基于MODIS数据的黄河流域草地景观演变分析

Analysis of Grassland Landscape Evolution in the Yellow River Basin Based on MODIS Data

  • 摘要: 基于MODIS土地利用数据及植被数据,采用斜率分析以及相关分析等方法,对黄河流域草地景观的面积变化、时空演变特征以及对整个流域景观的结构与功能的响应进行深入探讨.结果表明:近13 a间黄河流域草地景观面积下降明显,其中向农地转移最为显著;近13 a间流域草地景观西南和中东部地区年均植被覆盖指数较高,北部与西北部较低.中东部年均植被覆盖指数增长明显,部分地区增长率达到了0.08/10a;近13 a间黄河流域草地景观年均植被覆盖指数呈一定的下降趋势,趋势并不显著,月均植被覆盖指数季节性变化趋势明显,夏秋较高,冬春较低,8月植被覆盖指数最高,1月位最低;流域草地景观与滞后1月的气温、降水之间存在响应关系最为明显;流域草地景观的面积变化对黄河流域生态系统存在较为明显的响应.草地景观面积变化与流域聚集性指数、生物多样性指数均呈显著的负相关,随着草地景观面积的不断缩小,流域整体景观格局的聚集性不断增强,生物多样性指数逐步下降,流域生态质量有所降低.

     

    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.

     

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