The Ecological Security Assessment Of Chongming Based On System Dynamics Simulation

Ecological security is the important basis of sustainable development and constitutes the national security system together with military security, political security and economic security. And it is the basis of society and economic development. In addition, Ecological security is the important subject in the global setting. Island is the important carrier of oceanology in geographic space and character of the environment is special. Furthermore, rapid development of ocean economy and frangibility of island ecosystem combine to determine the austerity of island eco-security issue. At the same time, study on the eco-security theory and practice in representative areas is conducive to consummating and enriching the theory and means of the field and steering effectively the practice of eco-security system construction. Chongming Island is the important strategic space of Shanghai sustainable development in the 21th century. The orientation of "Ecological Island " and exploitation and opening bring about new opportunities and challenge for ecological construction and management of Chongming Island. Under that background, it is very meaningful for the acceleration of sustainable development and improvement of the island survival environment to assess eco-security of Chongming and study the measures of management and safeguard of eco-security.Based on review of the research at home and abroad, the paper defines the concept and system of eco-security. Taking the background of environment and policy into account, we try to discover the main problems of eco-security of Chongming Island. And taking the SENCE as the theoretical basis, we build models through the means and software tool of dynamics system for ecosystem of Chongming. Also, system development trend and main ecological risk are simulated based on the model. Moreover, the index system of eco-security assessment that is suitable for estuary island is constructed. And integrate assessment and space diversity research of Chongming eco-security are carried out based on the index system. According to the mechanism and characteristic of composite ecosystem of Chongming that are revealed by dynamistic model and the result of eco-security assessment, the measure of management and safeguard of eco-security is put forword. The main research results of the paper are embodied in the following:Firstly, the paper puts forward the conceptual system of eco-security based on the review the evolutionary course of the concept of eco-security. Eco-security refers to ecological quality and the state under threat. And it includes biological security, environmental security and the security of ecosystem. The eco-security can be analyzed and assessed from health and risk level of ecosystem. Moreover, ecological service function is representative of eco-security level of ecosystem.Secondly, space-time-change of eco-security pattern is influenced by the effect of nature and society. The special geographic character and regional condition decide complexity of the issue of eco-security of Chongming. And a new round of socio-economic development brings more pressure and challenge to ecology and environment of Chongming. The problem is maily embodied in the fragility and instability, diversity and multi-scalar nature of ecology risk fountain, the big change of future ground utilization will greatly influence eco-security.Thirdly, the system dynamic model of composite ecosystem of Chongming is built by the means and tools of system dynamics. The model is composed of five subsystem:population, economy, resource, environment and ecology. It is discovered that the simulation result of planned projects is superior to the actual trend. The cause is that higher aim of the plans in such aspects as infrastructure construction, environment protection, energy-saving and reduction and ecological construction. As a result, the loss of net GDP caused by disaster, pollution and resource scarcity is reduced. The rapid development of economy will be the main pressure of eco-security in next ten years. And resource will be main restricting factor and the issue of energy figures prominently. The rapid increase of environment contamination will greatly influence the quality of ecology and environment of Chongming. According to the system character and simulation result analysis and comparison, we can choose the index that can weigh the eco-security level and decide the threshold of the index.Fourthly, the paper uses the dynamic model to simulate the main risk (salt water erosion, storm tide and the change of traffic condition) that threatens eco-security of Chongming. The main conclusions are as follows. On one the hand, along with rapid increase of fresh water demand, salt water erosion will make freshwater gap more visible in future though the freshwater resource is surplus at present. Also, under the influence of traffic state change, some variables (gross energy consumption and gross contamination) will increase more quickly than previous state and environment will endure more pressure in whole system. And the disaster loss will increase with development of Chongming under different disaster intension index. At same time, it is discovered that we should scientifically plan ground using, renew and rebuild ecological function area which prevent disaster and increase the inverstmentof foundational establishment to prevent and decrease disaster according to understanding the function mechanism of the risk.Fifthly, the character of assessment of area eco-security has three points:the object is composite ecosystem; the assessment has spatio-temporal difference; the result is relative. Based on review of the means and index system of eco-security assessment, the paper puts forward the frame system of ANP-PRS-SENCE. And according to the frame, eco-security assessment and space difference are studied. The result can indicate two points:I. The general index of eco-security of Chongming is at the grade of III (middling). And there is a trend of gradual increase in the scores of eco-security in last years. In the second grade indexes, the index of ecological health is higher, while the index of ecological safeguard is lower and it is the main factor that restricts eco-security level.â…¡. We can find that eco-security level of most area units is in hyponastic middling grade that is more sensitive from the result of space difference research. The pressure index is relatively higher and less pressure is brought about because of low population density and underdevelopment of economy. The reason of low-level of eco-security index of most area is that the response index and state index is lower. Though health index is higher in general assessment of eco-security, the state index of most area units is lower because natural ecosystems are concentrated in few area units and the third industrial proportion is lower.Seventhly, eco-security of Chongming is faced with three contradictions:rapid economy development and frail environment, highly frequent nature disaster and unsubstantial foundation establishment, agricultural main status and high agricultural pollution. According to it, there are four countermeasures of eco-security management, which are to to effectively strengthen the protection and management of natural resources, and actively develop eco-industries and to achieve a Low-carbon economy, to improve environmental pollution control capability and public service system, and to establish Spatial Decision Support System (SDSS) of eco-security defense and alarming system.