Big, mature trees with no vegetation growing beneath them may look like a healthy forest to most people. Not to Janet Morrison, a biology professor who researches the interactions between invasive species that destroy biodiversity.
“The entire Northeastern seaboard, from Boston to D.C., is a large piece of land, but without a big contiguous forest, only forest patches,” she explains. “To understand the basic ecology of that part of the world, it’s all about understanding the suburbanizing forest landscape. I think it’s incredibly driven by deer and invasive species.”
Funded by a grant from the National Science Foundation, Morrison and a team of student researchers are conducting a six-forest study over the next few years with a “planned invasion” of two non-native species—Japanese stilt grass and garlic mustard—into controlled plots of forestland. By manipulating plant growth in the plotted areas, Morrison can examine the effects of deer browsing, co-invasion (when two species grow together), and competition on biodiversity.
“These are clearly driving forces in these forests, yet they haven’t been tested experimentally,” explains Morrison. “What actually are deer doing? What actually is competition from these invasive species doing? How are deer affecting the actual invasion of the invasive species?”
In order to reverse any adverse effects planting invasive species might cause, Morrison will undertake a complicated removal plan once her research concludes. “We’ll have to take out the cages and do the removals [of invasive species] in all the plots. I’ll organize some invasive species removal days every fall or spring, and get students and community members from local conservation groups to come and help. That will be an opportunity for us to teach people.”
Her study addresses an unexplored area in research regarding the restoration of biodiversity to the planet.
“I always thought there was a big missing piece in the invasion biology world,” Morrison says. “Land reserves often implement deer hunting or invasive species removal, but what is most effective? This study is a really powerful experimental approach to understanding these ecological interactions that, I think, are highly responsible for restructuring the plant community as we see it now.”