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Madame Butterfly

Camille Parmesan has been in the news after documenting the extent to which climate change has been affecting the wildlife of North America and Europe. With the science so sound and the consequences so grave, her call to action is much more than an academic exercise.

By Alex Shoumatoff

 

In the late 1970s I was the resident naturalist at a nature sanctuary in Mount Kisco, New York, an hour north of the city. On our Sunday morning bird walks we started noticing species that were unusual this far north: mockingbirds, tufted titmice, Carolina wrens, turkey vultures. They were moving up and becoming part of the local mix. One morning, drawn to juicy clucks, punctuated by drilling, coming from a massive dead chestnut oak, we spotted the first red-bellied woodpecker ever reported in Westchester County. What is driving these new arrivals? I wondered. A paper published in 1976 about birds that were moving north in Europe attributed that development to the warming trend that Europe, like North America, was experiencing. But the warming was assumed to be natural there, and in Westchester, as well.

Still, there was already speculative talk that something else was driving up the temperature: the “greenhouse effect” created by all the carbon dioxide being spewed into the atmosphere by enormous fires in the Amazon, by tens of millions of cars on U.S. roads at any given moment, and by a host of other human activities. Scientific evidence that the global warming trend was anthropogenic, not natural, began to appear in the late 1970s and early 1980s, but it was not until 1996 that hard scientific evidence of an animal's range moving northward was provided by a University of Texas population biologist—the delightfully named Camille Parmesan. She had been tracking a species of butterfly called the Edith's checkerspot, which ranges on the Pacific Coast, west of the Rockies, from Baja California to southern British Columbia and up along the Continental Divide to the species' easternmost populations, near Jasper and Banff national parks along Alberta's western edge. Parmesan reported that the species was almost extinct in Mexico but thriving in Canada. The progress of this shift could be explained only by climate change.

Having spent four and a half years studying this one species, Parmesan then decided to track 57 species of butterflies in Europe. She found that 35 were moving northward. The message these insects were sending, as indicator species, was clear: The entire global ecology is being affected by human-induced climate change. Last year Parmesan was the lead author of a meta-analysis for the Pew Center on Global Climate Study of the impacts of climate change on North American wildlife. It reports that pikas, rufous hummingbirds, starfish, red foxes, and many other species across the zoological spectrum are moving north.

Parmesan's seminal work catapulted her into the news. Since then hundreds of newspapers around the country have run stories about her, and she has become a frequent guest on radio and TV talk shows. Thomas Lovejoy, the climate and biodiversity scientist who coined the term biodiversity, includes a paper by Parmesan in his new book, Climate Change and Biodiversity. Lovejoy commends her for presenting “some of the very first nicely documented examples of responses in nature. What this does is to take the subject from a single example and anecdote to statistical significance and sound generality.”

The implications of her findings are disturbing. For some species, there is no viable habitat north of their current habitat. It has been usurped by agriculture, cities, or sprawl. In the case of many displaced British birds and butterflies, the only option is the Atlantic Ocean. Other species are being pushed up and off mountaintops, and unless there are more mountains to the north they can reach, they, too, are doomed. Migrating populations of monarchs, North America's best-loved butterfly, which make the longest migration of any insect, may not hang on much longer; north of the volcanic mountains of Michoacán, Mexico, where they overwinter, there is nothing but desert for 400 miles.

So global warming is another cause of the extinctions that are occurring worldwide at a rate unprecedented in the historical record—a subtler, more insidious one, because it can't be stopped and is much harder to detect than outright habitat destruction, contamination by pollutants, or being outcompeted by introduced species.

Recently I spent 12 hours, spread over two days, talking with Parmesan, mainly at her lab in Austin, at the university's Department of Integrative Biology, where she is an assistant professor. Built in the 1920s, the rooms are high-ceilinged and spacious. Parmesan, a handsome, petite, raven-haired 43-year-old woman, spends her time there at the computer in the rare moments when she's not traveling, managing and analyzing databases, writing up her findings, or doing graphics. She is rearing checkerspots in an environmental chamber. We sat in the cozy little area where she meets with her students.

 

Parmesan grew up in Houston, the grandchild of Sicilian and Swedish immigrants. “My mother was a geologist with a minor in botany,” she recalled, “and every summer she would take me and my sisters hiking for two weeks and would tell us every rock and plant.”

Parmesan enrolled in premed at the University of Texas, but “I realized that I was not any good at anesthetizing cute little white rats and cutting them open to learn from them,” she said, “so I switched to animal behavior. I studied the social behavior of captive primates, honeybees' foraging behavior, and the belted kingfishers along the Little Colorado River [which flows through Austin], to see if the kids could recognize their mother's specific song.” In the summer of 1983, before her senior year, she went to California with Mike Singer, a lepidopterist at the university who specialized in the Edith's checkerspot. “I fell in love with butterflies,” she said, “and eventually with him.”

Singer, a longtime professor in the department, showed me three raggedy live Euphydryas editha he had in his greenhouse. They were small, with inch-and-a-quarter wingspans, but strikingly mottled, with bands of red, brown, and yellow spots—warning coloration, Parmesan explained. Checkerspots mainly eat plants in the snapdragon family that are chock-full of nasty compounds, so birds leave the butterflies alone.

The Edith's checkerspot, she continued, spends its entire life in an area the size of a football field. It is a butterfly for just two weeks; for most of its life cycle, almost 11 months, it is a caterpillar. It is highly variable, with at least 14 subspecies, and is one of the best-studied butterflies in the world, by legions of lepidopterists, including Singer, going back to l959.

Parmesan followed individuals in the rubicunda subspecies on the wing at two sites in the Sierra Nevada, and her work was so good that it was published in Behavioral Ecology and Animal Behavior—a rare honor for an undergraduate. “I was encouraged to go into graduate work in the editha system, but I wasn't sure what I wanted to do with my life.” So after six years in the “real world,” she entered graduate school in 1989. She and Singer got married in 1992.

NASA had put a research funding priority for science on biological responses to global warming, and Parmesan got a three-year grant to study the whole editha complex. It was the ideal species, because its biology was so well known, and because you could start in Mexico in March and end up in Canada in August and hit half a dozen subspecies during their month- to six-week-long flight seasons (individual butterflies emerge at different times for their fortnight with wings). In short, you could get a lot of data in one field season. A 1962 study by Paul Ehrlich reported that editha's populations were driven by climate. They are wiped out fairly frequently by extreme weather—very heavy or very light snow—and by such events as a freeze during false springs that kills young shoots. This sort of weather, on the hot and dry end of the spectrum, is becoming more frequent and intense due to climate change.

Parmesan started with the southernmost subspecies, Euphydryas editha quino, which lives in the coastal foothills of southern California and Baja California. “ Editha quino used to be so thick at times that you had to run your windshield wipers to be able to see,” she told me. “There were so many populations that no one bothered to mark them. Quino was simply described as ‘ubiquitous.' Each mesa top in San Diego had a population, but they were all wiped out by housing development. Now quino is down to about six pathetic populations, from literally hundreds.”

The populations on the densely settled coast were gone, but it was impossible to say how much of this was due to climate change and how much to land-use change. Parmesan needed to find suitable intact habitat, with no statistical “noise.” Combing the records of collectors in the 1930s, she explored federal and ranch land in the interior of Baja California and Riverside County—gorgeous quino habitat. But there were no quinos. “Crawling down on my hands and knees during what should have been quino's flight season, I looked under thousands of little grasslike plantains and Indian paintbrushes and other potential food plants, and just didn't find any butterflies or larvae, except in a couple of places. Most of the populations in Mexico had gone extinct. I couldn't say what had caused the extinctions or when they had happened, but there was evidence of 80 percent extinction on the southern edge of editha's range.

“Matching them with the extinction records for the last 40 years that Mike was compiling,” Parmesan continued, “I could see a definite correlation with what you would expect from global warming. It was very likely that the warming and drying trend that had been going on since the 1970s had shortened the window of time in which the host plant was green, so that it was out of phase with quino's life cycle. Quino's hatching as a half-grown caterpillar is triggered by rain, and so is the greening of its food plant. But now the plants were shriveling up, because no further rain was falling, or they weren't coming out at all, and the caterpillars were starving. There had been droughts in the past, of course, but rarely ones so frequent or severe. The quinos had been pushed over the edge, out of their climate envelope.”

Parmesan then went to the northern edge of editha's range, in British Columbia, and along the butterfly's easternmost range, in western Alberta. Here the main subspecies is beani. She found the extinction rate in the known populations to be only 20 percent—within the sustainable range of what many butterfly species normally experience over the years. There had not been enough collecting to be able to talk about colonization or expansion. Throughout editha's entire range, the species has moved, on average, two degrees of latitude north from where it was historically recorded. So Parmesan had evidence of a biological response from editha, and she suspected that it wasn't an isolated case but part of a general trend affecting flora and fauna around the world. She wanted to assemble the big picture, and the place to do it, if you were using butterflies, was Europe. “It took me four and a half years to get data on a single species here, but in Europe everything was in place,” she told me. “There are records in the northern countries going back to 1760. Collecting is much more part of British and German culture. It was the Victorian thing to do on your vacation. The governments provide money for thousands of amateur lepidopterists every spring to monitor the state of the butterflies.”

In short order Parmesan learned that the showy white Parnassius apollo, an alpine species, had moved 125 miles in only 20 years. The spectacular purple emperor, Apatura iris, had arrived in Sweden in the early l990s; now there was a strong population, and the butterfly was spreading inland. African species like Danaus chrysippus, a cousin of the monarch, had come up to Spain, while a blue called Glaucopsyche alexis and the sooty copper, Heodes tityrus, were disappearing from the southern edges of their ranges. “This tells you that it's not just editha,” explained Parmesan. “It's a much more systematic response of wildlife.”

Habitat destruction was an even greater problem in Europe than it had been on the West Coast. Parmesan found the least-disturbed habitat in the mountain valleys and meadows of Spain and France, where traditional haymaking was still widely practiced—the grass was cut only once a year, with a scythe, and the sheep were moved in and out—and there was more continuity and harmony in the way things were done than in Germany and Austria, “where they want everything to be tidy,” she said. “Tidy destroys nature.”

In l999 Parmesan and 12 Europeans published a paper called “Poleward Shifts in Geographical Ranges of Butterfly Species Associated with Regional Warming.” She says “the Europeans were thrilled because all their running around and spotting butterflies with binoculars—what they loved to do—had meaning. Museum people came up to me and said the paper legitimized their collections, which they had been getting a lot of flak about. Referring to the rooms after rooms full of pinned butterflies, bird skins, and other moldering specimens, Prime Minister Margaret Thatcher once said something to the director of the British Museum to the effect, ‘Why do we need all this old dead stuff?' ”

So, I asked Parmesan, why should we care if editha and a bunch of butterflies in Europe are moving north? “Because,” she said, “it's more significant than just editha. Editha is an indicator species. It's being affected, so anybody who is empathetic to other forms of life needs to be worried. Do you want there to be bears in the Rockies, dolphins in Monterey Bay?

“In the past,” she added, “when there weren't humans around, there was a lot of shifting. Between each of the Pleistocene glaciations, there was a four- to six-degree-centigrade shift; species of shrews and pikas were moving a thousand kilometers north and shifting back again; spruces and oaks were going up and down mountains. The problem is that we've taken all the habitat away. It's not possible anymore for an animal or a plant to shift gradually through the scenery and end up in some spot thousands of miles away. Species are being asked to do things they have never done before, to make enormous genetic leaps in a short time. The average lifespan of a species is one million to three million years. The pace of most evolutionary change is so slow that it is not even noticeable to humans, and the rapidity of the warming is something many species are not going to be able to keep up with.”

Parmesan showed me a graph in the IPCC, the United Nations' Intergovernmental Panel on Climate Change's most recent report (2001), which concludes that the current, ongoing warming trend is definitely human-induced. The graph had a nearly vertical spike beginning in l971.

Parmesan is as compassionate and caring as you'd expect, given that she has dedicated her life to advocating for the health of the planet. But even when painting doomsday scenarios, she comes across as reasonable and well balanced, a scientist who seemingly has neutralized her personality to maximize objectivity. Her low-key approach makes her especially credible.

“Climate change is fundamentally different from the other causes of extinction,” she went on, “because it is the only one you cannot locally do anything about. There is no restoration technique or local management option that allows you to reverse it. It will take a huge collective effort, globally, and that makes it very scary for conservation. With enough money you can deal with other problems. We are recovering quino's habitat, for instance, and reintroducing it on protected land, so there will be new, healthy populations. But all that will come to naught if climate change continues.

“You can't stop it,” she said, “but you can keep the progressive warming to a minimum. If we can keep it down another two degrees until 2010, then we may lose some species, but I'm hoping we can still maybe keep coral reefs. I'm crossing my fingers. But if it goes over that by much, we will simply lose coral reefs, because their little algal symbiont can't persist above a certain temperature. And alpine environments will no longer exist, because there will be no more mountain for them to go up.

“The sea level has risen from four to eight inches in the last century [estimates vary] and will keep rising anywhere from five inches to six and a half feet in the next one. When New York City, Florida, Houston, and San Francisco Bay are flooded, people are going to finally demand action. But by then it will be too late. The climate system has a long lag time, and we can't reverse the effects that are happening or in motion even now. So climate change is un-like any other environmental crisis we face in that it is global and slow moving. It's like trying to stop the trajectory of a planet. It has a lot of momentum, and once it gets going, you're not going to stop it. Carbon dioxide stays in the atmosphere for hundreds of years. What we've already put up, we're not feeling the full effects of, so even if we stop it now, we will still feel its effects.

“But global warming is also the thing that the individual can do the most about, without asking anybody's permission, like trading in their SUV for a Honda Civic that gets 40 miles per gallon. If everyone just did that, it would make a huge dent.”

Parmesan struck me as a basically upbeat person. She was just someone who, by life's typically circuitous route, had come into possession of this information, which she feels an understandable obligation and urgency to disseminate. As she flipped through the massive, two-volume IPCC report, with its disturbing graphs and maps, she was actually humming to herself. I wondered if she was trying to keep her spirits up. People in this line of work must do a lot of humming.

Alex Shoumatoff writes and edits DispatchesFromTheVanishingWorld.com and is writing a book on Tibetan Buddhism to be published soon by Houghton Mifflin.

 

Body Heat

Like many cold-blooded creatures, butterflies are highly sensitive to temperature. Their bodies must be 90 to 100 degrees Fahrenheit for flight to occur, so a degree or two can make a big difference. In June 2003 Camille Parmesan trekked into the French Alps with a thermal-imaging camera to document temperature's effects on butterflies. In the top image the butterfly is too cold to fly but has spread its wings to gather up as much heat as possible. Eventually, as the sun comes out, the butterfly begins to warm (middle), the heat radiating from black “hot spots” that absorb heat very efficiently. Finally (bottom) the butterfly is hot enough to feed on the flower it has been sitting on all this time, and able to take off when it wishes. In fact, it flew away right after the picture was taken .

—Jesse Greenspan

 

 


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