SCIENTIA GEOGRAPHICA SINICA ›› 2017, Vol. 37 ›› Issue (2): 292-300.doi: 10.13249/j.cnki.sgs.2017.02.016

• Orginal Article • Previous Articles     Next Articles

Variations in Alpine Grassland Cover and Its Correlation with Climate Variables on the Qinghai-Tibet Plateau in 1982-2013

Qing Lu1,2,3(), Shaohong Wu1,2, Dongsheng Zhao1,2   

  1. 1. Key Laboratory of Land Surface Pattern and Simulation, Chinese Academy of Sciences, Beijing 100101, China
    2.Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-03-25 Revised:2016-07-05 Online:2017-02-25 Published:2017-02-25
  • Supported by:
    National Natural Science Foundation of China (41571193,41530749), National Science and Technology Support Program of China during the 12th Five-year Plan Period (2013BAC04B02)

Abstract:

The response of structure and function of terrestrial ecosystem to global climate change has become a major point. Vegetation is an essential component of the terrestrial ecosystem which has proved to be sensitive to climate change. Normalized Difference Vegetation Index (NDVI) is widely recognized as a good indicator of vegetation coverage and productivity, has been widely used to indicate vegetation activity and dynamics, also vegetation growth, ecosystem structure and functions respond to climate change. Climate warming has important influence on the vegetation coverage, and alpine grassland is one of the most significant vegetation type on the Qinghai-Tibet Plateau. This study used GIMMS NDVI data sets and climate data from 40 meteorological stations to investigate spatial and temporal variations of alpine grassland cover and the response of NDVI to climatic variables on the Qinghai-Tibet Plateau in 1982-2013. The results showed that the average growing season NDVI is high in the southeast and low in the northwest. As a whole, the alpine grassland cover tended to increase on the Qinghai-Tibet Plateau, with the rate of 0.000 3/a (p<0.05) in the past 32 years. Spatially, the tendency of alpine grassland NDVI showed great heterogeneity, with the significantly NDVI increased mainly distributed in the northeastern part of Qinghai-Tibet Plateau dominated by alpine meadow which approximates to 26.0% (p<0.05) of the total study area. The area with significantly decreased area accounted for 4.7%, mainly emerged in the western part where the grassland was dominated by alpine steppe. In the regional scale, the variation in alpine grassland cover was more closely related to precipitation than other climate factors. The spatial characteristics of the relationship between growing season NDVI and climatic variables were analyzed based on the eco-geographical regions. Significant lagged correlations between precipitation and seasonal NDVI were found for the alpine steppe. The results suggested that precipitation was the key limit variable in the northeastern part of Qinghai-Tibet Plateau with higher annual mean temperature. But in the eastern and central eco-regions with the more rainfall, temperature could limit the growth of grassland vegetation. In the southern plateau with more precipitation and higher temperature compared with other regions, the correlations between alpine grassland cover and climatic factors were significant positive. The change of alpine grassland cover was not significantly relevant to climatic variables in the middle and western part of Qinghai-Tibet Plateau.

Key words: Qinghai-Tibet Plateau, alpine grassland, NDVI, climatic variables, eco-geographical regions

CLC Number: 

  • K903