The Marian R. Byrnes Natural Area in Chicago. (All photography by Jason Smith)

Maybe it’s not just a brownfield or a wastescape. Maybe it’s a novel ecosystem.

An alvar is a strange, barren landscape: a flat sheet of limestone with just a sprinkling of loose soil on top. You might think nothing could grow there, and yet somehow, alvars host their own tough little communities of rare plants. Sometimes even trees. Severely stunted trees, but trees nonetheless—natural bonsai. “It’s like they’re growing on a parking lot,” says ecologist Alison Anastasio, SM’05, PhD’09.

Anastasio first visited Stora Alvaret (Great Alvar) in 2008 when she was in Sweden doing fieldwork for her dissertation. The alvar had nothing to do with her research, which focused on a plant known as thale cress or mouse-eared cress (Arabidopsis thaliana). But she was fascinated by this apparent wasteland that was home to all kinds of plants and animals: “What a beautiful, amazing ecosystem.”

A few years later, back in Chicago, she visited a less romantic landscape, the former US Steel South Works site on the southeast side of the city. It’s covered with slag, a byproduct of steelmaking. Slag was dumped while it was still molten. Like flowing lava, it killed everything it touched, then hardened into a substance similar to asphalt. At the US Steel site, Anastasio found cottonwood trees growing on it.

Cottonwoods are usually enormous—100 feet tall or more. These cottonwoods were stunted down to human size, closer to six feet. They made Anastasio think of the tiny trees she’d seen on Stora Alvaret.

When she looked more closely at the vegetation, she expected to find “all crap plants”—the same invasive, non-native weeds you might see in any vacant lot. To her surprise she spotted little bluestem, a native prairie grass, as well as three species of native milkweed. And the US Steel site is “not even one of the most exciting slag sites,” she says.

Anastasio had already completed her PhD and decided she did not want a career as an academic scientist. Nonetheless, a research idea was born.

Lauren Umek (left) and Alison Anastasio, SM’05, PhD’09, search for a rare sedge in the Marian R. Byrnes Natural Area.

That former mill site sits in the Calumet Region—sometimes called, more poetically, the Calumet Crescent. The region begins on the far South Side of Chicago and hugs the Lake Michigan shoreline into Indiana. Its ecosystems include dunes, oak savannas, prairies, wetlands, and woodlands.

The showiest part is the Indiana Dunes. In the early 20th century, faculty member Henry Chandler Cowles, PhD 1898, helped make this area internationally famous. His important early work on ecological succession (the idea that ecosystems transform into others over time) was based on his fieldwork in the dunes and around Chicago.

In 1916 Cowles testified in Senate hearings for a resolution to create a Dunes National Park. He ranked the dunes with the Grand Canyon, Yellowstone, and Yosemite as the nation’s top natural wonders. That resolution failed; the Indiana Dunes finally got its national park in 2019.

Despite the national park, natural beauty is not the first thing that comes to mind when you think of the Calumet Region. Its largest city (not counting the slice of Chicago) is Gary, Indiana. Seen from the Chicago Skyway, the landscape is defined by steel mills—a few still operational, but most long shuttered—and other heavy industry. When the mills closed, the slag was left, a permanent reminder of a more profitable time, with less environmental oversight.

In the Chicago section of the Calumet Region, some of these brownfields (a general term for former industrial sites) now belong to the Chicago Park District. The challenge for land managers is turning them into green spaces for people to enjoy. So how do you clean this mess up?

According to Anastasio and her research collaborators—Laura Merwin, SM’12, PhD’15, and Lauren Umek, who earned her doctorate at Northwestern—sometimes the answer is simple.

You don’t.

The many colors of slag, a byproduct of steelmaking.

Around 2018 Anastasio came up with the idea of forming a volunteer research group of urban ecologists, “a dream team of people I wanted to work with.”

She knew Laura Merwin from UChicago; they had overlapped briefly in the lab of Joy Bergelson, then the James D. Watson Distinguished Service Professor and chair of the Department of Ecology and Evolution. Anastasio had met Lauren Umek, a project manager for the Chicago Park District, through local ecology groups. “Somewhere someday,” Anastasio says. “We can’t really remember.”

She invited them to brunch to pitch her idea to research plants growing on slag. Not for any obvious career goal, just out of pure curiosity.

Anastasio had prepared a spreadsheet—“Because she knew our love language,” says Umek—that outlined which skills each person could bring to the project and how each might benefit. She didn’t need the spreadsheet. Merwin and Umek were excited to join her “reverse side hustle,” as Anastasio calls it. (It involves a lot of work, but rather than bringing in extra money, it brings extra costs.)

At the time Anastasio was teaching environmental and urban studies at UChicago; among other classes, she taught in the College’s Calumet Quarter. Merwin was teaching in the biology department at Concordia University. And at the park district, Umek’s responsibilities included two sites—Big Marsh Park and Marian R. Byrnes Natural Area—where slag had been dumped. With Umek in the group, they would have access to these sites to conduct research.

Anastasio had called her spreadsheet “Slag Research Group.” No one can remember who came up with their subsequent name, the Slag Queens. “You have to call the group chat something,” says Umek. Later they discovered it’s also the name of a post-punk band in Australia, where slag means something different.

Anastasio (left) and Umek, along with Laura Merwin, SM’12, PhD’15 (not pictured), formed the Slag Queens in 2018.

Outside the group chat, the three are better known as Merwin et al. Their first paper, “Urban Post-Industrial Landscapes Have Unrealized Ecological Potential,” was published in Restoration Ecology in 2022.

The Slag Queens (SQs for short) call this paper Slag 1. It included “very little data,” Merwin says, almost apologetically. Like Cowles and other early ecologists, their primary task was to describe what they saw—namely, “considerable extant biodiversity,” as the paper puts it.

Slag 1 makes a bold claim: These slag fields have ecological value in and of themselves. They’re not just a problem. They’re also a possibility.

When public agencies end up owning brownfields, they sometimes intervene, either by excavating the slag or by capping it and putting new soil on top. Both options—especially excavation—are expensive, and they wipe out anything valuable that might already be living there. “Rarely is the current ecological quality of brownfields preserved or even considered,” Merwin et al. write, “despite the common presence of volunteer species” (species that just show up) “and ongoing ecosystem processes.”

The paper makes the case for thinking of certain brownfields as novel ecosystems.

A novel ecosystem is an artifact of the Anthropocene; it’s an ecosystem transformed by human activity, replacing whatever ecosystem was there before. According to the paper, there is a “growing realization” among ecologists that these sites have value. Maybe they provide shade, or habitat, or plants that pollinators like.

They might help with stormwater management, slowing the flow of water to prevent flooding. Incredibly, these sites might help sequester carbon, keeping it out of the atmosphere, where it contributes to global warming. “Slag is good at that apparently!” Anastasio says.

In addition, Merwin et al. argue for something heretical among native-plant evangelists, that non-native species, including “problematic invasives,” should be “tolerated or even encouraged on slag sites” if they are hosting pollinators, for example. (But, importantly, only if there are no high-quality remnant sites—undisturbed ecological sites—nearby, where the invasive plants might spread and threaten native biodiversity.)

Finally, Merwin et al. suggest that land managers forget whatever ecosystem was there before. Instead they should look to more similar ecosystems as a guide, for example, alvar or—closer to home—dolomite prairie. (Dolomite is similar to limestone.) Endangered plants that originally grew on dolomite prairie, such as leafy prairie clover and lakeside daisy, might flourish on slag.

The novel ecosystem that has emerged in the Calumet Region is home to rare sedges.

The group’s next paper, Slag 2, is a survey of plants growing on 12 slag sites in the Calumet Region. It’s “the meaty one,” Anastasio says, chock-full of data: “If I do nothing else, all I wanted to do was characterize this ecosystem.”

The survey showed two basic categories of sites, wet and dry. Wet sites have a certain set of plants you see over and over again; dry sites have their own different set of regulars. “Not groundbreaking,” says Anastasio, “but whoa, really interesting!” And a question no one had thought to ask.

What they had not planned on was a paper they call Slag 1.5, coauthored by Nathanael Pilla and Anastasio, which appeared in a 2024 issue of The Great Lakes Botanist. The SQs had invited Pilla, a botanist with Midwest Biological Survey, to help them identify plants. At one of the wet sites, Pilla spotted a rare sedge, something “no one else would notice ever, except for supernerds,” Anastasio says. Eleocharis geniculata, commonly called capitate spike-rush, had last been recorded in Illinois in 1894 and was considered locally extinct. There it was, growing on slag.

The group’s long-term project is called Slag 5, because publication is somewhere in the distant future. “It’s slow science,” Anastasio says.

One of the first things the SQs did when they began their research was mark a transect (a fancy science name for “line”) across part of Big Marsh Park, a former industrial site on the southeast side of Chicago. Along the transect they defined both experimental and observational plots.

This part of Big Marsh is so red and crusty it’s known as Mars. But it’s home to all kinds of plants, including “a nasty invasive species, spotted knapweed,” Anastasio says, “a little thistle-y kind of thing.” The park district had planned to spray it, “but I’ve never seen more insects in one place,” Anastasio says. On the advice of the SQs, this notoriously invasive weed was left alone.

The transect is 600 meters long, and they sample every 25 meters. The SQs also laid out “paired plots” every 50 meters. On one of the plots, they cleared away the plant matter down to the roots. The second plot, the control, was left as it was. The plan is to study the patterns of plant succession to understand what happens over time.

“Shout-out to the University of Chicago. One thing I learned that made a big impression on me from Cathy Pfister [professor of ecology and evolution],” Anastasio says: “Get that long-term data set started, because you never know what you’re going to find.”

Tiny white orchids make their home on slag.

On a perfect autumn evening, Anastasio and Umek have agreed to give the Magazine a tour of the Marian R. Byrnes Natural Area. The SQs are busy with their day jobs, so it’s difficult to get all three together. (Since the group formed, those day jobs have shifted. Anastasio works as an environmental consultant at architecture/engineering firm Ramboll; Merwin has a similar role at engineering firm Sargent & Lundy.)

Marian R. Byrnes begins near 96th Street and Stony Island Avenue and runs along the railroad tracks to 103rd Street. The Chicago Transit Authority wanted it for a bus depot—a plan thwarted by neighborhood activist Marian Byrnes, AM’50, who fought to preserve it as green space.

Umek has an unlikely family connection to this diagonal sliver of land. Her in-laws, who grew up in the neighborhood, used to tell stories about “the Prairie.” When she was assigned to work on the Marian Byrnes area, she discovered it was the same thing: “That’s the Prairie?”

One day Umek walked it with her father-in-law and his 90-something mother so Umek could ask him about playing there as a kid in the 1970s. “A 10-year-old boy’s memory of tromping through the space is the perfect ecology memory,” she says.

They could catch tadpoles but not fish, he recalled. Umek’s translation: “It’s an ephemeral wetland, wet enough to have tadpoles, but not enough to have fish.”

There were more green snakes than brown ones; the green ones “made the best necklaces.” These snakes (called, endearingly, smooth greensnakes, one word) are “an indicator species” of a high-quality environment, says Umek. “And they’re abundant here, and they’ve apparently always been abundant here.”

When they played with matches, her father-in-law said, certain areas would catch fire, while others wouldn’t. That told her “how much standing water there was,” Umek says, as well as “what types of grasses were probably present that would easily catch fire.”

“You’re grounded,” her father-in-law’s mother told him at the end of the tour.

Marian Byrnes is one of the slag sites where the rare sedge grows. “Hi, baby!” Anastasio says, as she scoops one up for a photo.

“When Alison and Nathanael discovered these, I was like, ‘I assure you, I have stepped on that 400 times,’” says Umek.

It doesn’t look like much. You might say it’s a sedge only an ecologist could love. And how could they spot this scrubby, nubbly thing among all the taller, prettier plants? “If you had to describe a family member or a friend, it would be the hardest thing,” Umek says. “But if you saw them, you know who they are.”

Marian R. Byrnes Natural Area is also home to orchids. Tiny all-white orchids, known as sphinx ladies’ tresses (Spiranthes incurva), a common wetlands plant in Illinois. But orchids nonetheless. Growing on slag.

Rather than focusing on restoring postindustrial areas, the Slag Queens center their research on “these bigger questions of, ‘What is it? And what can it be?’” Umek says.

The SQs like to name things. Their proposed name for the landscape they study, courtesy of Nathanael Pilla: Chicago slag barrens.

A barrens is a specific type of habitat, describing a place where plant growth is sparse, stunted, or otherwise limited. “There are pine barrens, sand barrens, serpentine barrens,” Anastasio says. The SQs argue that the Calumet Region’s anthropogenic ecosystem belongs among these natural barrens in the classification scheme.

The work of Merwin et al. (a name that might change with their next paper, depending on who takes the lead on writing it) brings some pragmatism to the debate about what to do with brownfield sites. The idea of leaving some sites as they are, and maybe strategically adding a few native plants here and there, certainly holds allure for taxpayers.

Because of Umek’s job in the park district, the SQs are in the unusual position of being able to help shape policy. Already the park district has made changes “as a direct result of this collaboration,” she says. “Very real on-the-ground changes in our approach to how we manage parks.”

The pipe dream of restoring postindustrial areas to what they once were is “not a realistic goal,” Umek says. By the same logic, much of the lakefront would be under Lake Michigan. Instead their research centers on “these bigger questions of, ‘What is it? And what can it be?’”