Everyone can benefit from updated lighting in national parks, study finds.

National Park Service scientists and other researchers recently concluded an enlightening study on outdoor lighting practices in Grand Teton National Park.

Turns out, humans aren’t so picky when it comes to lighting. What does this mean for parks? Switching outdoor lighting practices could help park visitors and wildlife, while also saving energy and costs.

Park visitors now have the opportunity to view the Milky Way at Grand Teton National Park due to the new, lower levels of red-hued lighting.

NPS Photo

About the study

A recent study conducted by the NPS Natural Sounds and Night Skies Division (NSNSD), Grand Teton National Park, Boise State University, and The Pennsylvania State University queried park visitors in Grand Teton National Park’s Colter Bay Village to understand their perception of outdoor lighting. The village has thirty-two outdoor streetlights. For the study, the streetlights were replaced with lights that can be dimmed and switched between various shades and hues. The study measured visitor ratings of the cool white lighting and blended red-white lighting (amber), and the different hues’ perceived effect on wildlife and visitor experience.

Survey participants were asked about their perceptions of lighting, such as if the current lighting conditions created by the streetlights in Colter Bay make nighttime recreational activities more pleasurable. They also were asked how much they opposed or supported certain management propositions such as, adjusting hues of lights to be wildlife friendly.

Visitor Experience

Previous outdoor lighting research has shown that humans generally prefer brighter lights at night because they make people feel safer and more comfortable. Specifically, lights that resemble sunlight. So, in many settings such as parking lots, streetlights, parks, and elsewhere, society has opted for bright lights at night. However, such lighting has been found to have detrimental effects to humans, ecosystems, and night sky visibility.

This study found that park visitors support lighting that will benefit the park and the wildlife in it, over those that mimic daylight. Visitors also expressed greater preference, greater visual comfort, and better enjoyment of nighttime activities under red-and-white blended lights. This was the first outdoor lighting study to find such results.

The difference in results may be due to the different settings for the research. People in a national park likely do not have the same expectations for lighting as those in urban and suburban residential areas.

Humans often rely upon bright lights to aid our eyes in the dark. However, this can sometimes make it even harder to see at night. Going between very brightly lit areas and areas with minimal or no lighting is very hard on both human and animal eyes. It makes it hard to adjust our vision and to adapt to our surroundings. Night vision is better preserved when lighting is uniform and warmer in color, such as an amber hue.

The left and center lights are updated with warm white and red-white blended lights, while the light on the right is the old cooler-toned white light. The warmer lights create better visitor and wildlife experience.

NPS Photo

Lighting that is easier on human eyes is safer, and the safety of park visitors is important. In addition, warm, uniform lighting gives visitors greater opportunities to see stars, wildlife, and the beautiful environment.

Jennifer Newton is a social scientist in Grand Teton National Park and a co-author of the study. Newton believes that based on the overwhelming support for the new lighting, other parks could begin to explore similar lighting options.

“One park visitor in Colter Bay was wondering where they could buy the amber-hued light bulbs because they liked it so much. The wanted it for their own home,” Newton said.

Effects on Wildlife

Artificial outdoor lighting in any setting can affect wildlife behavior. In national parks where protecting and preserving nature are primary objectives, we want to minimize these affects as much as we can.

“Any organism that is active at night and has evolved vision is going to be affected,” said Kurt Fristrup, a former NSNSD Branch Chief and co-author of the study. For example, insects, bats, and migratory birds often mistake bright lights for stars and circle towards them, wasting time and energy while increasing risks of injury and death. Increased light on the ground also disrupts interactions between predators and prey at night.

Additionally, research found that the distribution and activity of twelve species of bats changed in response to different lighting

Effects on wildlife can be seen hundreds of meters away from the light sources in places there were thought to be undisturbed forests. In Grand Teton National Park, there is not a single area unaffected by the lights and their glow.

A model of the positive changes new light technology can create for park visitors and wildlife. Recent studies indicate that bat, insect, and bird populations decline in areas illuminated by artificial lights and have shown that visitor experience improves under dark skies

Barber Sensory Ecology Lab / Illustration by Carlos Linares

Bright lights aren’t always the best lights

“We can say that park visitors and wildlife experience many of the same benefits from dimmer blended red-white lighting: better conservation of night vision and easier transitions between lit and unlit areas,” Fristrup said.

Findings like these may aid park managers in making decisions that create an environment both comfortable for the wildlife that inhabits them, and the humans spending time in them.

It is also important to pair new lighting with education and communications on why it is necessary. “You don’t want to surprise anyone. Make sure the park visitors are kept in the loop, and they’ll usually be on board with something that is beneficial to everyone.” Newton said.

Beyond park visitors and wildlife, parks themselves will find reward from this new lighting strategy. Replacing older lighting saves energy and reduces maintenance costs, creating a long-term payback for the park.