shoreline restoration – My Chicago Botanic Garden

In a first-time summer internship research project, two college students set out to understand how plants were responding to the Garden’s shoreline restoration projects. They took a deep look into how variations in water levels may be affecting the health of the young plants. The results of their work will help others select the best plants for their own shorelines.

A silent troop of more than one-half million native plants stand watch alongside 4½ miles of restored Chicago Botanic Garden lakeshore. The tightly knit group of 242 taxa inhibit erosion along the shoreline, provide habitat for aquatic plants and animals, and create a tranquil aesthetic for 60 acres of lakes.

PHOTO: The North Lake shoreline. — The North Lake shoreline restoration was completed in 2012. Photo by Bob Kirschner

Now ranging from 2 to 15 years old, the plants grow up from tiered shelves on the sloping shores. Species lowest on the slope are always standing in water. At the top of the slope, the opposite is true, with only floods or intense downpours bringing the lake level up to their elevation.

Wading In

Jannice Newson and Ben Girgenti moved through clusters of tightly knit foliage along the Garden shoreline from June through August, taking turns as map reader or measurement taker. On a tranquil summer day, one would step gingerly into the water, settling on a planting shelf, before lowering a 2-foot ruler into the water to take a depth measurement. The other, feet on dry land, would hold fast to an architectural map of the shoreline while calling out directions or making notes.

Newson, a Research Experiences for Undergraduates (REU) intern and sophomore at the University of Missouri, and Girgenti, a Garden intern and senior at Brown University, worked under the guidance of Bob Kirschner, the Garden’s director of restoration ecology and Woman’s Board curator of aquatics.

PHOTO: Interns Ben Girgenti and Jannice Newson. — Interns Ben Girgenti and Jannice Newson gather plant data on the shoreline.

When the summer began, Girgenti and Newson had hoped to locate and measure every single plant. But after the immense scope of the project became clear in their first weeks, they decided to focus on species that are most commonly used in shoreline rehabilitation, as that information would be most useful for others.

View the Garden’s current list of recommended plants for shoreline restoration.

“We’re interested in which plants do really badly and which do really well when they are experiencing different levels of flooding, with the overall idea of informing people who are designing detention basins,” explained Girgenti, who went on to say that data analysis of the Garden’s sophisticated shoreline development would be especially useful for others.

“The final utility of this research will be to inform other natural resource managers,” confirmed Kirschner, who added that successful Garden shoreline plants must be able to withstand water levels that can rise and fall by as many as 5 feet several times in one year.

Steering the Ship

Along the shoreline, the interns followed vertical iron posts that were installed as field markers during construction, in order to find specific plants shown on the maps. “The posts are pretty key to being able to map out the beds,” said Girgenti.

PHOTO: The Malott Japanese Garden shoreline 3 years after the 2011-12 restoration project. — The Malott Japanese Garden shoreline two years after the 2006 restoration project.

Once they found a target plant, they then counted clumps of it, and put it into one of six categories based on the amount of current coverage, ranging from nonexistent to area coverage of more than 95 percent.

They also measured the average depth of water for beds with plants below the water line, noting their elevation. For plants above the water line, the elevation was derived from the architectural drawings.

Data about the elevation and coverage level of each measured plant, together with daily lake water level readings dating back to the late 1990s, was then entered into a spreadsheet and prepared for analysis to identify correlations between planting bed elevation and plant survival.

Beneath the Surface

For her REU research project, Newson was careful to collect data for one species in particular, blue flag iris. “As a preliminary test of the project hypothesis, data relating to 101 planting beds of Iris virginica var. shrevei were analyzed to see if there was a significant correlation between the assessed plant condition and each planting bed’s elevation relative to normal water,” she explained in her final REU poster presentation in late August.

PHOTO: Southern blue flag iris. — Southern blue flag iris (*Iris virginica* var. *shrevei*), photo by Jannice Newson

An environmental science major, she initially experienced science at the Garden as a participant in the Science First Program, and then as a Science First assistant, before becoming an REU intern.

Girgenti began his Garden work in the soil lab, where his mentor inspired him to focus on local, native flora. “I was kind of pushed up a little bit by the Garden,” he said. The following year he did more field work in the Aquatics department. “I wanted to come back because I really enjoyed being here the last two years,” he said. “Every year I’ve come back to the Garden, I’ve been very excited about what I’m going to do.”

Aside from the scientific discovery, the two also refined their professional interests. “I do enjoy being out in the field as opposed to maybe working in a lab; it’s a lot more interesting to me. And also just working in the water with native plants is very interesting,” said Newson.

“I was really interested in getting into more of the shoreline science and also learning which native species were planted there,” said Girgenti. “I really love working here. I’ve never really been involved this much in science, so this has been a really great experience—just all of the problem solving that we’ve had to do over the course of the summer.”

Newson also enjoyed the communication aspect of her work, as Garden visitors stopped to ask what work she and Girgenti were doing along the shoreline. She was especially excited to share with them and her fellow REU interns that “the purpose of why we are doing this is that it provides a beautiful site for visitors to see, it helps with erosion, and also improves aquatic habitat.”

PHOTO: View of the Kleinman Familly Cove. — A view of the Kleinman Family Cove highlights the small bay where our youngest science explorers can learn about the shoreline.

Although the interns have left the Garden for now, the data they collected will have a lasting impact here and potentially elsewhere. Kirschner is currently working with his colleagues on the data analysis to complete a comprehensive set of recommendations for future use.

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.)

Learn more about local frogs, toads, and their calls.

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.

Discover the details and challenges of our restoration project.

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.

Tag: shoreline restoration

Water Works

Spring Chorus