江河源区生态环境范围的探讨

摘要

Based on geographical and hydrological extents delimited, four principles are identified, asthe bases for delineating the ranges of the source regions of the Yangtze and Yellow rivers in thepaper. According to the comprehensive analysis of topographical characteristics, climate conditions,vegetation distribution and hydrological features, the source region ranges for eco-environmentalstudy are defined. The eastern boundary point is Dari hydrological station in the upper reach of theYellow River. The watershed above Dari hydrological station is the source region of the YellowRiver which drains an area of 4.49 × 104 km2. Natural environment is characterized by the majortopographical types of plateau lakes and marshland, gentle landforms, alpine cold semi-arid climate,and steppe and meadow vegetation in the source region of the Yellow River. The eastern boundarypoint is the convergent site of the Nieqiaqu and the Tongtian River in the upstream of the YangtzeRiver. The watershed above the convergent site is the source region of the Yangtze River, with awatershed area of 12.24× 104 km2. Hills and alpine plain topography, gentle terrain, alpine cold aridand semi-arid climate, and alpine cold grassland and meadow are natural conditions in the sourceregion of the Yangtze River.