dark infrastructure

Light Pollution or ALAN is known to cause harm to humans, flora and fauna alike.{{Cite journal |last1=Segrestin |first1=Jules |last2=Mondy |first2=Nathalie |last3=Boisselet |first3=Christelle |last4=Guigard |first4=Ludivine |last5=Lengagne |first5=Thierry |last6=Poussineau |first6=Sophie |last7=Secondi |first7=Jean |last8=Puijalon |first8=Sara |date=December 2021 |title=Effects of artificial light at night on the leaf functional traits of freshwater plants |url=https://onlinelibrary.wiley.com/doi/10.1111/fwb.13830 |journal=Freshwater Biology |language=en |volume=66 |issue=12 |pages=2264–2271 |doi=10.1111/fwb.13830 |bibcode=2021FrBio..66.2264S |issn=0046-5070}}{{Cite journal |last1=Sordello |first1=Romain |last2=Busson |first2=Samuel |last3=Cornuau |first3=Jérémie H. |last4=Deverchère |first4=Philippe |last5=Faure |first5=Baptiste |last6=Guetté |first6=Adrien |last7=Hölker |first7=Franz |last8=Kerbiriou |first8=Christian |last9=Lengagne |first9=Thierry |last10=Le Viol |first10=Isabelle |last11=Longcore |first11=Travis |last12=Moeschler |first12=Pascal |last13=Ranzoni |first13=Jessica |last14=Ray |first14=Nicolas |last15=Reyjol |first15=Yorick |date=March 2022 |title=A plea for a worldwide development of dark infrastructure for biodiversity – Practical examples and ways to go forward |url=https://linkinghub.elsevier.com/retrieve/pii/S0169204621002954 |journal=Landscape and Urban Planning |language=en |volume=219 |pages=104332 |doi=10.1016/j.landurbplan.2021.104332|bibcode=2022LUrbP.21904332S}}{{Cite journal |last1=Zielinska-Dabkowska |first1=K. M. |last2=Schernhammer |first2=E. S. |last3=Hanifin |first3=J. P. |last4=Brainard |first4=G. C. |date=2023-06-16 |title=Reducing nighttime light exposure in the urban environment to benefit human health and society |url=https://www.science.org/doi/10.1126/science.adg5277 |journal=Science |volume=380 |issue=6650 |pages=1130–1135 |doi=10.1126/science.adg5277|pmid=37319219 |bibcode=2023Sci...380.1130Z}}

For humans, this includes adverse effects on the visual system and sleep quality (e.g., by an impaired melatonin secretion, disruption of the circadian rhythm). Early-stage research also links ALAN to a higher risk of chronic diseases.

File:1-s2.0-S0169204621002954-gr2 lrg.jpg

ALAN has been linked as one of the causes of the collapse of insect populations which is happening around the world.

The skyglow caused by ALAN can sometimes cover areas of over ten to hundreds of kilometers, even affecting animals in unpopulated areas and protected habitats. {{Cite journal |last1=Davies |first1=Thomas W. |last2=Duffy |first2=James P. |last3=Bennie |first3=Jon |last4=Gaston |first4=Kevin J. |date=2016 |title=Stemming the Tide of Light Pollution Encroaching into Marine Protected Areas |url=https://conbio.onlinelibrary.wiley.com/doi/10.1111/conl.12191 |journal=Conservation Letters |language=en |volume=9 |issue=3 |pages=164–171 |doi=10.1111/conl.12191 |bibcode=2016ConL....9..164D |issn=1755-263X|hdl=10871/17713 |hdl-access=free }}{{Cite journal |last1=Gaston |first1=Kevin J. |last2=Duffy |first2=James P. |last3=Bennie |first3=Jonathan |date=2015 |title=Quantifying the erosion of natural darkness in the global protected area system |url=https://conbio.onlinelibrary.wiley.com/doi/abs/10.1111/cobi.12462 |journal=Conservation Biology |language=es |volume=29 |issue=4 |pages=1132–1141 |doi=10.1111/cobi.12462 |bibcode=2015ConBi..29.1132G |issn=1523-1739}}

One problem of the additional light exposure during the night is the disruption of the circadian rhythm and associated risks similar to humans.

Another issue arising from ALAN for animals in the sense that lit areas act as barriers that some animals cannot cross. They either avoid the light barrier altogether (bats, some mammals) (see Image, left) or are attracted by the light and enter the lit area, leading to entrapment inside and possibly death (see Image, right). This can subsequently lead to habitat loss and segmentation, reduces available resources, increases competition and can change predation. All artificial light at night that exceeds the equivalent of that of naturally occurring moonlight lunar phase has negative effects on physiology, behavior, and life-history traits.

The impact of ALAN on plants has been studied less than on animals. Plant leaf functions and resource-management strategies can be affected negatively as well as resource acquisition rate and disrupt the circadian rhythm and circannual cycle.{{Cite web |last=UFAM |first=Bundesamt für Umwelt BAFU {{!}} Office fédéral de l'environnement OFEV {{!}} Ufficio federale dell'ambiente |title=Dunkelheit und Licht: von beidem genug und am richtigen Ort |url=https://www.bafu.admin.ch/bafu/de/home/themen/elektrosmog/dossiers/dunkelheit-und-licht.html |access-date=2025-02-03 |website=www.bafu.admin.ch |language=de}}{{Cite journal |last1=Falcón |first1=Jack |last2=Torriglia |first2=Alicia |last3=Attia |first3=Dina |last4=Viénot |first4=Françoise |last5=Gronfier |first5=Claude |last6=Behar-Cohen |first6=Francine |last7=Martinsons |first7=Christophe |last8=Hicks |first8=David |date=2020-11-16 |title=Exposure to Artificial Light at Night and the Consequences for Flora, Fauna, and Ecosystems |journal=Frontiers in Neuroscience |language=English |volume=14 |doi=10.3389/fnins.2020.602796 |doi-access=free |issn=1662-453X |pmc=7701298 |pmid=33304237}}

Aquatic ecosystems close to the coast/shoreline are particularly exposed, since lit infrastructure/urban development are located along rivers, lakes, and sea shores.

Overall, ALAN acts as a pressure for biodiversity, especially contributing to habitat loss and landscape fragmentation.

In a notable article published in 2022, an international group of scientists have called to "promote the integration of darkness quality within the 'green and blue infrastructure', to implement a 'dark infrastructure'" and proposed a 4 step-process. They proposed that first the light pollution of the given territory must be quantified and mapped. Second, existing dark infrastructure, or areas where nighttime darkness is already maintained at an optimal level for wildlife, must be identified. Third, this dark infrastructure is to be preserved to prevent further light pollution and restored or expanded upon in areas where the lighting can be modified to increase darkness. Fourth, the infrastructure must be monitored and assessed for effectiveness.

File:Downtown Atlanta at night (39500731114).jpg

The restoration or expansion of dark infrastructure can be carried out via the reduction of artificial lighting across several parameters, including the strength of the illumination, the timing of the lighting period, and the direction and area of the illumination, in order to maintain these cores and corridors of nighttime darkness.{{Cite web |last=Pollutec |date=2024-05-06 |title=THE BLACK INFRASTRUCTURE - EXPLORING IMPACTS, ISSUES, METHODS AND TOOLS |url=https://learnandconnect.pollutec.com/en/the-black-infrastructure-exploring-impacts-issues-methods-and-tools/ |access-date=2025-01-31 |website=Pollutec Learn & Connect {{!}} English |language=en-US}} Light sources include street lamps, billboards, illuminated signs, car headlights, and indoor lighting that is visible through windows.

• Avoiding blue light in favor of yellow light, which has been shown to generally have a lower impact on wildlife{{Cite web |title=Urban lighting: 6 ways to create local dark infrastructures {{!}} Paysalia 2025 |url=https://www.paysalia.com/en/news/environment/urban-lighting-6-ways-create-local-dark-infrastructures |access-date=2025-01-31 |website=www.paysalia.com}}
• Diminishing the intensity of the light sources as to not exceed the natural luminosity of the full moon
• Directing light downwards
• Optimizing spacing and height of street lighting{{Cite book |last=Sierro |first=Antoine |title=La lumière nuit! LA NATURE FACE À LA POLLUTION LUMINEUSE |date=January 2019 |publisher=Canton du Valais: Departement de l'economie et de la formation |language=French}}
• Maintaining dark interstitial spaces between light sources to allow for wildlife to move uninterrupted
• Utilize lighting only in places of established need and eliminate lighting when possible
• Avoid lighting in existing ecological corridors such as waterways and woodlands
• Reduce the illumination of advertising billboards, signs, and panels
• Limit the hours that illumination is active to times of necessity

• Geneva, Switzerland integrated ecological corridors in the Biodiversity section of their Climate Strategy. Its 2021 revision of the Lighting Plan (Plan Lumière) introduces black corridors (Trame Noire).{{Cite web |title=Les corridors biologiques en vidéos |url=https://www.ge.ch/document/corridors-biologiques-videos |access-date=2025-02-02 |website=ge.ch |language=fr}} In 2024, the metropolitan area Geneva created an open data light pollution map encompassing a “dark grid”.{{Cite web |last=Jerdelet |first=Sébastien |date=2024-07-03 |title=Grand Genève {{!}} Une carte de la pollution lumineuse |url=https://www.grand-geneve.org/une-carte-de-la-pollution-lumineuse/ |access-date=2025-02-02 |website=Grand Genève |language=fr-FR}}

• Rouen, in Normandie, France, decided in 2021 to extend its public lighting optimization scheme. In 11 districts, the streets were no longer lit at night between 1 am and 5 am. A reduction in public spending as well as ecological motivation have been cited as motives by officials. A mobile-phone application called “J’allume ma rue” (“I light up my street”) could be used by inhabitants in some areas to turn street lamps on when needed. Nevertheless, several municipalities of the metropolitan area have since decided to reverse course.{{Cite web |date=2024-12-09 |title=Éteindre l'éclairage public dans la métropole de Rouen : pourquoi certains reviennent sur leur décision |url=https://actu.fr/normandie/rouen_76540/eteindre-l-eclairage-public-dans-la-metropole-de-rouen-pourquoi-certains-reviennent-sur-leur-decision_61959715.html |access-date=2025-02-03 |website=actu.fr |language=fr}}File:Fig._5._Example_of_dark_infrastructure_already_in_place_in_Douai,_France.png

• Douai, France identified previously-existing dark corridors using an acoustic bat survey that monitored bat activity, which is used to prioritize areas of preservation and restoration. The survey identified pathways of low, medium, and high intensity bat activity, which correspond to corridors of darkness from least dark to darkest.
• Australia trialed glow-in-the-dark street markings in rural Victoria in 2022. The original aim was to increase road safety, but the photoluminescent markings would also eliminate the need for street lighting.{{Cite news |date=2022-09-21 |title=Glow-in-the-dark roads trialled to reduce road toll, protect wildlife |url=https://www.abc.net.au/news/2022-09-22/glow-in-the-dark-roads-trial-in-rural-victoria/101459750 |access-date=2025-02-03 |work=ABC News |language=en-AU}} New South Wales also initiated a trial of photoluminescent road markings in 2024.{{Cite web |title=NSW to trial glow-in-the-dark road markings |url=https://www.drive.com.au/news/nsw-to-trial-glow-in-the-dark-road-markings/ |access-date=2025-02-03 |website=Drive |language=en}}

Dark infrastructures have numerous ecological and human health benefits, including reduced light pollution and the preservation of nocturnal biodiversity by functioning as sanctuaries for light-sensitive species.{{Cite web |title=ETC HE Report 2022/8: Review and Assessment of Available Information on Light Pollution in Europe |url=https://www.eionet.europa.eu/etcs/etc-he/products/etc-he-products/etc-he-report-2022-8-review-and-assessment-of-available-information-on-light-pollution-in-europe |access-date=2025-02-05 |website=Eionet Portal |pages= |language=en-gb}} Many species, including bats, moths, amphibians, and migratory birds, rely on darkness for critical behaviors such as foraging, mating, and navigation. Dark infrastructure helps reduce habitat fragmentation{{Cite journal |last1=Sordello |first1=Romain |last2=Busson |first2=Samuel |last3=Cornuau |first3=Jérémie H. |last4=Deverchère |first4=Philippe |last5=Faure |first5=Baptiste |last6=Guetté |first6=Adrien |last7=Hölker |first7=Franz |last8=Kerbiriou |first8=Christian |last9=Lengagne |first9=Thierry |last10=Le Viol |first10=Isabelle |last11=Longcore |first11=Travis |last12=Moeschler |first12=Pascal |last13=Ranzoni |first13=Jessica |last14=Ray |first14=Nicolas |last15=Reyjol |first15=Yorick |date=2022-03-01 |title=A plea for a worldwide development of dark infrastructure for biodiversity – Practical examples and ways to go forward |url=https://linkinghub.elsevier.com/retrieve/pii/S0169204621002954 |journal=Landscape and Urban Planning |volume=219 |pages=104332 |doi=10.1016/j.landurbplan.2021.104332 |bibcode=2022LUrbP.21904332S |issn=0169-2046}} and protect pollination networks that rely on nocturnal insects.{{Cite journal |last1=Knop |first1=Eva |last2=Zoller |first2=Leana |last3=Ryser |first3=Remo |last4=Gerpe |first4=Christopher |last5=Hörler |first5=Maurin |last6=Fontaine |first6=Colin |date=2017 |title=Artificial light at night as a new threat to pollination |url=https://www.nature.com/articles/nature23288 |journal=Nature |language=en |volume=548 |issue=7666 |pages=206–209 |doi=10.1038/nature23288 |bibcode=2017Natur.548..206K |issn=1476-4687}} Furthermore, these corridors benefit human health by increasing sleep quality and lowering the risks associated with artificial light exposure, such as sleep disorders.{{Cite journal |last1=Cho |first1=YongMin |last2=Ryu |first2=Seung-Hun |last3=Lee |first3=Byeo Ri |last4=Kim |first4=Kyung Hee |last5=Lee |first5=Eunil |last6=Choi |first6=Jaewook |date=2015-10-21 |title=Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessment |url=https://www.tandfonline.com/doi/full/10.3109/07420528.2015.1073158 |journal=Chronobiology International |volume=32 |issue=9 |pages=1294–1310 |doi=10.3109/07420528.2015.1073158 |issn=0742-0528 |pmid=26375320}} Aside from health benefits, they can help lower energy consumption by reducing unnecessary lighting.{{Cite web |title=Dark Infrastructure: an ecological network for night-time wildlife {{!}} Trame verte et bleue |url=https://www.trameverteetbleue.fr/documentation/references-bibliographiques/dark-infrastructure-ecological-network-night-time |access-date=2025-02-05 |website=www.trameverteetbleue.fr}}

However, implementing dark infrastructure also presents numerous challenges and risks that must be carefully managed. The opinions of various stakeholders, such as society, ecology, the economy, authorities, and private interests, must be considered. One major concern is public safety, as reduced lighting may increase feelings of insecurity, potentially limiting public support for these initiatives.{{Cite journal |last1=Beaudet |first1=Chloé |last2=Tardieu |first2=Léa |last3=David |first3=Maia |date=2022-10-01 |title=Are citizens willing to accept changes in public lighting for biodiversity conservation? |url=https://linkinghub.elsevier.com/retrieve/pii/S0921800922001896 |journal=Ecological Economics |volume=200 |pages=107527 |doi=10.1016/j.ecolecon.2022.107527 |bibcode=2022EcoEc.20007527B |issn=0921-8009}} Insufficient lighting along roads and pedestrian paths can also increase the risk of traffic accidents, necessitating the use of adaptive lighting solutions.{{Cite journal |last1=Jackett |first1=Michael |last2=Frith |first2=William |date=2013-03-01 |title=Quantifying the impact of road lighting on road safety — A New Zealand Study |url=https://linkinghub.elsevier.com/retrieve/pii/S0386111212000325 |journal=IATSS Research |volume=36 |issue=2 |pages=139–145 |doi=10.1016/j.iatssr.2012.09.001 |issn=0386-1112|doi-access=free }}

From an ecological point of view, dark infrastructure may unintentionally aid in the spread of invasive species or disrupt predator-prey relationships, thereby affecting conservation objectives.{{Cite journal |last1=Maurer |first1=Andrew S. |last2=Cove |first2=Michael V. |last3=Siegal |first3=Olivia M. |last4=Lashley |first4=Marcus A. |date=2022-06-01 |title=Urbanization affects the behavior of a predator-free ungulate in protected lands |url=https://linkinghub.elsevier.com/retrieve/pii/S0169204622000408 |journal=Landscape and Urban Planning |volume=222 |pages=104391 |doi=10.1016/j.landurbplan.2022.104391 |bibcode=2022LUrbP.22204391M |issn=0169-2046}}

Furthermore, businesses that rely on outdoor lighting (e.g., private and commercial lighting installations) may oppose stricter regulations, and urban planning initiatives may clash with existing zoning laws.

High initial costs and the need for continuous monitoring further complicate their implementation. They require thoughtful design strategies that balance ecological preservation with urban functionality.

• Anderson, S. J., Kubiszewski, I., & Sutton, P. C. (2024). The Ecological Economics of Light Pollution: Impacts on Ecosystem Service Value. Remote Sensing, 16(14), 2591. https://doi.org/10.3390/rs16142591
• Zielinska-Dabkowska K. M.,  E. S. Schernhammer, J. P.Hanifin, and G. C. Brainard (2023). Reducing nighttime light exposure in the urban environment to benefit human health and society. Science 380,1130-1135 https://doi.org/10.1126/science.adg5277
• Sordello, R., Busson, S., Cornuau, J. H., Deverchère, P., Faure, B., Guetté, A., …  &  S. Vauclair (2022). A plea for a worldwide development of dark infrastructure for biodiversity – Practical examples and ways to go forward. Landscape and Urban Planning, 219(104332), 104332. https://doi.org/10.1016/j.landurbplan.2021.104332
• Falcón J, Torriglia A, Attia D, Viénot F, Gronfier C, Behar-Cohen F, Martinsons C, Hicks D. (2020). Exposure to Artificial Light at Night and the Consequences for Flora, Fauna, and Ecosystems. Front Neurosci. 14: 602796. https://doi.org/10.3389/fnins.2020.602796

Category:Environmental movements

Category:Light pollution

Category:Infrastructure