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 (−2.69daysdecade−1) in spring-summer phenology from 1981 to 2011, with an even more rapid advancement during 2000–2011 (−3.13daysdecade−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.