Evaluation of ecological restoration through vegetation patterns in the lower Tarim River, China with MODIS NDVI data

The lower Tarim River had dried up nearly 30 years before an ecological water diversion project (EWDP) for ecological restoration was implemented in 2000. Since then, eight intermittent water deliveries have been carried out for restoring this seriously degraded riparian ecosystem. To evaluate the efficacy and effectiveness of these operations, the Normalized Difference Vegetation Index (NDVI) data set derived from bands 1 and 2 of the MODerate-resolution Imaging Spectroradiometer (MODIS) on board NASA's Terra satellite was applied to identify the spatial and temporal variations of vegetation cover along the river corridor with about 320 km in length. The goal of this study is thus to generate seasonally integrated NDVI (SINDVI) in growing seasons between April and October so as to investigate a general vegetation patterns as well as examine the inter-annual SINDVI for discerning the status of ecosystem restoration. The spatiotemporal variations of vegetation cover were further characterized based on those inter-annual SINDVI data with the aid of Coefficient of Variation (CoV). Research findings indicate that ecosystem integrity was strengthened after a series of water diversion efforts and groundwater table control in the past few years. As the degree of ecosystem restoration is in progress, continuous operation of water diversion is still necessary in response to the needs for restoration of dense vegetation in the riparian buffer within this arid or semi-arid region. (C) 2010 Elsevier B.V. All rights reserved.