黄河源的湿地演变及沙漠化

Evolution of various wetlands and desertification in the source area of the Yellow River

黄河源发育高原草甸、牛轭湖群、沼泽和月牙泉等类型的湿地。100年来,黄河源各种湿地发生了剧烈变化。通过野外调查分析和实验,对黄河源各种湿地演变规律、草原沙漠化及其治理方法进行了探讨。结果表明,近年,高原草甸大面积萎缩、沼泽地大片疏干,而牛轭湖群仍然遵循着裁弯生成、淤积消亡和再裁弯生成的自然演变规律;黄河源大坝建设抬高地下水水位,使黄河源沙漠出现大片月牙泉;黄河源农牧业开发引发大片草原沙漠化,可利用风动沙特性进行治理,如引入河流阻断沙漠入侵,或改变风动沙颗粒级配固定沙丘、绿化沙漠。

Alpine meadows, oxbow lakes, swamps and crescent lakes develop in the source area of the Yellow River on the Qinghai Plateau. In the past century these wetlands have been greatly changed and desertification occurred. The mechanisms of the wetland evolution and strategies for desertification control are studied through field investigation, measurement and experiments. Alpine meadows and swamp land have being greatly shrunk due to drainage by humans. Most of the oxbow lakes are still following the laws of formation due to cutoff of meanders-reduce and disappear following sedimentation-new meanders development. Dam construction and rising of the Erling Lake level enhanced the ground water table, which resulted in a lot of new crescent lakes in the Maduo desert. Desert expansion path can be cut off by introducing streams and desertification can be controlled by changing the size distribution of the sand dunes.