Urban spatial expansion and its impact on ecological service values of Chongqing City Proper in the last 30 years

Based on the remote sensing images of urban land use of Chongqing City Proper in the last 30years(from 1978 to 2011),The paper focuses on the impact of urban spatial expansion on urban ecosystem service.The charactereristics of urban spatial expansion pattern are expressed by Landscape Expansion Index and Index of Fractal Dimension.Taking advantage of calculation of these two indices,changes of the ecological service values in the main urban area of Chongqing caused by the variation of urban expansion patterns are evaluated and the interrelationship is analyzed.The main conclusions and results are as follows;in Chongqing City Proper,the ecological service value decreased rapidly from 1978 to 2011,especially in the period of 2002-2011.Urban spatial expansion pattern has exerted significant impact on urban ecosystem service value.Edge-expansion pattern broke into a great deal of urban enclaves and caused the disadvantage effect of the function of urban ecological system.At the same time,negative correlation existed between the indices of fractal dimension and the ecosystem service value.