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Feb

5

2014

Falling Off

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Animals once adjusted behavior as the seasons changed. But more and more, the effects of global warming dictate habitat, diet, and survival.

Climate change is pushing mountain species to the brink—and in some cases, over it.

By Patrick Doyle | Photographs by Steven Gnam

Dr. Erik Beever was exhausted. He had been clambering around Pinchot Creek, a remote area in the White Mountains along the border of California and Nevada, since 5 A.M. It was 2008, and the researcher was scouring the high altitude rock fields for the American pika, a small, cold-weather-loving, softball-sized relative of the rabbit. Amidst the scree he found pika “haystacks,” the piles of grasses that the industrious animals set out to cure in the sun. But when Beever stopped to listen for the animal’s trademark nasal, metallic squeak, all he heard was the whistle of the mountain wind.

Ten years earlier, in this same area, Beever’s graduate research project was to track and analyze pika populations at 25 sites across the Great Basin, an enormous watershed that extends from California’s Sierra Nevada in the west, to Utah’s Wasatch Range in the east. In the 1990s, he could hardly take a step at this altitude without pikas emerging to warn him off their turf. On this day, Pinchot Creek was empty.

As the sun set over the Sierra, Beever set up his tent next to a talus field. Pikas, like most animals, are most active at dusk and dawn, and if they were still living here, he’d know by morning. But at daybreak, he found silence. This was the fourth Sierra site where the pika had gone locally extinct—the scientific term is extirpated—since his initial study in 1994. Pikas were now being extirpated from study sites every two years, falling victim to higher temperatures and leaner snowpacks, yet another harbinger of climate change, or at least a harbinger by omission. Pikas aren’t falling victim to human development or some twisted sport hunting craze. Changing climate is killing them. Which is a bigger problem than a hardhearted person might think. Like prairie dogs on the plains, pikas serve as “ecosystem engineers.” They simultaneously manage plant composition and serve as prey for larger birds and mammals.

But up high near Pinchot Creek, says Beever, “there is nothing but cobwebs. And silence.”

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Media coverage of climate change tends to highlight rapidly melting sea ice: Chunks of glaciers falling into the sea make for stunning video and photography, as do shots of forlorn polar bears on melting icebergs. Equally at risk, however, are the plants and animals that live in the world’s biodiverse mountains.

According to a 2013 report from the United Nation’s Intergovernmental Panel on Climate Change, the past three decades are the warmest on record—and likely the warmest to occur in the past 1,400 years for the Northern Hemisphere. If we continue on our current path, average global temperatures are expected to rise two to seven degrees by 2100. That’s a life or death change for many alpine animals and plants. Some, like the pika, suffer deadly heat stress if the temperatures climb too high; others see critical food sources disappear. In response, many species are doing the obvious—trying to find someplace cooler.

In our hemisphere, that often means moving north. In 2011, Science published a meta-analysis that showed 764 plants and animals were shifting to higher latitudes by 10.5 miles per decade. In North America, the National Audubon Society’s annual Christmas Bird Count echoed that data, showing that the 305 most common species of birds have moved their population centers north by an average of 35 miles over the past 50 years. Some have gone much farther: The spruce grouse shifted north 316 miles. It used to be common in Montana, but now you’re more likely to see a spruce grouse in Alaska.

Animals that aren’t capable of long-range migration are moving up the mountain. Beever’s data shows that pikas moved an average of 475 feet upslope in the past decade, and the 2011 Science study showed that all species were shifting upslope a median of 36.1 feet per decade. An exhaustive study in Yosemite National Park, meanwhile, showed that the alpine chipmunk has moved a stunning 2,000 feet upslope over the past 90 years.

Unfortunately, since mountains narrow toward the top, intra- and inter-species competition for resources is increasing. Beyond that, moving upslope is only a short-term strategy—eventually, the animals run out of mountain. “When you’re at the top of the pyramid,” says Geoff LeBaron, the director of the Christmas Bird Count, “there is no place to go.”

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Large studies paint a bleak picture, but they can be frustratingly abstract. For an on-the-ground snapshot, few places have done better work than the Rocky Mountain Biological Laboratory (RMBL), a high-altitude research facility in the West Elk range near Crested Butte, Colorado. Its remote location, high elevation (9,500 feet), and data going back to 1928 make it the perfect site for studying mountain ecosystems.

While winter snow used to blanket much of the valley until late May, the snow is melting earlier each year. Over the past four decades, the average annual snowmelt has moved up 14 days. That may not sound like much, but snow melting two weeks earlier in the year has cascading effects, nearly all detrimental, on the mountain ecosystem.

Consider the work of Dr. David Inouye, a biologist who spends his summers at RMBL. In 1970, Inouye staked out 110, four-square-meter plots of land around the RMBL. In the years since, he’s spent every summer recording the daily temperature, annual snowmelt date, and abundance of various flower types at each site. Earlier snowmelts, Inouye has found, cause flowers to bud earlier in the year, exposing them to bud-killing, late-spring frosts.

While a single year with a bad frost won’t kill off the perennials, several years of frosts in a row means that they produce less flowers and seeds. Between 1974 and 1984, Inouye observed only two years of significant frost damage; between 1998 and 2008, there were nine such years. The delicate bluebell flower, which once thrived on the mountain meadows, has all but disappeared from the area. And since plants provide the basis for many ecosystems, their extinction reverberates. “Bumblebee pollinators won’t have as many flowers to collect from, and insects that collect seeds won’t find enough either,” says Dr. Inouye. “The effects trickle down.”

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Early snowmelt encouraged the bluebell flower to bud sooner, which left it exposed to killing spring fronts. Now it’s scarce in Colorado’s West Elk Mountains.

The early snowmelt has also caused new species to push into the area. Billy Barr, another scientist at RMBL, has cataloged marmots leaving hibernation up to a month early. Robins arrive sooner too. Foxes, which typically move downslope in deep winter, now live in the RBML year-round. “We’re seeing new species,” says Inouye. “We even saw a moose wandering up over 9,500 feet.”

While the moose might be new to RMBL, it’s in serious trouble in its more traditional range. Over the past two decades, Minnesota’s moose population has declined from 12,000 to around 3,000; Montana and New Hampshire have also seen their populations drop. Scientists believe that the shorter and warmer winters are causing heat stress in the built-for-cold-weather moose. The lack of sustained deep winter also makes them more susceptible to parasites like winter ticks and brain worms. One confused moose became a YouTube anomaly when it walked into the flower section of a Safeway grocery store in British Columbia. Biologists found it was infested with ticks and starving.

Given the moose’s struggle, it’s little surprise that another deer species, the caribou, is also suffering. In October, two Penn State biologists published a paper showing that earlier snowmelt in the Arctic means that young caribou can’t find tender shoots of tundra plants. Some of Canada’s caribou herds have declined by 85 percent. Again, like tropical reefs and rainforests, all life is interconnected. Caribou die-off means a die-off of their main predator—the wolf.

As the habitat changes, not all animals are on the decline. Warmer winters mean that grizzly bears have more food available and are actually growing fatter, often eschewing hibernation. A study by the University of Montana showed that elk, too, are thriving, now that they’re able to forage on plants once inaccessible due to deeper snowpacks. The problem is that the elk are eating the area dry, causing, as one scientist put it, a “classic ecological cascade.” Climate change is throwing forest and alpine ecosystems out of whack.

Few species have provided a better ecological cascade showcase than the pine trees and bark beetle in the Rocky Mountains (See: “Bugging Out,” Winter 2010). The bark beetle, which lays eggs and spreads blue-stain fungus into lodgepole and ponderosa pines, used to be kept in check by cold winters and forest fires. Humans, though, have simultaneously limited the fires and warmed up the winters, removing the restraints. Millions of acres of lodgepole pine are now dead; in 2011, NASA released images from space showing a wide swath of Colorado turned brown with dead trees.

According to the 2009 National Climate Assessment, spruce and fir forests are “likely to disappear from the United States altogether.” Maple, beech, and birch forests are expected to contract, while oak and hickory forests are expected to become dominant in the decades ahead. Vegetation models are projecting that in less than 100 years, up to a fifth of the ecosystems in America will be different.

What will that look like? No one’s quite sure. A 2003 study published by the Proceedings of the National Academy of Sciences stated that U.S. national parks are expected to lose an average of 8.3 percent of their current mammalian species—it could be as high as 20 percent in some parks—and gain nearly 50 percent new species. We’re heading toward an ecological jumble the likes of which we’ve never seen.

And that’s the most frightening element of climate change—we don’t know what’s going to happen. “Communities are getting mixed up and being put together in strange new ways,” says Shaye Wolf, the climate science director with the environmental group Center for Biological Diversity. “This is an experiment. But we don’t know how it’s going to fall out for different species.”

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Government, the only organization with the power to dramatically arrest the slide, has been slow to act. In May 2007, the Center for Biological Diversity filed petitions with both the federal and California governments to claim endangered species status for the American pika. The petition was a gambit: If the government recognized that the pika was endangered, they’d be required to protect the species from climate change. It was the same maneuver that the group used to gain “threatened” status for the polar bear in 2008.

In February 2010, the feds denied the petition, with the U.S. Fish and Wildlife Service ruling that while the pika may have been struggling in a few places, its range offered enough variability to protect it from extinction. After a few appeals, California came to a similar conclusion in 2013. “The Obama administration has a lot of tools it can use, but it’s being very timid,” says Wolf. “If we can reduce our emissions quickly and boldly, we can reduce the severity of the consequences we face. There is no inevitability here—that we need to head into massive climate chaos. We have a choice to protect ourselves and our climate.”

By the time we act, of course, it’s likely that the mountains will have already changed. The enormous forests of lodgepole pines spreading across the Rockies? Gone. Cold-weather behemoths like moose will continue to decline. Earlier snowmelts will change high-altitude ecosystems in unforeseen ways. And the little American pika, the squeaky greeter of hikers climbing above the treeline, will go quiet.

Still, Dr. Beever is continuing his annual pika survey of the Great Basin, hiking amidst the talus fields and cataloging the animal’s populations. But the early mornings have changed, says Beever. “That’s the most active time of the day for most birds and mammals,” he says. “And I’m hearing nothing. It’s just this silent emptiness. It’s unsettling. One also wonders: Does the silence of pikas portend the silence of rosy finches and other species? It’s striking.”

From the Winter 2014 issue.

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