玛多县高原湿地变化及其驱动因素分析

Changes and Driving Factors of Plateau Wetlands in Maduo County

利用青海省三江源区玛多县1990年前后Landsat TM影像、2000年前后Landsat ETM+影像和2010年前后HJ-1A/B卫星影像以及DEM和地形图等,建立玛多县湿地分类体系;目视解译提取湿地信息;利用湿地解译结果和湿地类型面积转移矩阵,对玛多县近20a来湿地面积的变化进行评价;结合气象数据和统计数据初步探讨了玛多县近20a来湿地变化的原因。结果表明,3个时期玛多县湿地总面积分别是3460.250km2、3158.223km2和3398.597km2;湿地面积变化总体趋势是先减后增,前十年沼泽的面积变化最大,其次是湖泊和河流;后十年湖泊面积变化最大,其次是沼泽和河流。影响玛多县湿地变化的自然因素为气温、降水量以及鼠害,人为因素为过度放牧、旅游开发和三江源生态保护工程的实施。

Wetland is a unique and important ecosystem with significant environmental function and ecological benefits on the surface of the earth. In recent years, wetlands have become one of the important worldwide concerned research fields. Owning the world＇ s unique large-area alpine wetland, the source regions of Three Rivers is the ecological barriers of ecological environmental security and regional sustainable development for the middle and lower reaches of rivers in China and Southeast Asian countries. Located in the core area of the Sanjiangyuan National Nature Reserve, Maduo County is the key area of regional ecological environment construction and control. The research results of this study can provide a reference to the wetland protection of the source regions of Three Rivers. The main data sources used in this paper were Landsat TM images around 1990, Landsat ETM＋ images around 2000 and HJ-1 satellite images around 2010 of Maduo county, the source regions of Three Rivers, Qinghai province, as well as other assistant data such as DEM, topographic maps and statistical data and so on. Referencing to the Wetland Convention and wetland classification system in China, considering the actual situation of Maduo County, the wetland classification system of Maduo County was established, in which the wetlands of Maduo County were divided into two major categories, inland natural wetland and artificial wetland. The natural wetlands include river, lake, swamp, flood plain. The artificial wetland was reservoir. According to the established wetland classification system of Maduo County, the information of the wetlands was extracted by artificial visual interpretation and then the wetland distribution maps of Maduo County in 3 periods were made respectively, which were used to evaluate the wetland area changes of Maduo County during the past 20 years. Change detection was made to raster images converted from the interpretation results to get the conversion matrixes of various wetland types during the two periods, and then analyzed the conversion matrixes to evaluate the dynamic changes of wetlands in Maduo County. Combining with meteorological data and statistical data, the reasons for the wetland dynamic changes of Maduo County during the past 20 years were preliminary approached. The results indicated that the total areas of wetlands in Maduo County in 3 periods were 3 460.250 km2, 3 158.223 km2, 3 398.597 km2. The total wetland area of Maduo County decreased firstly and then increased. During the first decade, the change of swamp area was the greatest, followed by that of lake and river, while the change of lake area was the greatest during the second decade, followed by swamp and river. The natural factors affected the change of wetlands of Maduo County, including temperature, rainfall and overgrazing, development of tourism and the implement of the Sanjiangyuan ecological protection projects.