Ecological light pollution

Moths circling an electric lightbulb
A composite satellite image of the Earth at night. Few naturally dark areas remain on the land surface of the Earth.

Ecological light pollution[1] is the effect of artificial light on individual organisms and on the structure of ecosystems as a whole.

The effect that artificial light has upon organisms is highly variable,[2] and ranges from beneficial (e.g. increased ability for predator species to observe prey) to immediately fatal (e.g. moths that are attracted to incandescent lanterns and are killed by the heat). It is also possible for light at night to be both beneficial and damaging for a species. As an example, humans benefit from using indoor artificial light to extend the time available for work and play, but the light disrupts the human circadian rhythm, and the resulting stress is damaging to health.[3][4]

Through the various effects that light pollution has on individual species, the ecology of regions is affected. In the case where two species occupy an identical niche, the population frequency of each species may be changed by the introduction of artificial light if they are not equally affected by light at night. For example, some species of spiders avoid lit areas, while other species willingly build webs directly on lamp posts. Since lamp posts attract many flying insects,[5] the spiders that tolerate light gain an advantage over the spiders that avoid it, and may become more dominant in the environment as a result.[6] Changes in these species frequencies can then have knock-on effects, as the interactions between these species and others in the ecosystem are affected and food webs are altered. These ripple effects can eventually affect diurnal plants and animals. As an example, changes in the activity of night active insects can change the survival rates of night blooming plants,[7] which may provide food or shelter for diurnal animals.

The introduction of artificial light at night is one of the most drastic anthropogenic changes to the Earth, comparable to toxic pollution, land use change, and climate change due to increases in the concentration of green house gases.

  1. ^ Longcore, Travis; Rich, Catherine (2004). "Ecological light pollution". Frontiers in Ecology and the Environment. 2 (4): 191–198. doi:10.1890/1540-9295(2004)002[0191:elp]2.0.co;2. ISSN 1540-9295.
  2. ^ Catherine Rich; Travis Longcore (2006). Ecological consequences of artificial night lighting. Island Press. ISBN 978-1-55963-128-0.
  3. ^ Chepesiuk, R (2009). "Missing the Dark: Health Effects of Light Pollution". Environmental Health Perspectives. 117 (1): A20–7. doi:10.1289/ehp.117-a20. PMC 2627884. PMID 19165374.
  4. ^ Navara, KJ; Nelson (2007). "The dark side of light at night: physiological, epidemiological, and ecological consequences". J Pineal Res. 43 (3): 215–224. doi:10.1111/j.1600-079X.2007.00473.x. PMID 17803517. S2CID 11860550.
  5. ^ Cite error: The named reference Rydell was invoked but never defined (see the help page).
  6. ^ Czaczkes, Tomer J.; Bastidas-Urrutia, Ana María; Ghislandi, Paolo; Tuni, Cristina (2018-10-30). "Reduced light avoidance in spiders from populations in light-polluted urban environments". The Science of Nature. 105 (11): 64. Bibcode:2018SciNa.105...64C. doi:10.1007/s00114-018-1589-2. ISSN 1432-1904. PMID 30377809. S2CID 53108567.
  7. ^ Gaston, Kevin J.; Bennie, Jonathan; Davies, Thomas W.; Hopkins, John (2013-04-08). "The ecological impacts of nighttime light pollution: a mechanistic appraisal". Biological Reviews. 88 (4): 912–927. doi:10.1111/brv.12036. ISSN 1464-7931. PMID 23565807. S2CID 5074170.