Since time immemorial, the Earth has been subject to the alternation of day and night, and living creatures have adapted to this circumstance. This rhythm and the seasonal changes in the length of the day in our latitudes are important sources of information for many organisms. When that changes as a result of the use of artificial light during phases of natural darkness, impacts on vital functions are inevitable.
Mammals, birds, insects, amphibians, reptiles, fish, plants and the structure and function of ecosystems can be negatively affected by artificial light.
Besides changes to physiological processes, there are also behavioural changes, which can relate to such aspects as attraction and rejection and to disturbed orientation.
Reproduction, development, communication, foraging, predator-prey relationships and radius of action are affected as a result.
The effects of light pollution range from changes in the mix of species within communities to the extinction of isolated populations, particularly in the case of sedentary, specialised and endangered species.