The night sky is the world’s oldest natural heritage and our ability to see it is slowly disappearing
Rapid development and urbanization have stopped many of us from seeing much of our night skies due to light pollution. The most obvious sign of light pollution can be seen above major urban developments as sky glow – a faint orange yellow haze in the sky. Along with increasing the visibility of the stars and the milky-way, reducing light pollution can be beneficial to humans and wildlife (Summers et al. 2012; Chepesiuk, 2009).
Increasing light pollution can create drastic effects for most animals. Affecting their feeding, reproduction behaviour, migration and social behaviour.
With artificial lighting increasing by 6 % globally every year (Holker et al. 2010) and over 10 % of land across 66 countries already affected by artificially brightened skies above natural background levels in 2001 (Cinzano et al. 2001), prolonged exposure to artificial light is becoming a key threat to biodiversity (Holker et al. 2010). Prolonged exposure to artificial lights has led to unforeseen impacts on flora and fauna across the globe.
Light impacts on sea turtles
Research within animal biology has found that light pollution can alter numerous animal behaviours including mate selection and breeding cycles, foraging ranges and detection of resources and navigation (Davies et al. 2013).
The poster animal for light pollution is the sea turtle. Approaching breeding season, adult females return to the beaches in the area where they were born. To lay their nests, females emerge onto beaches during the night. However, females can be easily disrupted whilst laying their nest or even discouraged from emerging all together along busy touristic beaches with artificial lighting. This can be detrimental to turtle species. Loggerhead turtles, for example, typically lay 1 to 7 clutches on average every 2 to 4 years (Limpus, 1985; Schroeder et al. 2003). However, when disrupted during a nesting attempt, they may decide to abandon the nest and re-emerge a few days later using more energy than was initially needed. Two months after the female has laid her nest, the hatchlings are ready to make their way to the ocean to start their new lives. As hatchlings depend on the natural light horizon to navigate their way to the ocean, artificial lighting on beaches causes many hatchlings to become disorientated, moving towards the bright lights rather than towards the ocean (Lorne & Salmon, 2007).
Light impacts on migrating birds
Migratory bird species have also been known to become disorientated and confused by the increasing light pollution along their natural migratory routes with species that migrate nocturnally being especially affected (Verheijen 1958; Poot et al. 2008). A phenomenon known as positive phototaxis suggests that some species are attracted to the artificial lights and it is proposed that both visual cues and a magnetic compass mechanism are used for orientation (Emlen, 1967; Emlen et al. 1976; Poot et al. 2008). Some scientific studies have found that birds were more attracted to the artificial lights on overcast nights than on clear nights as the birds could not use celestial cues, therefore depending more on magnetic compass orientation (Cochran & Graber, 1958; Avery et al. 1977; Evans Ogden, 2002; Poot et al. 2008). This has led to individuals straying far off course when they were attracted by large cities or offshore installations, leaving the individuals depleted of energy.
Large aggregations of migratory birds visit Lake MacLeod at Gnaraloo each year and may be impacted by artificial lighting.
International Dark-Sky Association
The International Dark-Sky Association was created in 1988. The mission of the non-profit organisation is to protect the nights skies for present and future generations. The organisation works to actively spread awareness about night sky conservation to both the public and policymakers with issues relating to light pollution, whilst educating the public about alternative lighting and alternative tools to prevent and reduce light pollution helping bring back dark skies across the globe.
Dark Skies at Gnaraloo
Here at Gnaraloo, we see the immense importance and benefits of having dark skies over wilderness areas.
We propose to have Gnaraloo listed as the first Dark Sky Reserve in Australia as it complies with all the requirements set out by the International Dark-Sky Association for such a reserve. This will also ensure the best possible outcome and protection for the nesting female loggerhead turtles and hatchlings later each season at the Gnaraloo Bay Rookery and the Gnaraloo Cape Farquhar Rookery. Dark skies are of ecological importance for biodiversity as a whole to be able to live naturally with the absence of man-made light pollution.
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Sea turtle conservation
The Gnaraloo Turtle Conservation Program protects nesting rookeries of endangered sea turtles on the Gnaraloo beaches.
Keep Gnaraloo Wild
We deeply believe that Gnaraloo should stay as it is, wild and undeveloped, to protect its biodiversity and wilderness experience.