上海市城乡梯度景观格局分析

Landscape pattern analysis along an urban-rural gradient in the Shanghai metropolitan region

利用 2 0 0 0年的土地利用数据 ,在 GIS的支持下 ,结合景观格局指数和梯度分析方法 ,研究了上海市景观结构及其在城市化梯度上的空间特征。结果表明 ,上海市的景观结构中 ,农田为优势景观 ,占整个景观比例的 6 0 %左右 ,而反映城市化的工业、居住和基础设施景观则占 2 2 % ,表明上海的城市化程度已经很高 ;郊区居住用地比例过大 (12 .6 9% ) ,城乡交错带居住区与工业区的高度混合显示上海市的景观结构需要优化 ,以提高土地利用率。样带上类型水平的景观格局指数分析表明各种景观类型表现出独特的空间特征 ,明显反映了城市化的梯度和前沿 ;而景观水平的格局分析则表明城市化导致景观的破碎化程度增大 ,景观异质性增高 ;景观格局指数曲线在城市化梯度上呈双峰型 ,是上海中心城区和浦东新区城市化区域的具体表现。研究结果表明景观格局指数和梯度分析相结合 ,是检测城市化和城市形态的有力工具。

Urbanization is one of the most important socio-economic phenomena that profoundly influence modern landscapes. This dramatic form of land transformation results in a number of changes in urban morphology and landscape structure, which further affect the physical, ecological and socioeconomic processes in and around cities. Shanghai, as the biggest and most rapidly developing city in China, is uniquely important in the study of the patterns, processes, and consequences of urbanization. Based on a land use dataset derived from 1∶50000 aerial photos, we combined landscape metrics with gradient analysis to quantify the landscape pattern along an urbanization gradient in the Shanghai metropolitan region. Several landscape metrics were computed along a 65km long and 5km wide transect with a moving window. The results showed that agricultural land accounted for 60% of the total area, and was the dominant landscape type. Industrial, residential and public facilities land uses, together indicative of the level of urbanization, accounted for 22% of the total area The proportion of residential land use in the suburban was as high as 12.69%, and the mixture of high percentages of residential and industrial land uses in the suburban zone suggests that the current landscape structure in the Shanghai metropolitan region may not be optimal. The spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach. The urbanization center and frontier could be identified precisely with class-level landscape indices. Different landscape types exhibited distinctive spatial signatures along the transect. Landscape fragmentation and heterogeneity induced by the urbanization could be quantified by landscape-level indices. The multiple peaks in the graphs of landscape metrics against the urban-rural gradient corresponded to the urban center and the newly developed Pudong District. The changes in landscape pattern along the transect suggests that landscape metrics combined with gradient analysis are a robust tool to study the spatial pattern of urbanization.