Study On Urban Ecosystem Carrying Capacity By The State Space Method

In recent years, the sustainable development was experiencing from general conception and qualitative research to quantitative research transformation, and the system carrying capacity was one of the cores in researching the measures and appraises about sustainable development. The city as a social-economical-natural compound system, the biggest carrying capacity which moves to the humanity is a question which the sustainable development research cannot be avoided, only then has we realized the biggest carrying capacity of urban ecosystem which sustained the humanity, and it can further determine the rational exploitation intensity, and then establish the integrate, practical and feasible sustainable development pattern.On the foundation of the domestic and foreign research results, this paper took the urban ecosystem as an object, unified the characteristic of a great compound urban system, used the principle of the state space method, and took the sustainable development as the regional goal. Then author established index system about the assessment of urban ecosystem carrying capacity, worked hard to devote oneself to Xi'an ecosystem carrying capacity demonstration research from 1990 to 2003. Through the study of these facets, we drew the following main conclusions:( 1 ) According to the Xi'an ecosystem characteristic, took the region sustainable development as the goal, refered related principle of establishment index system, and considered economy, society, resources and environment and so on which involves, writer constructed the index system of ecosystem carrying capacity appraisal in Xi'an.(2) Besides society subsystem carrying capacity was full-loading state in 1990, Xi'an society subsystem was under-loading state from 1991 to 2003. In order to understand Xi'an's loading state more, author established system carrying capacity rate formula, and obtained that Xi'an's society subsystem carrying capacity rate from 1990 to 2003 was fluctuated all through, but the undulation is small. By analyzing from 1990 to 2003, Writer obtained that the major effect factors were the condition of population and technical.(3)Economical subsystem carrying capacity was over-loading state from 1990 to 1993 in Xi'an, and it changed to better gradually from 1994, the actual carryingcapacity started to be smaller than the ideal carrying capacity. In other words, carrying capacity was under-loading state from 1994 to 2003 on economical subsystem in Xi'an. Carrying capacity rate on economical subsystem was fluctuation in Xi'an, and its collectivity tendency was on rise. By analyzing about economical subsystem carrying capacity in Xi'an, author obtained that major effect factors were the condition of economical development, industrial structure, and pollution discharges.(4) Environmental subsystem carrying capacity was under-loading state from 1990 to 2003 in Xi'an, and the state of carrying capacity rate was fluctuation all long, the range is big. According to some correlation information, Xi'an government was enlarging the father degree of ecological environment since the 90's while developed economy quickly. Through more than 10 years endeavor, it enormously enhanced the loading level of environmental carrying capacity in Xi'an. So the environmental subsystem carrying capacity was under-loading state from 1990 to 2003, and this condition conforms to the sustainable development tendency. By analyzing about environmental subsystem carrying capacity in Xi'an, author obtained that the major effect factors were the condition of environmental pollution father and ecological environment protection.(5) Besides the carrying capacity was over-loading state in 1990, the carrying capacity on the whole urban ecosystem was under-loading state in Xi'an from 1991 to 2003. But we could not satisfy the relatively stable state, we should enlarge the investment to father the environment, and coordinate the economical development and the environmental protection all our best, to further enhance the urban comprehensive carrying capacity in Xi'an. In the end of this paper, author proposed some correlation countermeasure in view of the special details in Xi'an.