If Dr. David Inouye had his way, Coloradans wouldn’t wear short sleeves before May—at least, not in Crested Butte, at nearly 9,000 feet in elevation. He’d prefer to see the town’s colorful Victorians covered in snow until late April. For Inouye, lingering snow signals good things for the state’s wildflowers, which he’s learned depend on the snows from the preceding winter. A wimpy cold season begets a wimpy wildflower show. Trouble is, feeble winters have become more common in recent years.
A professor of biology at the University of Maryland, Inouye has been studying Colorado wildflowers for more than three decades. Every Memorial Day since 1971, he’s lit out for Gothic, a scattering of old cabins near Crested Butte that houses the Rocky Mountain Biological Laboratory (RMBL). Here, Inouye notes exactly when, and how many, wildflower blooms appear. The length and continuity of his studies make the work some of the world’s most valuable wildflower research. But Inouye’s data illuminate a worrisome trend: Several species, including aspen sunflowers and subalpine larkspur, appear to be in decline, and swift snowmelts seem to be the culprit.
Wildflowers depend on a blanket of deep, persistent snow to insulate them from the frigid winter air. When coverage is thin—or when snow melts off early, thanks to atypically warm spring temperatures—the plants are exposed to cold snaps they aren’t equipped to handle. Hard frosts still strike as late as June 15 in the mountains, and they’re crisping the tiny showpieces before their buds have a chance to open. It seems like a paradox, but because it’s getting warmer wildflowers are succumbing to the cold. “If the frost dates don’t change, these wildflowers will no longer be able to replace themselves,” Inouye says. Which raises troubling questions about the future of Colorado’s blooms.
Checking his study sites in and around Gothic, the lanky Inouye looks like any other hiker who comes to bask in the legendary blooms of Crested Butte, the “wildflower capital of Colorado.” But he’s quieter than most, and along with the camera, backpack, and water bottle that most posy pilgrims carry, Inouye totes a clipboard and data sheet as he completes his daily two-mile hike through the aspen forests, open meadows, and dry, rocky hillsides surrounding Gothic. Above him rise the stark summits of the Maroon Bells-Snowmass Wilderness; at his feet, larkspurs, bluebells, and aspen sunflowers radiate brilliant shades of purple, blue, and yellow.
Inouye begins his rounds at a gentlemanly 9 a.m. to let the sun coax open the buds, which allows his petal counts to be more accurate. There’s plenty to track: About 100 species are included in the professor’s 30 study plots, roped-off squares measuring two meters by two meters. Some sit in the Upper East River Valley; others climb the hillsides above the lab’s cabins. Inouye delineated them back in 1973, but back then he wasn’t watching for climate change, a term that hadn’t been adopted yet. He was studying an aspect of simple phenology—the timing of plant behaviors and the abundance of their flowering.
But by the late 1990s, Inouye started seeing changes in his plots that made him suspect the rising thermometer. Inouye noticed wildflowers blooming earlier—the first flowers, such as glacier lilies and spring beauty, used to wait until the beginning of June to pop their petals; now they’re sometimes blossoming in mid-April. What’s more, the extended growing season doesn’t seem to benefit the flowers he studies, particularly aspen sunflower, subalpine larkspur, and aspen fleabane, which aren’t flowering as abundantly.
Data gathered by another Gothic observer provided clues about what was happening. Unlike Inouye, Billy Barr lives year-round at the RMBL, and since 1974 he’s measured snowmelt, charted springtime reappearances of marmots and robins, and recorded snowfall and temperature. Inouye compared his numbers with Barr’s and saw a correlation between early snowmelt and diminished flowering: April in Gothic now averages six degrees (Fahrenheit) warmer than it did 30 years ago, a difference that makes the snow melt faster and lengthens the amount of time wildflowers are exposed to frost. Cold snaps don’t kill the plants, but they damage their buds and keep them from reproducing. Late cold snaps have happened in 10 out of the past 12 years. If the current pattern continues, Colorado’s wildflowers will start disappearing. “As the older plants die, and they’re not replaced by new ones, we’ll see a slow decline in numbers,” Inouye says.
Inouye suspects global warming, but his colleague and fellow RMBL researcher Dr. John Harte wanted more causal evidence. So, in 1990, Harte launched an experiment that continues today: He’s been using heat lamps to warm wildflower plots by 3.6 degrees (Fahrenheit), the warming prediction for the year 2050 issued by the Intergovernmental Panel on Climate Change. By the fourth year, he began to see sagebrush (which had been growing on the margins of his sites) eclipsing the wildflowers. “We haven’t yet seen any species completely blank out of the plots,” Harte says. “But they’re way down in numbers.”
By century’s end, Harte says, Crested Butte could look like Gunnison, its sage-covered neighbor. “Likely we’ll lose subalpine meadows as we know them, and we will see sagebrush habitat maybe as high as 10,000 feet. To me, and to thousands of other people, those wildflower displays are some of the most beautiful things on the planet. To lose that would be dreadful.”
For his part, Inouye is fighting the change by pedaling his bike. He bought a house closer to where he works and uses only human power to make it to class. He also finds himself using his Ford Explorer less, and his fuel-sipping motorcycle more. And for his retirement home in Paonia, he’s installed a solar hot-water system.
Are such changes powerful enough to counteract the global transformation affecting the wildflowers he’s come to love? Inouye hopes so. “On a small scale,” he says, “people can make a big difference.” m
Kelly Bastone is a contributing writer for 5280. E-mail her at firstname.lastname@example.org.