9 9 ecology of darkness

Photo credit: Christopher V. Sherman

ECOLOGY OF DARKNESSTexas Master Naturalist Hill Country Chapter

September 9, 2015

Bridget Schneider Langdale

Milky Way over Pedernales Falls State Park

Life on Earth Depends on

Natural Darkness

• Wildlife and Ecosystems

• Human Health

• Crime, Safety, the changing light industry

• “YOU can prevent Light Pollution”

The Bortle Scale: A measure of light pollution

LIGHT POLLUTION

* Rhythm of day/night* DNA encoding

ReproductionNourishmentSleepProtection

Endangered and at RISK…..

WILDLIFE & ECOSYSTEMS

BIRDS

• Migration• (use moon & stars)• Crash/exhaustion• 450 species effected• Seabirds also

• Offshore drilling• Fisherman lights

REPTILES: Sea Turtles

FROGS*Tree Frogs…stop calling/less reproducing*Affects DNA synthesis & production of hormones* How much fat stored for winter and production of eggs

FIREFLIES*Mating disrupted

MOTHS:*vulnerable to predators

Photo courtesy Steve Irvine

Competition: These moths are stuck in the light. They aren’t out competing to get the best places to raise young. They aren’t avoid predators. They aren’t finding food to sustain their lives and outlive the competition. Photo by Steve Irvine

AMPHIBIANS*Salamanders….less eating time*Saccus Vasculousus/brain tissue….length of day/time for spawning

MAMMALS:

Annual Rhythms: Photoperiodism, the functional or behavioral response of an organism to changes of duration in daily, seasonal, or yearly cycles of light and darkness. Deer Oct-Nov-Dec: The shorter days trigger certain hormones causing the deer to go into “rut”. Hormone levels drop off in Jan triggered by shorter winter days. Feb-March: Bucks grow antlers due to an increase in hormones triggered by the more intense light and longer days.

Predation: Predators use the light to find prey. Predators might be at an advantage because of artificial light. On the other hand, some of their nighttime prey reduce their activity when the moon is full or when artificial lights make them think the moon is full. They may have more time to find food but their immune systems still need the darkness to keep them healthy.

Photoperiodism - Annular rhythms: Trees located under street lights often don’t sense it’s time to stop producing chlorophyll.

Photoperiodism: Determining the proper time to flower is important to ensure the reproductive success of plants. Flowering in many plant species is controlled by photoperiodism. And, the right pollinators may also be present or not based on the light / dark ratio.

PERMANENT FULL MOON (by humans…) 5 Species Threatened by LIGHT POLLUTION

5: Sea Turtles4: Fireflies3: Atlantic Salmon2: Tree Frogs1: Monarch Butterflies

EVERYTHING IS CONNECTED

Humans have outgrown dependence on the stars…

Wildlife/our environment have not.

Awareness. Make a Change. Help out wildlife. Restore your appreciation for the night sky.

HUMAN HEALTH ISSUES

MISSING THE DARKHealth Effects of Light Pollution on Humans

Increasing risks of:

• Obesity• Depression• Sleep Disorders• Type 2 Diabetes• Breast cancer• …..more

Sleep and Melatonin

• We need ‘restorative sleep’….6+ hours of dark• Biggest issue is …Melatonin and Blue Light

• Melatonin production– Keeps us healthy– Antioxidant properties– Induces sleep– Boosts immune system– Lowers cholesterol– Helps thyroid, pancreas, ovaries, testes and adrenal glands

Electronics Blue Wavelength, tricks our brains into thinking it is daylight.

Circadian Rhythm: Daylight/darkness

Sunlight: various wavelengthslots of blueKeeps us alert

BlueLight in Offices: reduce fatigue, improve mood, performance….

Evening: Pineal Gland secretes Melatonin…Quality/Quantity of sleep

Lower BLUE light

COLOR TEMPERATURE APPS.Adapts your electronic screen to the time of day…cool light during the day and warm light at night.

F.Lux for laptops, iPhones, iPadsLux for AndroidTwilight….smartphones or tablets

Navigation Sea Turtles - Dung Beetles - Birds

Reproduction Frogs - Flowers - Fireflies

Circadian Rhythms Rats - All Living things - Humans

Photoperiodism Flowers - Deer - Fish Spawning – Leaves Turning

Competition Moths – Seal

Predation Fox - Squirrel

General Habitat Destruction Snake

ECOLOGY ISSUES

Crime, Safety, the changing light industry

Wasting Energy and Money

Do you feel safe?

Glare Kills VisibilityGood Visibility = Safety & Security!

Photos courtesy of Cliff Hass.

Entrance Safety

Light Trespass

Will Light Clutter Attract Tourists?

Aim Lights Down

Good vs. Bad lighting: What do you look for?

Full Cutoff & Fully Shielding the Light Source

….the changing light industry…

WATTS – LUMENS…• Watts: measurement of power consumed • Lumen: measure of the total amount of visible

light emitted

….the changing light industry……..COLOR

• Color: use only warm-white bulbs• Color Temperature: 3500K or lower

• Glare, sky glow, and light clutter• Tennis court with GOOD lighting. See how its only going where it is needed?

Basic Guidelines

1. Fixtures shielded/no light above horizon (exception of landscape & holiday)

2. No Light Trespass (light source not seen)

3. Lumens: add up…under 100,000 per acre

4. Color…less than 3500K

5. Timers, Motion Detectors, Dimmers

6. Turn off if not using

Photo by Lauren Cook

BE WISEAlmost every living thing on our planet depends on the cycle of natural light and natural darkness. We disrupt our natural circadian rhythm when we fly across time zones. We may get “jet lag”. Wildlife and fish experience this same disorientation of time when there is too much artificial light at night. Behavior governing mating, migration, sleep, finding food and other behaviors are determined by the length of nighttime.

Life on earth depends on natural darkness.

Water, air, and soil pollution can take generations and massive changes in our culture to reverse.

LIGHT POLLUTION can be turned around. Maintain safe, functional levels of light

you can help

AWARENESS – EDUCATE COMMUNICATE

Dark Sky ProclamationsDark Sky Ordinances

TEXAS IS BECOMING THE LEADER

• Mason• Llano• Fredericksburg• Blanco• Pedernales Electric Co-op• CTEC…replace broken fixtures

IDA Recognition in Texas• Dripping Springs• Enchanted Rock State Natural Area• Copper Breaks State Park

Educate:• Individual land owner• Rural Communities• Subdivisions. Master planned areas.• Unincorporated townships.• City Councils• County Commissioners & Judges• Developers. Builders. Remodelers.• New businesses• Neighbor to Neighbor

• *Star Parties & MOON Tours

Amateur Astronomy GroupsMason Star Gazers (MSG) “PDF”

Low Mounted Full Cutoff Light

IDA RECOGNITION DARK SKY REGION?








Star Parties & MOON Tours

….all things came to be: the vast expanse of interstellar space, galaxies, suns, the plants in their course, and this fragile earth, our island

home.

“ZINGER with a Train”Recent Meteor Shower in early August 2015

Advice from the

NIGHT SKY

See the Big Picture

Be a Star

Keep Looking Up

Don’t be Afraid of the Dark

Stay Full of Wonder

Expand Your Horizons

Turn Off the Lights! Ilan Shamir

Bridget Langdale aka: MOON RABBIT

[email protected]

www.darksky.org (International Dark Sky Association)www.hillcountryalliance-org/HCA/NightSkies

Special thanks to Cindy Luongo Cassidy

mailto:[email protected]

http://www.darksky.org/

http://www.hillcountryalliance-org/HCA/NightSkies

9 9 ecology of darkness

Environment