Sports Stadium Lights May Harm Animals – Discovery News

Sports stadium lighting is like a dinner bell to some species, such as seagulls, letting them know that spilled food freebies are on the way, but new research finds that it can cause harm to animals too.

Amphibians, insects, turtles, certain birds, small carnivores, most rodents and other animals experience altered patterns of activity and feeding when exposed to artificial night lighting, according to the study, which found that bats are particularly affected by lights at outdoor stadiums.

“Light pollution arises when artificial light affects individual organisms and the structure of ecosystems as a whole,” author Corrie Schoeman of the University of KwaZulu-Natal in Durban, South Africa, wrote. “The extent of light pollution is global.”

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Prior estimates found that light pollution impacts 85.3 percent of the surface area of Europe, 61.8 percent of the United States (excluding Alaska and Hawaii) and 18.7 percent of emerging countries at the global scale. It has been increasing by about 6 percent on average all over the world, given the growing human population and our reliance on artificial night lighting — even for entertainment purposes, such as at outdoor sporting events held in the evening.

Since some bats, as for seagulls and pigeons, seem to be attracted to urban areas while others are not, Schoeman tested how both basic types were affected by stadium lighting. He compared the seasonal activity and feeding attempts of the two different types of bats at lit versus dark sport stadiums in Durban. Each of the stadiums differ in their distance from the urban center.

As predicted, “urban exploiter” bat species noted in the study (Chaerephon pumilus, Tadarida aegyptiaca, Otomops martiensseni and Scotophilus dinganii) dominated activity and hunting at lit stadiums, yet one such city-tolerant bat, Mops condylurus, was most active at dark stadiums. “Urban avoider” bats, like Rhinolophus simulator, stayed away from the lit stadiums and their environs.

Schoeman explained that urban avoider animals usually have very specific habitat requirements that are unattainable in human-altered settings.

He believes that “light pollution at sport stadiums may homogenize urban bat diversity by favoring selected urban exploiters.” Because urban areas continue to increase, bats that are not able to cope with such drastically changed landscapes have ever-smaller territories to inhabit.

Given the growing body of research supporting that artificial lighting impacts other animals as well, Schoeman suspects that there could be a cascading effect on still other organisms and on the ecosystem as a whole.

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“Increasing light pollution is a major feature of global change that’s attributable to humans, and it is a potential threat to biodiversity,” said Schoeman.

“Although stadiums are an integral part of the urban and social environment, light pollution from these structures could lead to biotic homogenization, which may ultimately threaten native biodiversity.”