A GIS-based gradient analysis of urban landscape pattern of Shanghai metropolitan area, China

Quantifying landscape pattern and its change is essential for the monitoring and assessment of ecological consequences of urbanization. As the largest city in the country, metropolitan Shanghai is now the fastest growing area among all major Chinese cities with more than 13 million residents. Using the GIS-based land use data set of the year 1994 and combining gradient analysis with landscape metrics, we attempted to quantify the spatial pattern of urbanization in the Shanghai metropolitan area. The results of transect analysis with class-level metrics showed that the spatial pattern of urbanization could be quantified reliably using landscape metrics and different land use types exhibited distinctive, but not necessarily unique, spatial signatures. The results of transect analysis with landscape-level metrics showed that urbanization in the metropolitan Shanghai region has resulted in dramatic increases in patch density (PD), edge density (ED), and patch and landscape shape complexity, and sharp decreases in the largest and mean patch size (MPS), 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. In addition, our results supported the hypotheses that, with increasing urbanization, patch density increases while patch size and landscape connectivity decrease. However, our results on patch shape seemed to reject the hypothesis that patch shape becomes more regular as human modification to landscapes intensifies.