Precipitation impacts on vegetation spring phenology on the Tibetan Plateau
Shen, Miaogen (Chinese Academy of Sciences. Institute of Tibetan Plateau Research)
Piao, Shilong (Chinese Academy of Sciences. Institute of Tibetan Plateau Research)
Cong, Nan (Chinese Academy of Sciences. Institute of Tibetan Plateau Research)
Zhang, Gengxin (Chinese Academy of Sciences. Institute of Tibetan Plateau Research)
Jassens, Ivan A. (University of Antwerp)

Data:	2015
Resum:	The ongoing changes in vegetation spring phenology in temperate/cold regions are widely attributed to temperature. However, in arid/semiarid ecosystems, the correlation between spring temperature and phenology is much less clear. We test the hypothesis that pre cipitation plays an important role in the temperature dependency of phenology in arid/semiarid regions. We therefore investigated the influence of preseason precipitation on satellite-derived estimates of starting date of vegetation growing season (SOS) across the Tibetan Plateau (TP). We observed two clear patterns linking precipitation to SOS. First, SOS is more sensitive to interannual variations in preseason precipitation in more arid than in wetter areas. Spatially, an increase in long-term averaged preseason precipitation of 10 mm corresponds to a decrease in the precipitation sensitivity of SOS by about 0. 01 day mm−1. Second, SOS is more sensitive to variations in preseason temperature in wetter than in dryer areas of the plateau. A spatial increase in precipitation of 10 mm corresponds to an increase in temperature sensitivity of SOS of 0. 25 day °C−1 (0. 25 day SOS advance per 1 °C temperature increase). Those two patterns indicate both direct and indirect impacts of precipitation on SOS on TP. This study suggests a balance between maximizing benefit from the limiting climatic resource and minimizing the risk imposed by other factors. In wetter areas, the lower risk of drought allows greater temperature sensitivity of SOS to maximize the thermal benefit, which is further supported by the weaker interannual partial correlation between growing degree days and preseason precipitation. In more arid areas, maximizing the benefit of water requires greater sensitivity of SOS to precipitation, with reduced sensitivity to temperature. This study highlights the impacts of precipitation on SOS in a large cold and arid/semiarid region and suggests that influences of water should be included in SOS module of terrestrial ecosystem models for drylands.
Ajuts:	European Commission 610028
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Climate change ; Precipitation ; Sensitivity ; Temperature ; Tibetan Plateau ; Vegetation spring phenology
Publicat a:	Global change biology, Vol. 21, Issue 10,(October 2015) , p.3647-3656, ISSN 1365-2486

DOI: 10.1111/gcb.12961

Post-print 38 p, 1.3 MB

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