light pollution

Welcome Little-Known Moths to Your Garden

Smerinthus jamaicensis


The little sphinx moth caterpillar was on a mission: To find a safe, secure spot where she could transform herself and stay alive during the cold, wet winter months ahead. On a warm September day last year I watched as she inched her way across half the length of my back yard, occasionally meandering around roadblocks like plant stems and small rocks that must have seemed like insurmountable boulders to her (although at one point she nimbly climbed up and over a small log in her path). A couple of times she burrowed down into loose leaf cover, but then moved on, perhaps surmising that a better place would come along. After I walked away for a few moments I lost track of her. Since my yard is a leafy nirvana for butterflies and moths such as her species (Smerinthus jamaicensis or twin-spotted sphinx) that need to nestle themselves in soil under fallen leaves so they can pupate over the winter months, she probably found a suitable place that would hold her until a warm spring day allowed her to emerge and take to her wings.  

We’re nearing the end of National Moth Week, a short stretch of time set aside to appreciate these gentle, humble, and nimble flyers who tirelessly supplement the daytime work of bees, butterflies, and other pollinators, as well as offer food for other animals. They get a fraction of the attention that butterflies do and are often vilified, despite their close relationship, beauty, and rich diversity. Within their hidden world are unusual, intriguing, and dramatic behaviors. Moth species outnumber butterflies by around ten to one; there are more than 11,000 species in the U.S., with another 160,000 globally. 

Gardens are very important places for moths since development and agriculture severely limit their habitat. There might be dozens of moth species inhabiting an ordinary urban or suburban garden, and the way you manage yours can affect the conservation of their populations, which are, as you might expect, seriously in decline, like most insects. Here are some tips:

Protect them from light pollution. For nocturnal and crepuscular moths, as well as other insects and migratory birds who use celestial navigation, unnatural lighting can cause disorientation and confusion, leading to exhaustion and death. The best way to help restore their natural behavior is to turn off all exterior lights, using motion sensors when necessary. If you must have lights on, use only dim bulbs in warm tones, which are less likely to attract moths. Draw shades and draperies indoors as well, to prevent light trespass.

Ease up on “clean-ups”. Adult moths and their caterpillars, as well as some butterfly species including the mourning cloak, need fallen leaves, stems, twigs and other plant debris to help them hide from predators and to provide suitable places to pupate and spend the winter. Let fallen leaves stay on soil and delay cutting back spent plants until well into spring (the later the better), rather than doing it in autumn or winter (and always check branches that may hold a chrysalis). If you must neaten up a portion of your garden in the spring/summer, leave collected plant material elsewhere in your yard.

Forget about herbicides and other pesticides, which can kill moths and other insects. This will also benefit your garden by increasing the number of predatory insects that help control the pesky ones. There needs to be a supply of prey in order to feed the predators—it’s a natural cycle that needs to be supported.

Limit hardscaping (concrete, gravel, decking) and increase the amount of area given to plants other than lawn, since moths and other wildlife can’t use hardscape for habitat.

Grow a wide variety of plants (preferably native species local to your area) to appeal to a diversity of moth species—everything from grasses and flowering perennials to shrubs and trees. Gardening for moths is similar to gardening for butterflies and other pollinators, although moths generally tend to feed on a greater variety of foods than butterflies. 

As adults, most moths need a sugar source and they may feed on plant nectar, rotting fruit, or tree sap. Moth-pollinated flowers tend to be fragrant and pale or white, such as western mock orange (Philadelphus lewisii), oceanspray (Holodiscus discolor), and snow brush (Ceanothus velutinus), which allow nocturnal moths to easily find nectar after dark, so think “moonlight garden”. Moths that pollinate by day typically feed at flowers that native butterflies do, since they usually have long tongues. Some moths, like the twin-spotted sphinx, have reduced mouthparts and digestive tracts so don’t eat at all in their adult stage; they exist briefly only to mate and lay eggs, which in turn may provide food for predators like birds.

Almost all moth species need a host plant on which to feed during their larval stage. Many moth caterpillars eat leaves like most butterflies do, but some species may eat seeds, woody stems, or roots. The most important native host plants for moths and butterflies in the Pacific Northwest — considering the abundance of species they host — include Oregon white oak (Quercus garryana), oceanspray (Holodiscus discolor), and species in the following genera: Acer (maple), Alnus (alder), Arctostaphylos (manzanitas and bearberries), Ceanothus (wild lilac), Populus (aspen and cottonwood), Ribes (currants and gooseberries), and Salix (willows). 


© 2019 Eileen M. Stark

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Posted on by Eileen Stark

Flip the Switch to Save the Dark!

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                        To Know the Dark
To go in the dark with a light is to know the light.
To know the dark, go dark. Go without sight,
And find that the dark, too, blooms and sings,
And is traveled by dark feet and dark wings.
                                                  —Wendell Berry

 

If you live in or near a city, chances are you don’t see many twinkling little stars at night because light pollution — the fastest growing form of human-caused pollution — is making the night sky glow brighter each year. In fact, night skies across roughly half of the U.S. are polluted by artificial light. A fairly recent study from the University of Exeter found that observable light emissions increased globally by at least 49 percent from 1992 to 2017. But that figure only includes light visible via satellites, and scientists estimate the actual increase may be much higher — as much as 270 to 400 percent, depending on  the region.

Excessive, poorly designed lighting that spills skyward changes the predictable day/night cycle that life evolved in. Even tucked into bed, our glaring human footprint trespasses into the nocturnal world to mess up biological rhythms and health, consume and waste energy, steal the beauty and wonder of the nighttime sky, contribute to climate change, and disrupt beings within complex ecosystems. 

As I wrote in a Portland Monthly article a few years ago, myriad wildlife species that work the dusk and dawn or graveyard shifts depend on uninterrupted darkness to provide exquisitely timed cues that direct communication, reproduction, protection, sleep, foraging behavior, and orientation. For long-distance migratory birds who travel at night during spring and fall using celestial navigation, artificial light can disrupt or kill them in several ways. The timing of migration (when wildlife leave their summer or winter grounds) is controlled by several factors, one of which is photoperiod (the duration of light and dark), a predicable indicator of time of year. When the haze of artificial lighting conceals this cue, birds may leave too early or too late, which may cause them to miss optimal nesting conditions. And when lured into a maze of city lights, migrants become confused and disoriented and often collide with unnecessarily illuminated buildings, or drop from exhaustion. It’s estimated that as much as a billion birds are killed this way each year in North America, but it’s not only birds that are affected.

Nocturnal moth (Cyclophora pendulinaria), awaiting the dark.

All animals—reptiles (including sea turtles), amphibians, mammals (including humans)—are negatively impacted. Arthropods, like nocturnal moths — their fate seamlessly interconnected with other ecosystem members — perish rather than pollinating, breeding, and supplying food for birds. And the seasonal cycle of plants, including trees — particularly those with the misfortune of being planted beneath streetlights or in the path of landscape lighting — is threatened. Researchers believe that early bud break caused by incessant light will have a cascade effect on other organisms whose life cycles work in tandem with such plants, as well as the plants themselves. A recent study suggests that intensified light at night may have serious far-reaching consequences in disruption of key ecosystem functions and services.

Plants need to “sleep” in darkness, just as we do, and sleep deprivation is as harmful to trees as it is to animals. Trees that are sensitive to day length tend to be more affected by artificial light, and changes to day length can cause disruptions in flowering patterns, growth of larger leaves (which can cause them to be more susceptible to air pollution or water stress), and even prevent trees — particularly young ones — from entering dormancy in autumn. Longer growing seasons are not a good thing! Tree species most affected by artificial light include dogwood, maple, birch, aspen and cottonwood.

The bright side
Although nights are getting brighter each year since continual development and sprawl amplify light pollution, there is a bright side: It’s reversible. Organizations such as the International Dark-Sky Association and many smaller groups, like Audubon of Portland’s Lights Out campaign, are working to preserve and protect the night skies, and there are Dark Sky communities, parks, and preserves. While it will take urban planners, designers of fixtures and buildings, and elected local officials to create standards for outdoor lighting that minimizes light pollution, glare and trespass overall, those of us who are homeowners can each do our part—and it takes very little effort. 

Hello darkness, my old friend
→ Switch it off: Turn off unnecessary outdoor lights or, better yet, install motion-sensors that are designed to turn on only when needed and turn off after a short period of time.
→ Shield it: Use fixtures that aim light downward and that are shielded to prevent glare and “trespass” on habitat and neighbors. Those that have a solid cap above the bulb that prevents light from traveling skyward are best; you can also buy shades to fit existing fixtures. Lowering fixtures sometimes can also help.
→ Warm it up: Select warm-colored LEDs (under a 3,000 Kelvin rating) that supply only the amount of light needed. Those that emit short cool or blue wavelengths are brighter, scatter light more, and are worse for wildlife.
→ Remember indoor lights: Close draperies, especially during peak migration seasons (April through June and August through November) to stop rays from straying outdoors.
→ Request shields: Shields on streetlights may be possible. Inquire with your local department of transportation.
→ Buck the trend of landscape lighting: Most “decorative” outdoor lighting is pointless, detrimental to wildlife and plants, and wasteful, particularly fixtures that point light upwards and sideways.
→ Close all blinds, shades and/or shutters to reduce nighttime light that attracts and confuses wildlife.

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Safety concerns?
Most home burglaries occur in broad daylight, not in the middle of the night, and excessive lighting does not lessen crime. _MG_0166In fact, studies show that bright lights can make victims and property easier to see, as well as create much greater contrast and excessive glare, which increases the deep shadows that may actually increase crime and vandalism and make it more difficult to see potential intruders on your property. To improve security, use motion sensors that don’t give criminals a leg up. 

 

 

© 2018 Eileen M. Stark

Updated 02/2024
Posted on by Eileen Stark

Ten New Year’s Resolutions For Your Eco-Garden

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Conjuring up some New Year’s resolutions? Don’t forget about your yard and the ecosystem of which we are a part. Promise to do something positive in your yard this coming year to help dwindling wild species whose habitats have been—and continue to be—ravaged.

You certainly don’t need to replace every plant in your yard or eliminate all of your lawn to give back to nature, although the more the better. And you don’t need to do everything all at once—baby steps are fine! In fact, incremental change is usually best, since wild species using existing plants and other elements might be harmed by a drastic, rapid change. If you don’t have a yard, think about volunteering with an organization that’s working on a restoration project—it can be satisfying and enjoyable.

Here are ten resolutions I recommend to help make your yard more humane and functional in the coming year. Some are very easy, some not quite so much. Choose one, two, or all! They are not listed in any particular order because each one is important.

Add some clean water. Birds, insects, mammals, amphibians—all creatures—need water year round to survive. Even just a shallow bird bath can help, but some maintenance is a good thing: Change the water every few Bird bath robin babydays, give it a good scrubbing every week or two, and keep it out of reach of marauding cats and dogs. Plates or shallow bowls filled with clean pebbles or gravel and water will provide for insects; butterflies will also appreciate mud puddles which they use to obtain moisture and nutrients essential for breeding. Artificial ponds should be shallow on one side and have gradually sloping sides so tiny animals can get out easily. More tips here.

Let natural systems flourish and harmonize by minimizing “clean-ups” and maintenance. Yes, this one lets you work less! Allow fallen leaves to stay on the soil to create cover for overwintering insects like bumblebees and butterflies as well as food for birds, raking or sweeping them only off areas that need to be clear (like sidewalks, driveways, or lawn). Leave dead wood such as snags (dead or dying trees that won’t crash on someone’s head) and “downed wood” —fallen branches, twigs, and bark—which is absolutely essential wildlife habitat that will protect and nurture soil, too. Create brush piles or rock piles to help provide cover and nest sites for birds pilesand other small creatures. Leave seed heads and flower stalks on perennials until spring is well under way to provide food, cover, and habitat. If/when you eventually cut them back, leave them on the ground for a month or longer in case they contain native bee larvae or other overwintering insects waiting for the chance to live out their lives.

Get rid of invasive plants that compete with natives. Depending on the plant species, this can be an easy job or one likely to give you headaches, backaches, and an urge to scream. It can take a few days or a few years. But once your task is accomplished, I guarantee that you will feel an extreme sense of satisfaction. And there will be more room to plant lovely, functional plants! If you have several invasive species in your yard, determine which may be the most invasive and start with that. Nonnatives that produce berries, like English holly trees, are particularly problematic because they spread into nearby natural areas by birds, but also via vegetative reproduction. English ivy also produces berry-like fruit and spreads by rooting on the soil surface and on tree trunks—at the very least, periodically cut it back at the base of trunks to prevent it from harming trees. There are numerous introduced plants that push out native species, so check with city, county, and/or state agencies to find lists and descriptions of invasive plants in your area; the USDA also offers information. My book offers some tips for removing invasive plants, as does Green Seattle Partnership and this post.

Remove lawn. Lawn for the sake of lawn is not beneficial and is awfully wasteful. When deciding which part(s) of your lawn will receive walking papers, start by choosing areas that you never or rarely use. Often this is the front yard. If you’re not ready to go all the way and remove a large area of turf, consider at least removing lawn under trees and in areas that are difficult to mow, such as slopes. Lawn can also be minimized by enlarging existing beds and adding ecologically beneficial native plants. The gentlest way to remove lawn is to simply cover it with about 6 sheets of overlapping newspaper (or cardboard) on a non-IMG_0403 sRGBwindy day. Dampen it, poke a some small holes, then top it with 4 or 5 inches of weed-free compost (leaf compost is good) and fallen leaves over that. Leave it to decompose for at least several months (until grass roots have died) before planting. Removing lawn via a sod cutter or spade can damage tree/shrub roots.

Grow native plants that are indigenous to your area. For this I suggest you consult a regional native gardening book like my book (if you live in the Pacific Northwest, west of the Cascades). Choose species (preferably “true species,” not cultivars) that are native to your area and that will flourish in your site’s soil, light, and moisture conditions. Grow them with other members the same plant community to provide the most benefit.

Provide for all life stages of pollinators. Many pollinating insects, including native bees and butterflies, will have gone through several stages by the time they reach adulthood and their needs differ greatly. So, in addition to providing water and growing groups of sequentially-flowering plants (preferably native to your area) that supply pollen and nectar from early spring through fall, provide the “host plants” needed for egg laying and for the feeding of larvae (in the case of butterflies and moths: caterpillars). For insects that undergo a complete metamorphosis, protect habitat for pupa (chrysalis). The latter mainly involves simply leaving fallen leaves and other organic matter on the soil, delaying any pruning of host plants until late spring, and not using leaf blowers, which eliminate the habitat of creatures needing a place to wait out the winter, such as chrysalis held in place on a twig by a fragile silken thread.

Don’t use pesticides or poisons. Synthetic pesticides should be avoided at all costs, but even so-called organic controls can be deadly and indiscriminate, especially if used improperly. If a pest if causing enough damage in your Aphid eaterkitchen garden to warrant a control, consider hand removal, barriers and screens, companion plants, or simply sprays of water from the hose. Allow a natural balance by welcoming natural pest control such as birds (see bushtit devouring aphids, right) and predatory insects. More than two billion pounds of pesticides are sold each year in the U.S, which severely threaten pollinators — without whom we can’t produce food — and damage water and soil quality. 

Protect birds from reflective glass. Up to a billion birds are killed or injured by colliding with buildings in North America each year. Though skyscrapers kill countless birds, large structures four stories or less in rural locales are responsible for the most bird deaths, according to a 2017 study. Many of those strikes can be prevented and here are some ways to help.

Keep Kitty indoors. Domesticated cats kill millions of birds each year, but it’s not their fault they’re outside. Whenever possible, keep your little predators indoors for their safety as well to protect little wild creatures. To prevent boredom and health issues: Add levels, especially around windows, widen windowsills with tables of appropriate height, or add window boxes. If you’re more ambitious, build a catio! They come in all sizes, shapes and price ranges and provide kitty with a safe outdoor experience.      

Turn on the dark. Look out your windows at night and chances are—if you live in an urban area—you won’t see the twinkle-twinkle of little stars because light pollution (any adverse effect of artificial light) is making the night sky glow brighter each year. Its most obvious effects are on migratory songbirds lured into cities where they collide with unnecessarily illuminated buildings, killing more than 100 million of them each year in North America. But lit up low-rise structures in rural locales also distract and have been found to pose greater danger than similarly-sized urban buildings, with what researchers call “the large scale beacon effect.” And for nocturnal animals, artificial light may be the most extreme change forced upon them. You can help by minimizing artificial lighting migration seasons, and anytime to prevent moths from exhausting themselves to death, to keep bats in the dark, and diurnal animals asleep. Choose fixtures that shine light downwards, not to the side or upwards, and use motion-sensors so that lights go on only when necessary. If you worry about crime, studies show that outdoor lighting does not decrease crime and may even exacerbate it; most residential crime occurs during daylight hours. In addition, cover windows with shades or draperies at night to cut down on light escaping your house. More info.


© 2017 Eileen M. Stark

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Posted on by Eileen Stark