Final Report Summary - ECOLIGHT (Ecological effects of light pollution)
The nighttime environment is being eroded across much of the world through the introduction of artificial lighting from static sources such as streetlights. This has long been known to alter the behaviour of some organisms (such as moths, turtles and seabirds) and more widespread impacts have long been suspected. In turn, these would be predicted to alter population dynamics and the structure and composition of ecological communities. This project conducted the first key experiments to test for such effects. It found that streetlighting changes the abundances of plants, herbivores and predators, that it changes the trends in those abundances, and that it alters community structure and function. These outcomes result from both bottom-up (resource controlled) and top-down (predation controlled) impacts of artificial lighting on species abundances. A variety of approaches to mitigation of these impacts were tested, including dimming lighting, changing the spectrum of lighting, and limiting the timing of lighting. Whilst some of these lessened the impacts of nighttime lighting, none alone was sufficient to remove them altogether. Streetlighting has quite pervasive ecological impacts, and nuanced approaches to such lighting will be required to limit these.