Preliminary Study On Assessment Method Of Island Groups Ecosystem

The ocean has abundant natural resources,and human beings obtain essential material and resources for development from the vast ocean.With the continuous development of China's economy and the orderly advancement of resource development and utilization,land space and resource supply are becoming more and more limited,and the imbalance between demand and supply of development activities is increasing.People are increasingly aware of the importance of the ocean in the development of natural resources.With the increasing importance of marine economy in the social economy,people focus on islands.Islands and island groups attract a lot of economic and trade activities,and island development and utilization activities are further developed.Islands and island groups are important geographical units of the ocean and an important part of the ocean.The ecological environment pressure of the island ecosystem itself is very limited.The limited area of the island ecosystem makes the species and quantity of plant and animal resources in the ecosystem less,and the level of biological diversity is usually at a low level.The ecological structure of the island group is simple,and the anti-interference ability of the ecosystem itself is weak.Under the interference of large-scale human development activities,the island group is vulnerable to serious damage.Once the damage of the island ecosystem exceeds the critical point of its own restoration capacity,it will bring irreversible damage to the island ecosystem and the economic development of coastal areas.At present,China is in a period of rapid development of island and island group development.Since the end of last century,with the large-scale development and utilization of marine resources,the coastal island ecological environment in China has suffered considerable damage.Therefore,the study of the coastal island ecological environment has become a hot spot and focus of current research.There are still many gaps in the study of island group development and ecosystem evaluation,and there is a lack of systematic and complete theory,especially for the ecosystem evaluation of large-scale engineering development island group.Therefore,this paper mainly takes the ecosystem evaluation of island group as the breakthrough point,studies the specific factors affecting the ecosystem of island group,tries to construct the evaluation index system of island group ecosystem through expert consultation method,and determines the index weight by using the analytic hierarchy process,so as to provide suggestions for solving the problem of island ecological environment deterioration caused by over-exploitation at the present stage.Applying the island group ecosystem evaluation system and combining with the case study of Zhoushan Petrochemical Base,this paper compares the island group ecosystem before the construction of Zhoushan Petrochemical Base in 2015 and during the construction of Zhoushan Petrochemical Base in 2017,and further analyses the main ecological environment problems caused by the development of major engineering island groups.The results showed that the ecosystem score before the development of the island group in 2015 was 73.66,and the ecosystem comprehensive evaluation was "good" grade.The environmental quality of the island group is good,only slightly polluted,biodiversity and other conditions are good,the naturalness is good,the disturbance of the island group by external pressure is very small,the ecosystem is relatively healthy,and the service function can normally play.In the development of island groups in 2017,the ecosystem score was reduced to 45.21,and the ecosystem comprehensive evaluation was "general" grade.The environmental quality of the island group is on the low side,polluted to a certain extent,the biodiversity is reduced,the landscape naturalness is decreased,the island ecosystem is greatly affected,and the stability of the ecosystem needs to be restored.