The Composite Bearing Capacity Of The Urban Ecosystem Research

Urban ecosystem is a Social-Economic-Natural Complex made of human beings and their surrounding environment, and is characterized by integrity and synthesis. In this system, the urban population and their activities jointly form the core component, which is inseparable with the urban eco-environment. It is understood that, because resource and environment are crucial to the existence and development of an urban ecosystem, the development of an urban ecosystem is necessarily built on the interactions between environmental carrying capacity (ECC), resource carrying capacity (RCC) and social-economic development capacity (SEDC). It can not be anything to study single component's carrying capacity by taking no account of system integrity. Here, in order to meet the challenges of urban sustainable development and eco-city building, the complex carrying capacity (CCC) are introduced and studied as an index of the interactions between ECC, RCC and SEDC. Through this index, how the three kinds of capacities function to sustain urban ecosystem is figured out in both theory fundamentals and quantitative models. The research specifically includes the followings: 1. Significance and function of urban ecosystem carrying capacity are interpreted in view of city development perspectives and characteristics of complex urban ecosystem. Then, beginning with natural ecosystem carrying capacity for population, the academic history of incorporating carrying capacity into human ecosystem studies is generally reviewed, and also the achievements and research stresses of researchers from domestic and overseas are analyzed. 2. Structure and function definition and analysis of urban ecosystem. An Egg-body model is set up to simulate the organic composition of urban ecosystem and analyze the basic functions and services ecosystem offered regarding the human needs which is the core component in an urban ecosystem. The urban ecosystems are also classified by the characteristics of society, economy and nature, et al, so that the study on CCC can be specialized. Moreover, self-adjustment mechanism for balance of urban ecosystem is outlined, and some tentative research has conducted to understand the principles of urban ecosystem evolvement. 3. Based on traditional outcomes of resource carrying capacity research, the R-S optimization model is built here to figure out the proper population in an urban area. This model should be used in the cities with high economic degree and over urbanization, since the population of these cities is affected more by urban planning. The effect on urban environment is always shown by resource over-use and pollution discharge. 4. The concept of CCC of urban ecosystem is introduced with comprehensive understanding of this system's structure and functions. Furthermore, its characteristics and connotation are also interpreted from aspects of objectivity, organism, hierarchy, integrity, evolvement phases and threshold and relative balance etc. Compared with traditional concept, the CCC of urban ecosystem includes development ability, which makes it more dynamic. It can be shown by the equilibrium with pressure. The CCC is in a nature of double limens. 5. Comparative study found that complex urban ecosystem functions like immune system of human being. Thus, complex urban ecosystem carrying capacity model is proposed here in light of biology immunity theory and under a series of assumptions. These assumptions include urban ecosystem storage is the material input and its main function is to offer eco-service, this amount of capacity is jointly determined by natural carrying capacity and acquired carrying capacity of urban, and human being is the receptor of the eco-service. This theoretic model shows the carrier, the carrying target and the carrying mechanism of the CCC of urban ecosystem. 6. Methodology for complex carrying capacity calculation and mechanism of adjustment are outlined according to the conceptual model of complex urban ecosystem, and with the reference of urban ecosystem healthy index and evaluati...