Author(s): Guotao Dong; Feng Feng; Suzhen Dang; Xiaohui Jiang; Hongmou He
Linked Author(s): Feng Feng
Keywords: Vegetation fractional coverage; Water transferring; Yellow River delta; Remote sensing
Abstract: Diaokou River is one of the old courses of the Yellow River access to the sea before 1976 and its estuarine delta is an important part of National Nature Reserve of Yellow River Delta. To recover the increasingly degenerated environment of the wetland in the estuarine delta of Diaokou River，the Yellow River Conservancy Commission decided the ecological water supplement to the wetland during the water and sediment regulation period in 2010. In this study，we analyzed the vegetation coverage changes before and after the ecological water supplement. Using HJ-1B CCD data (acquired on Sep. 9, 2009 and on Sep. 6, 2011), which was similar to Landsat TM data to explicit enough to meet for monitoring vegetation coverage, to monitor the dynamic vegetation coverage changes of Diaokou River in national reserve of Yellow River Delta. The Normalized Difference Vegetation Index (NDVI) data were used to extract the series characteristics of vegetation changes. The result shows that the ecological efficiency from the ecological water supplement to Diaokou River is remarkable. There was an increasing trend of total vegetation coverage from 2009 to 2011 and the mean FVC value increased from 0. 531 to 0. 597 before and after supplement ecological water. The area of poor vegetation had greatly decreased, which was decreased 63. 83 km2, accounting for 15. 1% of the whole area. Level 5 and Level 4 which represented high coverage both showed increasing trends, and percentage was from 46. 9% to 54. 3% . The spatial variations of the FVC were intensively affected by the moisture. The western portion and areas along the river bank in wetland protection zone changed to higher FVC obviously. The water transferring had no distinct effect on FVC outside of wetland protection zone. There was no significant different in precipitation and temperature for two years, which demonstrated the ecological water supplement was the main reason for the improved FVC.
Year: 2013