A Complex Model For Evaluation Of Port Ecological Carrying Capacity

With the rapid development of construction of port infrastructure and port throughput, issues such as environmental pollution, ecological damage, excessive consumption of resources become increasingly prominent in some ports. All the issues lead to deterioration of the ecological environment in the harbor and surrounding waters, and decline of regional ecological carrying capacity, which threatens the sustainable development of port ecosystems. Ecological carrying capacity is an important measure of regional sustainable development, therefore studying on port ecological carrying capacity scientifically and grasping the future evolution trend are conducive to take appropriate measures in the construction, operation, management of port and promote the sustainable development of port.The research digs into the process mechanism and causal effect in port ecosystem, based on discussion of essential attribute of port ecosystem and connotation of port ecological carrying capacity. Then establish the conceptual model of port ecosystem, causal feedback loop and system dynamics structure model, from the perspective of environment, resources and socio-economic subsystem. In accordance with the connotation of ecological carrying capacity, from the aspects of environmental carrying capacity, resources supply capacity and human support capacity, propose the evaluation index system of port ecological carrying capacity, giving full consideration to the characteristics of nature-economy-society complex ecosystem and ecological carrying properties of port. Introduce the state-space evaluation model, evaluate port ecological carrying capacity from three dimensions of environment, resources and human activity, and build the complex model for evaluation of port ecological carrying capacity.In a case study of a harbor, apply the complex model to evaluate the ecological carrying situation, then conduct parameter sensitivity analysis to recognize the main factors impacting the ecological carrying situation. Design natural development scheme and comprehensive control scheme, under which the evolution trend of the ecological carrying situation are predicted and evaluated dynamically. The results indicate the comprehensive control scheme based on the key impact factors can effectively improve the ecological overshoot problem under the natural development scheme and significantly improve the level of port ecological carrying states.The research integrates system dynamics model with state-space evaluation model, and structure the complex model for evaluation of port ecological carrying capacity, which makes up for the insufficient consideration of temporal dynamic and process mechanism in previous research on port ecological evaluation and achieves evaluation and evolution trend prediction on port ecological carrying capacity. The research can provide a scientific basis and decision support for the construction of ecological port, operation and management of port.