Medusahead grassBurmese pythons in Florida, zebra mussels in the Great Lakes, feral pigs and other mammals in Hawaii: These are just a few of the dozens of stories about animals introduced -- accidentally or deliberately -- in the U.S. that have ended up playing havoc on regional ecologies and economies.

But invasive species also extend to plant life. Residents of the South are well acquainted with kudzu, the fast-growing and disruptive vine originally intended as livestock feed and for erosion control. Purple loosestrife arrived in New England back in the 1800s as an ornamental plant, but now threatens to clog and dry out great areas of America's wetlands -- while reportedly costing communities across the country about $45 million a year in control efforts.

Here's yet another invasive plant species, and a particularly nasty one, to add to the list: Medusahead, aka medusa's head. It's a Mediterranean grass accidentally brought to the Western U.S. in the 1880s. Researchers at Oregon State University and the Agricultural Research Service have a new report warning that Medusahead is threatening to crowd out native grasslands in the West -- to the detriment of both wildlife and livestock.

"Medusahead is now spreading at about 12% a year over 17 Western states," says Seema Mangla, an OSU researcher. "Once established, it's very hard to get rid of."

It Puts Cattle on a Diet

The plant contains a high level of the mineral silica, which makes it inedible. Its spiky head and seeds cut the mouths of animals attempting to graze on it -- from cattle to deer to rodents. And Medusahead creates thick mulch that pushes out other plant life and increases the risk of wildfires.

Agriculture, experts say, doesn't have much to fear from Medusahead, thanks to the industry's regimen of herbicides, tilling, clearing and controlled burns. But the story is very different for livestock. Joseph DiTomaso, a specialist in noncrop weeds at UC Davis's Department of Plant Sciences, calls Medusahead a "landscape transformer." Two things happen, he says, for ranchers confronted with large areas of Medusahead.

"Your cattle will gain weight at a much slower rate because this is not a high-forage crop," he notes. "The second thing is that you will have to use more land to raise the same number of cattle because your cattle will go elsewhere to try and feed. So, this land becomes lower value, lower productivity, and you have to use more land to achieve the same [weight gain]. That's what ranchers are concerned with. It's not like they can go out and say we'll use more land. They have to raise fewer cattle, and that's the bottom line."

"Unchecked Medusahead poses a great economic threat to our Western rangelands," says Ron Torell with the Nevada Cattlemen's Association, in an email. "Revegetation after wildfire, such as reseeding with a desirable and, yes, introduced plant such as crested wheat grass is one alternative and a suggested management protocol that could lessen [its] spread."

While the media may just be catching on to the challenges posed by Medusahead, control of the plant has been under study for years. The major issue is how cost-effective those control options are -- especially for ranchers. "A rancher can hardly put anything in and be profitable. They're already working on the margin as it is," says DiTomaso. "[If] you say, 'I have a chemical that will get rid of this thing, it'll only cost you $15 an acre,' they just look at you and say: 'I couldn't spend $4 an acre and make it profitable.'"

Increase your money and finance knowledge from home

Socially Responsible Investing

Invest in companies with a conscience.

View Course »

Introduction to Economic Indicators

Measure the performance of the economy.

View Course »

Add a Comment

*0 / 3000 Character Maximum


Filter by:

How about using some of the Stimulus Money ?

November 27 2010 at 8:39 AM Report abuse -1 rate up rate down Reply

if this invasive species of grass is so prolific ,,,why are they not looking for positive uses,,,biofule, building materials, maybe the ranchers should diversify instead of looking for govt subsidies

November 27 2010 at 8:33 AM Report abuse rate up rate down Reply

So you are saying that goats won't even eat this? Not much my goats won't eat including sumac.

November 27 2010 at 3:11 AM Report abuse rate up rate down Reply

Tell me again how globalization is good for us ???

November 26 2010 at 11:04 PM Report abuse +2 rate up rate down Reply
Hugh & Alice

I cannot understand the cattle owners who are grazing their cattle on "public land" complaining about what exists on "public land". If they don't like the wild horses, wolves and plants that are part of the "public land" then they should turn their private land into feed lots and fatten their cattle there. Then ship their cattle to slaughter, which is what they are doing anyway. If they can't make a living doing that, then maybe they should not be in the business and I don't consider that just because their family has been raising cattle for generations any reason to justify why the government should subsidize their business.

November 26 2010 at 8:41 PM Report abuse +1 rate up rate down Reply
2 replies to Hugh & Alice's comment

Is there any reason for wild horses, wolves and plants to be on "public land" because you prefer them to some other animal?

November 27 2010 at 12:55 AM Report abuse rate up rate down Reply

i suppose people are just supposed to stop eating too. in your twisted mind anyway.

November 27 2010 at 2:36 AM Report abuse +1 rate up rate down Reply

Pesticides aren't a practical solution for medusahead, especially on grazing areas because there's no selective pesticides that won't also kill the productive grasses. Burning is effective, but only if you do controllrd burns before the seed matures.

November 26 2010 at 7:21 PM Report abuse +2 rate up rate down Reply
1 reply to dvdsn61's comment

Pesticides kill bugs, herbicides kill weeds.

November 27 2010 at 6:02 AM Report abuse rate up rate down Reply

When they were digging gold out of the Black Hills, they kept having to remove tons of this nasty black dirt to get to the gold. They piled the black dirt up into a big mound yards away from the mine. Turned out the black dirt was silver ore worth millions. When they first refined crude oil to make grease, they kept getting this nasty smelly liquid they had to dump in the river to get rid of it. It was gasoline. Everything that God makes is valuable. Just because nobody has figured out a way to use it, doesn't make it bad....Alfred-

November 26 2010 at 3:41 PM Report abuse +7 rate up rate down Reply

Can't believe the comments of a few left-winged, tree hugging, socialists. Need to get off your perch and out in the real world. To think that the disturbance of soil, by cattle, is causing the increased propagation of "medusa-head", is one of the most idiotic statements of record.

November 26 2010 at 2:46 PM Report abuse rate up rate down Reply

We have the Asian Tiger Mosquito. This Asian import is a ferocious daytime biter that can withstand the heat of the day. A few summers ago we were attacked and rec'd 40 bites in 5 mins. Since then we can't use the backyard.

November 26 2010 at 2:39 PM Report abuse +5 rate up rate down Reply

I guess we can thank those government officials who are suppose to make sure certain animals and plant life get past the border and into the country. Here in PA we have the stink bug. The stink bug is from China. Came in via container. The stink bug does bite. But he stinks, when you try to crush him. In the summer when you have a rain storm you can come outside and instead of smeilling a a fresh rain smell you smell STINK BUG. We also have quoi in the river. Thanks again for protecting the borders from Pests.

November 26 2010 at 12:34 PM Report abuse +8 rate up rate down Reply
1 reply to jkennedy806's comment
Pat Violi

Also in PA and spent Thanksgiving Day killing stink bugs. Since it is cold out I cannot figure out how they are getting in. Have had exterminator 3 times.

November 26 2010 at 12:54 PM Report abuse +6 rate up rate down Reply