There’s the kind of science that involves white lab coats, test tubes and highly controlled environments.
And then there’s the kind that calls for hip waders and tick repellent.
This time of year, Shedd Aquarium biologist Melissa Youngquist can be found in the woods, sloshing through ponds in search of signs of amphibian life.
Forest-dwelling frogs, toads and salamanders converge on these waters to breed, a safer option for their eggs and young than streams and lakes populated with fish.
“A lot of these species can’t co-exist with fish, their tadpoles have no defenses,” Youngquist said. “These (ponds) are vital breeding habitat. If they don’t have a place to lay their eggs, they’ll die out.”
But not all ponds are created equally. Some are year-round, others are ephemeral vernal pools — sometimes they’re wet, sometimes they’re not. Some are found in well-managed forests, others are in areas undergoing restoration to remove invasive buckthorn.
What Youngquist wants to know is how amphibians respond to these different conditions.
Large numbers of frogs and salamanders have been lost in the greater Chicago region — both in terms of total population and diversity of species — for lack of quality habitat. The question is, what’s the threshold amphibians need to thrive?
Do they require pristine forest or can they tolerate some degradation, and if so, how much? Is it essential to remove buckthorn entirely, or maybe just in a perimeter around a pool’s edges? Should that perimeter be 30 meters, or 15 or 5?
To find out, Youngquist’s got to get her hands dirty.
Video: What’s in the muck? Look closely. (Patty Wetli / WTTW News)
Earlier this spring, Youngquist checked in on monitoring sites located in protected natural areas in the western suburbs. (The whereabouts are being withheld to guard against poaching.)
During the strictest of the COVID lockdown periods, the only data she collected was from critter cameras and sound recording boxes. But now she’s back to mucking around in person, which is how she likes it.
Youngquist’s primary tool when she’s out in the field is a small, low-tech handheld net, the kind you can pick up for $10 or less at a sporting goods store.
After scanning the surface of a pond for eggs or tadpoles and not seeing any, she dipped the net into the murk and scooped out a load of goop. Gently but with a practiced efficiency, Youngquist picked through the goop, which was mostly mashed leaves, aka leaf litter.
“This is what gets me going,” Youngquist said as she hit paydirt, exposing a layer teeming with chorus frog tadpoles, damselfly larvae, crayfish and fingernail clams (picture a dried lentil).
The tadpoles could easily be mistaken for clumps of dirt but they wriggled to life after a prod from Youngquist’s finger, their shimmering bellies catching the sunlight.
Less experienced observers would just have to take her word for it that these tadpoles have the chorus frog’s telltale eye placement, “kind of on the outside of the head” compared with, say, leopard frogs or toads, where “the eyes are all up on top.”
This scoop had all the diversity Youngquist had hoped for, minus any salamanders, but it also came from her “control site,” a high-quality permanent pond with the right mix of all the ingredients amphibians prefer.
Other dips of the net at vernal pools were less fruitful. There was plenty of zooplankton — aquatic microorganisms that form the base of the food chain — and more of the fingernail clams, but not much else. What Youngquist would have liked to have seen is evidence the amphibians are expanding their range into these restored areas.
In terms of habitat, restoration sites where buckthorn’s been hacked back 15 meters have nearly replicated the characteristics found at the control pond, but “in terms of the biodiversity — the insects, the amphibians — we’ve not reached that point,” Youngquist said.
The challenge is figuring out whether there’s a missing piece in the restoration efforts or whether the amphibians are reacting to conditions outside human control. This year at least, theories are leaning toward the latter.
Youngquist noted that water levels at the ephemeral pools were significantly lower than what she would have expected — water that’s now just shin-high had reached to her hips in past years — and the “most important aspect of a wetland is that it’s wet.”
The day’s results were a snapshot of a single moment in time, and she would need more observations — not just in the coming weeks or months, but rather, years — to put together a complete picture.
Restoration is a “long game,” Youngquist said.
So how does a person come to be a herpetologist?
Youngquist has an unusual origin story.
Her family lived in Tanzania when she was a small child and as she recalls it, her fascination with frogs started when she contracted malaria. That’s when her mom told her that frogs eat the disease-carrying mosquitoes, so Youngquist started keeping frogs and toads by her bedside as an insurance policy. And she’s been drawn to them ever since.
“My earliest memories are of catching frogs,” Youngquist said.
But hers is not a typical experience, she acknowledged. Amphibians tend to stay out of sight during the day — it’s possible to be standing atop a salamander burrow and not know it — and even when they do come out of hiding, they’re more likely to elicit an “eek” rather than an “aww” from people.
This lack of connection can make it a “harder hill to climb” to get people interested in the conservation of frogs and salamanders, Youngquist said.
So it’s not surprising that when people ask her “Why should we care about toads?” Youngquist responds by not only mentioning amphibians’ role in controlling mosquito populations, but in linking them to creatures she knows carry greater weight with humans.
“What’s your favorite animal? I will tie that back to wetlands and frogs,” she said. “If you like owls, they eat frogs. If you enjoy any animal, (frogs) are the base of the food web. People have no idea.”