Science & Nature

Step Into Chicago’s Swamps, Where a Shedd Researcher Has Found Surprising Biodiversity

Chicago was once a swamp. In some places, it still is.

In some places, the water is high enough to require hip waders and the murk at the bottom is inches deep, a goo that grips at feet with the suction force of concrete. Reeds, grasses and cattails tower overhead. Birdsong competes with the call of a chorus frog.

Standing in the center of a pond like this, it’s easy to feel transported, easy to picture what the landscape might have looked like hundreds, even thousands, of years ago. All it takes is a little imagination: Just ignore the road noise and block out the smokestacks in the distance.

Here in the Calumet region at Big Marsh Park and nearby Indian Ridge and Hegewisch Marsh, biologist Melissa Youngquist has found a surprising amount of biodiversity.

She’s identified more than a half-dozen species of frogs and salamanders, or nearly as many as she’s come across in far less degraded habitats.

“These Southeast Side parks give me so much hope,” said Youngquist, who specializes in amphibians.

For such abundance to exist on the fringe of the third-largest city in the U.S. is one thing. To come across such diversity in Calumet — where the scarred land suffered from decades of abuse and pollution during the heyday of the steel industry — is remarkable.

“These sites were dumped on and trashed. And somehow, some bits of marsh stayed wet long enough,” she said. “If all these frogs can survive here … there’s never no hope.”

Today, hundreds of acres of what were once slag heaps — a byproduct of steel manufacturing — have been reclaimed as natural and recreational areas managed by the Chicago Park District. Partners including Friends of the Chicago River, The Wetlands Initiative and Audubon Great Lakes have poured resources, both in terms of funding and manpower, into wetland restoration projects, including knocking back invasive species like phragmites, a tall grass.

Youngquist is measuring the effectiveness of those efforts: Are existing amphibian populations growing? Are fussier species moving in?

And if progress is being made, does climate change threaten to undo it all?

Researcher Melissa Youngquist at Big Marsh Park on Chicago's Southeast Side, where distant smokestacks are a reminder of the Calumet region's industrial use. (Patty Wetli / WTTW News)

Youngquist is monitoring some 30 wetland sites, mostly in Cook County. Some are in woodlands and others, like in Calumet, are in marshes; some are permanent, others are ephemeral, as in not-always-wet wetlands.

Frogs, toads and salamanders rely on these temporary wetlands to breed because they’re a safer option than streams, lakes and ponds populated with fish.

“A lot of these species can’t coexist with fish, their tadpoles have no defenses,” Youngquist said.

But what makes these ponds safer also makes them less reliable.

This year, forest preserve pools were dry in early spring, but park sites in Chicago were wet, Youngquist said. Yet by the beginning of May, the previously shin-deep water she’d observed at Big Marsh had shrunk to ankle-deep.

“It shows how unpredictable the hydrology is at these modified sites,” she said.

Now layer on climate change.

“It’s less about temperature and more about how much rain falls and when does it come,” Younquist said.

She’s specifically concerned with what happens if the timing of rains — the kind that creates those ephemeral pools — no longer synchs up with amphibians’ biological clocks.

In 2023, WTTW News tagged along with Youngquist as she visited one of her woodland wetland sites. (Patty Wetli / WTTW News)

Youngquist uses audio loggers to record frog calls at her monitoring sites. The equipment helps her not only identify which species are present at which locations — each species has a different mating call — but when they arrive.

Among the big questions the audio recordings will help her answer: If winters become shorter and warmer, will amphibians recognize the earlier arrival of “spring”? Can species adjust mating seasons if ponds form sooner or later?

In some drought years, Youngquist said, there’s evidence that spring breeders like the American toad and chorus frog can adapt.

“If we get a big summer rain,” she said, “they’ll breed if spring failed.”

But other species, particularly most native salamanders, have narrower reproductive windows that could best be described as “one and done,” and those are the creatures she worries about the most.

“Most of our salamanders are the first out in spring. March is salamander month,” Younquist said.

That’s when these reclusive creatures, which spend most of the year living underground, emerge to make their annual journey to their breeding pond — a “migration” that’s typically just a few hundred feet.

“What if they’re all waking up in March and there’s no water?” Youngquist asked. “That would have catastrophic consequences.”

Salamander larva also take much longer to mature, meaning even if the adults do find conditions ripe for breeding in spring, those temporary pools needs to stay wet through mid-summer.

“If it dries up, they’re done,” said Youngquist.

So are salamanders doomed?

Not if humans give them a hand.

Eastern tiger salamanders are the most abundant native species in the Chicago region but few people ever set eyes on these reclusive creatures. (U.S. Fish and Wildlife Service Midwest Region)

We can manage our landscapes to create permanent wetlands without fish, so that amphibians would have options other than temporary pools, Youngquist said.

“Amphibians, if you build it, they will come,” she said, with Calumet’s marshes a case in point. “If you give them a little water, they’ll hang on.”

But championing wetland expansion can be admittedly challenging, Youngquist conceded.

Historically, wetlands have faced intense development pressure, be it for agricultural use or urban sprawl. A 2023 Supreme Court decision made preservation even more precarious, stripping away environmental protections for wetlands not connected to a larger body of water.

Rallying public support behind wetlands is generally a heavier lift than for, say, a forest with waterfalls and canyons. Marshes are more difficult for people to access, and as a result appreciate, than other habitats, usually requiring boardwalks to glimpse even a fraction of their expanse. Then there are the mosquitoes and swarms of midges.

Birders and herpetologists will make the effort to explore marsh lands and swamps, Youngquist said, but to the casual observer, wetlands are a tougher sell.

It’s also harder to create empathy for creatures like salamanders when most people have never seen one in the wild.

“They’re not just out and about,” said Youngquist, who characterized native salamanders as “the coolest secret we have.”

“They live underground all their life, they go to a pond to lay eggs and leave. There’s a two-week window where if you’re in the right spot at the right time, you’ll see one,” she said. “It’s really hard to find them.”

Still, Youngquist said she was encouraged to see voters across the greater Chicago metro area approve tax hikes in support of their local forest preserve districts, funds that would be used to acquire more land and restore more acres.  

It’s a sign, she said, that people understand the value of healthy, native ecosystems — what you support for salamanders, you also support for herons and humans.  

Big Marsh is a good example, she said, with recreational areas for biking and fishing but spaces that humans are also managing exclusively for wildlife.

“We can coexist, we can make compromises,” Youngquist said. “It’s not all doom and gloom.”

Contact Patty Wetli: @pattywetli | (773) 509-5623 |  [email protected]

---