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Annie Snider/MEDILL

Oliver Pergams shows a student from Chicago Bulls College Prep how to cut down an invasive honeysuckle bush at Cranberry Slough near Hickory Hills.  Pergams puts his conservation biology training into practice as a volunteer steward at the nature preserve.

Tracking rapid evolution in our own backyard

by Annie Snider
Dec 09, 2009

Oliver Pergams is a man with ash on his nose. There’s also a streak of dirt on his jeans and a bramble stuck to his shirt. Like the swarm of ninth grade boys around him, though, Pergams hardly seems to notice.

On a fine Saturday morning, Pergams and two of the boys from Chicago Bulls College Prep high school are sawing up the trunk of a honeysuckle bush in a low-lying section of the Cranberry Slough Nature Preserve hear southwest suburban Hickory Hills. Pergams is at home here as volunteer land steward.

When all of the manageable chunks lay in pieces, the three worked together to heft the large remaining trunk over their heads and, on the count of three, into the burning brush fire. Then, for a moment, they pause. They are transfixed, watching the fire with what the boys, at least, admit is a mixture of glee and pride.

Pergams encourages the boys as they saw and weed and climb the occasional tree, but he doesn't often have the time during these busy volunteer ventures to tell them about his other life. Still, hints of his day job – as a conservation biologist with joint appointments at the Field Museum and the University of Illinois at Chicago – slip through.

When a ladybug lands on the arm of one of the boys, Pergams interrupts the conversation to swat it away. It is not a ladybug at all, he tells the boy, but a Mexican beetle - an invasive species that brings sharp little bites instead of good luck.

The 52-year-old Pergams is a respected scientist at the forefront of research articulating the increasingly dramatic impacts humans are having on the natural world at the very moment our relationship with it seems to be declining.

When we think of evolution, we think of hundreds and thousands of years, but a study Pergams published this summer reports Chicago-area mice changing shape and size in a period of just 30 years. Nor were the changes subtle: some mice shrank as much as 15 percent in less than four decades. That’s the equivalent of a 6-foot man shrinking to just over 5 feet tall. Though the groups of mice studied came from Chicago and California, Pergams also drew on data about rodents from across the world.

Pergams says he thinks the changes in human population density and changes in climate caused this rapid evolution. As previously wooded areas have turned into subdivisions and strip malls, for instance, a different tail length helps the mice climb the human-built structures. As Illinois’ environment has gotten warmer and wetter, an altered ear shape regulates temperature a little better. That’s how mice adapt.

“We are changing the world,” he says. “Who knows what it will look like if we keep going?”

And yet, some of Pergams’ other studies show that people are spending less and less time out in nature. Visits to state and national parks are dropping and children increasingly chose time in front of the computer over time playing outside.

Before people can understand what a game-changer the human species has become for the natural world, they first have to get to know it.

Pergams, who lives in Oak Park, defies the stereotype of environmentalists as hippies in tie-dye and poets with ponytails. A sturdy man with working-class roots and an unrelenting determination, he still exudes his childhood awe of the world.

It’s an awe he first discovered as a 5-year-old living in Chicago’s Little Village. When he went outside to play one day, he discovered city workers tearing up the sewer main in front of his house. Slipping under the cordon of yellow tape, he peered down and saw layers of dirt and organisms he never realized were thriving beneath his feet the whole time.

“It was like a puzzle laid open,” he says. “There were all these arthropods in there, and snakes…and I think that’s when I wanted to be a biologist. Now that I knew it was down there, I wanted to understand it.”

Later, when his family moved to the Northwest Side, he would spend his afternoons biking to a nature preserve and catching critters to examine and then release.

But in college at the University of Chicago, Pergams got sidetracked. Working fulltime as a second-shift manager at a paint warehouse in Melrose Park to earn tuition, he couldn’t put in the hours for a biology major. Instead, he switched to German, his native tongue.

That left his path after graduation uncertain. He ended up taking a job as a commodities trader and discovered he had a talent for it. Before he was 30, he had cofounded his own trading company and soared to financial success. But, after 12 years and the birth of two children, Pergams realized the 80-hour work week was untenable. He also realized he missed science.

At age 39, he went back to school for a Ph.D. in conservation biology at the University of Illinois at Chicago.

“It was a matter of doing what I’d wanted to do in the first place,” Pergams says.

Unlike most academics, though, Pergams isn’t forced to chase grants, thanks to the success of his previous career.

“The fact that I have some money has made some difference,” he says. “It’s allowed me to look at issues that I’m interested in and worry about finding funding later.”

What interested him first was conservation biology – how invasive species can be effectively removed and a particular place returned to its natural state.

For example, in the mid-1990s, the National Park Service became fed up with rats on California’s Channel Islands. The isolation of the islands had sheltered an ecosystem for thousands of years but the park service is intent on removing the non-native species that did eventually make their way there.

Rats, which arrived via shipwrecks more than 100 years ago, were a particular problem at the time. They ate shorebirds’ eggs and native mice.

The conservation group charged with eliminating the rats planned to spread little wax pellets filled with strychnine over the islands. Rodents, hardwired to gnaw, would eat the poison, but other animals wouldn’t.

The flaw, though, was that rats shared the islands with native mice, which the park service wanted to keep.

So, they hired Pergams to determine which mice should be removed from the island. He studied their genetics to pinpoint a diverse mix that, when reintroduced, was able to thrive and repopulate the islands.

The operation was a “complete success,” says Pergams, and it led him to his next project.

While studying the mice genetics, he realized that older specimens (skins and skulls he borrowed from museums) were larger than the live mice on the islands. Wielding the electronic digital caliber his machinist father had used to measure ball bearings, Pergams documented the changes in tail, ear and hind-foot length of thousands of mouse specimens from different islands in the Channel chain over a hundred years.

What he found was that the smaller and the further from the mainland an island was, the faster its mice evolved.

“It makes sense,” says Pergams. “If just a few mice come to the island, then they adapt. If there’s a continual flow from other islands, there’ll be less adaptation.”

Pergams suspected the shape changes he documented in the Channel Island mice might be happening more broadly. But he knew he’d have to look at animals from the mainland in order to prove it.

A Chicagoan to the bone, he set to studying white footed mice native to Northeastern Illinois, and also pulled together other research scientists had collected from disparate regions of the globe.

He found that, over those same 100 years, more than 70 percent of the locations he studied showed rodents evolving rapidly.

“This was kind of mind-blowing,” he says. “Nobody thought this kind of stuff was happening on the mainland.”

It forced scientists to rethink their understanding not only of evolutionary scale, but also of human impact on it.

“His research suggested change was happening in places with higher population density,” says Emily Minor, an ecologist at UIC who collaborates with Pergams. “It’s just fascinating how humans can alter the environment and different populations within it.”

Still, Pergams says he felt like the Dutch boy with his finger in the dam.

“You know, you solve stuff like the Channel Islands deer mice, and 20,000 [problems] come to replace it,” he says. “It’s disheartening. You devote your life toward fixing these problems and you realize rather rapidly that you can’t catch up.”

So about five years ago, Pergams branched out into a new area of research: conservation sociology.

He started with a 2004 paper putting his economics background to work in understanding how conservation activity follows larger economic trends. His hypothesis was that conservation is treated as a luxury good rather than an essential. Indeed, as economic indicators declined, so too did donations to conservation groups.

“I felt for some time that the way your average person looks at conservation gives it nowhere near the priority that a conservation biologist thinks it should have,” he says.

His studies since then, many done with collaborator Patricia Zaradic, of the Red Rock Institute in Pennsylvania, have looked at how conservation funding correlates with time spent in parks.

They found that nature-based recreation is at record lows and that time spent in nature is strongly correlated with the tendency to support conservation efforts.

With electronic media supplanting time spent outdoors, Zaradic and Pergams say conservation efforts face an even steeper battle.

“Unless we who are interested in conservation do something to make it more relevant to a greater portion of the public, we will find ourselves becoming less and less relevant when it comes to support and legislation,” says Zaradic.

If it sounds as though the team’s research has an explicit agenda, that’s because it does. Pergams and Zaradic are supporters of the No Child Left Inside Act, a bill introduced in Congress this year by U.S. Rep. Paul Sarbanes (D-Md.) to set a new bar for environmental education.

“The notion of a scientist as separate from the rest of the world is something of an outdated notion,” says Pergams. “I’m trying to do some good and I’m interested in affecting policy.”

Despite the impact his research is having – including an invitation to testify in Congress for the House bill – his tactics may soon be shifting.

This fall, he taught two biology classes at Olive Harvey College in Chicago, a community college where the majority of his students are in their late 20’s, low-income and poorly educated. There, Pergams says he is as likely to spend a class breaking up a fight between students as he is to get to the implications of basic biological processes.

But, he says he enjoys the teaching more than almost anything else he has done, even research.

“I think these kids need me a lot more than they need me at UIC,” he says. “I do think it’s possible for one person to do quite a bit.”

Clapping the boys on the back at Cranberry Slough that autumn day, Pergams hoped to pass along the sentiment.

And maybe, just maybe, he did

“We’ll be here tomorrow!” one of the boys called out as they waved good-bye.

Pergams smiles and calls back, “So will I.”