Spring leaf phenology is highly sensitive to climate change, and earlier spring leaf flushing in temperate and boreal trees is caused by warmer winters and raising spring temperatures, but may in turn affect summer climate and water availability. However, temperature, winter chilling, and photoperiod co-determine the leaf flushing process in ways that vary among species. As a result, species differences in spring phenology advances can be expected, inducing a suite of ecological consequences. But we currently know very little about the temporal change of the interspecific differences in tree phenology at large spatial-temporal scales. In this study, we addressed this gap using multiple statistical analysis methods based on long-term in-situ observations of six, co-existing temperate tree species from 305 sites across central Europe. We measured the changes of the interspecific differences in spring phenology between 1951-1983 and 1984-2016, and assessed the potential underlying mechanisms.
Results/Conclusions
It was found that the advance of leaf flushing was significantly larger in early flushing species than in late flushing species between marginally warming period (1951-1983) and rapidly warming period (1984-2016), indicating an extended interspecific difference in spring phenology. Such phenomenon could be explained by a larger increase in heat requirement and higher photoperiod sensitivity in late flushing species than in early flushing species. Under future climate warming conditions, differences in timing of spring leaf flushing among species may continue to increase, and may result in a change in the order of spring phenology in temperate forests. Therefore, we suggest insightful experimental studies to improve our understanding of shifted interspecific difference in plants phenology, and encourage future research focuses on its potential implications for ecosystem carbon and water balance, as well as plant-animal interactions.