This fall, five turtles poked their snouts into the same waters of the University of Chicago’s Botany Pond that they once called home.
While their surroundings might have seemed familiar, the nearly 125-year-old pond they were encountering had noticeably changed. The water was much clearer, tinged a healthy light green by algae and phytoplankton and filtered by deep layers of crushed rock. Native aquatic plants swayed in the gentle current circulating water from one end of the pond to the other. And tiny native fish darted in the shallows.
Over the past several years, Botany Pond has undergone a substantive restoration in order to rework the pond’s circulation system and shore up its century-old bridge.
The physical construction was only the first step, however. After refilling the pond, the next task was to reintroduce the pond’s inhabitants.
But the restoration team—led by UChicago landscape architect Katie Martin Peck, with guidance from faculty experts—didn’t want to simply return to the way it was before.
Instead, they wanted the pond to be an ecosystem—one that nodded to the original pond’s biodiversity, but that could sustain itself with as little human intervention as possible. They also sought to honor the pond’s origins as a sanctuary shaped by scholarship.
“There wasn’t really a blueprint for this kind of project,” Martin Peck said. But, with help from UChicago biologists, outside consultants and the Illinois Department of Natural Resources, she and her colleagues at UChicago Facilities set out to rebuild the pond’s ecosystem from scratch.
An invisible ecosystem
Botany Pond has a long and storied history.
Originally designed in 1902 by John C. Olmsted, nephew and “architectural heir” of famed American landscape architect Frederick Law Olmsted and his son, Frederick Law Olmsted Jr., in collaboration with Professor John Coulter, the pond initially was envisioned to host exotic species collected by the Botany Department.
But over a century later, the pond’s purpose and uses had changed—and it needed shoring up. By the time the restoration began, the pond had nearly four feet of sediment built up at the bottom, including surface runoff and years of waste from ducks, said Facilities project manager Lindsay Haskins.
The team hoped that building a fully functioning ecosystem would help the pond regulate itself with as little intervention as possible, while offering rest and refuge both to human visitors and wildlife alike.
The restoration started from the ground up—literally.
Botany Pond’s new filtration system starts with five feet of varied sizes of crushed rock at the bottom of the pond, designed to capture debris and sediment for easy removal every few years. A series of pumps pull the water down through the rocks, and jets create a light current, oxygenating the water through the depths of winter and ensuring it doesn’t fully freeze. This laid the foundation for the pond’s inhabitants to thrive.
To remake Botany Pond as a functioning ecosystem, Facilities recruited the help of expert consultants and faculty biologists, including Prof. Emeritus Michael LaBarbera, who told them they needed to start at the very bottom of the food chain.
When we think about pond life, we tend to focus on the creatures we humans know and love, such as fish, turtles or ducks.
But the pond ecosystem rests on a foundation largely invisible to us. At the bottom of Botany Pond’s food chain are bacteria, billions of them, seeded during the pond restoration by transplants of mud from nearby bodies of water. They float alongside single-celled plants, algae and phytoplankton.
These feed the next layer, which is LaBarbera’s favorite: zooplankton, tiny swimming creatures that are just barely visible to the naked eye.
Last year, LaBarbera and Martin Peck traveled to nearby Jackson Park Lagoon to collect a small sample of local zooplankton to seed the pond.
‘I could watch these guys all day’
LaBarbera has spent a lot of time in Jackson Park. For decades, he took his classes there to track wildlife, so he knows the good spots for collecting zooplankton.
For this trip, that meant the southern end of Wooded Isle. There, he rigged up a very fine mesh net in a pulley system, which allowed him and Martin Peck to stand on either end of the bridge to the island and pull the net back and forth between them, gathering microscopic swimming creatures.
After a few rounds, they hauled up the net and gently poured the contents into a clear container. LaBarbera tilted the jar to peer inside.
“Oh, look! See these little swimming white spots? Those are copepods. They’re in the crustacean family. And some of them, you’ll see a dot where the body joins the tail—those are egg sacs. So this looks really good,” he said, pleased. “They’ll populate the whole pond very quickly.
“Most people don't find copepods terribly charismatic,” LaBarbera said. “I do—I think they're very cute. I could watch these guys all day.”
In addition to a couple thousand copepods, the bottle also contained rotifers (“Strange little things. They look like little R2D2s with hairs,” LaBarbera said), and water fleas, among other creatures.
But LaBarbera was adamant about the zooplankton for more than their cuteness. A key food for baby fish, these zooplankton are an essential link in the ecosystem.
“The pond would acquire these eventually—on the feet of migratory birds like ducks, perhaps—but it might take several years, and until then the fish will have a hard time,” LaBarbera explained. “The adult fish can probably live. But if they spawn there, their larvae would not have anything to eat.”
Establishing the food chain
With the bacteria, plankton and zooplankton established, the pond was ready for the next step up the food chain—fish.
The team consulted with faculty and the Illinois Department of Natural Resources to select native species found in a typical Illinois pond or river, covering multiple parts of the food chain.
“There’s actually quite a lot of interesting, diverse fish in the streams and ponds here in Illinois—more than fifty species of minnows alone,” said Mark Westneat, a professor of organismal biology and anatomy who studies fish.
In the end, they settled on six species of fish: channel catfish, golden shiner minnows, fathead minnows, creek chubs, pumpkinseeds and white suckers.
The success rate for establishing fish populations is better in the fall, thanks to the cooler temperatures. So, on a drizzly September day, a truck arrived on campus and unloaded bags of wildly swimming fish.
Martin Peck and Haskins carefully lowered the bags into the water to let the temperature equalize, which helps reduce the shock to the fish. Then the pair cut the bags open and allowed the fish to pour out in a flashing stream. The catfish cruised lazily beneath a clump of water lettuce, but the minnows immediately darted to all corners of the pond.
“More than 700 native fish have been added to the pond so far,” said Martin Peck. “Look closely in the deep end and you’ll see schools of the different species swimming around.”
Next came the turtles. They had been removed when the pond was initially drained and handed over to a licensed wildlife rehabilitator, who assessed the turtles’ health and kept them safely over two winters while the pond construction was completed.
The turtles will forage for plant life, small fish and insects. When the temperatures start to drop, they will burrow down into the mud and crushed rocks at the pond bottom for the winter.
Botany Pond’s beloved ducks, on the other hand, are wild migratory animals that come and go as they please. But the team also planted a stand of native sedges, grass-like plants that ducklings particularly like to nestle in, as well as a series of stepped stones for them to easily enter and exit the pond.
There will be one more step for the pond’s ecosystem. In the spring, the team will add snails, crayfish and tadpoles of native frog species, such as leopard frogs and spring peepers.
“You’ll also start to notice dragonfly larvae, little aquatic beetles, different species of algae—so that the whole food chain fills out,” said Westneat.
In addition to its fauna, the pond is now home to 11 different species of aquatic plants, including a fragrant water lily, an American species of lotus, a blue iris and several kinds of rushes.
The land plants surrounding the pond are a mix of native and introduced species, designed to offer color and interest throughout the year to human and wildlife visitors. Native wild geraniums bloom in spring with periwinkle-colored flowers; roses pop in summer; bright purple asters and cheerful pink Japanese anemones follow in fall. Around the flowers, native ferns and sedges shelter wildlife and offer a lush backdrop.
“We wanted to parallel the original plan for the pond,” said Martin Peck. “It’s not a showcase for exotic species anymore, but we wanted to nod to its past with a very biodiverse mix of plants. We have a lot of variety between the perennials, shrubs and trees, with just enough repetition to create a curated look.”
The new pond design includes viewing patios and seating for humans, but also islands in the middle of the pond for animals to retreat to when they need to feel safe.
The bridge, a gift from the Class of 1922, remains there too—shored up for another century of curious visitors, excited children and photo-ops.
The reconstruction was recently recognized with the President’s Award of Excellence by the Illinois Chapter of the American Society of Landscape Architects, in the Historic Restoration category.
With these adjustments, the team hopes the refresh will offer years of enjoyment to the campus and Hyde Park community.
“We know this is a really beloved and meaningful spot for a lot of people,” said Martin Peck. “People seem to love to see it revived, and we think it’ll be fun for visitors to watch the ecosystem evolve.”
