Measuring the Impact of Invasive Plants

“I have always been fascinated by the complexity of nature and the way that [organisms] interact with one another,” says Kristina Stinson, 38, a plant population biologist at Harvard Forest in Petersham, Massachusetts.

After obtaining two bachelor’s degrees, one in literature and languages and another in natural sciences and mathematics, Stinson did a Ph.D. at the Department of Ecology and Evolutionary Biology at Princeton University, conducting her research on how global warming influences the flowering time of alpine plants on the verge of extinction at the Rocky Mountain Biological Laboratory in Crested Butte, Colorado. After graduating in 1998, Stinson took a postdoc at Harvard University, where she studied the dynamics of ragweed populations in elevated atmospheric carbon dioxide levels as well as the physiological processes that turn plants into invasive species outside their home ranges.

Stinson’s fieldwork took her to Harvard Forest, where she applied a population perspective to studying how invasive plants affect forest ecosystems. They “really change the way the forests work because they form very dense populations of single species and often replace or displace the native plant,” Stinson says. After a couple of years working on this topic as a research associate at Harvard, she was offered her current staff position at Harvard Forest.

Stinson’s work on garlic mustard–an invasive plant able to kill fungi essential to the growth of tree seedlings–involves “crouching down in the woods [with] a clicker counter to count individuals” at 1-by-1-meter sampling sites all around New England. It is “small-scale, meticulous work.” She brings soil samples back to the lab to monitor the presence of fungi and quantify how much garlic mustard affects the growth of tree seedlings in greenhouses. “It really spans the whole spectrum of fieldwork to lab work,” she says.

Stinson’s work has implications for forest management. “It’s very important to be able to demonstrate when an invasive plant is actually having a negative impact and what the negative impact is, because forest managers are working to manage an ecosystem that has all kinds of management problems and limited resources,” she says. She has also done research and management advisory work for U.S.-based conservation charity The Nature Conservancy. It’s “very gratifying to see that your research has the potential to have an impact,” Stinson says.

A SelfMade Climber

Sustaining Forests in a Changing World