| The Yellow River source, located in Qinghai-Tibet Plateau the frigid and dry area and semi-arid area, is the fragility subarea of Chinese ecological environment. Owing to natural and human-caused disturbance factors, the complex and varied ecological composition and special environment conditions make its ecosystem more fragile and mutable. As the important water source supplying area of Yellow River, known as "impounding reservoir" and "ecological source", Maqu, underneath Yellow River source, is the frontiers of ecology and ecological securities. With the global warming and human interference phenomenon getting worse and worse, in Maqu, there have been phenomena of constantly shrinking wetlands area, serious soil erosion, deterioration of grasslands, intensive desertification, and water yield in the upper reaches of the Yellow River has been decreasing in recent years. The effect of Maqu wetlands, plateau’s water tower, is becoming weaker and weaker, and Ecological protection form remains grim.The research on yellow river source Maqu alpine wetland degradation and restoration suitability assessment was almost based on the principium of the landscape ecology, the model utilizes Geographic Information System (GIS) and Remote Sense (RS) to analyze temporal dynamics in spatial landscape pattern and ecological degradation of20years. Furthermore, the driving force of the wetland landscape dynamic change for12years in the Maqu alpine wetlands is analyzed as well. With the well combination of suitability evaluation model and wetland degradation status, Maqu alpine wetland restoration suitability evaluation model is built. Restoration suitability evaluation model with consideration of geographical factors and human factors may prove useful to restoration planners as they attempt to identify restoration sites. Maqu alpine wetland restoration model is established and applied in sites identifying and decision-supporting in study area. This paper presents a practical restoration suitability evaluation model identifying priority sites and discusses its application to the alpine wetland in Maqu. The main work and conclusions in this paper included:1. The spatial landscape pattern dynamic of Maqu alpine wetland was analyzes. Using the method of transfer matrix, we can analyze the relationship of transfer trends and quantities between Wetland landscape and non-wetland landscape from1990to2010. The total area of Maqu alpine wetland had a reduction for736.96km2while wetland rate declined from21.84%to14.16%. Area of Marsh wetland has decreased sharply while the subalpine meadow showed an expansion to the Northeast. We also take landscape pattern index as the method to study the dynamical changes in the past20years. The landscape pattern index shows the characteristic of broken Landscape, complicated shape and discrete distribution in study area. The study also shows the Phenomenon that there are great changes in area and also in spatial pattern of Maqu alpine wetland.2. Changes in Maqu alpine wetland landscape quality were analyzed. In this research, we built the relationship between NDVI and the total vegetation biomass. The results showed that from2000to2011, NDVI has a significant positive correlation with vegetation cover, vegetation height and vegetation dry weight. We found that wetland in several places has degraded after analyzing the dynamic changes of annual average NDVI value from2000to2011. The decreasing average annual NDVI value and the declining quality indicated the degradation of Maqu alpine wetland. After analyzing the NDVI cumulative changes, we found that wetlands in Manrima and Hequmachang which is staying the status of frequent fluctuations have a great change both in spatial landscape pattern and in quantity. Through the changes of vegetation cover, we found that annual mean values of vegetation cover in Manrima, Qihama, Cairima, Maqu were decreased, the wetlands were degenerated, and vegetation cover of Mucihe in the alpine areas of the southeast was descended obviously. That the values of cumulative vegetation cover in Nima, Awancang and Maqu southeast border with Sichuan province were large showed that there had actively varied conditions.3. The restoration suitability evaluation model of Maqu alpine wetland was established. We evaluated8criteria from two main interference factors of physical geography and humanity which were designed to identify and prioritize sites for Maqu alpine wetland restoration. The index layers were selected as8criteria:tomography (DEM and slope), landscape types, soil types, vegetation, hydrological conditions, resident interference and road interference. Wetland suitability evaluation model was built using the method of Analytic Hierarchy Process (AHP). Results show that the suitable areas of study area are1816.97km2, accounting for18.94%of its total area. After combining Maqu alpine wetland suitability evaluation model and Maqu alpine wetland degradation status data, wetland restoration suitability evaluation model was established. The result run by wetland restoration suitability evaluation model provided the high priority location and suggested that wetlands in Cairima and Manrima should be given the priority being firstly restored in the case of limited condition with time, manpower and funds. |
PDF Full Text Request