Ecosystem Assessment Of Nanji Island Based On PSR Model

Islands are important parts of national territory with high value of economy and national defense. However, the islands ecosystem is so fragile that is susceptible to be damaged by human activities and disturbance. Along with the islands exploitation activities intensifying, the conflicts between human and ecological environment are increasing. So we should enhance the conservation and management of the islands. Conservation and management of islands should be based on ecosystem, while doing islands ecosystem assessment is the foundation of the ecological planning, developing and management of islands.At present the research on islands ecosystem is not mature yet. There are not an integrity assessment indicator system and assessment methods of islands ecosystem. This article took Nanji Islands in Zhejiang Province as an example, attempted to establish an assessment indicator system and assessment methods of islands ecosystem based on "Pressure-State-Response" (PSR) model, and made research on the status, the change tendency and management strategies of islands ecosystem. This paper includes theoretical research and case studies, principally as follows:(1)In the theoretical research part, first, the connotation and research progress of ecosystem as well as the concept, characteristics and research progress of islands ecosystem had been introduced. As outlined in Chapter 1, the islands ecosystem assessment can be defined that, it took the entire island ecosystem as the object basing on the fundamental characteristics of ecosystem, and made comprehensive assessment of the ecosystem structure and function as well as the interaction mechanism among subsystems by applying the principles and methods of ecological assessment. Second, the idea of this paper had been described based on the analysis of PSR model. Finally, the basic framework of islands ecosystem assessment indicator system had been constructed based on the structural features of islands ecosystem, and the islands ecosystem assessment approaches had been discussed, including the establishment of the indicator system, the calculation and analysis of single indicator as well as the integrated analysis of all the indicators.(2)In the case studies part, the general situation of Nanji Islands ecosystem had been introduced by analyzing the natural characteristics of the ecological environment, socio-economic characteristics and resource characteristics of the Nanji Islands. The representative of Nanji Islands is rich in mollusca and algae resources, reflects the high biodiversity, and the distribution of many marine species has its specificity and can fill the vacancy. These make Nanji Islands National Marine Reserve. Its features of socio-economic development and resources are closely related with the representation. Then, followed by the selection of the main island Nanji Island, research of the ecosystem assessment had made with the early 1990s national islands investigation and the investigation data from some units in recent years. Three levels of indicator system of Nanji Island ecosystem assessment had been constructed with the scientific and practical factors selecting from the pressure, the state and the response of the Nanji Island ecosystem.(3)The qualitative and quantitative analysis of indicator system had been carried out by the application of the theoretical research methods. The major pressure of Nanji Island ecosystem are climatic factors, current conditions, red tides and storm tides, traveling population, socio-economic development and some resources use such as catch and cage culture. The results of quantitative analysis showed that the index of Nanji Island ecosystem state was 0.86, ecosystem state presented "excellent". The results also showed that the Nanji Island ecosystem state had "0.14" space efforts to the ideal goal, the positive development of the ecosystem state also had considerable potential. But it also found that if we satisfied with the present status, relaxed our vigilance and protection, ecosystem state might also drop"0.06" and point to the "good" status. The ecosystem response mainly included pollution control, ecological environment management and ecological protection and construction. It indicated that there were still some issues which had not been effectively controlled, such as beaches and sea pollution and a decrease in biodiversity, etc. Finally, the prediction of development tendency of Nanji Island ecosystem had been made, that it would still take biodiversity conservation as a major objective, develop tourism-oriented and focus on developing the "Man and the Biosphere" demonstration projects. Further more, the future management and protection strategies of Nanji Islands National Marine Reserve had been proposed.(4)The content and results of this paper were discussed and summarized, the results were: the recognition of the differences among ecological assessment, ecosystem assessment and environmental assessment, and the proposition of the connotation of island ecosystem assessment; the selection of representative indicators of Nanji Island and the establishment of the indicator system according to the actual situation; the establishment of assessment standards; and the conclusion of Nanji Island ecosystem assessment. In addition, a study of the innovations and the outstanding questions, as well as the prospects of future study was made.