干旱区生态环境知识资源中心

Large-scale engineering projects such as mines and dams cause ecological damage that can persist after construction is complete. The Qinghai-Tibet Railway (QTR) from Golmud to Lhasa was constructed entirely during the Landsat era and began operating in 2006. Therefore, it presents an opportunity for determining both the extent of ecological damage and the time required for some level of natural restoration after a major construction project. We have studied the effect of the QTR construction on vegetation abundance measured using multi-endmember spectral mixture analysis (MESMA) of a time series of Landsat TM/ETM+ images (2001, 2007, 2010) covering the 231km stretch of the railway from south of Kaixinling Station to north of Chumaerhe Station. We found that the effect of QTR construction on vegetation abundance was limited to within 5.0km of the tracks, the largest decrease, 2.9%, occurring within 0.125km of the tracks from 2001 to 2007. There was only 0.4% further decrease in vegetation abundance from 2007 to 2010. We attributed the decrease in vegetation abundance within 0.125km of the tracks mostly to the accumulation of drifting sand resulting from the barrier of the railway and the measures adopted to keep the sand away from the railway under the prevailing west or northwest winds. It appears that in this sensitive cold desert, vegetation damage was limited to the period of railway construction.