Study On Assessment Method Of Island Ecological Vulnerability Influenced By Seawater Aquaculture Activities

Island ecosystem is a crucial human dewelling place except terrestrial ecosystem.As a small land exited in open sea,island ecosystem with its unique location and biological resource provides aboundant material for people survival and plays a significant role in the life of resident and the development of country.However,the increasing exploitation and construction activities have posed a threat to the stable ecological environment of island which different components heavily exposed to the risk of various hunman activities lead to the structure function more sensitive and adaptive ability weaken.Finally,the quality of island environment will worse,system stability decrease and ecological vulnerability increase.The area adjacent to Nanchangshan and Beichangshan Islands and nearby the Daheishan Island coupled with stable marine hydrological conditions and superior water quality are the natural place for the development of aquaculture activities.Intensely using area and diverse aquaculture species result from excellent quality of seawater aquaculture products and considerable benefits of industry.Seawater pollution,island landscape destruction and ecological environment recession due primarily to the establishment of aquaculture factories and the high-intensitive aquaculture activities.Therefore,bulid effective island carring on aquaculture activities ecological vulnerability assessment system is great significance for risk identification,sensitivity and adaptivity analysis of sea aquaculture,protection and sustainable development of island ecosystem in Nanchangshan and Beichangshan Island.This paper discusses the theory and evelation metod of ecological vulnerability of seawater aquaculture activities island and choose the Nanchangshan and Beichangshan Island situated in Miaodao Archipelago belongs to Shandong Peninsula as the tipical islands to carry out the case study.The main contents of this paper are as follows:1.Study on the mechanism of island ecological vulnerability influenced by seawater aquaculture activities.This dissertation summarize the national and worldwide development of ecological vulnerability concepts and assessments.On that basis,according to the primary activities occuring in island ecosystem,VSD(Vulnerability Scoping Diagram)ecological vulnerability framework,integrated with the features of island ecosystem consisted of island land,tideland,and offshore subsystems,the effect mechanism referencing the exposure degree of island ecological under the risk of aquaculture activities,the sensitivity of island organisims and habitats,the structure charaterastics of island and the adapativity under various influences and interferences of aquaculture activities on the island ecological vulnerability is explored.2.Construction of island ecological vulnerability assessment systemAccording to systematic features,the island ecosystem is divided into island land,tideland,and offshore subsystems.On the basis of seawater aquaculture activities occurring in three subsystems,the island ecological vulnerability index system composed of expoure,sensitivity and adaptivityis established.The subscales indators in three index subsystems are selected.in order to more measurable,the weights of indicators are calculated by means of Analytical Hierarchy Process(AHP).Finally,the comprehensive index evaluation model of island ecological vulnerability is constructed by means of the combination of exposure,sensitivity and adaptivity index.3.A case study about the ecological vlnerability assessment of island eosystemThe Nanchangshan and Beichangshan Islands located at Changdao County,Shandong Province working mainly on seawater aquaculture activities are selected as the typical investigation island.Expoure,sensitivity and adaptivity index data for island land and offshore subsystems are collected and weights of indicaotrs are determained.Then,they would be combined with ecological vulnerability assessment model of island to calculate the values of vulnerability.Furthermore,the index data involving Nanchangshan and Beichanshan Island spstial are processing based on Arcgis10.2 software platform,vectorization,rasterization,spatial interpolation(Spatial Analyst)and reclassify in order to obtain the spatial distribution results of different indicators and comprehensive ecological vulnerability of islands.The results indicate that,due to the impact of aquaculture,the seriously ecological vulnerability zones mainly distribute in the Neichangshan Island characteristiced with highly unbanization,whereas the most area of Beichangshan Island are show lower ecological vulnerability.The ecological vulnerability zones of offshore subsystem are mainly distribute in waters surrounding the Beichangshan Island,waters between Nanchangshan and Beichangshan Islands and northwest and northeast waters of Nanchangshan Island.These areas gatehered with aquaculture activities and aquaculture outfall.Overall,the effects of the sea aquaculture activities nearing the offshore subsystem are more obvious than island land subsystem.