Guangxi Offshore Areas Ecosystem Health Assessment

Since the gulf goes deep into the inland, it has natural relationship with human beings. A great number of human activities occurs in the offshore areas, and the gulf ecosystem is vulnerable to interference by human beings. As the results, the gulf ecosystem health evaluation can contribute to a better understanding of the gulf ecosystem and provide an important basis to the gulf ecosystem management in order to promote a better harmony between human beings and nature.Guangxi offshore areas are located in the north of the Beibu Gulf, near the Fangchenggang city, Beihai city and Qinzhou city. As the keystone places in the Beibu Gulf, Guangxi offshore areas have rich biological nature resources, mineral resources, harbor resources, tourist resources and other superior resources, showing huge developing potential. With the rise of pan-Beibu gulf economic zone in recent years, multiple pressures were exerted on the ecosystem health of Guangxi offshore areas, such as fishery activities like overfishing and aquaculture, marine development activities like reclamation and coastal industry, human activities like terrigenous pollutants and tourism, and global changes like seawater warming, frequent ecological disasters and biological community structure abnormalities.In this article, previous research work on gulf ecosystem health by domestic and foreign scholars were summarized, and pressure-state-response (PSR) model was selected to construct the gulf ecosystem health evaluation index system through three subsystem known as press subsystem, state subsystem and response subsystem. By the comprehensive index method, the ecosystem health of Guangxi offshore areas were evaluated as the score of0.69, which represented "good situation" according to the standards of the assessment of ecosystem health. It could be concluded that Guangxi offshore areas ecosystem were under good situation with consummate ecosystem structure and function and strong resilience from disturbance. But it was prone to be interfered by human activities. Specific evaluation results of each subsystem are as followed:(1) Press subsystem was in "good" situation. It indicated that with the rapid development of social economy, the development and utilization of resources had already brought great effect to the ecology environment, more than that brought by nature ecology disaster. Aquaculture showed the biggest pressure in press subsystem, so it was necessary to control the aquaculture areas. Coastal reclamation needed to be reasonably supervised as well. Besides, the development of tourism was disordered and disorganized, develop mechanisms were not inadequately standardized.(2) State subsystem was in "good" situation, indicating the overall good condition in Guangxi offshore areas. The ecosystem was able to maintain relatively complete community structure, normal energy flow and material cycling. Self-regulation ability was equipped to resist and recover from the long-term nature interference. The situation of environment quality was generally good. The condition of intertidal organisms and coastal organisms was satisfied, yet still in the need of strengthened protection. Rare or endangered species stayed dangerous. Although protection efforts had been strengthened, recovery was found out to be a long process and consistent protection was quite necessary. The biological productivity was relatively good, including the entire ecosystem energy flow and material cycling. As for biological habitats, mangrove was being best protected, even though it still suffered a lot from the red tide and alien species invasion. More protection efforts should be done for sea-grass beds and coral reefs.(3) Response subsystem got the score of0.66, indicating that the local government has done a good job. All the management work could meet the requirement of ecosystem protection and ecosystem protection has been led onto the correct track. Among all the indexes, the sewage treatment rate index, the protection areas construction and management plan index and regulations and policies index were the highest. It meant that with more attention to environment pollutions by Guangxi government, stricter requirements were executed on sewage treatment especially on terrigenous pollutants treatment. This has important significance for protecting ecosystem. But the education index, tertiary industry index, investment index in environmental governance and public participation index were significantly lower than other indexes, suggesting that there were much space to enhance and improve in the social response.According to the analysis of the assessment results, this article came up with some suggestions including aquaculture, alien species invasion, coastal reclamation, tourism industry, rare or endangered species, establishment of integrated management system and network cooperation, and the marine talent training, consequently offering scientific advice of ecosystem management in Guangxi offshore areas.