Ecosystem Vulnerability Assessment Of Luoyuan Bay

The bay ecosystem can provide human beings with all kinds of ecological service function, which is of great significance for human survival and development. Bay, however, because of its special geographical location, exposed to the frequent development and utilization of human activities and the disturbance of natural disasters, which caused marine ecological environment quality declining and ecosystem increasingly fragile. The bay ecosystem vulnerability assessment will help us be aware of the vulnerability degree of ecosystems and effectively identify major stress factors and sensitive factors, which is of great significance to achieve the sustainable development of the gulf and the scientific management of ecosystem.Luoyuan bay is a typical semi-enclosed bay, with broad tidal wetland, long marine coastal resources and rich marine biological resources. Because of the frequent exploitation and utilization of the gulf, Luoyuan bay ecosystem is exposed to great pressure. Currently, domestic and overseas studies on bay ecosystem vulnerability assessment are even less, and the evaluation method and index system are not mature and perfect enough. Based on the reviewing of theoretical and empirical studies on the ecosystem assessment both at home and abroad, an index system framework with19indexes was set up as "exposure-sensitivity-adaptive capacity". Fuzzy evaluation method combined with comprehensive index method was applied to quantitative evaluate the vulnerability of Luoyuan bay ecosystem in1986-1990,1986-2006and2010-2006respectively. In the end, key factors would be analyzed and discussed. The main research contents and results are as follows:(1) This article summarized related researches on the concept and evaluation method of ecosystem vulnerability at home and abroad, put forward the concept of the bay ecosystem vulnerability, made clear the main research contents of bay ecosystem vulnerability assessment. Furthermore, comparative study between the ecosystem vulnerability assessment and other related ecosystem assessment was carried out.(2) Since1986-1990, Luoyuan bay ecosystem tended to be increasingly fragile. According to the results of comprehensive index method, the vulnerability degree of Luoyuan bay ecosystem of1986-1990was "micro-vulnerability", scored0.190; vulnerability score of2004-2006rose to0.244, at this time Luoyuan bay ecosystem was in a "mild-vulnerability"; From2010to2012, although the vulnerability degree was still in the "mild-vulnerability", the vulnerability scoring up to0.300. (3) Luoyuan bay ecosystem is faced with increasing degree of exposure. The results of Fuzzy evaluation method showed that the degree of exposure corresponding to the largest membership of Luoyuan bay ecosystem was "low", which was42.53%in1986-1990; In2004-2006, the degree of exposure corresponding to the largest membership was "very high", which was36.67%; and in2010-2012, the degree of exposure corresponding to the largest membership was still "very high", but57.89%indeed, which was higher than the degree in2004-2006. Results of comprehensive index method demonstrated that the indexes of exposure were0.083,0.125and0.174respectively. Luoyuan bay ecosystem was under a circumstance of increasing frequency and degree of external disturbance. The major artificial stress factors, which resulted in increased degree of exposure, include the proportion of enclosed tideland, the density of marine culture and the development of harbor industry.(4) The sensitivity of Luoyuan bay ecosystem is obviously intense. The sensitivity of Luoyuan bay ecosystem in1986-1990, the degree corresponding to the largest membership was "low", and the membership was46.30%; In2004-2006, the ecosystem sensitivity degree corresponded to the biggest membership was "low",32.65%; In2010-2012, sensitivity degree corresponding to the biggest membership was "high",38.35%. For the trend, the membership corresponding to "low" sensitivity degree declined in these three periods, but the membership corresponding to the "very high" sensitivity degree increased significantly. The membership corresponding to the "high" membership represented a slight decline from1986-1990to2004-2006, and a sharp risen from2004-2006to2010-2012. As the results of comprehensive index method, the indexes of sensitivity were0.156,0.209,0.236respectively which showed a slight rise. The main sensitive factors of Luoyuan bay ecosystem were comprehensive index of marine biological quality, biological diversity indexes of zooplankton and intertidal benthic, and species and density offish larvae.(5) Adaptive capacity of Luoyuan bay ecosystem presents a good tendency. The results of Fuzzy evaluation method showed that the adaptive capacity degree corresponding to the largest membership of Luoyuan bay ecosystem in1986-1990was "low",59.79%indeed; In2004-2006, the ecosystem sensitivity degree corresponded to the biggest membership was "general",50.47%; In2010-2012, sensitivity degree corresponding to the biggest membership was "high",58.76%. Results of comprehensive index evaluation indicated that the indexes of adaptive capacity were0.049,0.09,0.113respectively, which showed a slight rise. This illustrated that as the degree of exposure and sensitivity increasing, the adaptive capacity of Luoyuan bay ecosystem which caused by social environmental protection efforts also enhanced. Optimum strategies were supposed to include completing the laws and regulations of environmental protection, improving management mechanism, strengthening sea pollution control, advancing sewage treatment, and enhancing the citizens’ environmental awareness and participation.