My favorite moment of spring is the blooming of daffodils. But this year, I am adding a new highlight: the uplifting sound of…frogs.
I have to admit, I’ve never heard such spring peeping at the Chicago Botanic Garden before. But last weekend, as I enjoyed several long walks here (including one with my sons on Mother’s Day at 6:45 a.m.!), I felt serenaded by a loud chorus of frogs and toads. (Some visitors are even mistaking the sound for chirping birds.)
A northern leopard frog (Rana pipiens) peers at the camera suspiciously. Photo by Benny Mazur from Toledo, Ohio (Mister Leopard Frog) [CC-BY-2.0], via Wikimedia Commons.
Working off the hypothesis that the Garden’s shoreline restoration efforts have helped increase frog and toad populations here, I turned to Garden scientists for answers.
And this is what I learned: of the Garden’s 385 acres, nearly one-quarter (81 acres) is water. More than three-fourths of the Garden’s shoreline has been restored since 1999, addressing long-standing erosion problems. Most recently, the Garden restored 1¼ miles of shoreline around the North Lake; the ten-month project was completed in summer 2012. As part of the project, we added more than 120,000 native plants—the largest perennial planting project in the Garden’s history—to stabilize shoreline soil. The sturdy plants, some with roots more than 6 feet deep, resist erosion and enhance water quality by filtering eroded soil and excess nutrients. The renovated shoreline provides an enhanced habitat for our aquatic life, which includes wood ducks, double-crested cormorants, and snapping turtles, along with bullfrogs, American toads, and other members of their croaking chorus. Build a healthy habitat and they will come!
Adding to the cacophony is an even bigger chorus than usual because of our “compressed” spring this year. Usually, the frogs emerge first, followed by the toads. This May, the frogs and toads are singing together—but not for long; come to the Garden soon if you want to hear them.
Abloom in May, native plants and sedge create habitat, protect shorelines, and create a beautiful border around the North Lake.
Even if you miss hearing them, I encourage you to listen to the short audio clip above and think about frogs (at least for a few seconds). Sometimes, we overlook the humble frog in favor of the more romantic songbirds in spring. In popular culture, the frog tends to fare better in other parts of the world. In Japan, for instance, the frog is considered a symbol of good luck. The Japanese word for frog is kaeru, which also means “to return.”
When I hear the frogs at the Garden from now on, I will think about how their return, spring after spring, announces that they’ve come home. I am proud that our conservation actions here have given them a healthy habitat in which to thrive, and I feel grateful to the frogs for giving me a moment to reflect on the importance of the Garden’s mission: We cultivate the power of plants to sustain and enrich life.
The dress rehearsal is complete, spring is preparing to turn on the lights, and within a few weeks the curtains will go up on the Chicago Botanic Garden’s newest shoreline restoration—the North Lake.
According to Bob Kirschner, Woman’s Board Curator of Aquatic Plant and Urban Lake Studies, the project that began in 2010 will come to full fruition this year.
“One of the most important details is the maintenance and management after it is installed,” he said.
Since the restored North Lake was dedicated in September 2012, its 120,000 native plantings have been busy growing their roots as far as 6 feet deep into the soil, trying to establish themselves in their new home. The process has been all the more tenuous due to the barrage of extreme weather during that time, from droughts to floods to the deep freeze.
Bob Kirschner was trained as a limnologist, or freshwater scientist.
“The first few years after a large project is installed, we’re out there babying the native plants as much as we can because these plants are serving an engineering function,” said Kirschner, who explained that plant roots play an integral role in the long-term stability of the shoreline and are essential to the success of the entire restoration.
Wading In
The Garden’s lakes were rough around the edges when Kirschner arrived 15 years ago. Wrapped in 60 acres of water, the land was eroding where it met the lakes.
Although the Garden could have surrounded the shores with commonly used barriers such as boulders or sheet piling, Kirschner advocated another route.
“We’re using much more naturalized approaches,” he explained. “They are taking the place of conventional, structural approaches.”
Why? In the long run, the shoreline becomes relatively self-sustaining. In addition to preventing erosion, it offers habitat for native wildlife such as waterfowl and turtles, and filters water to help keep it clean. When the plants flower, a shiny bow of blooms wraps all of those benefits up in a neat package.
The North Lake shoreline restoration surrounds the Kleinman Family Cove.
Bright Ideas
For many Garden visitors, a stop at the shoreline is inspirational. “We’re trying to help them visualize that native landscapes can be created within an urban context to be both beautiful and ecologically functional at the same time,” said Kirschner, who counts on the attractive appearance of the plantings to open conversations about restoration, and how individuals can generate similar results. “When thoughtfully designed, you can have both the ecology and the aesthetics,” he added.
It was this concept of incorporating the art and science of restoration in a public setting that brought him to the Garden in the first place, after more than 20 years as an aquatic ecologist with Chicago’s regional planning commission.
Kirschner, who is also the Garden’s director of restoration ecology, has managed six Garden shoreline restorations incorporating a half-million native plants.
Marsh marigold is a harbinger of spring.
He and his team know where all of the plants are, and they track them over time to identify those best suited for urban shoreline conditions. His favorites include sweet flag (Acorus americanus), common lake sedge (Carex lacustris), swamp loosestrife (Decodon verticillatus), and blue flag iris (Iris virginica). Perhaps the most exciting of them all is marsh marigold (Caltha palustris), the first shoreline plant to bloom each spring.
Natural areas comprise 225 of the Garden’s 385 acres.
According to Kirschner, the Garden’s hybrid approach to shoreline restoration, which incorporates ecological function and aesthetic plantings, is unique. “Part of our mission as environmental scientists is finding a way to make our work relevant and valued by as much of the public as we can reach,” he said. “It’s emotional for me because I believe so strongly in it, and that this is a path to increase ecologically sensitive landscape values within American culture.”
Changing Seasons
Drifts of native plants are a hallmark of the Garden’s restored shorelines.
The North Lake was his last major shoreline restoration for the time being. He is looking forward to taking a breath of fresh air and enjoying the show this spring. “It should be really interesting to watch how this year progresses,” he said. Because the long winter may mean a compressed spring, he said the blooms could be that much more intense once they begin in about May. “Every day when we come to the Garden, the plants will be noticeably bigger than they were the day before,” he anticipated.
When Kirschner finds a moment for reflection, he wanders over to the Waterfall Garden, where he enjoys serenity in the sound of the rushing waters, and walking the two staircases that invite discovery along the way.
