外围的圈层梯度景观,也同样呈现阶段性变化特点。表明经济发展与对绿色空间的重视未尽同步,未来城市的可持续发展必须足够重视和优化绿色空间。

The Spatial-temporal Differentiation of Green Space and Its Fragmentation during the Past Thirty-five Years in Guangzhou

As one of the fundamental elements in urban area, the scarcity and importance of green space are becoming more and more prominent along with the urbanization. This paper firstly quantified the change and the intensity of urban green space using spatial data acquired from Landsat TM images from 1979 to 2014. Secondly, the spatiotemporal patterns of green space fragmentation were quantified at landscape gradients from the center to the periphery of the city and at the administrative district level. The results show that the city has expanded from central area to outskirts, which results in the increasing landscape fragmentation of urban green space. The green space has not been observed great change over time, while slight variations occurred in different time periods, i.e., ascending from 1979 to 1990 (2.3%) and from 2000 to 2005 (5.3%) and descending from 1990 to 2000 (-2.7%). Fragmentation of green space and its periodic difference of decrease (1990-2000) -increase (2000-2005) -decrease (2014-2005) are widely observed in spherical gradient of landscapes from central to peripheral area, as well as in the districts of Panyu, Baiyun and Huadu which are all adjacent to the city center. All these characteristics indicate the unequal attentions paid to the economic development and green space. The latter, however, is worthy of great emphasis and optimization for the sustainable development of the city in the future. Conclusions are helpful to understand the characteristics of the evolution of regional ecological environment, enrich research case and theory of urban green space, and also provide information for urban planning and spatial structure optimization of Guangzhou in the future.