Abstract: The spatio-temporal variation trend of natural vegetation in arid and semi-arid region,the Aksu River basin in Xinjiang Autonomous Region of China as a case study in this paper, and its response to ecological water transport are examined according the GF remote sensing images and monitoring data.Results unveiled that the vegetation ecological system kept stable with the natural vegetation area expanding gradually from 2015 to 2020, in particular, the area of Populus Euphratica forest and shrubs increasing by 237.65 km² and 784.36 km², respectively. The results of annual transfer matrix also showed that the area of stable Populus Euphratica forest and shrubs widened gradually. From 2015 to 2020, the annual NDVI values of four key areas of natural vegetation showed an apparent upward trend. Especially, the NDVI values of Eichmann Lake Wetland and the fringe of the First Division of Xinjiang Production and Construction Corps climbed by 0.12-0.15, indicating an initial effect of ecological water transport. According to seasonal variation of natural vegetation area and NDVI, the response time of natural vegetation to ecological water transport is about one month;however,the response time varies in annual,seasonal and spatial scales depending on the vegetation types. The Populus Euphratica forest responses notably and the quickest to ecological water transport. The research findings are of guiding significance for the restoration of surrounding vegetation,regional water resource allocation,and ecological water demand dispatching in the Aksu River irrigation area.

Key words: natural vegetation, spatio-temporal evolution, ecological water transport, response process, Aksu River Basin