In her role as an urban ecologist and project manager for the Chicago Park District, Lauren Umek has overseen a number of ecosystem restorations.
There is a well-established set of best practices to build upon, which typically begins with the removal of invasive species and ends with the reintroduction of native plants that support a greater diversity of wildlife, she said. .
But how to “restore” a landscape where nothing grows at the start?
That’s the challenge Umek faces at Big Marsh Park in southeast Chicago.
The park district acquired the 278 acres that became Big Marsh in 2011. Portions of the land were once covered in slag, a waste from the now defunct steel mills in the area. To clean up the soil contaminated with slag, the park district covered it with a “transparent hat” of soil.
“From an environmental point of view, the ‘cap’ needs to be at least a foot from something,” Umek said.
In Big Marsh, that “something” was a mixture of cheap clay soil and earth from construction sites, including dirt trucks pulled out of Legion Park along the North Branch of the Chicago River and Pullman’s. Gately Park.
But what works ecologically doesn’t necessarily work ecologically. A clay cap can control contaminants, but it’s not ideal for growing native plants, Umek said.
This is why it is common practice to convert covered land into recreational uses such as toboggan hills, golf courses or bicycle parks, and not fields of wildflowers.
Yet native plants and prairie grasses are what Umek is trying to restore on 30 of Big Marsh’s capped acres. “Here we are building from scratch,” she said. “There is no guide on how to do this.”
So she creates one.
Universities, conservation organizations and community scientists conduct research in Chicago’s parks, sharing data and results with park district staff, as appropriate. In 2020, more than 30 such projects took place, studying everything from the distribution of crayfish in ponds to bird populations.
The restoration of Big Marsh enabled Umek to hold a doctorate. in plant biology and conservation, the opportunity to carry out your own experience. She was joined by Alifya Saify, a graduate student from Northwestern University, who signed up as an assistant to Umek, eager to learn more about the reclamation potential of industrial and hard land on behalf of of nature.
“There is so much land that no one focuses on,” said Saify, who grew up in Munster, Indiana. “I feel like this is the future. How can we make the Midwest beautiful again? ”
The goal of their project is to determine which of the three soil amendments added to the clay layer at Big Marsh would produce the best results for growing native plants.
They tested different combinations of topsoil, a nutrient-rich commercial compost, and a biosolid compound (called EQ Compost) of the Metropolitan Water Reclamation District of Greater Chicago. (EQ is a mixture of treated waste and materials such as wood chips, grass clippings and leaves.)
In April, Umek and Saify applied the different treatments – seven inches deep – to three groups of 20 plots of soil (or 60 plots in total, spread over three different sections of the clay cap). In May, they sowed flower seeds, and in June, they placed plant root simulation probes in the plots.
The probes, which were withdrawn in July, collected data on the presence of nutrients in the soil, giving insight into how different treatments affected plots over time, Saify said.
Beyond soil health, the researchers looked at which treatments promoted seed germination and where fertile ground was for weeds.
“Weeds always find a way,” Saify said. “There was a lot of crab grass.”
Preliminary results indicate that EQ Compost is the “winner”, at least the first year of the experiment. Because the seeds of many native plants sleep for a year before germinating, Umek wants to see what happens in the second year. In the longer term, it must also take into account considerations such as maintenance costs once the plants are established.
Treatment might be more expensive initially, she explained, but might do a better job of suppressing weeds or retaining moisture, requiring fewer resources down the road.
Ultimately, the research findings will have implications beyond Big Marsh, and even beyond Chicago.
“There is a lot of abandoned and unmanaged post-industrial land,” Umek said. “No one wants a barren clay landscape.”
Contact Patty Wetli: @pattywetli | (773) 509-5623 | [email protected]