Light Pollution in National Parks: Impacts and Importance

Now that we have understood the different components of light pollution, let’s take a look at some of its impacts, as well as find out the importance of night skies and naturally dark environments.

Impacts of Light Pollution
Human Health
There have been several studies on the severe health impacts of Artificial Light At Night (ALAN) on humans and other biotas. For instance, ALAN may suppress the body’s production of melatonin and influence our biological clock, also known as the circadian rhythm. The suppression of melatonin may also lead to irregular cell development and deactivation of cancer-suppressing genes, thus resulting in negative impacts on human health, such as the increased risks of obesity (Park et al., 2019) or cancers (Haim & Zubidat, 2015). Cho et al., (2015) also found that the health effects of ALAN are related to the exposure conditions and characteristics of the lights, and not only to the amount of light. This is similar to any other environmental pollutants that cause negative health effects, which are dependent on not just the amount but the exposure, as discussed during Lecture 2. There are also some studies that reported that the duration and the time of exposure to ALAN plays a huge factor in determining its negative health effects. For example, evening light exposure before bedtime affected the circadian phase more than did afternoon exposure. Thus, excessive exposure to artificial light does not involve only too bright light, but also too long or irregular exposure (Cho et al., 2015).

Disruption of the World’s Ecosystems
ALAN does not only affect humans, but animals too, as they depend on Earth’s daily cycle of light and dark rhythm to govern life-sustaining behaviors such as reproduction, nourishment, sleep and protection from predators. As nocturnal animals sleep during the day and rise at night, the presence of excessive light at night radically alters their nighttime environment, which may cause drastic effects on nocturnal ecology. For example, a research study by Robert et al., (2015) shows that ALAN disrupts the reproductive cycle of wild wallabies on Garden Island, Australia, due to the significantly suppressed nighttime melatonin levels, thus resulting in a month-long delay in the birth of their offspring.  In consequence, mismatches with optimal food resources to raise their young may occur (Robert et al., 2015).

Experimentele groene verlichting met meer blauw en minder rood

Experimenting with green artificial lighting in the Netherlands to study the effects of light pollution on the health of animals. Source: https://nioo.knaw.nl/en/light-nature

There have also been various experiments by ecologists that seek to study the effects of ALAN on ecosystems. A field experiment in the Netherlands which involved placing several rows of street lamps in eight locations, and the monitoring of the activities of small mammals, found physiological evidence of the detrimental effects of light pollution on the health of the animals. For instance, songbirds that were found to be roosting around the white light were restless through the night, and therefore slept less and had metabolic changes that could indicate poorer health (Irwin, 2018). Another project, known as Ecolight, made use of “glowing cubes” to look for evidence of the “cascade effects” of light pollution on the ecosystem and subsequently found some experimental evidence of a strong, bottom-up effect of exposure to artificial light (Irwin, 2018).

A mesocosm experiment of box lights at night

Artificial light in the form of “glowing cubes”, used to understand the ecological effects that it may bring about. Source: Irwin (2018)


Psychological Health
According to a laboratory study of the psychological impact of light pollution in national parks, participants who experienced even moderate levels of light pollution reported lower mood scores as well as lessened scenic quality when compared to lower light pollution scenes. This suggests that pristine night skies in national parks could become important for creating satisfying visitor experiences and preserving the beneficial outcomes associated with natural scenery (Benfield et al., 2018). While this may seem like a stretch, there has also been another study that found a statistically significant relationship between ALAN and measures of depression and suicidal ideation among Korean adults. This further expounds the multiple detrimental health and psychological impacts on both humans and ecosystems.


Importance of Night Skies and Naturally Dark Environments
Aesthetics
Like clean air and water, wildlife, or the sounds of nature, a clear dark night sky is an intrinsic part of the national park experience. According to visitor surveys at two National Parks in Utah, 99% of visitors prefer to stargaze in a national park over other locations, while 80% indicated that the quality of night skies was an important part of their visit (Mace and McDaniel, 2013). Hence, many of them also felt that efforts should be made to protect dark skies in national parks, and that the surrounding communities should help support such protection.

Grand Canyon Officially Awarded Dark Sky Park Status

Grand Canyon National Park, earned its status as a Dark Sky Park by the IDA in 2019. Source: Matthews (2019)


Astrotourism and its Economic Value
The growing public appreciation for activities involving nighttime programs and stargazing has also spawned a new form of tourism- astrotourism. Astrotourism involves people travelling to nature-rich destinations like national parks, that experience considerably less amount of light pollution, which in turn allows visitors to spot starts and constellations more easily. These places are often categorized as “dark sky parks/reserves”, by the International Dark-Sky Association (IDA), which has identified them as places that implement good outdoor lighting and provide dark sky programs for visitors, as well as places where policy controls are enacted to protect the darkness of the location. Another way of finding places that can offer pristine dark sky areas, is through the dark site finder, that highlights places based on a dark-bright scale, as shown below. As a result of these astrotourism activities, additional spendings through other means such as food and lodging could bring about increased revenue for the local economy as well. According to a case study on The Colorado Plateau that is known for its dark skies, the current economic impact of astrotourism activities is substantial, where the increasing number of visitors may contribute to the creation of more jobs, as well as increase wages and gross state product (Mitchell and Gallaway, 2019). Hence, with the increase in efforts to promote night sky or astrotourism, the economic impacts would continue to grow substantially (Mitchell and Gallaway, 2019).

Location of Dark Sites in the USA. Source: Darksitefinder.com

 

Till next time,
Irsyad

——————
References:

Benfield, J., Nutt, R., Taff, B., Miller, Z., Costigan, H. and Newman, P., 2018. A laboratory study of the psychological impact of light pollution in national parks. Journal of Environmental Psychology, 57, pp.67-72.

Cho, Y., Ryu, S., Lee, B., Kim, K., Lee, E. and Choi, J., 2015. Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessment. Chronobiology International, 32(9), pp.1294-1310.

Haim, A. and Zubidat, A., 2015. Artificial light at night: melatonin as a mediator between the environment and epigenome. Philosophical Transactions of the Royal Society B: Biological Sciences, 370(1667), p.20140121.

Irwin, A., 2018. The Dark Side Of Light: How Artificial Lighting Is Harming The Natural World. [online] Nature.com. Available at: <https://www.nature.com/articles/d41586-018-00665-7> [Accessed 4 November 2020].

Mace, B. and McDaniel, J., 2013. Visitor Evaluation of Night Sky Interpretation in Bryce Canyon National Park and Cedar Breaks National Monument. Journal of Interpretation Research, 18(1), pp.39-57.

Mitchell, D. and Gallaway, T., 2019. Dark sky tourism: Economic impacts on the Colorado Plateau Economy, USA. Tourism Review, 74(4), p.937.

Park, Y., White, A., Jackson, C., Weinberg, C. and Sandler, D., 2019. Association of Exposure to Artificial Light at Night While Sleeping With Risk of Obesity in Women. JAMA Internal Medicine, 179(8), p.1061.

Robert, K., Lesku, J., Partecke, J. and Chambers, B., 2015. Artificial light at night desynchronizes strictly seasonal reproduction in a wild mammal. Proceedings of the Royal Society B: Biological Sciences, 282(1816), p.20151745.

Leave a Reply

Your email address will not be published. Required fields are marked *