The idea of investigating weeds in a parking lot may not look very exciting, but to a botanist –and especially to an urban ecologist interested in plants and biodiversity – this car-filled area represents an extreme, urban treasure trove of thriving and flowering plants. These are mostly the same species as those pesky weeds that spring up in the cracks of our driveways at home that we can’t wait to remove with the latest weed killer. Yes, those very weeds. Hundreds of species bear seeds, produce flowers and propagate in parking lots all over the country, but not much is known about their survival and persistence.
In the spring of 2014, Lauren Frazee, Ph.D. student in the graduate program of Ecology and Evolution, found herself taking on a project investigating the biodiversity of weeds in Rutgers parking lots that was launched in 2012 by Lena Struwe, associate professor in the departments of Ecology, Evolution and Natural Resources as well as Plant Biology and Pathology, and her other graduate student, Jennifer Blake-Mahmud. A global botanist, Struwe is one of two co-advisors to Frazee in her doctoral program, along with Steven Handel, professor in the Department of Ecology, Evolution and Natural Resources.
Frazee’s interest is in urban plants and how urbanization affects plant life. “Parking lots are fascinating, since they can serve as a proxy for answering many questions about extremely disturbed urban ecosystems.”
She reasons that parking lots must be among the harshest environments in which plants can grow—pollution from vehicles, heat radiating from the asphalt, and herbicides, road salt, and weed whackers makes this a true killing field for plants. Yet their research has showed that there is a huge diversity of plant species populating the curb edges and cracks in these asphalt deserts.
The parking lot research project by the Struwe lab is part of a larger effort to look at weeds in cities and suburbia. According to Struwe, “weeds are truly the success stories of evolution. They survive despite us. They thrive in our artificial environments, and, if you want to study fast evolutionary processes in plants, just look to the weeds.”
“Research in evolutionary adaption to harsh environments is very important in our understanding and planning for climate change and ever-increasing urbanization on this planet,” she adds.
This summer, Frazee has gotten help for this project from Alisha Sharma, a sophomore Biology major at SAS and Aresty Scholar in its Summer Science Research Program.
For Sharma, who took a First-year Interest Group Seminars (FIGS) course where she learned about the Aresty program, the most interesting Aresty research option to apply for was the “Biodiversity of Weeds in Rutgers Parking Lots.”
“It felt intriguing, like a question mark, to me,” Sharma says. “I wanted to see for myself just what there was in terms of plant biodiversity in a parking lot.”
And, guided by Frazee and Struwe, she set out to focus on “how urbanization affects the growth and reproduction of wild plant species,” the big question she plans to answer in her Aresty research presentation in August.
Weeds in Rutgers Parking Lot Project
Together, Frazee and Sharma have identified over 100 plant species in parking lots on Rutgers campus in New Brunswick. Sharma proudly announces that since she began this project at the end of May, she’s now able to identify about 70 percent of the plants she encounters in this urban environment. Frazee can identify about 90-95 percent, she says. And whatever they cannot identify in the field, they take back to the lab to investigate further with the help of Struwe. Working alongside her graduate mentor, Sharma was keenly interested in understanding various habitats and their effect on plant reproduction. The pair consulted the Center of Remote Sensing and Spatial Analysis at Rutgers and used GIS technology to identify over a dozen study sites surrounded by varying levels of urbanization on campus for comparison.
As they travel around campus and spend long hours cataloguing and identifying the diversity of species in each parking lot, Frazee finds that “you can’t separate people from urban ecology studies, and most of the time the people that see us in the parking lots are curious, always asking questions.” The project has been planned in collaboration with Dianne Gravatt, executive director of operations and services at Rutgers Facilities Maintenance, who provided the team with access several parking lots that were not undergoing weed removal during the summer. This is an example of how scientific research can be successfully done at very local scales and even on-campus, when academic and logistical departments collaborate.
Among the most frequent questions that Frazee and Sharma encounter from students, faculty, Rutgers police and other frequent parking lot users are “Aren’t they just weeds?” “What’s the point of what you’re doing?” and “How can I get rid of the weeds in my yard?” Frazee is not likely to answer the latter question, though, because to her, “urban species are some of the only wild and spontaneous biodiversity that still exists in the cities where we live. There may not be orchids here, but there’s a vast diversity of quirky and successful species to explore. You just have to look a little closer.”
To Sharma, a budding biologist, it’s that “despite how much we disturb nature, the weeds still find a way to grow and multiply.”
So, what did Sharma’s first research project show? That weeds in more disturbed, urbanized areas have less energy to put into making seeds. Still, even these parking lot weeds make many hundreds of seeds per plant and will survive and come back, year after year.