Cheatgrass. The purplish, frondy invasive weed causes tens of millions in agricultural losses each year as it chokes out native plants. When it really takes over, it can also make areas burn more frequently. That’s a concern in the Bighorn Basin near Thermopolis. The sagebrush sea there used to burn every 30 to 40 years. But now, some spots are burning every five years or so.
Nancy Fleming is the Wind River Big Horn Basin District Invasive Annual Grass Coordinator for the University of Wyoming.
“I usually tell folks I work with I'm the cheatgrass lady,” she said during a recent conference and field tour hosted by Intermountain West Joint Venture.
She talked to Wyoming Public Radio’s Nicky Ouellet in a pasture of sagebrush, prickly pear and invading weeds at the northern end of the burn scar from last year’s Red Canyon Fire.
Editor’s Note: This story was produced with support from Intermountain West Joint Venture. This conversation has been lightly edited for clarity and brevity.
Nancy Fleming: What we're looking at right now is an ecosystem of our sagebrush mixed in with our bunch grass community. But what we see is actually a higher invasion of cheatgrass within this system.
We have cheatgrass that's slowly come into this system and invaded it. We don't see much inner space. Typically, we would see more dirt on the ground here, more inner space between species, but that inner space has been taken over by cheatgrass and Japanese brome, and so that's how this has changed this landscape.
It’s scary in the sense of fire because when fire comes through a system that has sagebrush, it burns a lot hotter, and it causes more damage to our perennial species, our sagebrush species, than a traditional grassland fire would. It's just one lightning strike away to burn and virtually eliminate the species for at least a 20 to 30 [year] period of time until we can reestablish that species back into the ecosystem.
Nicky Ouellet: So these invasive annual grasses, how are they so successful at invading a sagebrush ecosystem, where there are perennials that kind of have a leg up on them in terms of growing roots?
NF: Our perennial grasses, they start feeling good growing in early spring and summer, versus these guys [invasive annual grasses] are germinating in the winter, and they're the first thing to green up in the spring. So they're taking all of that resource, that water, that nutrient, and they're the first things that's sucking it all up for their one purpose: to produce seed. And then, they're dying.
So what's left for our perennial species is not much. Cheatgrass really kind of creates almost a drought state, even if there's not a drought that we're facing, because they're taking all of those resources before our perennial species get a chance. They start suppressing these species, and that's where we start to see cheatgrass have that competitive edge because our good guys aren't feeling good. They're being cheated out of what makes them grow. And so that's how cheatgrass does what it does.
NO: And you said it's filling in the space between these healthier, wetter plants that would repel fire. But now, if you drive your truck, and it's got a hot engine or something, it catches the grass [on] fire. That's why you're going to see those shorter intervals between wildfires.
NF: Yeah, exactly. So this grass, our invasive annual grass, is just like you said: They are greening up earlier in the season, and then they dry out very quickly. They dry out, cure out, by June, and so that fine fuel load is just hanging out all over the landscape. And so that's what helps carry these fires in this area.
NO: This is happening around the state already. Cheatgrass was the focus of several different initiatives from the governor. The feds are really into mitigating cheatgrass. What can we do to block its advances or eradicate it?
NF: When we're talking about cheatgrass and Japanese brome, those are species that we're not gonna eradicate. They're part of our system. So it is a management effort, and that's why [the] work that we're doing here in the Bighorn Basin in the state of Wyoming is so critical in this proactive approach.
We're working in areas that still have a good understory, our perennial species, to where we're going in with treatments like herbicide that have a more long-term control on these species to hopefully target the seed production of these invasive annual grasses and then eliminate that seed source that's in the seed bank.
These cheatgrass seeds are viable in the ground for six years. The idea is that, hopefully, we can get into that area and put at least two treatments down and eliminate that seed source and that cheatgrass from the system, allow our perennials to feel good again, get vigorous, be productive, produce seed, and be able to compete against the cheatgrass.
What we're trying to do is build these more healthy, resilient plant communities.
NO: A fire like the Red Canyon that came through the area right near us, would that be hot enough to kill all the seeds in the seed bank?
NF: Actually, the really awesome thing about these perennial grasses is they've adapted to fire, right? Because they're typically used to fire in longer spans than what they're seeing now. But the seed itself can withstand fire to a certain extent, and it's very viable in the ground for a very long time. So if this fire comes through, it's not completely, ‘Oh, shoot, like, we lost all our perennial in that area.’ They have those adaptations to fire that helps them come back.
NO: The invasive grasses, specifically cheatgrass, Japanese brome, do we know where they came from?
NF: They both came from Eurasia. They are not native to North America. And because of that, they have these invasive qualities. They don't have anything that's a predator to it. And so it comes into the system, and it, especially here in the West with the type of ecosystem we have, the drier climate, it really thrives here.
NO: And how did they get here?
NF: They got here in the late 1800s, is kind of when we first saw reports of these species in our states, and they've just slowly made their way from the coast inward.
When folks were making their way to the Americas, they were using these grasses almost as packing peanuts for their dishes or goods, or if they were bringing over hay for animals, that cheatgrass and Japanese brome was intermixed with that, and that's how this species of grass came to the Americas.
NO: We've been talking about cheatgrass and what it does to the landscape in terms of fire regimes, but there are other ways, other impacts that it has to the land.
NF: Cheatgrass, for a long time, folks just thought it was a plant issue, but it's much more than that.
It affects our quality and quantity of forage out in the landscapes for our wildlife and our livestock. It increases this wildfire risk, and it competes with perennial vegetation out in the landscape, which is the backbone to Wyoming's productive, healthy rangelands.
I like to say that it's an ecological issue, it's an economic issue and it is a cultural issue, because truly, what makes Wyoming so great, cheatgrass and Japanese brome, these invasive annual grasses, truly threaten that and what makes Wyoming so wonderful.
