干旱区生态环境知识资源中心

The Tarim and Konqi Rivers in western China have experienced dramatic changes in streamflow and riparian vegetation due to climatic variability, land cover change, and water management including interbasin water transfers. To assess the extent and evolution of vegetation dynamics along these rivers, we use Landsat and MODIS images for land cover classification, spectral mixture analysis, and landscape phenology analysis. From 1998 to 2011, agriculture nearly tripled in extent, from 1376 to 3742 km(2). Natural riparian vegetation persisted in aggregate but experienced losses (to agriculture) in some areas while expanding into barren land elsewhere. Spectral mixture analysis suggests that interbasin water transfers from the Konqi to the Tarim River increased near-channel riparian vegetation on the Tarim at the expense of vegetation on the Konqi. A time-series of MODIS images reveals a pattern of increasing and decreasing greenness across the region, including loss of vegetation in distal regions that were formerly subject to sporadic seasonal flooding but now are cut off from their water supply due to water management. These results suggest that satellite remote sensing may play a valuable role in monitoring the effects of changing land use and hydrology on riparian systems in Central Asia and other arid regions. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)