Light Pollution Solutions to Help Wildlife: Turtle-Friendly Lights

Light pollution poses a significant threat to a diverse array of wildlife and ecosystems. Excessive artificial light at night disturbs the natural mating, hunting, and migratory behaviors of wildlife, causing cascading effects throughout the ecosystem. Luckily, there are light fixtures you can use that reduce the effects of artificial light on both sea and land wildlife. This article explores the specific impacts of light pollution on a number of vulnerable species and discusses lighting solutions designed to mitigate these harmful effects.

Before we begin, we must first understand what light pollution is. Light pollution is the excessive spillage of artificial light at night (ALAN) caused by exterior lighting fixtures in suburban and urban areas where there are influxes of artificial light sources. In many locations, light pollution is a growing form of habitat loss. Bright lighting at night causes wildlife to move away from overly lit areas into unideal landscapes or keep them confined to smaller territories. It can also create a hazy diffusion in the sky that diminishes the visibility of stars and interferes with the natural behaviors of wildlife that rely on celestial cues. 

The effects of light pollution on various ecosystems have been carefully studied to help understand the direct correlation between artificial light at night and changing animal behavior. In the paragraphs below, we reference observed animal behaviors from scientific studies from the ALAN database and other wildlife protection agencies.

Beachfront light pollution poses a critical threat to sea turtles during nesting and hatching periods. Nesting sea turtles rely on dark beaches to safely lay their eggs and return to the water. However, bright beachfront lighting can lead nesting females away from suitable nesting locations and to unsafe or potentially hazardous areas instead. This can also harm hatchlings by making them crawl further to the water or through treacherous terrain.

Sea turtle hatchlings instinctively use the moonlight's reflection to guide them to sea safety after they hatch. However, they can confuse unshielded white artificial beachfront light with moonlight and crawl inland instead. This disorientation increases their vulnerability to predators, dehydration, and exhaustion. Across shoreline states like Florida, where 90% of US sea turtle nesting occurs, it is important to utilize turtle-friendly lighting to assist in the conservation of nesting sea turtles, sea turtle hatchlings, and other wildlife. 

Migrating songbirds use the stars and celestial cues to navigate during their flight. Bright artificial lights, however, can draw these birds away from their migration paths and lead them into urban areas, where they can easily become disoriented and trapped. These birds often waste energy circling illuminated areas and even collide with buildings, windows, or structures. 

Artificial light can also disorient seabirds who use the moon and stars to navigate toward the ocean by leading them astray. Seabirds commonly collide with man-made structures, resulting in injury or death. Bright light at night has been found to disrupt their ability to hunt effectively and hurt their overall health and breeding capabilities.

Many nocturnal species, such as bats, foxes, and various rodents, rely on darkness for hunting. However, bright lighting at night shortens the times that these mammals can hunt and exposes them to predators. Light pollution around forests and wooded areas can hinder the night vision ability of certain nocturnal animals, resulting in less successful hunts. Disruptions in hunting periods interfere with their circadian rhythms, causing these nocturnal species to get less sleep and experience irregular reproductive cycles.

Bright light sources attract the interest of many insects and lead them away from their usual habitat, often concentrating them to be easily preyed upon. Other activity and behavioral changes are common among certain insect species as well. Moths commonly reduce feeding and calling activities in areas with high light pollution. Artificial light at night has been shown to reduce the lifespan of crickets and affect their mating behavior. Similarly, fireflies reduce their flashing activities and mating success when exposed to light pollution. These disruptions, especially in nocturnal pollinators, can quickly cascade through the food chain and affect entire ecosystems.

Can Humans Be Affected by Light Pollution?

Yes, light pollution can cause negative affects for humans. One of which is caused by light trespass, where unwanted artificial light spreads into homes or businesses. Light trespass into homes can disrupt the circadian rhythm. Throughout the day, light changes from a warm white color at dawn to natural white, then to a cool white in the afternoon, back to natural white, and eventually to an ultra-warm white color at sunset. Our bodies are used to this cycle of light. Artificial lights that deviate from the natural lighting cycle can throw off our circadian rhythms. The National Institute of General Medical Sciences states that, “Circadian rhythms are physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism’s environment. On their website, the IDA cites important information from a report about human and environmental effects of LED streetlights. According to this report, studies have shown that being exposed to light with a higher CCT before going to bed can negatively affect sleeping patterns. The report goes on to say that continuous sleep disruptions can lead to cancer, obesity, heart disease, and diabetes.

Another type of light pollution that affects humans is glare, which is when lights create too much brightness, causing eye strain or vision issues. Glare decreases driver safety and can lead to traffic accidents.          

To limit the amount of excessive light pollution at night and combat the harmful effects on surrounding wildlife, protection agencies such as the Florida Fish and Wildlife Conservation Commission (FCC) recommend using certain light fixtures outdoors. Turtle-friendly lights are commonly recommended because they follow the following three regulations set by the FCC:

1. Keep it low
1. Tall light fixtures can be mistaken for the moon by animals on the ground, and excessive light spillage can create a “sky glow” or haze that limits the view of the night sky. Therefore, the FCC recommends mounting your exterior lights as low as possible. “Low” also refers to the brightness of your exterior lights. If your lighting is dimmable, keep it at the lowest lighting level necessary for its intended purpose.
2. Keep it shielded
1. Shielded and full cutoff light fixtures limit the amount of light spillage visible to wildlife. This can stop migratory birds from becoming attracted to bright lights on roadways or buildings and keep them on route. There are also energy benefits to buying shielded lighting. Full cutoff LED light fixtures feature directional LED chips that emit only the essential light beams, eliminating wasted energy on unnecessary lighting.
3. Keep it long
1. White light emits wavelengths over a broad spectrum with a peak usually around 450-460 nanometers (nm). However, studies have shown that certain wildlife responds better to and perform their usual behaviors under amber or red lights. True amber and red lights emit a long wavelength of light above 560 nm. Fixtures emitting light above this wavelength are less likely to be confused with moonlight.

Besides installing turtle-friendly lights, the FWC recommends other steps you can take to reduce your light pollution on beachfront properties. To minimize light pollution from interior lights, keep your blinds and curtains closed, place moveable light sources such as lamps away from the window, or apply window tint ranging from 15%-45%. For exterior lighting, limit the amount of decorative lighting around your property. The FWC also recommends using tall fences and bushes to create a shield or buffer between your home and the beach. To reduce the amount of time your exterior lights stay on, utilize a motion detector and use the shortest time setting.