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Do Embedded Roadway Lights Protect Sea Turtles?

Abstract

Street lighting on coastal roadways is often visible at sea turtle nesting beaches, and disrupts the nocturnal orientation of hatchlings as they crawl toward the sea. Our objective was to determine whether an alternative lighting system (light-emitting diodes, embedded in the roadway pavement) prevented orientation disruption. Hatchlings at the beach oriented normally when only the embedded lights were on, or when all lighting was switched off. However, turtles showed poor orientation when street lighting was on. Measurements confirmed that street lighting was scattered to the beach, whereas embedded lighting was not. We conclude that embedded lighting keeps the beach dark and thus protects sea turtles. However, on two overcast evenings, lighting (“skyglow”) from nearby development, reflected by cloud cover to the beach, weakened hatchling orientation. Thus, both indirect (reflected) and direct sources of lighting negatively impact the turtles.

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Acknowledgments

We thank A. Broadwell (FDOT) for administering the contract that supported this study, B. E. Witherington for suggesting the embedded lighting project, and the Florida Department of Transportation and the City of Boca Raton for financing it. This study served as a Masters thesis in Biology for L. B. Its design was approved by the State (Florida Fish and Wildlife Conservation Commission, turtle permit No. 72) and by the Florida Atlantic University Institutional Animal Care Committee.

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Correspondence to Michael Salmon.

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Bertolotti, L., Salmon, M. Do Embedded Roadway Lights Protect Sea Turtles?. Environmental Management 36, 702–710 (2005). https://doi.org/10.1007/s00267-004-0288-2

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  • DOI: https://doi.org/10.1007/s00267-004-0288-2

Keywords

  • Artificial lighting
  • Orientation
  • Sea turtle
  • Loggerhead
  • Caretta