青藏高原湿地退化的气候背景分析

根据对与青藏高原湿地退化有关的水分、温度和日照等气候背景条件变化趋势及其生态环境效应的研究结果,认为全球和区域气候变化是青藏高原湿地退化的重要原因,其中年度内降水不均匀性的增加、日照时数的延长以及气温与地温的升高对高原湿地水分丧失和退化有着重要的影响,而主要气象要素在中小尺度上时空分配状态的变化和局地气候特征的改变则可能是湿地退化的更直接的原因和动力.湿地水分平衡是研究湿地干涸和退化的关键环节,今后应该加强对高原湿地蒸散发过程和模式的研究才能真正阐明湿地退化的机理.人为因素在湿地退化的过程中起着加速器和倍增器的作用,保护和恢复青藏高原的湿地必须坚决减少和限制人为活动的负面影响.

Analysis of Climatic Background of Wetlands Degradation in the Qinghai-Xizang Plateau

The climatic background and major climate causes for the wetland degradation in the Qinghai - Xizang Plateau were explored through analysis on the trends of precipitation, temperature and sunshine factors and their ecological effects in 4 wetland research sites chosen. The results showed that the initial and prominent occurrence of climate changes was an important cause of wetland ecosystemg degradation in the Qinghai - Xizang Plateau, among the analyzed climate factors, the increased unevenness of annual precipitation, the prolonged sunshine duration and the rise of air and soil temperature have shown important impact on water loses and the degradation of plateau wetlands. Furthermore, because of changes of the temporal and spatial distribution patterns of key cli- mate features on small and meso -scale and local climate characteristics were changed that could be the direct cause and driving force for wetland degradation. Water balance of wetlands is the key in understanding wetland drying up and degradation. Therefore, in future the research emphasis should be on the evapotranspiration process and models of plateau wetlands so as to reveal the mechanism of wetland degradation. Human factor plays the role as amplifiers and accelerators in wetland degradation processes, to restore and rehabilitate wetlands in the Qinghai -Xizang Plateau, it is absolutely necessary to reduce and restrict human activities in wetland areas.