Island Ecosystem Risk Assessment Method And Applied Research

Supported by Natural Science Foundation of China (NSFC), to meet the demand of insular environmental management of China, the paper probed into four aspects: island ecosystem theoretical exploration, nonlinear assessment model development for multiple probabilistic risks, island exploitation and utilization risk assessment, and application study of remote sensing in island ecological risk assessment. Meanwhile, it verified the models and frameworks in South five-island of Miaodao Archipelago, China. The thesis is divided into the following parts:1. After analyzing the range of island ecosystem, three subsystems of insular terrene, tideland and shallow sea are put forward on the basis of hydrological, geographic and biological characteristics and the scopes of them are defined. Then delimitation methods by using remote sensing technique are presented and interrelations among the different subsystems are researched.2. Based on the linear assessenmt model currently used, a nonlinear assessment model for regional multiple probabilistic sources is developed for addressing the nonlinear effects of joint actions among sources, and a three-dimensional risk matrix is introduced for explaining the joint actions in the model. On this basis, a Regional Ecological Risk Assessment (RERA) framework for island ecosystem is designed and a case study in the South five-island of Miaodao Archipelago is performed.3. The Relative Risk Model (RRM) for RERA is tentatively put into application in assessing the island exploitation and utilization risks. To reduce the uncertainty of risk assessment, the discrete ranks of regional habitats and stressors in RRM is tentatively developed into continuous ranks. A case study in South five-island illuminates the regional risks hence suggestions for risk management are presented.4. The Monte Carlo analysis is used to evaluate the uncertainies of the assessment results. Based on this analysis, the uncertainties of the assessment results on South five-island and the sources of these uncertainties have been discussed and analyzed, and the signification of the Monte Carlo simulation curve has been explained.In the end, the paper points out the future work concerning the application of the nonlinear assessment model of multiple probabilistic risks and the improvement of the island exploitation and utilization risk assessment methods.