The effects of over-illumination on other organisms are poorly understood. Biologists have, however, come to a consensus on the following points:
- Artificial lighting disrupts biological rhythms by resetting the hormonal processes that control the internal clocks of plants and animals.
- Lucifugous species, which are generally those that are nocturnal or live beneath the ground, bark, etc., attempt to escape from light even at night.
- Over-illumination in cities and along the coast causes migrating birds to become disoriented. Large structures, such as bridges and skyscrapers, then kill birds by the millions.
- Most nocturnal animals are disturbed by artificial lighting and sometimes disappear completely from suitable but illuminated habitats.
- Many insects are attracted to light, which results in huge numbers being killed by unprotected bulbs and predators that take advantage of light sources to locate prey. Both factors bring about a disruption in the food chain.
For more information, consult the article entitled Ecological Light Pollution, which is a literature review on the subject and was published by the Ecological Society of America, or the book entitled "Ecology of the Night".