Health Evaluation Of The Wetland Ecosystem In Zoige Plateau District Based On Remote Sensing

The wetland, known as the"kidney of the nature", is one of three greatest ecosystems in the world. It is an ecological landscape with the richest biodiversity in the nature and is one of the environments on which human existence and development depends. Therefore, the protection and the sustained use of the wetland has become a hot and frontier research area in the world which has caught widespread attention from the international society.The Zoige plateau district is the biggest peatery swamp area in China with abundant peatery swamp amounting to 1.3 ~ 1.5 billion tons. The area is located in the source area of the Yangtze River and Yellow River and this special geographical position has established itself as the headwaters self-restraint ground for the Yangtze River and the Yellow River, and also the protection area for ecological function. As a result, the vicissitude of the Zoige plateau district has exerted tremendous influence not only on the improvement and protection of ecological environment in the Yangtze River and the Yellow River areas , but also on the sustainable development of regional economy and society.Besides, the Zoige wetland, a miniature of the wetland landscape in the Qinghai-Tibet Plateau, stands as the most typical wetland ecological landscape in the Qinghai-Tibet Plateau area, thus, the analysis and research on the status-quo and the rules of dynamic change of Zoige wetland, the health evaluation of the wetland ecosystem, as well as the discussion on the influence factors of its dynamic change will be of great significance to the studies on the evolution of the Qinghai-Tibet wetland and even on the Qinghai-Tibet area as a whole.The evaluation of wetland ecosystem aims to diagnose the degree of destruction or degeneration of the wetland system and then send out early warnings to provide the superintendent and the policy-maker with target information so that the wetland resource can be used, protected and managed in a more reasonable way. However, since the factors of the wetland ecosystem health appraisal often have certain spatial characteristics, the traditional analyzing method and the traditional research method are unable to carry out the health evaluation in the terms of space. Their main flaws lie inthe following aspects: the appraisal indexes are hard to quantify by the space; the evaluation unit is difficult to subdivide, the appraisal results are hard to be demonstrated from the space and the charting, the dynamic evaluation and the contrast analysis are difficult to carry out. Therefore, by making full use of the remote sensing and the GIS technology, we can acquire the wetland information, analyze the spatial characteristics, and output the achievement, which will be beneficial to the wetland ecosystem health evaluation.By taking advantage of RS and GIS technology and former research achievement, together with field investigation, this paper analyzes and studies the rules of wetland growth and development from the environmental factors for wetland formation, including both natural and human factors, and then incorporates these rules into the wetland ecological environment health evaluation and the research of driving factors of the dynamic change.The detail technical method is: applying the remote sensing data of 1976 MSS, 1994 TM, 2000 ETM, referring to the relevant materials, and establishing the interpretation symbols so as to obtain the land utilization\ land cover information for each period; using 1:25 ten thousand DEM data with the help of ArcGIS software to realize small watershed in the Zoige plateau .According to the evaluation principle of wetland ecosystem health appraisal, we take small watershed as an evaluation unit and select the pressure-state-response frame model to evaluate the wetland ecosystem and combine various methods such as measurable geography, mathematical statistic and mathematical model by meeting the need of the model, so as to obtain the required factors for the wetland ecosystem health appraisal. Then in light of the regional characteristics of Zoige, we apply the expert experience rule to bestow on to the different index factors by the weight through the weighting summation method, thus, we can obtain the appraisal results for wetland ecosystem health evaluation of the Zoige district in 1994 and 2000, and we can further discuss the environmental change of the wetland ecosystem from 1994 to 2000.According to the wetland ecosystem health evaluation of the Zoige district in 1994 and 2000, including both the natural factors and the human factors, we probe into the changing factors of the wetland ecosystem, namely, the driving influence analysis.This article shows that:1. As far as the research results of this article is concerned, the appraisal model, the appraisal method as well as the processing of the appraisal indexes are of practical significance to the wetland ecosystem health evaluation for Zoige district.2. Applying RS and GIS technology, we obtained the land utilization \ land cover information of the Zoige district. The results indicate that the fragmentation phenomenon of wetland landscape is evident, the wetland degenerates seriously, and the Sandification of grassland continues.3. The wetland ecosystem health evaluation system and the evaluation model need to be further improved.4. We should strengthen the protection and the reasonable use of the wetland in the Zoige, to make sure the Zoige wetland-"kidney of the Earth"-plays a vital role in safeguarding the ecological security of the mother river Yellow River, in promoting the economy in multi-national areas, and in maintaining social stability of the Qinghai-Tibet Area.