VARIATIONS IN GRASSLAND VEGETATION COVER IN RELATION TO CLIMATIC FACTORS ON THE TIBETAN PLATEAU
VARIATIONS IN GRASSLAND VEGETATION COVER IN RELATION TO CLIMATIC FACTORS ON THE TIBETAN PLATEAU
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DOI：
10.17521/cjpe.2006.0001
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发表时间：
2006
影响因子：
2.7
通讯作者：
Yang Yuan
中科院分区：
文献类型：
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作者：
Yang Yuan
为了加深对气候变化对草地生态系统影响的认识，我们利用1982-1999年的归一化植被指数(NDVI)时间序列和历史气候资料，分析了青藏高原草地植被覆盖的年际变化，并探讨了NDVI与气候因子的关系。在整个生长季，植被指数显著增加，增幅为0.41%a-1，幅度为0.001 0 a-1(p=0.015)。生长季NDVI的增加是生长季提前和植被活动加速的结果。春季NDVI值增幅最大，为0.92%a-1，幅度为0.001 4 a-1。夏季NDVI值的增加是生长季NDVI值增加的第二贡献者，其比值为0.37%a-1，幅度为0.001 0a-1。春季，高寒草原(高寒草甸和高寒草原)和温带草原的植被指数显著增加(p<0.01；p=0.001；p=0.002)。夏季，高寒草甸植被指数显著增加(p=0.027)。而高寒草原和温带草原的植被指数增加幅度不大(p=0.106；p=0.087)。秋季，三种草地均未见明显增加(p=0.585；p=0.461；p=0.143)。春季，三种草地NDVI的增加与气温的升高相对应。夏季高寒草原(高寒草甸和高寒草原)春季NDVI与温度相关，对降水敏感。然而，在温带草原，NDVI与气候因子之间没有显著的统计关系。高寒草原(高寒草甸、高寒草原)降水量与NDVI之间存在显著的滞后相关。
To advance our understanding of the effects of climate change on grassland ecosystems, we used a time series (1982-1999) data set of the Normalized Difference Vegetation Index (NDVI) together with historical climate data to analyze interannual variations in grassland vegetation cover and explore the relationships between NDVI and climatic factors on the grasslands of the Tibetan Plateau. The NDVI increased significantly by a ratio of 0.41% a -1 and a magnitude of 0.001 0 a -1 during the growing season (p=0.015). An increase in NDVI during the growing season resulted from both the advanced growing season and accelerated vegetation activity. The largest NDVI increase was in the spring with a ratio of 0.92% a -1 and a magnitude of 0.001 4 a -1 . The NDVI increase in the summer was a secondary contributor to the NDVI increase during the growing season with a ratio of 0.37% a -1 and a magnitude of 0.001 0 a -1 . In the spring, the NDVI increased significantly in the alpine grasslands (alpine meadow and alpine steppe) and temperate steppe (p 0.01 ; p= 0.001 ; p=0.002). During the summer, a significant NDVI increase was found in alpine meadows (p= 0.027 ). However, the NDVI increase in alpine and temperate steppe was not significant (p=0.106; p=0.087 ). In the autumn, no significant increase was found in the three grasslands (p=0.585; p= 0.461 ; p=0.143). In the spring, the NDVI increase in three grasslands was corresponded to an increase in temperature. In the summer, the NDVI was related to temperature and sensitive to precipitation in the spring in the alpine grasslands (alpine meadow and alpine steppe). However, no significant statistical relationship was found between NDVI and climatic factors in temperate steppe. Significant lagged correlations between precipitation and NDVI were found for alpine grasslands (alpine meadow, alpine steppe).