Natural cycles of light and darkness structure the environment of the majority of eukaryotic organisms. Artificial light can influence myriad biological processes, including sleep, metabolism, germination and flowering. It can alter the distribution and abundance of organisms and disrupt predator–prey relationships. In fact, such effects are probably pervasive, given the importance of natural-light cycles on circadian clocks and organisms’ physiological responses to day length.
Many animals regulate their activity over a 24-h sleep–wake cycle, concentrating their peak periods of activity to coincide with the hours of daylight, darkness, or twilight, or using different periods of light and darkness in more complex ways. These behavioural differences, which are in themselves functional traits, are associated with suites of physiological and morphological adaptations with implications for the ecological roles of species.
Our research considers a wide range of temporal issues related to artificial light at night such as time partitioning, dark repair and recovery and duration of artificial light at night.