A patch of medusahead in Sheridan. (Jennifer Strickland, U.S. Fish and Wildlife Service/FlickrCC)

On a mid-fall day in 2016, Brian Mealor opened an email with a picture attached asking for verification of a worst-case scenario. 

Oakley Ingersoll, a soil conservationist in Sheridan, sent a photo of a plant that looked like a little tree from Dr. Seuss’ Lorax except made of needles instead of hair. Ingersoll thought it was medusahead, an invasive species that had not yet been found in Wyoming and that most ecologists say makes destructive cheatgrass look like nutritious forage. 

Mealor, an associate professor of plant sciences at University of Wyoming and director of the Sheridan Research and Extension Center, knew immediately that Ingersoll was right. The plant had puny roots and distinctive awns — the needle-looking part of the plant. A short drive later, specimen in hand, he confirmed the news. 

In the war against invasive species, finding the first plant is only the beginning of an endless series of battles. 

“If you value the natural resources of an area that can serve both recreation and tourism and an agricultural economy, then the potential degradation of the natural resources by invasive plants is huge,” Mealor said. 

The problem is so knotty and consequential, in fact, that Gov. Mark Gordon formed a task force in 2019 requesting a formal plan on how to tackle invasive plant species. The final 40-page report released recently covers everything from policy gaps to research needs. It’s part of a broader effort on the part of the University of Wyoming, county weed and pest agencies, nonprofits, landowners and the state to combat the scourge. 

The report also recognizes that Wyoming has not yet been inundated quite like some of our western neighbors. We still have a chance, experts say.

If Wyoming is to be successful fighting invasive grasses and plants — species that hitchhiked here on the bottoms of shoes, on the fur and wings of animals, tucked under wheel wells or hidden in bundles of hay — it’s going to depend on research projects by scores of scientists from counties, the state, the nation and the world. And while the reality of invasive plants are daunting, the prospects for new methods of combating them are promising. 

“I feel hopeful, and I feel like part of that is because it’s not just one small group of us working on it now,” Mealor said. “A lot of other people, who historically their emphasis has not been focused on invasive species, are getting involved… and because of that I feel like we’re in a good place to move forward.”

First, find the weeds

Imagine, for a moment, that every person living in Wyoming is a trained botanist. Then imagine they’re all assigned a piece of the state to monitor for invasive weeds. Each one of us would be responsible for patrolling over 100 acres, said Dan Tekiela, an assistant professor at UW and invasive species researcher. 

That scenario helps demonstrate just how weighty and wide-ranging  the state’s invasive species issue is, according to Tekiela. 

So how can researchers even begin to find the would-be invaders — some as short as 5 inches? What about in a state where land ownership changes frequently and some areas come with grizzly bears or long winters?

Drones. And not drones taking pretty, high resolution video. Drones detecting a plant’s unique electromagnetic energy. 

You read that right.

Chloe Mattilio, a University of Wyoming PhD graduate research assistant, watches as a drone flies August 2019 in the Shoshone National Forest near Cody. Mattilio is studying how drones can be used to identify invasive species in areas that are difficult to reach on foot. (Courtesy of Chloe Mattilio)

Everything reflects electromagnetic energy in the form of light. Our eyes see colors when they detect a certain range of that light. But plants emit plenty of energy that we can’t see, and each plant species at certain times of the year has a unique energy that can be detected with the right technology, Tekiela said. 

As futuristic as this sounds, Tekiela’s UW graduate student, Chloe Mattilio, is using the technology right now on an invasive plant called dalmatian toadflax in a remote area of northwest Wyoming. 

Her success rate identifying the highly competitive, nonnative plant is currently a little over 90%. 

“Instead of getting someone up in that mountain, you hit a button and we program it,” Tekiela said. “The drone goes up and just flies.”

Some researchers are looking into the possibility of drones flying equipped with herbicide backpacks to not only identify invasive species, but also spray individual plants. The possibilities are, potentially, endless. 

“It won’t replace boots on the ground. There will always need to be experienced eyes on the landscape looking for invasive plants,” he cautioned. “But there’s a place for remote sensing to be a tool to assist in this whole process.”

Then combat them

Finding the weeds that choke out native grasses, spread wildfire and leave livestock and wildlife hungry is half the battle. Figuring out how to eradicate them is the other half. 

And if you were thinking the electromagnetic drone sensor seemed strange, allow Andrew Kniss, a weed scientist and the head of UW’s plant sciences department, to explain shade avoidance.

If you’ve kept your house plants alive, you’ve likely noticed they tend to grow toward windows. The same strategy that makes them grow toward light makes them avoid shade. 

Kniss’ lab has been working mostly on invasive species like downy brome and their impact on crops, but the knowledge of how plants act with new neighbors can be helpful for understanding invasives in the wild. 

“We’re looking at how do [desirable] plants respond when this new plant comes in or how does the invasive plant change its growth if it’s alone or near other cheatgrass plants or near other [desirable] species,” Kniss said. 

What they’re finding, is that crops like sugar beets will be significantly smaller when surrounded by weeds, even if they’re not competing for nutrients and soil. 

The connections to fighting invasive species are not, right now, as direct as they are to crops. But, Kniss said, it’s all part of understanding why invasive grasses — which generally don’t wreak havoc on ecosystems where they evolved — are so destructive when they move into new habitat.

Ventenata, one of the invasive grass species making its way into Wyoming.
(Jennifer Strickland, U.S. Fish and Wildlife Service/FlickrCC)

As for control, herbicides are a frequent topic. Mealor and others at UW often work through new herbicides to understand if they will kill native plants along with the nonnatives, essentially doing more harm than good.

A team of researchers out of Italy are trying something less chemical: Scouring parts of Asia for mites or midges that target only invasive grasses like ventenata, medusahead or cheatgrass, said Timothy Collier, a UW associate professor in ecosystem science and management.

Before anyone panics about introducing a nonnative insect to combat a nonnative grass, Collier said the screening process is rigorous, and it’s been done successfully before. UW, European and Canadian collaborators are currently working with a type of mite that only feeds on the flower buds on Russian olive trees, allowing them to remain in areas where they’re valuable for wind breaks but discouraging their spread. 

An imported flea beetle has worked well in some areas to control leafy spurge, another nonnative. 

But there is hope

In the meantime, researchers, county weed and pest officials and even wildlife biologists are beginning to coordinate to better understand where limited resources are best spent.

A crowd gathers July 2018 in Sybille Canyon to watch drones that are capable of identifying invasive species. (Courtesy of Chloe Mattilio)

Herbicides are expensive. Controlled burns can be expensive. Research is expensive. And the state is increasingly strapped for cash. 

So researchers are also looking at ways to change grazing to give a boost to native plant communities. 

But knowing what to treat isn’t easy, Mealor said. “You’re forced to make tough decisions and sometimes there are winners and sometimes losers.”

Even through all of the complications, budget restraints and questions that lead to more questions, Mealor is hopeful for the future. Wyoming is putting an unprecedented effort into finding solutions, he said, and many of the worst plants like ventenata and medusahead are only beginning to gain a foothold.

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Christine Peterson has covered science, the environment and outdoor recreation in Wyoming for more than a decade for various publications including the Casper Star-Tribune, National Geographic and Outdoor...

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