Assessing Environmental Quality Dynamics and its Response to Vegetation Change in the Upper Minjiang River Watershed by Modis and Spot Products.

The upper Minjiang River watershed provides critical ecological services to sustain downstream populated cities in the Chengdu plain of China. Understanding its environmental quality dynamics and associated response to vegetation change can help with vegetation restoration program designs for better protection of watershed ecosystems. In this study, five environmental quality indices were first calculated to evaluate environmental quality dynamics by use of MODIS MCD12Q1 and SPOT NDVI products. Then, responses of environment quality to vegetation change from 2001 to 2017 were assessed. Key findings were: (1) there was a slight decline in the integrated ecological index (EI), indicating a relatively stable environment quality in the study watershed; (2) EI had significant positive correlations with forest land or grassland area, while its relationship with the sparse woodland area was significantly negative; and (3) environmental quality changes were mainly driven by soil erosion, earthquake, landslides, vegetation change, and human activities. This study has important implications for the protection of environmental quality by vegetation restoration.