Dynamic of the Alpine Wetlands and Its Response to Climate Change in the Yarlung Zangbo River Valley in Recent 30 years

The knowledge about dynamic of the alpine wetlands in the Yarlung Zangbo River Valley and its response to climate change would help understand in depth variation of the alpine ecosystem of the Qinghai Tibet Plateau and its response to global climate change. Information dynamics of the wetlands, in area, in the Yarlung Zangbo River Valley was extracted from the remote sensing images and data transmitted from the Landsat and Environmental Satellite #1 in 1980, 1990, 2000 and 2010, and collated with the data obtained in field surveys and the recent 30 years of metereological, hydrological and snow-accumulation data to explore dynamics of wetlands and its response to climate change. Results show that in 2010 alpine wetlands accounted for 3.73% of the whole valley in area, with swampy wetlands being the largest in area and accounting for 59.46% of the total area of the wetlands, followed by riverine wetlands (30.19%), lacustrine wetlands (10.13%) and man-made wetlands (0.23%). In the recent 30 years riverine and lacustrine wetlands have been on a rising trend in area, while swampy wetlands on a reverse trend. The Yarlung Zangbo River Valley has been on a rising trend in annual mean temperature, mean annual maximum temperature, and mean annual minimum temperature, fluctuating greatly or on a slightly, but not apparently, rising trend in precipitation, and a declining trend, though not apparent, in mean relatively humidity. The changes in annual mean temperature and mean annual maximum temperature were significantly related to the changes in the area of the lakes in the valley; the increases in the area of the riverine wetlands and in the length of the main streams of the five major tributaries of the Yarlung Zangbo River were to the changes in annual mean temperature, mean annual maximum temperature, and mean annual minimum temperature; and the area of the swampy wetlands was to the air temperature and annual mean relative humidity. The country's strategy of construction, like building dams and reservoirs is the major driving force of the increase in the area of man-made wetlands in the river valley.