July 16, 2015, BY Heather Johns

Bucknell University Professor Chris Martine, biology, believes that some plant species may have evolved to be almost too specialized — and that this phenomenon poses a new threat to a particularly well-adapted group of wildflowers.

The idea came to Martine while he was teaching his class about the three-way interaction among host plants, fungi that live on their roots and the parasitic plants that steal from them both by tapping into the fungi. He was also discussing recent work showing that invasive plants can disrupt the plant-fungus relationship by taking out the fungi, and had drawn diagrams of the two seemingly disparate concepts side-by-side on the same blackboard.

"I stood back, looked at the drawings, and thought, Wait, these two things go together," explained Martine.

He emailed Alison Hale at the University of Pittsburgh, assuming she could point him to studies that had described the effects of exotic invader chemistry on native parasitic plants. "She said those studies don't exist," said Martine.

The two biologists delved into the literature showing that some invasive plants out-compete native species by chemically attacking their fungal partners. Based on these studies, they began developing the hypothesis that these attacks might be indirectly causing localized extinctions through "parasitism disruption."

About eight weeks later, Martine and Hale published "Parasitism disruption a likely consequence of belowground war waged by exotic plant invader" in the March issue of the American Journal of Botany.

One potential loser in this deadly relationship is a wildflower called Indian pipe. "It's in the same family as the blueberry, cranberry and rhododendron," said Martine. "But their particular branch of the family tree made the choice to sponge off others — kind of like your cousin Rob, who lives in your aunt's basement.

"What happens when your aunt stops cooking? That's what could be happening to Indian pipe, only it doesn't have the option of putting actual pants on and getting a job."

Instead, explained Martine, some populations of Indian pipe will probably die out, unless humans intervene.

"It's tempting to say, 'Why do I care?'" Martine admitted. "But understanding the threats to complex relationships among organisms is imperative if we hope to address the global problem of biodiversity loss — which is an issue that affects us all."