Abstract
Vegetation phenology in spring has substantially advanced under climate warming, consequently shifting the seasonality of ecosystem process and altering biosphere–atmosphere feedbacks. However, whether and to what extent photoperiod (i.e., daylength) affects the phenological advancement is unclear, leading to large uncertainties in projecting future phenological changes. Here we examined the photoperiod effect on spring phenology at a regional scale using in situ observation of six deciduous tree species from the Pan European Phenological Network during 1980–2016. We disentangled the photoperiod effect from the temperature effect (i.e., forcing and chilling) by utilizing the unique topography of the northern Alps of Europe (i.e., varying daylength but uniform temperature distribution across latitudes) and examining phenological changes across latitudes. We found prominent photoperiod-induced shifts in spring leaf-out across latitudes (up to 1.7 days per latitudinal degree). Photoperiod regulates spring phenology by delaying early leaf-out and advancing late leaf-out caused by temperature variations. Based on these findings, we proposed two phenological models that consider the photoperiod effect through different mechanisms and compared them with a chilling model. We found that photoperiod regulation would slow down the advance in spring leaf-out under projected climate warming and thus mitigate the increasing frost risk in spring that deciduous forests will face in the future. Our findings identify photoperiod as a critical but understudied factor influencing spring phenology, suggesting that the responses of terrestrial ecosystem processes to climate warming are likely to be overestimated without adequately considering the photoperiod effect.
| Original language | English |
|---|---|
| Pages (from-to) | 2914-2927 |
| Number of pages | 14 |
| Journal | Global Change Biology |
| Volume | 27 |
| Issue number | 12 |
| DOIs | |
| State | Published - Jun 2021 |
Funding
This work was supported by the NASA FINESST Program (80NSSC19K1356) and the College of Liberal Arts and Science’s (LAS) Dean’s Emerging Faculty Leaders award at the Iowa State University. A.D.R. acknowledges support from NSF’s Macrosystems Biology program (award EF-1702697). J.P. acknowledges support from European Research Council grant ERC-SyG-2013-610028. J.M. was supported by the Terrestrial Ecosystem Science Scientific Focus Area (TES SFA) project funded by the US Department of Energy, Office of Science, Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the DOE under contract DE-AC05-1008 00OR22725. We acknowledge the E-OBS dataset from the EU-FP6 project UERRA (http://www.uerra.eu) and the Copernicus Climate Change Service, and the data providers in the ECA&D project (https://www.ecad.eu). We also acknowledge all members of the PEP725 project for providing the phenological data. This work was supported by the NASA FINESST Program (80NSSC19K1356) and the College of Liberal Arts and Science’s (LAS) Dean’s Emerging Faculty Leaders award at the Iowa State University. A.D.R. acknowledges support from NSF’s Macrosystems Biology program (award EF‐1702697). J.P. acknowledges support from European Research Council grant ERC‐SyG‐2013‐610028. J.M. was supported by the Terrestrial Ecosystem Science Scientific Focus Area (TES SFA) project funded by the US Department of Energy, Office of Science, Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT‐Battelle, LLC, for the DOE under contract DE‐AC05‐1008 00OR22725. We acknowledge the E‐OBS dataset from the EU‐FP6 project UERRA ( http://www.uerra.eu ) and the Copernicus Climate Change Service, and the data providers in the ECA&D project ( https://www.ecad.eu ). We also acknowledge all members of the PEP725 project for providing the phenological data.
Keywords
- chilling
- climate change
- daylength
- phenological model
- spring leaf-out
- temperature
