Great Basin scientists unleash new weapons to fight invasive cheatgrass

  • Beth Leger looks for native plants amid a field of invasive cheatgrass near Winnemucca, Nevada.

    Stephanie Paige Ogburn
  • Beth Leger and Owen Baughman study a test plot of cheatgrass on Peavine Mountain outside Reno, Nevada.

    Stephanie Paige Ogburn
  • A mature Poa secunda in early October, with leaves greening up in response to fall rains.

    Beth Leger
  • Petri dishes in Susan Meyer's Provo, Utah, lab hold the fungus called Black Fingers of Death, which works against cheatgrass.

    Stephanie Paige Ogburn
  • A T-shirt celebrating the fungus called Black Fingers of Death, which works against cheatgrass.

    Stephanie Paige Ogburn
  • A scanned image of the roots of the invasive annual grass Bromus tectorum. Extensive fine-root production is probably key to this plant's success in capturing water and nutrients in arid ground.

    Beth Leger
  • The native annual forb Amsinckia tessellata with its broad leaves does a great job suppressing Bromus tectorum (linear leaves, barely visible) in an outdoor experiment.

    Beth Leger
  • A fire line in the 2006 Basco Fire in Elko County, Nevada, protected the mature sagebrush community on the right side of the mountain.

    Beth Leger

Page 3

"Ugh, it's so depressing." Beth Leger is tromping through a golden-thatched valley in northwestern Nevada near the town of Winnemucca. It's full of dried cheatgrass. As a chill wind whips our clothes, our eyes comb the ground, searching for plants other than cheat. "It's remarkable to me that there can be this little diversity," sighs Leger. She's surprised, too, because although it's common to think of fields of cheatgrass as devoid of any other species, her research has found otherwise.

When Leger first came to Reno, like most restoration scientists, she viewed cheatgrass-invaded landscapes as monocultures, where native plants no longer existed. Yet one day, exploring nearby Peavine Mountain, Leger noticed a sprinkling of native grasses among the weeds. She wondered if they'd be useful for restoration, since they must have adapted somehow in order to fight off the weed and survive. So she waded out into a cheatgrass sea, dug up a few native plants, and started conducting experiments.

Leger collected natives from cheat-covered areas and natives from more intact ecosystems, planted them alongside cheatgrass, and measured how they grew. "It's kind of like boxing. You put them in a ring and see who wins." Her early results were impressive. A number of plants from the weedy areas suppressed the growth of cheatgrass and were also able to successfully reproduce.

"A native plant! I found one native plant!" shouts Leger. Kneeling, the ecologist grins for the first time since our arrival in the cheatgrass sea. "It's a Lomatium. In terms of its restoration potential I don't think it's really one of the big players for competing with cheatgrass, but in terms of diversity it's good."

Back at her University of Nevada test plots, Leger has experimented to pinpoint the most competitive natives. She takes me to a dry field surrounded by fencing, where a few green plants have a foothold. "This is squirreltail," she says, pointing out plants that have proven to outcompete cheatgrass. "Amsinckia is one, Mentzelia, this is a lovely one, pretty big after fires."

Leger calls the Amsinckia a "weedy native," because it likes disturbed sites. Her test plots have largely failed this year due to lack of rain, but a few plucky Amsinckias persisted. Last year, when Leger experimentally planted Amsinckia near cheatgrass, the native reduced the weed's size by 97 percent and suppressed its seed production from 576 seeds per plant to just 76.

In a natural succession scenario, Amsinckia and other weedy natives would be some of the first plants to colonize a burned or disturbed area. But plants like Amsinckia have seldom been included in restoration seed mixes, partly because they are toxic to cattle, and partly because managers have wanted to seed plants like sagebrush that would be found in a mature Great Basin plant community. If Amsinckia were used in restoration, though, Leger believes it could truly act like a colonizer. It would fight off cheatgrass, but only stick around for a couple years. That would give some time for other perennial natives like squirreltail or Poa to establish, after which they can also do their part fending off cheatgrass.

Leger sees her and James' work as complementary to what Meyer is doing with Black Fingers of Death. "If you could knock this whole (cheatgrass) seed bank down by 90 percent (with BFOD) and could put some plants in there that could just survive for that first year, the next year might be awesome."

As Leger and I crunch through the patch of dead cheatgrass outside Winnemucca, the ever-present wind stiffens and the sky grays. The effusive scientist's optimism falters slightly, as she ponders the magnitude of the problem. "The scale of this is ridiculous. This is just one little spot. Think about how many native seeds would need to be planted here. It's unbelievable. And we don't even have a recipe (for restoration). So our hope is that we can find a recipe."

That recipe might go something like this: October comes, and a specially modified drill seeder trundles across the thatch, planting fungicide-coated Poas, Amsinckias, and squirreltails -- the tough ones Leger bred from her collections -- at depths where they are more likely to succeed in the upcoming dry winter. Soon after, a plane flies over, dropping herbicide for the early cheat seeds and granules of death-dealing Black Fingers for the later ones. In a few years, small sagebrush are sprouting, Indian ricegrass reappears, and latecomer perennials like larkspur and penstemon start to make a comeback. The next fire to sweep through doesn't come for 20 more years, and by that time, enough native seeds have dropped in the soil that plants regenerate on their own, or with only a little human help. Leger, I think, imagines this too, but her hope is somewhat tempered.

"You look at this place and you can see very realistically: We could still fail. But I think we at least need to try some of those more carefully designed ways. And then if we still fail, I think we need to stop. But I'm not ready to stop trying."

This story was funded by a Fund for Environmental Journalism Grant from the Society of Environmental Journalists.