Study Says Fungus Plays Big
Role In Health Of Rangeland

Earth's rich carpets of grasslands owe their diversity to partnerships with underground fungi, new research published late last week suggests.

The findings could prompt scientists to rethink ways of restoring endangered habitats such as America's shrinking tallgrass prairies, and help farmers become more productive.

Scientists had thought that competition between plant species and grazing by animals controlled the amount of diversity in grasslands.

"What this says is that it's the below-ground that controls the above-ground, instead of the other way around," said John Klironomos, an assistant professor of botany at the University of Guelph, near Toronto.

Klironomos and a separate team of Swiss researchers found that specialized species of fungus dictate how many and what type of species sprout on the surface by feeding nutrients to the plants.

While such a relationship had been suspected by scientists, this research is the most persuasive work demonstrating the theory, said David Janos, an associate professor of biology at the University of Miami. "It's a really interesting, provocative paper that takes us that next step forward. It's a major contribution."

Similar links have been shown between fungus and trees.

Klironomos' team created bare outdoor plots, introduced varying numbers of species of fungus, then scattered a uniform amount of seeds from 15 species of grasses and wildflowers.

In a study published in last Thursday's issue of the journal Nature, they report that plots with the most fungal species sprouted the greatest variety of surface plants.

Their findings were complemented by similar work in greenhouses at the University of Basel in Switzerland. Researchers there found that even a slight shift in the number of fungal species can lead to big swings in plant diversity.

The studies' suggestion that some fungi favor specific plant species was particularly intriguing, said Elaine Ingham, an associate professor of botany and plant pathology at Oregon State University.

"I think this gives us undeniable proof that fungi are controlling the plants," she said.

Ingham said learning which fungi favor which plants could help farmers create more productive pastures without fertilizer.

The findings also explain why efforts to restore tallgrass prairies often fall short, said Mike Miller, senior ecologist at Argonne National Laboratory near Chicago, which has created a tallgrass prairie on the grounds of its underground atomic accelerator.

"We have something that looks like a prairie, but is not really functioning like a prairie because it lacks this large population of fungi that play a big role in enriching and stabilizing the soil," Miller said.