Christmas lights not so joyful for animals

Cosmos Magazine

Cosmos

Cosmos is a quarterly science magazine. We aim to inspire curiosity in ‘The Science of Everything’ and make the world of science accessible to everyone.

By Cosmos

Australians are being asked to consider the debilitating impact the use of lighting can have on native plants and animals.

Porch lights, flood lights, street lights and even Christmas lights can make animals more vulnerable to predators, increase stress, cause disorientation and change their sleep patterns.

As Australians increasingly mount festive lighting to homes across the country, an expert group of scientists is asking for people to consider their non-human neighbours by adopting a range of measures like lower-intensity lighting, saying: “it’s supposed to look pretty, not light up a surgery”.

Lit up like a Christmas tree… but not brightening the lives on animals it seems. Credit: Supplied, Michael from Calgary Wikimedia commons

Dr Loren Fardell, a community wildlife ecologist at the University of Queensland, led the Biodiversity Council’s recent study on lighting. She says 24-hour light cycles can impact development and reproduction.

As well as low-intensity lighting, the Biodiversity Council has issued 6 recommendations for December, which in the southern hemisphere is a brighter time of year. These include:

  • Switching to ‘daytime’ decorations.
  • Using lights for window displays, rather than rigging fences and whole houses.
  • Not leaving lights on all night.
  • Use of amber and red lights rather than white and blue lights, as these are less disruptive to wildlife.
  • Angle spotlights to the ground
  • Leaving trees and shrubs as dark refuges for wildlife.

Fardell says energy-efficient LED lighting is a more climate-friendly lighting alternative, but it too can have a greater effect on animal species.

The Biodiversity Council’s recommendations come in response to a campaign by the Department of Climate Change, Energy, the Environment and Water this year, which encourages people to minimise poorly designed or excessive light pollution while adopting a range of measures to reduce its impact on animal life. Principal among them is the use of “natural darkness” as a starting point from which light may be added.

Other recommendations include the use of low-intensity and adaptive lighting, non-reflective and dark-coloured surfaces near lighting fixtures and the use of amber lighting with no blue wavelength. National light pollution guidelines for wildlife also exist.

“Most of Australia’s native mammals and frogs, and many of our birds and reptiles are active at night and very good at hiding, so you may not see them but that doesn’t mean that our gardens and suburbs aren’t really important places for them,” says Professor Sarah Bekessy, a Biodiversity councillor and conservation scientist from RMIT. 

“Many native animals will avoid using or travelling through areas that are brightly lit, so leaving our gardens as dark refuges is a great way to help wildlife. Like other types of pollution such as carbon emissions, light pollution adds up. This means that every extra light you can turn off, turn down or stop pointing into nature makes a difference.” 

Some regulations to protect wildlife from light pollution currently exist. Australian standards provide some guidelines for the use of outdoor lighting after dark while legislation like the Environmental Protection and Biodiversity Conservation Act. Some jurisdictions in the US have also introduced ‘dark skies legislation’ to improve environmental outcomes. Abundant lighting has even been used by NASA and to assess holiday season energy usage.

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