Vulnerability Assessment Of Yellow River Delta Wetland

Wetlands, honored as the"kidney of nature", have an important impact on the landscape, which provide numerous beneficial functions for people and wildlife. Some of them include replenishing groundwater, protecting and improving water quality, providing fish and wildlife habitats, storing floodwaters, and maintaining surface water flow during dry periods. The Yellow River delta is a vast neonatal wetland that is abundant in biodiversity in China. The wetland resources provide remarkable benefits for regional economy, but fewer measures are performed for the wetland ecological protection. At present, the main challenges during protection of the wetland ecology include excessive exploitation of oil and gas resources, wetland pollution, enhancement of human activities, annual reducing of water and sands from the Yellow River, and extensively economic model of agriculture and industry, etc.Assessment of the wetland ecological vulnerability could reveal the spatial distribution of ecological vulnerability in this delta and further clarify some critical factors that posed therein. The results of this study will provide scientific evidence for improvement of wetland management, making of wetland protection policy, and exploitation and utilization of wetlands. In this thesis, the analytical hierarchy process (AHP) is selected and performed to determine the relative weight of each parameter for evaluation of the Yellow River wetland ecological vulnerability, based on thorough analysis and discussion of a series of theories and methods used in wetland ecological vulnerability assessments. Subsequently, these assessment parameters are quantitatively calculated applying the expert cluster method. A brand-new method containing multi-layer overlap and calculation are introduced, which is integrative and easy to illustrate and partition assessment results. The final assessment results are divided into four grades in terms of the total assessment scores accumulated. The vulnerability grades are ranked in the order of slight (78-60), low (60-50), middle (50-40), and high (40-0).Assessment results show that the total score of ecological vulnerability ranges between 40-60 and its grade fluctuates from middle to slight. Areas with middle vulnerability cover 38% and ones with low grade is 26%. Human activity is the most important factor in control of the ecological stability of the Yellow River delta. Most of high vulnerability areas are accompanied with plenty of human activities. For example, the assessment scores in the Gudao oil field, the river mouth area, the Dongying harbor, and the man-made dam area range between 0-40, covering 23% of the whole assessment region. Fresh water resources has a crucial impact on the eco-environment of the Yellow River delta. The ecological vulnerability is lowest in the both sides area along the present main watercourse of the Yellow River and in the areas of tributary rivers and reservoirs, next followed by areas along the ancient watercourse of the Yellow River and the newly-formed alluvial plain. The assessment scores of these areas are in the range of 60-78, covering 13% of the whole region that is evaluated.