Yellow River Delta Wetland Ecosystem Health Assessment Study

The Yellow River delta wetland is the most typical estuary wetland ecosystem in the warm temperate zone. Due to the influence of the large-scale development of oil and gas, the Yellow River runoff reduction, wetland environmental pollution, sea level rising, the blind development of industry and agriculture and so on, this aspects lead to increasingly prominent contradictions of economic development and wetland ecological protection, the wetland ecosystem health is seriously threatened.The assessment of the Yellow River delta wetland ecosystem health has the important theoretical and practical significance. It may abundant wetland ecosystem health research theory in our country and reveal the Yellow River delta wetland health status and its influencing factors, and then the wetland protection measures are put forward specifically. Based on the predecessors’ research about the theory and method of wetland ecosystem health evaluation, this article analysed the changes of Yellow River delta wetland landscape pattern using3S technology and built evaluation index system according to PSR model. Then a comprehensive appraisal was made on the whole wetland ecosystem health using the analytic hierarchy process (AHP) and comprehensive index evaluation model. At last, this paper analyzed the factors affecting the Yellow River delta wetland health and put forward the corresponding protective measures. The results show that the Yellow River delta wetland presents a degradation trend and stay in sub-health state as a whole. The main research content includes:(1) This paper summed up the theory and methods of wetland ecosystem health research at home and abroad and discussed the research progress and trend of ecosystem health concept, evaluation methods. The definition of wetland ecosystem health has not been unified. As a special dynamic ecological system, the structure and function of Wetland ecological system is the basis of evaluation, so the wetland ecosystem health is dynamic. The evaluation methods of wetland ecosystem health mainly include the indicator species method and index system method.(2) Taking three stage TM images in2000,2006,2010as information source, the paper obtained the dynamic change of wetland landscape pattern in research area and according to the characters of the wetland ecosystem in the study area, the Yellow River delta wetland was divided into two categories. From2000to2010the wetlands in the study area had obviously change in time and space, the overall showed a trend of deterioration. And the artificial wetland increased, natural wetlands decreased.(3) According to the basic principles of evaluation index selection, combining the actual conditions of the Yellow River delta, the article selected pressure-state response (PSR) model to construct the evaluation index system of the wetland ecosystem health, then the data of each index was extracted and standardized, the index to judge the extent of the impact of wetland ecological health, and refer to the previous studies about evaluation standard of the wetland ecosystem health, the state of the wetland ecosystem health was divided into five healthy levels such as disease, General pathologica, subhealth, health and very good health.(4) This paper got the evaluation results. The results showed that the pressure index of the Yellow River delta wetland ecological system is0.62, staying in a relatively range that could withstand pressure; The wetland ecosystem health of the Yellow River delta is0.61, being in good condition; The response index of the Yellow River delta wetland was0.57, close to a positive response; On the whole, the health degree of the Yellow River delta wetland ecological system is0.59, in a sub-health.(5) Combining with the actual situation of the Yellow River delta, the paper analyzes the reason of being the sub-health state of the Yellow River delta wetland. It mainly affected by natural factors such as low background of biodiversity, the Yellow River flow instability, high degree of soil salinity etc. and the artificial factors such as resources over development, environmental pollution, the oil development etc.. And the wetland protection measures are put forward in order to achieve the healthy development of the Yellow River delta wetland ecosystem.