We arrived in late May this spring, as we always have for over three decades, to our summer subalpine field station in the Colorado Rockies. Driving past clones of leafy yellow green aspens, we watched dust clouds billow in our wake along the dry dirt road. Neither the aspens nor dust were good signs. Normally... no, I'm not sure what is normal anymore here in the Gunnison Basin, a heavenly mix of mountains, forests and wildflowers. But I remember in the '80s and '90s that late May meant snow-draped mountains, with mounds of the stuff about our cabin. I would trudge through slush as it rapidly melted under the hard spring sun, exposing yellow curled sprouts, ready to explode green and upwards, fueled by icy water saturating the soil.
Two years ago, the southwest drought had rained red dust on those white mountains. The dust and unnatural heat had combined to create a spectacularly rapid snowmelt. Copper Creek jumped its banks by the bridge, lightly flooding the road and puddling the lab road sign. Oldtimers had never seen or heard the like from previous generations at the lab. Things clearly weren't normal.
We got out of the car. My husband John looked around, commenting, "Not bad... for July," a portent for what was to follow. To understand fully how different this summer was, let's look at how a typical mountain summer, the type to which wildlife is adapted, progresses.
Snowmelt, the day at any one place when snow disappears, is the starting bell for plant growth. Typically it occurs here around late May, early June. The first plants grow up fast, flower and seed, before the next Ziegfeld act of even taller wildflowers pushes them out of the way. And so it goes. Throughout May and early June cold air coming down from the Arctic and mountaintops causes occasional nocturnal frosts and even late spring snow flurries that can cover developing plants. But because they are just beginning to show, the damage is pretty minimal. Most are adapted to late flurries. It's always amazing to watch a delicate glacier lily get briefly smothered by a few inches of snow, and then appear 24 hours later, none the worse from wear. Snowmelt water feeds these plants throughout the dry month of June until midsummer July rains kick in.
Plants are the green engine fueling the rest of wildlife. Insects feed and breed on plants. Deer, elk, bears, and other grazers will follow the snowmelt line up the mountain through the summer, breeding and fattening to survive the next winter. Hungry mice and marmots, the groundhogs of mountains, pop up from winter burrows and immediately start foraging. Weasels, coyotes and fox go after mice and marmots. Martens (think weasels on steroids), go after birds and more, while mountain lions and occasionally bear stalk the big grazers.
Freeze-dried Larskpur blossoms, victims of frost
But what happens if the plants take a hit? We found out this summer. Winter left a low snowpack in the spring. That, and unusually early heat caused a record-tying early snowmelt around mid-April this year. None of the effects on plants were good. The plants started shooting up on cue, but lacking snowy protective layers, they were vulnerable to late frosts, which killed leaves, buds and flowers on already well-developed wild flowers. Normally colorful spring fields were drab this early June. Attracted to a rare spot of color, I stared at a blue freeze-dried larkspur bloom, frozen in death. Living flowers were few, small, often damaged. At this point, wild flowers were in the midst of a mini-drought. Snowmelt water had long since run off, while banks of clouds rolled by daily, barely spitting into the dust as they passed. Fields of blooming blue lupine, and later, yellow aspen sunflowers and magenta fireweed, failed to show.
Sunflower field, Copper Creek Trail, 2008 and 2012
Butterflies seemed to be more numerous, an illusion created by the lack of plants that would normally hide them, noted one lab butterfly expert. Watching an emerging butterfly in a sunny dry field desperately trying to pump its wings open was a poignant example for me of how drought was affecting them. Competition for flowers became fierce. It was the first time I noticed a fly pushing a moth off a flower, while others dive bombed flower-hogging beetles. The early, warm spring fueled an explosion of mice.
Butterflies on the trail ahead, resting on the ground.
An emerging, overheated butterfly, exhausted from trying to pump up its wings.
I watched this fly butt-head the moth to the side... clearly, he wanted the scrawny flower to himself
Butterflies swarmed this group of large daisies, the sole ones blooming in a meadow
Below ground, the effects are equally dramatic. Lack of water inhibits soil microbes from breaking down organics and releasing nutrients, as well as plants and fungi from taking up those nutrients. One result was stunted vegetation. Normally six-foot tall cow parsnip were blooming at two feet tall. Other wild flowers were blooming at half their height. For fungi, which spend summer gathering nutrients underground, it meant that even after copious rains came in late summer, they did not create those large, luscious edible mushrooms prized by locals.
Last year's flowering stalks loom above this year's stunted blooming cow parsnip.
The effects of the floral devastation rippled upward into the larger grazers. John Wenum of the Colorado Division of Wildlife observed that summer deer and elk herds did their traditional trek up the mountains, but the virtual absence of rain from mid-March through June sent them down again into wetter, greener areas.
Summer fawn among the aspens.
An unusual number of bears were prowling for food opportunistically in towns, hunting out garbage cans and entering buildings as August waned, trying desperately to get the calories needed to survive winter. For a bear, Wenum noted, that's about 15,000 to 20,000 Calories daily, and means averaging 20 hours or more daily to forage for berries and other food. In this context, scoring two slices of discarded pizza was a windfall. Ultimately, though, the results are tragic. Two local bears have already been shot and killed by threatened homeowners as summer slides into fall.
Two bears have already been killed by threatened homeowners this season.
(photo, courtesy of David Inouye)
How did the drought affect the local economy? The nearby town of Crested Butte thrives on summer tourism; a star July attraction is the Crested Butte Wildflower Festival, located in the "wildflower capital of the world, Crested Butte." Festival Director Sue Wallace noted that despite news about droughts and wildfires, attendance was down only 8% from last year, although disappointment in feedback surveys invariably mentioned the lack of flowers. Despite this, 90% said they would return. About 75% come from neighboring, hotter states, however, with Texas leading the pack.
Sue further observed that the town's finance department reported an increase in the town's revenues for July, the peak summer month, from 2011, indicating an increase in tourism. This might sound counterintuitive. But, as in the wildflower festival, the tourists are coming from neighboring, hotter states -- indeed, states that were much drier and hotter this year than last. Despite our regional drought, it wasn't anything like Texas, and the uptick quite possibly reflected a migration of people away from the devastating heat elsewhere.
But what of the future? In 1990, the first field global warming experiment began at our lab, the Rocky Mountain Biological Laboratory (RMBL) by John Harte, an ecologist and my husband. The experiment tracked how subalpine field plots fared under a constant warming of 3.6 degrees Fahrenheit, the heating estimated at that time to occur under a doubling of atmospheric carbon dioxide, the main gas behind global warming. Heated plots alternated with unheated ones.
The global warming field experiment at the RMBL.
(photo, courtesy of John Harte)
The result? Basically, heated plots went from wildflower meadow to sagebrush habitat, while unheated ones kept their flowers. As John puts it, imagine the opening scene of the "Sound of Music" occurring outside Elko, Nevada.
Lately, the unheated plots are starting to show the same initial changes that the original heated plots showed, many years back. And now improved climate models indicate that a doubling of carbon dioxide will probably cause more warming than 3.6 degrees.
The effects of climate change are starting to be seen, and will get worse. What then?
All photos, unless specified otherwise, were taken by the author. Making the U.S. a global clean energy leader will ensure a heck of a lot more jobs, and a clean, safe future. If you'd like to tell Congress you'll VOTE for clean energy you can join the increasing numbers of people doing so here.