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
 

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In her U.S. Forest Service laboratory in Provo, Utah, ecologist Susan Meyer wends through piles of petri dishes. Each holds a fungus she calls the Black Fingers of Death, which grows on cheatgrass seeds, poking out like grasping fingers. Aptly named, it has the power to mass-murder those seeds.

Meyer discovered this power while trying to solve a restoration problem. Typically, after a fire, teams would spray a pre-emergent herbicide in the fall, to kill cheatgrass when it sprouted after autumn rains. At the same time, they'd seed natives to sprout the following year, after the cheatgrass was killed off.

But the grass is clever; not all its seeds germinate with that first rainfall, and the leftovers, often as many as 10,000 per square meter, go dormant, usually until the rains of the following fall. By then, the herbicide is gone, and spraying again isn't possible, because it would kill germinating natives. "It's common to have a reasonably successful seeding that then gets overwhelmed by cheatgrass the next year," because of those second string germinators, says Meyer.

But Meyer's fieldwork also showed her that some of those second-year seedlings were dying off, even without herbicide. "We found this fungus that was eating 60 to 90 percent of the seeds."

That fungus, which hitched a ride across the ocean attached to cheatgrass, was Black Fingers of Death, or BFOD. In its natural state, BFOD is not potent enough to kill all the late germinating seeds. Meyer thought she could get around that by seeking out the most deadly strains and culturing them, so that all those late-germinating cheatgrass seeds "won't be there next year to haunt your seeding." Meyer's achieved a pretty consistent 90 percent seed death rate, with 100 percent in a few cases. She has applied for a patent, and has been contacted by a couple of biocontrol companies.

In order to make Black Fingers as deadly as possible, Meyer's collaborators have gone so far as to change how it reproduces. In the lab, it typically does this clonally, but biologist Julie Beckstead is working on getting the fungus to "do sex," says Meyer, which would allow the researchers to breed the most effective BFOD strains together.

When used in concert with an herbicide that takes out the first-year crop of cheatgrass seedlings (because they germinate so quickly, the fungus doesn't work on those early seeds, although Meyer is researching that problem), Meyer's work may create the perfect conditions for restoration. She's tested to see if it kills native grasses, and has found little evidence that it would affect them.

There is a catch, though. Even if a biological control like Meyer's succeeds, land managers are still left with an open desert landscape. It's up to her fellow scientists to keep cheatgrass -- or something worse -- from seizing the moment yet again.

Lack of rain is the main culprit in most Great Basin restoration failures. A wet year makes everyone a good range manager, as the saying goes. Yet even though land managers know their seedings fail more often in tough, dry years, they do not know exactly why. Jeremy James, a range ecologist with the University of California Agriculture and Natural Resources Program, reasoned that if he knew exactly what caused plants to die, he could help them survive.

In 2007, James experimented with tracking seeds planted after four different fires in Great Basin ecosystems in eastern Oregon. To his surprise, the ecologist found that it wasn't that seeds failed to germinate. "In most years, we can get 60, 70, 80 percent germination in the field," says James. "But we also found that about 90 percent of those seeds that have initiated germination never make it. They never actually get above the soil surface."

To understand the many ways seeds can germinate but still fail, think about Beth Leger's Poa. Say one of its seeds drops down onto that hard pebbly dirt and makes its way into the soil. Come spring, the 3.5 millimeter oblong kernel might swell with water as the ground warms and snow melts. Then it stretches out its first root, and sends the beginnings of a leaf upward, towards the soil surface. But in a light snow year, the seed may stop there, lacking the moisture to continue. Maybe there's a late hard frost, and the tiny root freezes and withers. Perhaps a fungus in the soil devours the seed, or the seedling simply cannot push its way through the hard, dry soil crust.

In a normally functioning ecosystem, none of these failures would really bother the Poa. Sure, its seeds might not make it one year, but they'd succeed the next, or the one after that. But while Poa might not be in a hurry, rangeland managers lack the luxury of time. They need natives to establish quickly, before cheatgrass takes over again.

In James' next experiment, a three-year study that he is conducting with Leger and a few other scientists, he will try to narrow down the causes behind seed failure. What he finds could radically change BLM practices after a fire. If those native seeds are mostly becoming pathogen fodder, the BLM could order seed coated in fungicides. If the problem is lack of moisture, seeds could perhaps be planted to have better seed-soil contact, especially in dry years. James' colleague, ecologist Matthew Madsen, has been working on a technique called "bundling," where many native seeds are coated and clustered together, like clumps of granola. In his trials, this has helped them retain moisture, emerge through thick soil crusts and better survive dry winters.

James is also working with a plant physiologist and modeler, Stuart Hardegree of the USDA Agricultural Research Service in Boise. The models Hardegree is developing, based on historic weather patterns, will help land managers predict weather conditions months into the future. That way they'll know, when seeding after a fire, if they should give seeds extra help, depending on whether that spring will be drier or colder. In some cases, if the model is pessimistic about restoration conditions, land managers might elect to plant something like crested wheatgrass, which is more successful at establishing than native plants, says Hardegree. Even planting a field of non-native crested wheatgrass might be better than doing an expensive seeding of natives and having them fail, followed by a return to flammable cheatgrass.

Katherine A Ball
Katherine A Ball Subscriber
Sep 18, 2012 02:35 PM
The devil..... one of the benefactors of cheatgrass in the Great Basin is another 'fernr', the chukar partridge. If the cheatgrass goes away, will the chukar , too? It's handsome confounding quarry that resides in the most god-forsaken-human breaking rugged terrain in that wilderness of publicly-owned, easy access lands... I curse the cheatgrass in my dogs fur, tear ducts, even sub-cutaneous intrusions... not to mention my clothes etc, the devil...
Erica Husse-Jerome
Erica Husse-Jerome Subscriber
Sep 18, 2012 07:54 PM
Many- actually, the majority- of BLM fire rehabilitation programs in the Great Basin are already using Poa secunda and Elymus elymoides (squirreltail) in their seed mixes. The other forbs mentioned in the article (Lomatium, Amsinckia, Mentzelia) would certainly be used and have actually been requested, but they are not available for purchase (remember, that one forb seeded at a reasonable rate of 1 lb per acre over a relatively small 5,000 acre fire is 5,000lbs of that seed. When the Great Basin burns several hundred thousand acres per year, where will that seed come from?). I also think it is important to note that herbicide application is being increasingly restricted, despite how effective it is at battling cheatgrass.

Finally, and most importantly, "success" or "failure" in post-fire rehabilitation efforts is almost always measured in the first 3 years after a fire. Could it be that we need to give these dry areas of the Great Basin and Mojave need more than 3 years to determine if a treatment is a success or a failure?
Stephanie Paige Ogburn
Stephanie Paige Ogburn Subscriber
Sep 18, 2012 09:16 PM
Hi Erica, thanks for commenting. I take your point about rehab programs already using natives, but I do not believe Beth Leger is saying Poa and squirreltail are not used, but that the cultivars that are often used are not ones that evolved to fight off cheatgrass -- remember, she tested the same plants from different areas, cheatgrass infested and not, and found that ones from fields of cheatgrass were able to fend off the weed. I'm not sure if you've read the sidebar to the article (it's listed below the main photos on this article, called "Native plant growers face many challenges,") but if you do, you'll see I address some of the problems facing the BLM in purchasing native seed and the problems in producing it, and also a chart showing the ratio of natives to non-natives used -- as Paul Krabacher says, it's just impossible to get enough native seed and it's too pricey a lot of the time. It is my understanding however that some natives like Amsinckia are not desirable for reseeding because they are not good for cattle, though, so I don't know if they would be used all the time if available or not. Thanks again for your close read. - Stephanie Paige Ogburn, online editor.
Howard Johnson
Howard Johnson Subscriber
Sep 24, 2012 11:36 AM
Stephanie, Good article, but I did not understand the term, "Red Army-like"? Could you explain that phrase, please?.. Thanks..
Stephanie Paige Ogburn
Stephanie Paige Ogburn Subscriber
Sep 24, 2012 11:52 AM
Thanks, Howard. The reference is historical, to the Russian Red Army and the large number of soldiers in that Army that they used to their advantage in both the Russian Civil War and WWII.
Howard Johnson
Howard Johnson Subscriber
Sep 24, 2012 01:33 PM
Stephanie, Thanks. A better analogy might be USA Army-like, in relation to the number of unwanted military bases installed in foreign countries. The Red Army did not invade a large number of foreign lands but simply tried to defend itself from such, ie Germany.