Continuous but diverse advancement of spring summer phenology in response to climate warming across the Qinghai Tibetan Plateau
Abstract The Qinghai Tibetan Plateau (QTP) is more vulnerable and sensitive to climate change than many other regions worldwide because of its high altitude, permafrost geography, and harsh physical environment. As a sensitive bio indicator of climate change, plant phenology shift in this region has been intensively studied during the recent decades, primarily based on satellite retrieved data. However, great controversy still exists regarding the change in direction and magnitudes of spring summer phenology. Based on a large number (11,000+ records) of long term and continuous ground observational data for various plant species, our study intended to more comprehensively assess the changing trends of spring summer phenology and their relationships with climatic change across the QTP. The results indicated a continuous advancement 2.69 days decade 1 in spring summer phenology from 1981 to 2011, with an even more rapid advancement during 2000 2011 3.13 days decade 1 which provided new field evidence for continuous advancement in spring summer phenology across the QTP. However, diverse advancing rates in spring summer phenology were observed for different vegetation types, thermal conditions, and seasons. The advancing trends matched well with the difference in sensitivity of spring summer phenology to increasing temperature, implying that the sensitivity of phenology to temperature was one of the major factors influencing spring summer phenology shifts. Besides, increased precipitation could advance the spring summer phenology. The response of spring summer phenology to temperature tended to be stronger from east to west across all species, while the response to precipitation showed no consistent spatial pattern.