Assessment of Ecological Carrying Capacity on the Typical Resources-based Cities-a Case Study of Tangshan City

The power of human activities in resource-based cities overload its ecological carrying capacity,such as mining,land occupying,and ore smelting supported by resources and environment. The relative research on the development of the cities is a hot topic over the world,the sustainable development of resource-based cities has become one of most prominent issues in China. The ecological carrying capacity reflects the harmony of human and ecosystem,including their interactive and symbiotic relationship,which should be used as an important criterion of region sustainable development. In past,the studies on ecological carrying capacity were largely confined to basin and region scales until the urban complex ecosystem theory was put forward. Thereby it is very inevitable to study the urban ecological carrying capacity and eco-regulation for its sustainable development. Tangshan,nearly hundred years of mining history,may be one of the fastest developing resourcebased cities in China,as well as one of most prominent representative of the cities which has poignant contradiction of the location: population boom,resources depression and environment deterioration. Based on the regional unique characteristicsof Tangshan and the connotation of ecological carrying capacity,a complete evaluation index system of ecological carrying capacity in the city was established from the aspects of resource subsystem,environment subsystem,social subsystem and economic subsystem. After determining the weight of each index by the method integrated subjective and objective factors according to the integrated index system,a quantitative model of ecological carrying capacity from the perspective of ecosystem resilience,support force and stress was proposed and employed in Tangshan during the period 2001-2010. With this comprehensive assessment model,the values of ecological carrying capacity of Tangshan city from 2001 to 2010 were computed and the factors which infected the decade trend of the ecological carrying capacity was analyzed and discussed.The results showed that the ecosystem resilience index had waved strongly in the process in spite of a slightly rising trend,which may suggest that the stability of Tangshan's ecological system harbors obvious frail characteristics. Accompanying the population boom and the economy growth,it is easily observed that the contradiction between the supply and demand of the water resources exposed gradually,which in turn restricted the social and econ