Assessment On The Ecological Risk Of Islands Under Development

Islands are invaluable ocean resource, and as one of the important platform for implementing the strategy of marine development and protection. The assessment of islands ecological risk is important premise to develop and manage islands. According to the Major Function Zoning of Zhoushan City and Zhejiang Province, we divide the Zhoushan Archipelago into six major function islands:comprehensive development islands, coastal tourism islands, coastal industrial islands, logistics islands, contemporary fishing island, marine ecological islands, then assess the ecological risk of these six major function islands.Firstly, based on expert questionnaire investigation, assess the main ecological risk sources and the hazard degree of these risk sources; Secondly, based on the transfer matrix of land use change, assess land use ecosystem vulnerability of six major function islands; Thirdly, based on fragstats software, assess landscape ecosystem vulnerability of six major function islands. Weighted sum land use ecosystem vulnerability and landscape ecosystem vulnerability to get the ecological system vulnerability of six major function islands. At last, according to the equation:ecological risk degree=risk source degree* ecosystem vulnerability, quantify the ecological risk degree of six major function islands. On the basis of above research, refering to PSR model, establish evaluation index system which consists of three first level indexs, six secondary indexes,18 three-grade indexs, to research internal distribution difference of ecological risk degree. And choose 20 representative islands (from comprehensive development islands, coastal tourism islands, coastal industrial islands, logistics islands) for empirical research.The research results show that:(1) The results of expert questionnaire show that:the top 10 ecological risk source of Zhoushan Archipelago’s are:the typhoon and storm surge, the explosion of petroleum and its products, oil spilling, red tides, landslides and debris flows, shortage of fresh water resources, overfishing,excavation of sand and reef, biological invasion, the emissions of industrial waste waters. The risk resource degree of six major function islands from large to small is arranged in the following order:marine ecological island, coastal tourism islands, contemporary fishing islands, comprehensive development islands, coastal industrial islands, logistics islands.(2) The analysis of the land use and landscape pattern change helps calculate ecosystem vulnerability of six major function islands. The degree from large to small is arranged:marine ecological island, coastal industrial islands, logistics islands, coastal tourism islands, comprehensive development islands, contemporary fishing islands. The order is consistent with the rapid development of harbor industry, port logistics industry, and tourism in recent years, indicating that these three major function islands islands are disturbed deeply by human activitives, so the fragile degree is obvious.(3) According to the equation:ecological risk degree= risk source degree* ecosystem vulnerability, Get the ecological risk degree of six major function islands. The degree from large to small is arranged:marine ecological islands, coastal tourism islands, coastal industrial islands, contemporary fishing islands, comprehensive development islands, logistics islands. The ecological risk degree of marine ecological islands is obvious more serious than other major function islands.(4) Based on PSR model, calculate internal ecological risk degree difference.In this article, take 20 representative islands as research objects. The result shows that:Daishan island, Gouqi island, Hunishan island are the islands whose ecological risk degree are the largest. Then Dayangshan island, Aoshan island, Fodu island, Changbai island, Dayushan island, Xiazhi island are islands with ecological risk degree ranked second serious. Zhoushan island, Putuoshan island, Taohua island, Xiushan island, Zhujiajian island, Qushan island, these six island’s ecological risk degree are calculated to be the third serious. Sijiao island and Xiaochangtushan island’s ecological risk turn to be last but one serious. And for Cezi island and Dachangtushan island, their ecological risk degree are minimal.Based on the results of the study above, the last section of this article, state the risk control measures and suggestions.