Color: Standing Out or Blending In?

“We really want the plants to match the color of the window trim,” a client who’s building a new house on the outskirts of Santa Fe tells me. The trim is a deep red. “Maybe roses . . .?” She trails off.

“I like the colors that really pop! You know, something that’s going to stand out against this color of stucco,” another client says, gesturing toward a courtyard wall that emanates a warm, peachy, earthen tone. “You know, something that I can really see, not a pale pink or anything that just blends in.”

Other people request cool blues, purples, and whites or hot pink, fiery orange, and electric yellows as hues to create a wow effect for front entrances, back portal viewsheds, and natural canvases seen through the deliberate frame of windows. In my work as a landscape architect, color is both central and elemental. Color excites and entertains; it signals the spring and summer seasons of bloom and growth, the peak periods of a plant’s life cycle.

Color—hue, saturation, light—pleases, dazzles, and seduces. But even when manifesting as ornament or adornment, color is more than a skin-deep composition. It is a primary source and ingredient from which flows creativity, identity, nuance, and ambience. Personal wardrobe styles, interior decor, and countless forms of artistic expression course through visual art media, with color as currency. In the wild, color is both an innate and chosen tool by which animals identify themselves, their food sources, and one another. Beyond creative expression and outdoor aesthetic, color plays a critical role in plant and animal behavior. This might be most familiar as a bright red male tanager showing off to a pale yellow female or a hummingbird’s attraction to brightly colored penstemon, but as scientists are now learning, it also includes color adaptations in response to climate change.

We humans are used to manipulating our environment to suit our desires and needs, but how can we learn from the other-than-human world as the earth changes beneath our feet? What do flowers, pollinators, mammals, birds, and other life-forms demonstrate about what’s at risk and how we can adapt? How do we heed the warnings of our plant and animal kin? Can seemingly simple changes in flower and animal colors—even when they occur in parts of the spectrum we can’t see—serve as powerful cues and a call to action?

The autumn 2024 issue of Orion magazine celebrates green as the first color in the spectrum that the human eye seeks out, the one we equate with nature’s healing power, a signifier of shelter, safety, and sustenance. Development and extractive industries deliver daily death blows to habitats and living plant material that embody the color green as photosynthate alchemist, converting—so long as they live—sunlight and atmospheric gases into food and clean air. With Earth.Org reporting that more than 70 percent of the earth’s surface has been altered at the hands of humans, an undercurrent of fear and panic is amplified as the catastrophic disappearance of green becomes palpable; the loss of green symbolizes the loss of our universal source of life. In the Southwest, drought, bark beetles, and fire have hastened the loss of forests and magnified the fragility of riparian woodlands.

As green fades and falters, stirring unrest in humans, a subtle yet equally powerful color change is occurring in the petals of flowering plants. While ultraviolet-blind humans cannot detect the deepening of certain hues, beings including bees, butterflies, hummingbirds, and other pollinators are experiencing a potentially dramatic shift in the appearance of their floral lifelines.

A 2020 article in Current Biology reports on this phenomenon, summarizing recent research on flower color adaptations to climate change and the likely effects on pollinators. For several years, plant ecologist Matthew Koski of Clemson University has been investigating how ultraviolet pigmentation in plants is changing in response to rising temperatures and ozone decline. Curious about the effects of human-induced climate change on petal color, Koski embarked on a study of 1,238 flowers from forty-two different species in plant collections from North America, Europe, and Australia from 1941 to 2017. He and his research team found that, globally, flowers had increased UV-absorbing pigment in their petals by an average of two percent annually over the seventy-six-year period. According to a January 2022 article in Evolution, this variation in petal pigmentation is also known as UV-induced pigmentation plasticity. While this shift in color may seem subtle and perhaps insignificant in the scheme of more obvious climate-induced changes, it represents a radical shift in the relationships between pollinators and the plants on which they depend (and which, in turn, depend on them).

Here in New Mexico, the sixth-fastest-warming state in the nation, with an average increase in temperature of 2.7 degrees since 1970—experienced and sometimes magnified via earlier springs, hotter summers, and inconsistent precipitation—both wild and cultivated plants are increasingly stressed, making them susceptible to pest infestations and disease. Not only are they having to adapt to drought and other environmental conditions, but their very adaptation techniques, like modified petal color, may also compromise their pollinator-attracting abilities.

In some cases, color adaptations might benefit a plant, whether by decreasing pigment to protect its pollen from too much heat or increasing pigment to absorb more ultraviolet rays at high altitudes. But, as Koski and others have noted, increased UV-absorbing pigment in petals will likely make some flowers harder for pollinators to see. Because pollinators prefer flowers with a bull’s-eye pattern, with UV-reflecting petal tips and UV-absorbing pigments near the center of the flower, the loss of contrast between the ray petals and the nectar- and pollen-rich target will make these preferred species less obvious. Pollinators “might miss the flowers entirely,” said plant biologist Charles Davis of Harvard University, commenting on the implications of Koski’s study for Science.

Plant and pollinator survival depend on a reliable, recognizable color palette. Flowers must flaunt conspicuous contrast, a clear target to attract and guide pollinators to the critical core landing and feeding zone, the literal center of plant reproduction and foundation of life on earth.

While flowers’ survival depends on their own physiological strategies to stand out and be seen, other species’ evolutionary color adaptations help them blend into their habitats, camouflaging themselves as stealthy predators seeking prey, and as elusive prey avoiding predators. Animals, like their plant neighbors, evolving in relation to regional environmental fluctuations, provide visual indicators of climate change, warning signals that their home—our home—is in danger.

Bottom: Christie Green turkey hunting up by Tres Piedras, photo by Gabriella Marks.

On a mid-November elk hunt in 2023, near Red Hill at the base of Canjilon Mountain, I headed north into dense spruce timber, excited to have access where thigh-deep snowdrifts had previously prohibited entry. A faint skiff of new snow barely covered wisps of dormant grama grasses and fallen limbs. Elk tracks zigzagged across drainages and over saddles between slopes, but the snow had melted by 9 am. With the rising sun and warming ambient and ground temperatures, I shed layers of clothing, tucked them into my backpack, and continued, unimpeded, farther into the hunting grounds.

Although I welcomed the relatively easy trekking, I was keenly aware that the fall weather was peculiarly warm and dry, more temperate than “normal” at this 10,900-foot elevation. In seasons past, near-zero temperatures, ice, and layers of snow with hardened crusts from freeze-thaw cycles have challenged my ability to move quietly and efficiently. This year, the daily pilgrimage from low ground to high, cresting saddles between peaks and following deep, contoured drainages, felt like a cakewalk. Could hunting the high ground really be this easy? Would future autumns and winters be as warm or warmer? How would the animals move and adapt? Would they, too, migrate higher up and farther away without the physical challenge of post-holing through snowbanks and scraping away at accumulations of snow and ice to reveal remnant meadow forage and shrub tips to browse?

As I stretched one leg and then the other over a maze of fallen spruce timber, navigating among aspen stands and through clusters of cinquefoils, mountain mahogany, and carpets of bearberry, a flash of white caught my eye. Holding still, slowly raising the binoculars to my eyes, I watched and waited for the white spot to reappear. Had I imagined it or was something that conspicuous really afoot?

There, skittering along the length of a flattened, decomposing fir log, a white weasel busied herself with daily chores. Moving with fluid agility, she hugged the woody apparatus like a balance beam gymnast, stopping intermittently to sit up, scan, and survey her surroundings, then she dropped down, belly low to the tree trunk, and poured herself into a slivered opening beneath a mass of coniferous ground cover. “She’s going to get snatched right up,” I thought to myself, “sticking out like a sore thumb. Guess she didn’t get the memo that winter has yet to come.”

After watching her fastidious busyness for a while longer, I moved upward toward the ridgeline, intending to cross over to the cooler, north-facing slope where elk would likely be headed to bed down for the morning.

A similar experience lingered in my memory from three years ago, bowhunting for rabbit in the Santa Fe National Forest. I’d chosen an easily accessible, close-to-home location for a spontaneous midmorning hunt. In the dark cover of the spruce and Douglas fir mountains, a very white rabbit dashed in front of me, darting across open ground toward the cover of thick understory. She, too, had donned the wrong winter coat, her gray-brown summer fur turned to pure white, a programming error that could cost her her life. Without a backdrop of snow into which she could tuck herself, becoming inconspicuous, making herself safe from the threat of watchful, hungry eyes, the white rabbit was literally a moving target.

Weasels, ptarmigan, and snowshoe hare change their color in response to the photoperiod, or length of daylight hours. This change is involuntary. Unlike us, they can’t reach into the closet and opt for appropriate outerwear that will protect them best on any given day. Reduced daylight triggers hormonal responses that decrease production of dark pigments, allowing the lighter fur to grow in as winter progresses. In spring, increased daylight triggers the opposite response and the animals’ fur and feathers revert to the corresponding seasonal camouflage of beigy browns.

In 2018, researchers investigating seasonal coat and color change in eight species, including hares, weasels, and foxes, found that, as suspected, animals at higher latitudes tend more predictably toward winter white, while those at lower latitudes molt to white or both white and brown. When molting doesn’t correspond to environmental conditions, scientists call this “mismatched camouflage.”

“As snow duration decreases, animals in winter white coats become more conspicuous against snowless ground, increasing mortality,” explain researchers in the Fisheries, Wildlife and Conservation Biology program at North Carolina State University in a March 2019 article in Ecosphere.

As a hunter, I use my own adaptive strategies to blend in or stand out. When pursuing spring turkeys, the goal is to conform to the surrounding earth tones and plant shapes and textures. Covered in camouflage from head to toe, a sturdy ponderosa trunk at my back helping me hold still, I call gobblers hoping to trick them into believing I’m a lusty hen ready to mate. The juvenile and adult male turkeys magnify their visibility so the hens can see their inflamed pursuit. With their bulging heads changing color on the spot, they appear as emboldened, red-hot beacons with each hurried step my way. Often, however, a real hen spots the hot-to-trot tom and whisks him off before my eyes. His conspicuous flare, like the glitzy glam of colorful flowers, serves to bolster his chances to propagate. His lineage and ability to pass on his genes depend on being seen.

Similarly, though for different reasons, my survival while hunting species like elk and deer requires that I am visible not to the animals but to humans. Donning blaze-orange caps and vests, I make myself noticeable to minimize potentially lethal contact with other hunters. When we cross paths in the field, we can avoid the interference of unexpected encounters and potential for mistaken identification as a moving, viable target.

More than twenty thousand species of bees worldwide and over a thousand species of bees in New Mexico, among Earth’s most important pollinators, in search of nectar- and pollen-rich flora, zero in on the bull’s-eye landing zone centered between showy rays of color-rich petals. How will plants’ shifting pigments affect our pollinator gardens? What are the implications for agricultural crops, for the planet and its peoples and, in particular, for the drought- and heat-stressed desert Southwest? Will animals be able to adapt their winter coats to match a drier, browner future? How will such changes impact the increasingly precarious dynamics of predator and prey?

“We love birds and bird-watching, and hummingbirds and butterflies! We’d really like to have a place for pollinators,” my landscape clients often tell me with optimistic enthusiasm. “You know, they’ve got to eat too,” some say, generously offering to share garden harvest bounty and prime landscape space with insect, bird, and mammal neighbors. Though some folks tend toward aesthetic-centric design preferences, more and more request gardens and landscapes that give back, offering food, habitat, and biodiversity for our other-than-human relatives.

The lilt of spring green, deep cool of indigo, raucous reds, hot pinks, and melty yellows seduce and delight as colorful floral costume. Our eyes and hearts open and soften to nature’s allure. Plant and animal regalia, however, are not exclusively tailored for our pleasure. Their bodies, like indicator species, reflect shifting environmental conditions and challenges, demonstrating how we, too, may learn to adapt. Hope, humanity, and all species’ survival depend on us.