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Invasive weeds are a big headache for cattle ranchers. Left to grow, they become food for the herd, and it's not exactly what ranchers want their cattle to eat. So the ranchers spend thousands of dollars to get rid of those weeds. Research now suggests that climate change may make the problem even worse. In a warmer climate, the weeds will thrive. Luke Runyon reports from member station KUNC in Colorado.
LUKE RUNYON, BYLINE: Ellen Nelson has a weed problem.
ELLEN NELSON: How about if we go this way?
RUNYON: In the summer, one hillside of her small ranch near Bellvue in North Central Colorado turns bright yellow. The culprit? A tall, rubbery weed with golden flowers called Dalmatian toadflax.
NELSON: See there's these little rosettes.
RUNYON: The plant is a pain. It crowds out native grasses that her cattle actually like to eat.
NELSON: And it's such a tough, waxy plant that by the time it really gets going, you just can't get the herbicide in it.
RUNYON: The expensive herbicide is a relatively new weapon for Nelson. It's already cost her thousands of dollars. She's tried pulling the plant by hand and releasing weevils that burrow into its stalks. Lately, Nelson's put her faith in her livestock, her steers, trying to convince them toadflax doesn't taste so bad.
NELSON: You kind of have to teach them about a new plant. I've gotten some of them to eat some, but in general, that's a hard one.
RUNYON: Nelson admits, so far, the toadflax is winning. And as climate change takes hold, it's likely to only get worse, not just for Nelson but for ranchers across the country.
DANA BLUMENTHAL: Right. There's Dalmatian toadflax.
RUNYON: U.S. Department of Agriculture researcher Dana Blumenthal studies how climate change will affect large swathes of grassland. For about eight years, Blumenthal and his team simulated a possible future climate - warmer and more concentrated with carbon dioxide - in the Wyoming grassland. Under those conditions, Dalmatian toadflax flourished.
BLUMENTHAL: The simplest reason that invasive species are likely to do well under future conditions is that they are pretty much, by definition, good at dealing with change.
RUNYON: Invasive plants are invasive because they can adapt quickly and more rapidly than the tastes of the grazing cattle that end up on your plate. To help ranchers adapt, Blumenthal says scientists need more data to make solid predictions.
BLUMENTHAL: There are going to be cases of invasive species, some of which we care a lot about, becoming much more problematic. And there are going to be cases of invasive species retreating from areas where they now exist.
RUNYON: What will America's grasslands look like a century from now? The answer to that question affects ranchers across the country who will face expensive headaches when weeds out-compete native grasses. Blumenthal says Dalmatian toadflax is just one piece of a much larger ecological puzzle.
BLUMENTHAL: We don't know enough to say how common this is going to be yet.
STEVE RYDER: We are just treading water at the moment.
RUNYON: Steve Ryder is with the State of Colorado's Noxious Weed Management Program. He says like managers in most states, his focus is on keeping new weeds out. Some have already gained a foothold.
RYDER: If climate change is going to accelerate that, then we need to decide whether we're going to accelerate the response.
NELSON: Come on. Go.
RUNYON: Back at Ellen Nelson's ranch outside Bellvue, she's formulating this year's plan of attack against Dalmatian toadflax. She's welcoming a new class of steers. The first lesson? Learn to love the taste of toadflax.
NELSON: Maybe we're going to learn how to live with some of these weeds, I don't know. That might be heretical to say.
RUNYON: But it's a heresy that many of her fellow ranchers will have to get used to to keep producing beef for American tables. For NPR News, I'm Luke Runyon in Greeley, Colorado.
SIEGEL: And that story came to us from Harvest Public Media, a reporting collaboration that focuses on agriculture and food.
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