The Spatiotemporal Pattern Of Eco-Environment And Urbanization Efficiency In The Yangtze River Delta Urban Agglomeration

China’s rapid urbanization is based on huge consumption of water resource, built-up land and energy. Facing a series of eco-environmental problems, it is significant to understand the coupling relationship between urbanization and eco-environmental system in order to achieve a sustainable development among society, economy and environment. The Yangtze River Delta Urban Agglomeration (YRDUA), the biggest urban agglomeration in China, has paid a great eco-environmental price for its burgeoning urbanization and industrialization. The spatiotemporal dynamic patterns and the developmental tendency of eco-environment and urbanization efficiency in the YRDUA during 1990-2010 were analyzed. Moreover, the coordinated degree between eco-environment and urbanization was studied based on Ecological Index (EI) and urbanization efficiency indices. The results showed that:(1) As to the eco-environmental status, the YRDUA showed an average classification of "moderately high" level. The El rose slowly during 1990-2010 which demonstrated that the eco-environment kept steady growth during the period. Concerning to the spatial distribution, the eco-environmental quality (EEQ) demonstrated distinct variability with Shanghai-Suzhou-Wuxi-Changzhou-Nanjing belt as a demarcation belt. The EEQ within the belt performed worst while the southern area in Zhejiang province ranked the best. The EEQ in the YRDUA showed serious polarization which means it was improving in southern area while the northern area showed a good-bad rebound phenomenon.(2)As to the urbanization efficiency, the classification of it in the YRDUA was comprehensive "moderately high" level. It showed a decreasing pattern before 2005 and an increasing trend after that. Concerning to the spatial distribution, the urbanization efficiency indicated great spatial heterogeneity, but the differentiation degree within the area was decreasing, which demonstrated that the urbanization efficiency was towards to general balanced status.(3) As to the coordinated degree between eco-environment and urbanization, it showed an inverted "U" type pattern with the coordinated degree increasing first, reaching the peak and then decreasing. The general coordinated degree was high in the YRDUA. Meanwhile, the differentiation degree of it within the area was decreasing which indicated that the YRDUA was heading to more balanced developmental trajectory. As the urbanization system was extremely sensitive to the change of the EEQ, duo to the urbanization failed to effectively promote regional the EEQ during this period, most cities included Shanghai, Suzhou and Wuxi experienced relatively uncoordinated degree. However, the urbanization process was still in the range of what the eco-environment could load.