Lights cast a shadow over conservation
Studies show night glow contributes to decline of nocturnal birds and pollinators
Stretching from St. Louis to Kansas City, bustling Interstate 70 is among the busiest highways that crisscross Missouri. But one thoroughfare that is just as busy is the migration highway of birds that fly through the Show-Me State.
More than 250 bird species navigate over our heads during their migration’s day and night hours. That may seem like a hefty number, but Missouri also has a vast network of insects—a number that cannot be quantified. Looking at bees alone, there are more than 450 species in the state, surpassing the number of bird species. That is a lot of little furry insect bodies to count. The habits of these insects can also be a mystery, one that we are starting to shine a light on.
As you drive I-70 or other major highways, you may have noticed that your windshield requires less cleaning these days. The night skies are becoming increasingly crowded with the glow of light pollution and not insects. Just in the past few years, it has become increasingly apparent that much of the world lives under this sky glow. With more light pollution, it’s not only becoming harder for us to see the Milky Way galaxy, but birds and insect populations are also feeling the struggle. Studies show how light is a contributing factor to bird and insect decline.
Just like birds, night pollinators use the moon and the stars to navigate their surroundings. With moth species outnumbering butterfly species, this may be a concern. Moths also pollinate, and many species of plants, such as the Missouri primrose, require the assistance of such nocturnal insects to help them reproduce. In fact, when butterflies check out for the night, moths and other insects pick up one-third of plant pollination.
Sadly, predators easily feast on moths that get caught in an endless flying loop around streetlights, and more migrating birds get misdirected due to sky glow. Other confused travelers are the swarms of mayflies laying eggs on reflective streets rather than streams and creeks.
People who live in rural areas might assume they don’t have to worry about this issue. But look around. The city glow is becoming brighter and closer each year. Storage units are popping up along country roads, rural warehouses are becoming beacons, and discount retail stores are being constructed in what seems to be the middle of nowhere.
Another big question is whether this light pollution has any effect on our crops such as soybeans, which are short-day plants that require a certain number of dark hours to flower. Most artificial light is blue light, which chlorophyll A and B need to capture energy and transfer it to the plant for photosynthesis. The Illinois Center of Transportation has conducted a study suggesting that pollution of blue light does cause development delays, yield reduction and height increase of soybean plants.
While more studies need to be conducted on how this may affect soybeans in Missouri, especially those next to highways and industry, it is not hard to connect the dots. The detrimental effects of blue light to human health has been in the news as smartphones and computer screens become increasingly a part of our daily lives.
One remarkable thing about light is that, unlike other pollutants, it is a relatively easy fix and can even save you money. Talk about a win-win for everyone! Directing outdoor light downward instead of sideways reduces the contribution to sky glow. Another simple change is using red-spectrum lights. These emit warm tones, instead of LEDs that replicate the blue light we get during the day. Making the switch to dimmers, motion sensors and timers at night will also save money by cutting out unnecessary expenses. Consider exploring the various solar-powered options to potentially enhance your savings.
With these relatively straightforward measures, you can do your part to help curb light pollution. The result will not just benefit you and your family but will also improve the health of our yards, farms and parks for animals, insects and plants.
-Emily Beck
Natural Resources Conservation Specialist for MFA Incorporated
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