Recon

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  • Recon

    1. 1. Artificial Night Lighting and Sea Turtles (by Michael Salmon) Reconciliation Ecology
    2. 2. Main Points <ul><li>Marine Turtles- nesting and hatching </li></ul><ul><li>Photopollution- affects of artificial lights on turtles </li></ul><ul><li>How Photopollution also affects migratory birds </li></ul>
    3. 3. Marine Turtles <ul><li>In danger because of direct and indirect human activity </li></ul><ul><ul><li>Directly by egg and adult harvesting </li></ul></ul><ul><ul><li>Indirectly by incidental capture by fisheries, habitat modification and degradation </li></ul></ul><ul><li>Artificial lights are a major problem for marine turtle reproduction </li></ul><ul><li>(Habitat modification) </li></ul><ul><ul><li>photopollution </li></ul></ul>
    4. 4. Sea Turtle Nesting <ul><li>Process is much the same for all species </li></ul><ul><ul><li>Female emerges from the water </li></ul></ul><ul><ul><li>Move onto beach up to a location between the dune vegetation and high </li></ul></ul><ul><ul><li>tide wrack </li></ul></ul><ul><ul><li>Female digs an egg chamber </li></ul></ul><ul><ul><li>Drops soft shelled eggs into chamber </li></ul></ul><ul><ul><li>Covers eggs with sand </li></ul></ul><ul><ul><li>Scatters surface sand to hide nest </li></ul></ul><ul><ul><li>Finally, female returns to the sea </li></ul></ul>
    5. 5. Females <ul><li>Reach sexual maturity in 10-50 years depending on species </li></ul><ul><li>Nesting occurs 2-8 times in a season </li></ul><ul><li>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 </li></ul><ul><ul><li>Nesting beach can be adjacent to feeding grounds or hundreds of kilometers away </li></ul></ul><ul><li>Reproductive life spans can exceed 40 years </li></ul>
    6. 6. Hatchlings <ul><li>Eggs incubate for about 50 days </li></ul><ul><li>After hatching they dig almost to the surface, then wait for the sands to cool </li></ul><ul><li>When night falls they make a mad dash for the ocean </li></ul><ul><li>They swim non-stop for 24-36 hours to reach “nursery areas” </li></ul><ul><li>Only 1 of every few thousand will survive to maturity </li></ul>
    7. 7. Seafinding <ul><li>Process of locating the ocean from the nest </li></ul><ul><li>Accomplished by visual cues </li></ul><ul><li>Hatchlings scan 180 º wide areas close to the horizon </li></ul><ul><ul><li>Turn away from areas that are dark and elevated </li></ul></ul><ul><ul><li>Move towards areas that are flatter, lower, and bright </li></ul></ul><ul><ul><li>Depending on the environment, cues can be equally important, or one cue may be more important than the other </li></ul></ul>
    8. 8. The Effects of Artificial Lighting on Females <ul><li>White light repels turtles </li></ul><ul><li>“ Dose dependent” - some nesting will still occur if levels are low enough, but not in great numbers </li></ul><ul><li>Presence of lighting is now becoming a major factor in nesting location choice </li></ul><ul><ul><li>Nesting sites normally chosen for their remoteness, low wave energies, proximity to favorable oceanic currents, and absence of predators </li></ul></ul><ul><li>As humans continue to modify more </li></ul><ul><li>and more habitat, nesting will become </li></ul><ul><li>more concentrated on the few </li></ul><ul><li>remaining “dark” beaches </li></ul>
    9. 9. Consequences of Concentrated Nesting due to Human Lighting <ul><li>Spatial concentration will attract predators (both marine and terrestrial) and increase hatchling mortality rates </li></ul><ul><li>Destruction of nests due to over crowding </li></ul><ul><ul><li>Females that come to nesting site after others may destroy other nests while creating their own </li></ul></ul><ul><li>Microbial blooms due to larger numbers of dead eggs </li></ul><ul><li>Increases the probability of chance events destroying nests </li></ul><ul><ul><li>Local storms, hurricanes, etc. </li></ul></ul>
    10. 10. Effects of Lighting on Hatchlings <ul><li>Lighting keeps hatchlings from locating the sea </li></ul><ul><li>Results in disorientation or misorientation </li></ul><ul><ul><li>Disorientation: crawl for hours in circuitous paths </li></ul></ul><ul><ul><li>Misorientation: crawl away from ocean toward lighting </li></ul></ul><ul><li>Thousands die annually in Florida alone </li></ul><ul><ul><li>Exhaustion, predators, entanglement in vegetation, dehydration, crushed by cars </li></ul></ul>
    11. 11. Hatchling Orientation as Effected by Light
    12. 12. Why does Artificial light have this affect ? <ul><li>The physiological changes responsible for the break down in normal orientation systems is unknown </li></ul><ul><li>It may be that lighting results in directional cues that misinform hatchlings </li></ul>
    13. 13. Difference Between Natural & Artificial Light
    14. 14. Artificial Light <ul><li>Differences between artificial light and natural light result in pathological behavior </li></ul><ul><li>Directness of light is major factor in causing abnormal behavior </li></ul><ul><ul><li>Increasing illumination in the background diminishes effect </li></ul></ul><ul><li>Laws have been passed to regulate/restrict lights around nesting beaches </li></ul><ul><ul><li>Nesting is slowly increasing </li></ul></ul><ul><li>New threat from lights farther inland </li></ul>
    15. 15. Photopollution <ul><li>In the U.S., 30% of outdoor lighting is wasted by illuminating the atmosphere </li></ul><ul><li>Costing an estimated $1.5 billion in wasted electricity </li></ul>
    16. 16. Photopollution Also Affects Migratory Birds <ul><li>Every year about 90,000 migratory birds die in New York City </li></ul><ul><li>Lights confuse and blind birds causing them to collide with the buildings </li></ul><ul><ul><li>New York started a Lights Out NY campaign in 2005 </li></ul></ul><ul><ul><li>Empire State Building and Chrysler Building dim their lights </li></ul></ul><ul><li>Asking the Public to: </li></ul><ul><li>From September 1 to October 31st </li></ul><ul><li>Tall buildings (40 stories or more): </li></ul><ul><ul><li>Turn off decorative lighting on the upper stories by midnight and leave lights off until daylight. </li></ul></ul><ul><ul><li>Tenants on the upper floors are encouraged to turn out lights or draw blinds by midnight. </li></ul></ul><ul><li>Low buildings (with extensive glass exteriors along Hudson River and East River): </li></ul><ul><ul><li>Turn off exterior lighting by midnight and leave lights off until daylight. </li></ul></ul><ul><ul><li>Turn off interior lighting or draw blinds by midnight. </li></ul></ul><ul><li>This campaign saves birds and money </li></ul><ul><ul><li>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. </li></ul></ul>
    17. 17. Photopollution Also Affects Migratory Birds <ul><li>Chicago was the first U.S. city to initiate a Lights Out Campaign </li></ul><ul><ul><li>Buildings dim their lights 5 months of the year </li></ul></ul><ul><ul><li>It is estimated that this program saves 10,000 migratory land birds each year </li></ul></ul><ul><li>Other cities that have similar programs </li></ul><ul><ul><li>Boston </li></ul></ul><ul><ul><li>New York City (as discussed) </li></ul></ul><ul><ul><li>Baltimore </li></ul></ul><ul><ul><li>Minneapolis </li></ul></ul><ul><ul><li>San Francisco </li></ul></ul><ul><ul><li>Denver </li></ul></ul><ul><ul><li>Detroit </li></ul></ul><ul><ul><li>Indianapolis </li></ul></ul>
    18. 18. Management Solutions <ul><li>Turn off unnecessary lights </li></ul><ul><li>Reduce wattage to the minimum required for function </li></ul><ul><li>Redirect and focus lighting so it only reaches the ground or areas where it is intended </li></ul><ul><li>Eliminate all upward-directed decorative lighting </li></ul><ul><li>Use alternative light sources where possible and practical </li></ul><ul><li>In any new construction, incorporate the latest light management technology </li></ul>
    19. 19. The End Citations Salmon, M. 2003. Artificial Night Lighting and Sea Turtles . Biologist, 50 (4): 163-168. Richard. 2010. http://www.treehugger.com/files/2010/08/audubon-lights-out-campaign-save-migratory-birds-this-fall.php http://lightsout.audubon.org/

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