摘要
定量分析景观格局及其变化对于监测和评价城市化的生态后果十分重要。该研究应用基于GIS的梯度分析与景观指数相结合的方法定量分析了上海市城市化的空间格局。沿一条自西向东 6 4km长 6km宽和另一条自南向北 6 6km长 6km宽的样带 ,应用移动窗口计算了一系列景观指数。结果表明 ,城市化的空间格局可以用梯度分析与景观指数来定量 ,不同的土地利用类型沿景观格局梯度确实表现出明显的“空间特征”。多项景观指数可准确地、定量地指示上海地区东西和南北发展轴线上城市化的前沿和城市景观梯度分异的特征。城市化的总体格局是随着城市化程度增加 ,景观在组分上更多样化 ,形状上更为复杂以及生态学上更破碎化。此外 ,该文显示的上海市城市化景观格局比较符合同心圆论的城市发展理论 ,研究结果支持斑块密度随城市化程度而增加 ,斑块大小和景观连接度则下降的假说 ,但与随人类干预程度增强 ,斑块形状变得更规则的假说不相符和 ,因此 。
Urbanization is arguably the most dramatic form of land transformation that profoundly influences natural environment, biological diversity and human life. Understanding the causes, processes, and consequences of land use and land cover change is essential in ecology as well as in landscape and urban planning, and urbanization represents the extreme form of land transformation. Quantifying landscape pattern and its change is essential for the monitoring and assessment of the ecological consequences of urbanization. As the largest city in the country, metropolitan Shanghai is now the fastest growing area among all major Chinese cities that have more than 13 million residents. Using the 1994 GIS-based land use data set and combining gradient analysis with landscape metrics, we attempted to quantify the spatial pattern of urbanization in the Shanghai metropolitan area. Seventeen landscape metrics were computed along a 64 km long and 6 km wide west-east transect and another 66 km long and 6 km wide south-north transect, crossing at the urban center, with a moving window. The research was designed to address two questions: 1) do different land use types have their own unique spatial signatures (e.g., the shape of the change curve along an urban-rural transect)? 2) can urbanization gradients be detected using landscape pattern analysis? The results of transect analysis with landscape-level metrics showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be identified precisely and consistently with multiple indices of the 17 landscape metrics used in this study. Urbanization in the metropolitan Shanghai region has resulted in dramatic increases in patch density, edge density, and patch and landscape shape complexity, and sharp decreases in the largest and mean patch size, agriculture land use type, and landscape connectivity. The general pattern of urbanization was that the increasingly urbanized landscape became compositionally more diverse, geometrically more complex, and ecologically more fragmented. Although some of these changes were discernable visually from the land use maps, landscape metrics provided a useful way of quantifying these changes so that they could be further used to relate ecological patterns and processes in this urban landscape. In addition, our results supported a series of hypotheses on landscape structural responses along a human modification gradient: that, with increasing urbanization, patch density increases while patch size and landscape connectivity decrease. However, our results on patch shape seemed to disagree with the hypothesis that patch shape becomes more regular as human modification to landscapes intensifies. Our interpretation is that, when the degree of urbanization is high, not only the density, but also the shape complexity, of patches will increase. Future studies are needed to further confirm these findings.
出处
《植物生态学报》
CAS
CSCD
北大核心
2004年第1期78-85,共8页
Chinese Journal of Plant Ecology
基金
国家自然科学基金重点项目 ( 4 0 13 10 3 0 )
上海市重点学科建设项目
"十.五""2 11工程"重点学科建设子项目
关键词
城市化
梯度分析
景观格局
景观指数
Urbanization, Gradient analysis, Landscape pattern, Landscape metrics
