Light pollution affects pumas

The study on nighttime light pollution used geolocation data from 102 pumas in central and southern California. These cats avoid artificial light from human settlements reflected on the horizon, rather than artificial light reflected from the sky or moonlight.

Light pollution has increased by nearly 49% in the last quarter of a century, according to data from the Higher Council for Scientific Research (CSIC), a figure that researchers describe as “alarming.”

Light pollution, produced by lighting at night, is an environmental problem whose impact on human health and ecosystem health has already been proven.

The constant increase in nighttime lighting has caused half of Europe and a quarter of North America to suffer a widespread "loss of night", with the consequent modification of the day and night cycles.

A study, prepared by Italian and American scientists using satellite data and images, revealed that half of Europeans and two-thirds of Americans cannot see the Milky Way with the naked eye. 

Research on light pollution and its effects on pumas

According to international research carried out at the Complutense University of Madrid, when choosing a habitat, the puma (Puma concolor) prevents glare in areas with a lot of artificial light, associated with densely populated areas, more than the light reflected from them in the sky or moonlight.

Other variables found in previous studies that influenced the use of space by pumas, such as distance to roads or land uses, had a much smaller influence compared to that exerted by the glare of the closest lighting. .

"This avoidance is probably due to the fact that animals associate these human settlements with areas of risk for them.", supposes Rafael Barrientos, researcher at the Department of Biodiversity, Ecology and Evolution of the UCM.

GPS collar with geolocation

The work, published in the journal Philosophical Transactions of the Royal Society, is the first to combine research on sky brightness with nearby light pollution from cities on the horizon and natural light from the Moon.

The study, in which American universities in California and Texas also participated, tracked 102 pumas between 2002 and 2022 and added GPS collars to their geolocation.

In this way, the researchers were able to conclude that the habitat options of the pumas are diverse during the day and night and avoid areas highly contaminated by artificial light during the night, even during daylight hours.

Artificial light is increasing worldwide, altering the sensory systems, orientation and behavior of animals, and may cause ecological and evolutionary damage.

In addition to the general pattern of avoiding glare from nearby light sources, the responses of each of the 102 pumas were more or less intense, suggesting that future research should also take into account differences in individual responses.

"The results suggest how, even for generalist animals like the puma, artificial light at night can alter their habitat selection patterns. Therefore, it is a source of contamination what should we reduce“Barrientos concluded.

Of the pollution produced by humans, such as air, water, soil and garbage production, light pollution is the easiest to combat and eliminate.

Bibliographic reference: 

Barrientos R. et al. “Nearby night lighting, rather than sky glow, is associated with habitat selection by a top predator in human-dominated landscapes. Philosophical Transactions of the Royal Society (2023)

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