Abstract
Satellite-derived Normalized Difference Vegetation Index (NDVI), a proxy of vegetation productivity, is known to be correlated with temperature in northern ecosystems. This relationship, however, may change over time following alternations in other environmental factors. Here we show that above 30°N, the strength of the relationship between the interannual variability of growing season NDVI and temperature (partial correlation coefficient RNDVI-GT) declined substantially between 1982 and 2011. This decrease in RNDVI-GT is mainly observed in temperate and arctic ecosystems, and is also partly reproduced by process-based ecosystem model results. In the temperate ecosystem, the decrease in RNDVI-GT coincides with an increase in drought. In the arctic ecosystem, it may be related to a nonlinear response of photosynthesis to temperature, increase of hot extreme days and shrub expansion over grass-dominated tundra. Our results caution the use of results from interannual time scales to constrain the decadal response of plants to ongoing warming.
Original language | English |
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Article number | 5018 |
Journal | Nature Communications |
Volume | 5 |
DOIs | |
State | Published - Oct 16 2014 |
Funding
This study was supported by a Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No.XDB03030404), the National Basic Research Program of China (grant number 2013CB956303), Chinese Ministry of Environmental Protection Grant (201209031), National Natural Science Foundation of China (41125004 and 31321061) and the 111 Project(B14001). J.M. and X.S. are supported by the US Department of Energy (DOE), Office of Science, Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-BATTELLE for DOE under contract DE-AC05-00OR22725.