When most people think of light pollution, they usually think of human health and energy conservation, but light pollution affects much more. Pollinators, mammals, birds, plants, amphibians, and others are all affected by the unnecessary amounts of light filling up our planet. The many species on our planet use the sun as their clock; both the length of days and of the seasons affect how species live. When tree leaves change in the fall, they do not change because of the cold air, but because of the steadily decreasing amounts of light throughout the season. Pollinators and other insects are heavily affected by even the smallest amounts of light pollution, as their vision relies on different and more sensitive scales than our own. Many species of amphibians, reptiles and birds use light amounts as their triggers for migration, mating, feeding seasons and so much more. Light pollution causes change and disruption to these cycles, confusing or changing long-beneficial patterns.

But how does something like a streetlamp affect so much? Prior to the industrial revolution, there were minimal amounts of outdoor light, and the moon, sun, and stars were the only sources of light. Thus, many species use these in their cycles. But as amounts of outdoor light have increased so rapidly in the last 100 years, species have not had time to adapt. Particularly in this current season of spring, the increasing amounts of light trigger multiple areas in the environment. This season is when many salamanders make their yearly movement back to their own nesting sites. They are triggered by a multitude of factors, including light, but artificial lights can make this trek difficult. Frogs and toads are also affected in similar ways, with not only difficulties in locating breeding sites, but also in growth and overall health. Migratory birds are also affected by light pollution, as their migratory cycles are linked to changing light levels. Even non-migratory birds feel side effects from light pollution, as light amounts trigger their daily cycles. Mammals struggle with light pollution as well. The obvious example would be small nocturnal mammals like opossums, which are often hit by cars due to having poor eyesight accustomed to dark environments. But crepuscular mammals, which are those that are most active at dawn and dusk, are highly affected by light pollution as it can make it difficult to tell exactly when these times start.

So, we have looked at all the different ways that various species around our planet are affected by light pollution, but what can one person do to help these species? The simplest answer is to turn off outside lights. However, there are some other obstacles that also have to be taken into account. What about places that do need 24/7 light? A possible solution to these areas is to use purple or blue light to decrease the effects on eyes of both humans and other species. There are constantly more studies coming out with more possible options and solutions to these issues. Turing off one porch light might not change the world, but it could mean the world to a salamander or fox.

Further Readings
Wise SE, Rohacek A, Scanlon AE, Cabrera T, Buchanan BW. The Effects of Artificial Night Lighting on Tail Regeneration and Prey Consumption in a Nocturnal Salamander (Plethodon cinereus) and on the Behavior of Fruit Fly Prey (Drosophila virilis). Animals (Basel). 2022 Aug 17;12(16):2105. doi: 10.3390/ani12162105. PMID: 36009695; PMCID: PMC9405242.