City Ants Rule: Ecologist Finds Diverse Ant Population in Urban Environments

By Ed Moorhouse

Unless there is an army of them converging on discarded food on the sidewalk, ants largely go unnoticed in cities. But among the hustle and bustle of daily urban life, there is a diverse ecosystem thriving beneath our feet.

Rutgers-Camden biology professor Amy Savage examines ant populations in New York City. Photo by Lauren Nichols.

Rutgers-Camden biology professor Amy Savage examines ant populations in New York City. Photos by Lauren Nichols.

“There’s this idea that ecology stops when you get to the city, but if you look closely, there are really interesting ecological dynamics happening,” says Amy Savage, an assistant professor of biology at Rutgers University–Camden.

Savage, who joined Rutgers–Camden’s faculty in September, is bringing the study of ants from the fields and the forests into the city, an often overlooked habitat for the arthropods. She also is about to examine New Jersey’s own ant population, focusing her research on Camden and on the Pine Barrens.

“As ecologists, we generally don’t study where we live and work, so those areas become neglected,” Savage says, explaining that she flew to Samoa to research ants while she was a doctoral student at Rice University.

“I was giving a talk about ant diversity in Manhattan and someone from the American Museum of Natural History was there. She said the museum had no ants from New York City.”

That inspired Savage to continue to study urban ecosystems as a postdoctoral scholar at North Carolina State University. She performed her field work in New York City and says what she found there was surprising. By primarily observing grassy medians that separate lanes of traffic, as well as public parks and playgrounds, Savage discovered 46 different species of ants, a remarkable number, especially given that most were native to the city.

“It shows that all of these species are able to live in these small, high-stress environments,” Savage says.

“They’re really interesting to watch, but they’re also ecologically very important. From the very tops of the tree canopies all the way to below the ground, ants are affecting ecological processes,” she says. “I think they might be keystone predators in urban ecosystems.”

A close-up of a pavement ant typically found in an urban environment. Photo by Lauren Nichols.

A close-up of a pavement ant typically found in an urban environment. Photos by Lauren Nichols.

In other words, they determine the types and numbers of other species in an urban environment. Savage says she observed insects with natural defenses to ants — such as millipedes and rove beetles — living in the city. During a feeding experiment she performed, Savage says the city ants chose to eat crickets over hot dogs, cookies, and potato chips, signaling low numbers of insect prey in urban environments.

As she begins her research in Camden, Savage says she is most interested in the level of ant species diversity she’ll find and suspects it will be even more diverse than what she found in New York.

“Camden is an ideal place to continue my research,” she says. “There are different environments here, and there are also places here where the elements of urbanization are present, but the stresses are although it’s been depopulated.”

Savage is also interested in expanding her research to compare ant diversity in affluent parts of cities to abandoned or undisturbed areas, and will soon start observing the impact ants have on the soil in the New Jersey Pine Barrens.

“In cities, there is a lot of interaction between people and the environment, which makes it an ideal place to study how that interaction impacts ecosystems. I’m excited to discover more,” she says.

A Pennsauken resident and native of Montana, Savage earned her bachelor’s degree from The Evergreen State College in Washington, her master’s degree from Western Washington University, and her doctoral degree from Rice University.

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