Artificial Light at Night Advances Spring Phenology in the United States

Plant phenology is closely related to light availability as diurnal and seasonal cycles are essential environmental cues for organizing bio-ecological processes. The natural of light, however, have been dramatically disrupted by artificial at night (ALAN) due recent urbanization. influence on plant ALAN its spatial variation remain largely unknown. By analyzing satellite data intensity across the United States, here, we showed that tended advance start date growing season (SOS), although overall response SOS was relatively weak compared with other potential factors (e.g., preseason temperature). phenological impact a spatially divergent pattern, whereby mainly advanced climatically moderate regions within States Virginia), while effect insignificant or even reversed very cold Minnesota) hot Florida). Such pattern attributable high sensitivity chilling insufficiency, where advancing only triggered premise days exceeded certain threshold. Other mechanisms may also play part, such interplay among chilling, forcing photoperiod difference in species life strategies. Besides, urban areas ecosystems were found suffer from similar magnitudes ALAN, albeit much higher baseline areas. Our findings shed new relation space cues, which beneficial better understanding projection changes under warming urbanizing future.