title: Plant phenological synchrony increases under rapid within-spring warming.
abstract: Phenological synchrony influences many ecological processes. Recent climate change has altered the synchrony of phenology, but little is known about the underlying mechanisms. Here using in situ phenological records from Europe, we found that the standard deviation (SD, as a measure of synchrony) of first leafing day (FLD) and the SD of first flowering day (FFD) among local plants were significantly smaller in the years and/or in the regions with a more rapid within-spring warming speed (WWS, the linear slope of the daily mean temperature against the days during spring, in (o)C/day) with correlation coefficients of -0.75 and -0.48 for FLD and -0.55 and -0.23 for FFD. We further found that the SDs of temperature sensitivity of local plants were smaller under the rapid WWS conditions with correlation coefficients of -0.46 and -0.33 for FLD and FFD respectively. This study provides the first evidence that the within-season rate of change of the temperature but not the magnitude determines plant phenological synchrony. It implies that temporally, the asymmetric seasonal climatic warming may decrease the synchrony via increasing WWS, especially in arctic regions; spatially, plants in coastal and low latitude areas with low WWS would have more diverse spring phenological traits.
authors.affiliation: State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, 100875, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, 100875, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Chen
mesh_terms: D000704:Analysis of Variance; D001110:Arctic Regions; D057231:Climate Change; D066264:Datasets as Topic; D004463:Ecology; D005060:Europe; D035264:Flowers / Q000502:physiology*; D015233:Models, Statistical; D063245:Plant Development / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology*; D012621:Seasons; D062211:Spatio-Temporal Analysis; D013696:Temperature