石羊河下游生态输水对区域生态环境的影响

通过遥感(RS)与地理信息系统(GIS)技术手段,选用2001、2006、2009年和2015年的Landsat TM/OLI遥感影像作为数据源,通过提取植被覆盖度指数(VFC)、沙漠化指数(DI)、土壤盐渍化指数(MSI)、土壤湿度(WI)、绿度指数(GVI)和地表温度指数(LST)等指标,构建遥感生态综合指数(RSECI),对生态输水项目实施以来石羊河下游生态环境状况进行定性和定量评估。结果表明:(1)从时间变化来看,RSECI值从2001年的0.42上升到2015年的0.48,这表明2015年的生态环境比2001年显著改善。从不同时段分区面积变化情况来看,2001—2006,2006—2009,2009—2015年3个时段内,生态环境改善的区域面积分别为357.08、397.77、1 637.98 km~2,而恶化的区域面积分别为100.24、1 386.14、398.83 km~2。这表明在实施生态输水初期,石羊河下游的生态环境没有显著改善,且绿洲部分地区还有恶化趋势,但在生态输水持续进行后,石羊河下游绿洲的环境得到显著改善。(2)从空间变化来看,绿洲边缘沙漠区的环境显著改善,绿洲内部生态环境总体上呈下降趋势。这说明在2001—2015年间,石羊河下游的生态环境变化状况具有明显的空间异质性。综上所述,随着相关生态治理项目的实施,虽然石羊河下游的总体生态环境状况得到显著改善,但绿洲内部区域的生态环境恶化趋势却不容忽视,当地的生态环境治理工作仍然任重道远。

The impact of ecological water transport on the regional ecological environment in the lower Shiyang River

This paper uses Landsat TM/OLI remote sensing images from 2001, 2006, 2009, and 2015 as data sources through Remote Sensing (RS) and Geographic Information System (GIS) techniques, by extracting vegetation coverage index (VFC), desertification index (DI), soil salinity index (MSI), soil moisture (WI), greenness index (GVI), and surface temperature index (LST), etc., to construct a Remote Sensing Ecological Environment Comprehensive Index (RSECI), and the ecological environment of the lower the Shiyang River was qualitatively and quantitatively evaluated since the implementation of the ecological water transfer project. The results showed that: (1) From the temporal change, the RSECI value increased from 0.42 in 2001 to 0.48 in 2015. This showed that the ecological environment in 2015 improved significantly compared to that in 2001. In addition, in the initial stage of ecological water transport, the ecological environment in the lower Shiyang River had not improved significantly, and some areas in the oasis deteriorated. However, when the ecological water transport continued, the environment of the oasis in the lower reaches of the Shiyang River had been significantly improved. (2) From the perspective of spatial changes, the environment in the desert area of the oasis was significantly improved, and the ecological environment inside the oasis was generally declining. This showed that during the period of 2001-2015, the ecological environment changed in the lower reaches of the Shiyang River have obvious spatial heterogeneity. In summary, although the overall ecological environment of the lower reaches of the Shiyang River had been significantly improved with the implementation of relevant ecological treatment projects, the deterioration of the ecological environment within the oasis cannot be ignored, and the local ecological environment management still has a long way to go.