Abstract:
Based on MODIS land use types and vegetation data, the slope and correlation analysis were used to discuss the area change, temporal and spatial evolution characteristics of grassland landscape and the response to the structure and function of the whole river basin. During the past 13 years, the landscape area of grassland in the Yellow River basin decreased obviously.The most significant shift was to the agricultural land. The average annual NDVI in the Southwest and Middle Eastern areas of the grassland landscape in the past 13 years were higher, and the North and Northwest were lower. The growths of average annual NDVI in the eastern part of grassland was obvious at the rate of 0.08/10a. The average NDVI of the grassland during the period showed a flat decreasing trend, the seasonal variation trend of NDVI was obvious, the summer and autumn were higher, the winter and spring were lower,and NDVI was the highest in August,but lowest in January. The area change of grassland had an obvious response to the ecological system in the Yellow River basin. There was a significant negative correlation between the area change of grassland and aggregation index and biodiversity diversity index. With the decrease of grassland landscape area, the aggregation of the overall landscape was increasing and the biodiversity index decreased gradually indicating ecological quality reduced.