Ecological Risk Assessment Of Pearl River Estuary Coastal Area Under Human Disturbance

Coastal zones are important regional and strategic centers for world population agglomeration,national economic and social development.However,the composition,structure and function of coastal ecosystems have undergone tremendous changes under the influence of human activities such as population concentration,rapid urban expansion,intensive agricultural production,high-intensity industrial activities and transportation pressure.Coastal ecological security and risk assessment has aroused widespread concern in society and academia.In this paper,the ecological risk system of coastal zone is identified by combing the ecological risk source,ecological risk receptor,ecological risk assessment endpoint and exposure-hazard process under human disturbance.With the theories of landscape ecology,risk measurement,distance attenuation,the methods of remote sensing,regional comprehensive analysis and cumulative cost distance model,we developed an landscape ecological risk assessment model of Pearl River Estuary Coastal Zone based on human disturbance stress probability,landscape ecological fragility and landscape ecology loss degree.Finally,we conducted and analyze the ecological risk of Pearl River Estuary coastal area under human disturbance,based on the landscape data and the risk assessment model.According to the results of the study,the following conclusions can be drawn:(1)The main ecological risk sources of Pearl River Estuary Coastal Zone can be generalized as urbanization and industrialization,agricultural cultivation,aquaculture.These human disturbance activities not only take up a lot of ecological area,but also resulting in energy consumption,pollutant emissions and other ecological damage.(2)The ecological meaning of the ecological risk assessment model we developed is clear,as it is based on the identification of ecological risk system.Besides,the evaluation data is easy to attain,and the evaluation process is simple and operational.It has obvious advantage in ecological risk assessment in place where human activity is violent.(3)With the disturbance of human activities,the regional ecological risk of Pearl River estuary is at a slightly high level,which coastal area suffers the largest ecological risk,and then followed by the coastal waters.The ecological risk value of the east coast of the Pearl River estuary is obviously higher than that in the west coast of the Pearl River estuary.Among them,coastal areas of Dongguan City,Shenzhen City suffer the highest ecological risk,and need urgent ecological risk management.Ecological risk of Guangzhou,Zhuhai coastal area is at a moderate level,in which the overall ecological status of the region is better,but still need to strengthen the ecological risk management in some areas.The ecological risk of coastal zone in Zhongshan is at such a low level,that it is the lowest ecological risk in the coastal areas of the Pearl River estuary,and nearly do not need risk management.Based on the identification of risk system,this paper constructs the ecological risk transmission coefficient of coastal zone based on the spatial property of adjacent plaque,distance between risk source and risk receptor,in order to characterizes the propagation process of ecological risk in heterogeneous spatial region quantitatively,and to provide application reference for the landscape ecological risk assessment model.The study focused on the artificial disturbance and stress of the Pearl River Estuary,and carried out the ecological risk assessment and analysis of the Pearl River estuary under the disturbance of human disturbance.It is of great practical and guiding significance to the ecological environment management of the Pearl River estuary and the sustainable development of the coastal zone.