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  • Transcript

    • 1. Artificial Night Lighting and Sea Turtles (by Michael Salmon) Reconciliation Ecology
    • 2. Main Points
      • Marine Turtles- nesting and hatching
      • Photopollution- affects of artificial lights on turtles
      • How Photopollution also affects migratory birds
    • 3. Marine Turtles
      • In danger because of direct and indirect human activity
        • Directly by egg and adult harvesting
        • Indirectly by incidental capture by fisheries, habitat modification and degradation
      • Artificial lights are a major problem for marine turtle reproduction
      • (Habitat modification)
        • photopollution
    • 4. Sea Turtle Nesting
      • Process is much the same for all species
        • Female emerges from the water
        • Move onto beach up to a location between the dune vegetation and high
        • tide wrack
        • Female digs an egg chamber
        • Drops soft shelled eggs into chamber
        • Covers eggs with sand
        • Scatters surface sand to hide nest
        • Finally, female returns to the sea
    • 5. Females
      • Reach sexual maturity in 10-50 years depending on species
      • Nesting occurs 2-8 times in a season
      • After completing a nesting cycle, it may take 2-5 years for females to accumulate enough energy to travel to the nesting beach again and lay eggs
        • Nesting beach can be adjacent to feeding grounds or hundreds of kilometers away
      • Reproductive life spans can exceed 40 years
    • 6. Hatchlings
      • Eggs incubate for about 50 days
      • After hatching they dig almost to the surface, then wait for the sands to cool
      • When night falls they make a mad dash for the ocean
      • They swim non-stop for 24-36 hours to reach “nursery areas”
      • Only 1 of every few thousand will survive to maturity
    • 7. Seafinding
      • Process of locating the ocean from the nest
      • Accomplished by visual cues
      • Hatchlings scan 180 º wide areas close to the horizon
        • Turn away from areas that are dark and elevated
        • Move towards areas that are flatter, lower, and bright
        • Depending on the environment, cues can be equally important, or one cue may be more important than the other
    • 8. The Effects of Artificial Lighting on Females
      • White light repels turtles
      • “ Dose dependent” - some nesting will still occur if levels are low enough, but not in great numbers
      • Presence of lighting is now becoming a major factor in nesting location choice
        • Nesting sites normally chosen for their remoteness, low wave energies, proximity to favorable oceanic currents, and absence of predators
      • As humans continue to modify more
      • and more habitat, nesting will become
      • more concentrated on the few
      • remaining “dark” beaches
    • 9. Consequences of Concentrated Nesting due to Human Lighting
      • Spatial concentration will attract predators (both marine and terrestrial) and increase hatchling mortality rates
      • Destruction of nests due to over crowding
        • Females that come to nesting site after others may destroy other nests while creating their own
      • Microbial blooms due to larger numbers of dead eggs
      • Increases the probability of chance events destroying nests
        • Local storms, hurricanes, etc.
    • 10. Effects of Lighting on Hatchlings
      • Lighting keeps hatchlings from locating the sea
      • Results in disorientation or misorientation
        • Disorientation: crawl for hours in circuitous paths
        • Misorientation: crawl away from ocean toward lighting
      • Thousands die annually in Florida alone
        • Exhaustion, predators, entanglement in vegetation, dehydration, crushed by cars
    • 11. Hatchling Orientation as Effected by Light
    • 12. Why does Artificial light have this affect ?
      • The physiological changes responsible for the break down in normal orientation systems is unknown
      • It may be that lighting results in directional cues that misinform hatchlings
    • 13. Difference Between Natural & Artificial Light
    • 14. Artificial Light
      • Differences between artificial light and natural light result in pathological behavior
      • Directness of light is major factor in causing abnormal behavior
        • Increasing illumination in the background diminishes effect
      • Laws have been passed to regulate/restrict lights around nesting beaches
        • Nesting is slowly increasing
      • New threat from lights farther inland
    • 15. Photopollution
      • In the U.S., 30% of outdoor lighting is wasted by illuminating the atmosphere
      • Costing an estimated $1.5 billion in wasted electricity
    • 16. Photopollution Also Affects Migratory Birds
      • Every year about 90,000 migratory birds die in New York City
      • Lights confuse and blind birds causing them to collide with the buildings
        • New York started a Lights Out NY campaign in 2005
        • Empire State Building and Chrysler Building dim their lights
      • Asking the Public to:
      • From September 1 to October 31st
      • Tall buildings (40 stories or more):
        • Turn off decorative lighting on the upper stories by midnight and leave lights off until daylight.
        • Tenants on the upper floors are encouraged to turn out lights or draw blinds by midnight.
      • Low buildings (with extensive glass exteriors along Hudson River and East River):
        • Turn off exterior lighting by midnight and leave lights off until daylight.
        • Turn off interior lighting or draw blinds by midnight.
      • This campaign saves birds and money
        • For a building with 2.5 million square feet of floor space, turning off the lights after midnight would conserve more than 750,000 kilowatts and save approximately $120,000 this fall.
    • 17. Photopollution Also Affects Migratory Birds
      • Chicago was the first U.S. city to initiate a Lights Out Campaign
        • Buildings dim their lights 5 months of the year
        • It is estimated that this program saves 10,000 migratory land birds each year
      • Other cities that have similar programs
        • Boston
        • New York City (as discussed)
        • Baltimore
        • Minneapolis
        • San Francisco
        • Denver
        • Detroit
        • Indianapolis
    • 18. Management Solutions
      • Turn off unnecessary lights
      • Reduce wattage to the minimum required for function
      • Redirect and focus lighting so it only reaches the ground or areas where it is intended
      • Eliminate all upward-directed decorative lighting
      • Use alternative light sources where possible and practical
      • In any new construction, incorporate the latest light management technology
    • 19. The End Citations Salmon, M. 2003. Artificial Night Lighting and Sea Turtles . Biologist, 50 (4): 163-168. Richard. 2010.