The camouflage tactics of many animals, such as snails, are endangered by Light pollution. While humanity has found a formula to consume less energy in cities thanks to LED bulbs or other high-efficiency lighting, snails have run into their worst enemy: excess light. These animals have not been able to adapt to the rapid change that cities have undergone and today the light bulbs that illuminate them at night (which spend less, but illuminate more) prevent them from fleeing from predators.
This has been confirmed by a new investigation, published in the Journal of Applied Ecologywhich shows that the lighting revolution has considerably improved the ability of predators to carefully choose their prey, since without their characteristic camouflage, the task becomes much easier.
“This study clearly shows that More effective luminaires increase the visibility of prey by reducing the effectiveness of its camouflage&rdquor ;, highlights Oak McMahon, researcher at the University of Plymouth and principal investigator of this article.
The work, carried out by researchers from the University of Plymouth and the Plymouth Marine Laboratory (PML), both in England, sought to study the potential of artificial light at night (ALAN) in the camouflage mechanisms of coastal species.
The results showed that “the species of snails littorinid, which are found on our shores, remain camouflaged when illuminated by old light bulbs & rdquor ;. However, when illuminated with LED bulbs, for example, “they are clearly visible to predators and, as a result, they are at much greater risk in the long term & rdquor ;, McMahon stressed.
This impact is not the same in all snails, it depends on their color, which, on the other hand, means that certain chromatic variations are much more at risk than others. On the shores of Plymouth the Littorinid snail can be three different colors: yellow, brown or olive green.
Depending on the type of light, they can be camouflaged or not
The researchers compared how the species managed to camouflage itself under different forms of lighting.. To do this, low pressure sodium (LPS) lights were included, widely used during the 20th century, three types of modern lighting: high pressure sodium (HPS); light emitting diodes (LEDs); and Metal Halides (MH), as well as the natural light provided by the sun and the moon.
Under artificial LPS lighting, all snails were effectively camouflaged.. However, when illuminated by LEDs, MH, the sun, or the moon, yellow snails were significantly more visible compared to brown and olive snails in most cases.
The lighting of cities has achieved many improvements in the quality of life of humanity. As Thomas Davies, the paper’s lead author and Professor of Marine Conservation at the University of Plymouth, insists, “As technologies develop, there has been a shift in lighting that allows us to live and travel safely.”
The plague of light pollution
Yet a quarter of the planet between the Arctic Circle and Antarctica is being bombarded by light pollution. “Some predictions say that LED bulbs will account for 85% of the global street lighting market in about five years And such advances will have repercussions for both humans and animals now and in the future.”
“The advance of cities has consequences in the natural world & rdquor ;, highlights, for his part, biogeochemist Tim Smyth, also a signatory of the article, who insists that nature is forced to “adapt at an ever-increasing rate to artificial changes”, something that is often impossible. For this reason, he highlights that human beings “need to learn to adapt our technologies to nature”, rather than the other way around.
In the study, the researchers highlight the need to take measures to mitigate this natural impactand describe various methods available to reduce the ecological impact of efficient luminaires.
Among the proposals is reduce the amount of light usedprotect the lights to reduce their effects on the surrounding environment, use partial night lighting during times of greatest demand and vary the light spectra -to make them warmer- and thus minimize ecological impacts.
Reference study: https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.14146