Dynamic Monitoring of Fractional Vegetation Cover in Fuxian Lake Watershed Based on Multi-Temporal Landsat 5/8 Images

Fractional vegetation cover (FVC) is an important indicator of terrestrial vegetation density and provides basic dynamic information of regional eco-environment for research on global change. This paper uses dimidiate pixel model and 11 scenes of Landsat 5/8 images from 1974 to 2-14 and DEM data for monitoring of FVC in Fuxian Lake watershed. Combining geographical information, administrative division and industrial sectors data, vegetation cover for different slope gradients is analyzed. Results show that (1) in the past 40 years, the area of grade Ⅰ FVC fluctuates very little in Fuxian Lake watershed, as opposed to large fluctuation of area of grade II-IV FVC; (2) Bare land and extremely low vegetation cover are mainly distributed in areas with small slope gradient and mild terrain. In steep terrain, moderate, moderate-to-high, and high vegetation cover are dominant; (3) Across the years, the area of grade I FVC is the largest. In 1974, 1977, 1989 and 1996, the area of grade II and III FVC is larger, and that of grade IV and V FVC is smaller. After 2000, the area of grade II, III and IV FVC is smaller. In 2006, 2009, 2012 and 2014, the area of grade IV and V FVC is larger, while that of grade II and III is smaller.