The Temperature Response of Spring Phenology Benefit More in Habitats with Higher Predictable Temperature

The timing of plant spring phenological events such as leaf-unfolding day shows large year-to-year variation. The yearly variation is assumed to benefit plants by avoiding environmental stresses such as frost damage, and/or utilizing more efficiently environmental resources and conditions. However, it is often difficult to assess quantitatively the benefit due to timing change of phenology events. In this study, we examined 10060 time series of first leaf-unfolding day (FLD) in 8 species from PEP725 in comparison with a set of simulated phenological data by removing the temperature effects. Our results show that 49.3% individuals gain more thermal energy (accumulated temperature) without suffering more frost risk, while a proportion of 25.3% individuals lost thermal energy but also without avoiding frost risk. More importantly, we found that the benefit by responding yearly temperature change increased with the increase of the temperature predictability during the phenological period. This study suggests that the year-to-year variation of phenological timing in responding temperature change benefits plants, in particular under the environments with high predictability of the temperature in the phenological period.