Las Vegas Sun

March 29, 2024

Mustard busters’ relish yanking of invasive weed

For information on volunteering to be a "mustard buster," call Elizabeth Powell at (702) 293-8759.

An invasive weed is spreading rapidly along the drawn-down shores of Lake Mead's waters, along the roads and well beyond them, and it is threatening to wreak havoc on the wild flower displays and rare plant habitats there, park conservationists said.

But until Nevada's Department of Agriculture authorizes placing the weed -- commonly called Sahara mustard -- on the state's list of noxious weeds, state and local agencies are not held legally responsible for its control.

And the department is not expected to put the weed on the list until the end of this year, Dawn Rafferty, an invasive plant specialist with the department, said.

In the meantime, conservationists at the Lake Mead National Recreation Area are doing what they can to control the weed's spread within the park. They're recruiting "mustard busting" volunteers to help seasonal crews uproot the weeds by hand. Without additional laborers, the problem threatens to get completely out of control, said Elizabeth Powell, a park botanist.

"Every plant we don't pull this year, is five next year," said Powell, who is doing the volunteer recruiting. Last year, paid crews and volunteers pulled 2 million individual weeds from the park. But millions more are still spreading there, Powell said.

That's because the weed is incredibly adaptable and can grow just about anywhere, Powell said. The weed thrives in a range of environmental conditions, from soil with salt water deposits to desert pavement, making its control that much harder, Powell said.

Last Tuesday, workers with the park pulled about 45,000 individual Sahara mustard plants, said Jessica Spencer, one of the workers. Still, more weeding and more workers are needed, Powell said.

"We could have 10 crews working full-time, and I don't know if we could do it," Powell said.

Since it was first spotted in the park in the 1970s, the Sahara mustard population has increased exponentially, Powell said. Despite efforts every year to uproot as many of the weeds as possible, they now densely cover at least 2,500 of the park's 1.5 million acres, Powell said.

Left completely unchecked, the weed threatens to dramatically diminish the number of wild flowers that blossom in the park each spring. The wild flowers, which naturally germinate later than Sahara mustard, compete with the weed for natural resources, including water and nitrogen in the soil. By jump-starting other annuals in the early phases of the growing season, the weed can grow to more than three feet high, overshadowing and outcompeting the smaller wild flowers.

That is exactly what is happening near Willow Beach on the Arizona side of the park. There, densely packed clusters of Sahara mustard tower above smaller wild flowers, such as gold poppies and suncups. The wide, long leaves of the Sahara mustard stretch out across the base of the plant and block the sun from other plants trying to grow below them.

Scrambling up and down the rolling hills of the Willow Beach area last week, Powell enthusiastically searched for different varieties of wild flowers. The heavy rains that have swept across Southern Nevada in recent weeks likely will bring a colorful display of wild flowers this spring, Powell said. The display will be unlike anything anyone at the park has seen in at least 10 years, she added.

"This is what we want to have when we have good years, not weeds," Powell said, as she gestured at the yellow and purple blossoms shooting up from the desert.

Meanwhile, natural and human forces are threatening the annual displays. A steady drove of new seeds appear to be entering Lake Mead along U.S. 95 and U.S. 93, likely on vehicle tires that have the weed's seeds stuck to them, Powell said. And wind and rodents are spreading the seeds further and further from the roads into the park.

Unfortunately, other environmental conditions are also worsening the weed's spread, Powell said.

And there's only a limited amount of money to support the removal, most of which comes from funds established by the Southern Nevada Land Management Act of 1998. With that money, about $59,000 for two years, Powell said she can pay for a full-time crew of four people for three months.

Dawn Rafferty of the state department of agriculture's noxious weed group said Sahara mustard likely would be added to the state's noxious weed list by the end of the year. Powell had made this request to her in the hopes that, among other things, the Nevada Department of Transportation, which has jurisdiction over U.S. 95 and U.S. 93, would begin spraying there.

Adding the invasive plant to the noxious weed list would mean state and local agencies would have to use money out of their budgets to control the weed's spread, Rafferty said.

Biologically speaking, the weed's seeds are incredibly fit. After rains and before they take hold in soil, they're covered in a gelatinous coat that allows them to remain under water for up to 11 weeks unharmed, Powell said. The coat is also incredibly sticky, which is how the seeds cling to animals and vehicles moving through the park.

On the positive side, if the weeds are pulled out before they drop their seeds, they may not be able to come back the next year, Powell said.

Under most circumstances, picking or harming living things in federal parks is against the law and punishable with a hefty fine. But "mustard busters" who want to volunteer their services to control the weed can do so, if they have a special license. Powell will offer classes for volunteers and then assist them in securing the license.

"I love those wild flowers so much," Powell said. "As a private citizen, not just a botanist, I don't want to see a Sahara mustard field in their place."

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