Man vs. mussel: Buckeye mayor testifies on threat from invasive species

WASHINGTON – Buckeye Mayor Jackie A. Meck said drinking water is scarce enough for cities in the West – they don’t need to be competing with invasive species for it, too.

Meck was one of several witnesses Wednesday at a Senate hearing on the impact of nonnative species – mostly quagga and zebra mussels that clog water intake pipes and force out native species, but also salt cedar that line the region’s riverbanks.

The mussels, native to Europe, were discovered in the Great Lakes in the 1980s and had spread to Lake Mead, Lake Mojave and Lake Havasu by 2007. The fast-breeding freshwater mussels can quickly take over boat hulls, intake pipes, hydroelectric dams – anything under water, as evidenced by the mussel-encrusted shoe displayed on the desk at the hearing.

“It’s been a problem since 2007 and it hasn’t gotten any better,” said Sen. Catherine Cortez Masto, D-Nev., during the hearing of the Senate Energy and Natural Resources subcommittee. “We need to make this a priority.”

Scott Cameron, principal deputy assistant Interior secretary for policy management and budget, testified that the Bureau of Reclamation’s fiscal 2021 budget request includes $5.6 million to deal with finding and controlling mussels on its facilities.

“The last thing Nevada or Arizona needs are more endangered species because these things are smothering them, or sucking up their food or otherwise occupying their habitat,” Cameron said.

Sen. Martha McSally, R-Ariz., said these invaders can be “devastating” to U.S. waters and that they are “a huge and growing problem in the Southwest.”

Sen. Catherine Cortez Masto, D-Nev., left, and Sen. Martha McSally, R-Ariz., at a hearing on invasive species, where a shoe that has been covered by nonnative quagga mussels is displayed on the table in front of them. (Photo by Jessica Myers/Cronkite News)

But while others were focused on mussels, Meck said the problem for his city are the thirsty salt cedar trees that line the Gila River, sucking up 200-300 gallons of water per day.

Salt cedar trees were first planted in the state in the late 1800s to control erosion and have since spread to 15,000 acres along the Gila River in Buckeye, Goodyear and Avondale. Besides being thirsty, the trees deposit salt around their bases and are highly flammable, which can pose a wildfire threat.

“In Arizona, our desert rivers like the Verde, Salt and Gila have been hit particularly hard,” McSally said in her opening statement. “Right now these riverbeds are choked with up to 4,000 salt cedars per acre.”

The trees are also hard to kill. They quickly grow back from stumps when they are cut down, unless the stumps are treated with chemicals. Federal officials thought they had an answer with a nonnative beetle that can defoliate the trees, but stopped that experiment in 2010 after it became clear that getting rid of the trees would remove nesting areas for the endangered Southwestern willow flycatcher.

Buckeye Mayor Jackie A. Meck greets Sen. Martha McSally, R-Ariz., after a Senate subcommittee hearing on invasive species. Meck and McSally both expressed concern about the spread of invasive salt cedars along the Gila River. (Photo by Jessica Myers/Cronkite News)

“The only solution to this problem is to remove the salt cedar,” Meck told the subcommittee, expressing frustration at the bureaucratic red tape that he said is slowing efforts to remove the trees.

George Diaz, the government relations manager for Buckeye, said after the hearing that salt cedars have been removed from 60 acres in the city, which is working to restore native vegetation, like cottonwood and willow trees. But there are challenges, he said.

“Because the area that we’re concerned with lies within a waterway, we have to get specific 404 permits and other kinds of permits,” under the federal Clean Water Act, Diaz said.

The Gila River Restoration Project – a collaboration between Maricopa County, the cities of Buckeye, Avondale and Goodyear and the Maricopa Flood Control District – estimates that removing salt cedars would provide water for 200,000 households, or 600,000 people.

But Robin Silver, a co-founder and board member of the Center for Biological Diversity, said the “holy war against salt cedar” is misguided. He said there is no evidence that removing salt cedars will result in more water for nearby cities.

Buckeye Mayor Jackie A. Meck greets Sen. Martha McSally, R-Ariz., after a Senat subcommittee hearing in invasive species. Meck and McSally both expressed concern about the spread of invasive salt cedars along the Gila River. (Photo by Jessica Myers/Cronkite News)

“It’s not going to give his community any more water – that’s nonsense,” Silver said.

He said that part of the problem is that watersheds in the West have been so changed by human interference that the salt cedar is the only vegetation left in some areas. Silver also challenged the claim that one tree can soak up hundreds of gallons a day, calling that an insignificant amount in the larger picture.

“Even if it were true, you think 300 gallons is going to last very long in Buckeye or Avondale?” he said. “It’s like, that’s probably a shower for the mayor.”

But Meck, who is planning to step down as mayor soon, is not deterred.

The Gila River Restoration Project is working to eradicate salt cedars and restore an 18-mile stretch of the Gila river, the latest in what he called a 25-year effort of “trying to get something done.”

This story is part of Elemental: Covering Sustainability, a multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal.

Buffelgrass Blues: Phoenix Campaign Kicks Off to Combat an Invasive Species

PHOENIX – Every week, thousands of hikers climb Piestewa Peak to take in the views and get in some exercise. In early April, hikers started to see plants splashed with bright blue chalk.

It’s part of an effort to raise awareness about buffelgrass, an invasive species that worsens a problem many Arizonans are already familiar with. Buffelgrass makes excellent kindling for summer fires, and it’s prone to burning fast, hot, and often.

Ranchers introduced the shrubby grass into Arizona in the late 1930s, hoping it would reduce soil erosion and feed cattle. The plant took off in Tucson, and has spread to Pinal, Maricopa and Yuma counties in the decades since. It also has established itself from California to Florida and has been found in New York and Hawaii, the National Park Service says.

Hikers going up Piestewa Peak in north-central Phoenix will see buffelgrass marked with nontoxic blue chalk to draw attention to this invasive species. Buffelgrass was brought to Arizona in the late 1930s from South Africa to control soil erosion and feed livestock. (Photo by Gabrielle Olivera/Cronkite News)

Now the Buffelgrass Blues campaign aims to raise awareness about the problems with buffelgrass. The Phoenix Parks and Recreation Department, the Desert Botanical Garden and the Central Arizona Conservation Alliance are all involved in the effort. Organizers hope to highlight how Pennisetum ciliare, which is native to South Africa, is outcompeting native plants for water and eliminating food sources for native wildlife, including desert tortoises.

Buffelgrass produces many seeds, which are easily spread by wind and water, according to the National Park Service. In addition, each seed has bristles that allow it to hitch a ride on passing humans and animals.

“This grass can have a lot of negative impacts on this landscape,” said Annia Quiroz, with the Buffelgrass Blues campaign. “First and foremost is fire. This grass carries the fireload that is very heavy, and can burn up to 1,600 degrees Fahrenheit, which is pretty much in the same range as lava.”

Since the campaign launched last fall, dozens of volunteers have attended Buffelgrass Bootcamps, where volunteers and Phoenix park rangers learn how to use an app called Collector to map areas where buffelgrass is prevalent so it can be removed on “pulling days.”

Pulling is a bit of a misnomer, though, because removing buffelgrass properly requires a pickax and hours of painstaking labor. Clearing a 10-by-10 foot patch of buffelgrass is a three hour process.

Because it’s such a strenuous process, Buffelgrass Blues won’t hold any pulling days until the fall when it cools down. Buffelgrass Bootcamps and mapping days still will take place over the summer, however.

For removal in the most heavily infested areas, options are limited. There’s chemical spraying by helicopters and manually removal the plants, Quiroz said. But both are expensive and disrupt the local wildlife she explained.

There’s a new education campaign around Piestewa Peak to raise awareness about buffelgrass, which is crowding out native plants and wildlife. It also poses a huge fire risk. (Photo courtesy of Annia Quiroz)

“It’s up to the cities to best determine how they want to handle their invasives problem,” she said.

Sandy Bahr, the chapter president of the Sierra Club of Arizona, has volunteered to remove buffelgrass in the past.

“It will crowd out other plants and before you know it, you have a field of buffelgrass instead of our beautiful Sonoran Desert vegetation, and also creates unnatural fire conditions,” Bahr said. “I guess it’s just a reminder that we need to be careful about what we bring into our environment.”

Other organizations are joining in. The McDowell Sonoran Conservancy and Maricopa County Parks and Recreation also are involved with Buffelgrass Blues. Maricopa County Parks and Recreation calls their program Desert Defenders, but it’s the same training with the same app.

Quiroz will lead a training session for the county at 8:30 a.m. on Saturday, June 1, at the White Tank Mountain Regional Park Nature Center.

Reaping Rhythms: LA River’s Invasive Reeds Find an Artistic Purpose

LOS ANGELES – The L.A. River is full of things that, one way or another, people put there – candy wrappers, plastic bags, shopping carts, concrete, clothing, goldfish, pigeons and the giant, invasive arundo donax reeds.

Under his huge straw hat, Steve Appleton chops at a huge dry mat of arundo reeds. Three or four good thwacks, and he’s sheared an eight-foot stalk from the plant’s thick rhizome.

The rhizome, which looks like a giant piece of ginger or an armor-plated potato, is the plant’s root. It spreads underground, sending up tall, green stems like bamboo shoots that form dense stands and account for a lot of the greenery in the soft-bottomed portion of the L.A. River that flows through Elysian Valley. “A lot” because of arundo’s incredibly rapid growth: these stalks can grow between 1.5 and 4 inches a day. “On a hot day I swear you can see them growing,” says Appleton.

Because the reed grows so fast it tends to crowd out other plants, including the native species that are the focus of plans to “restore” the River’s habitat. The invasive plant also takes up space in the River’s channel, which somewhat impairs the River’s capacity to contain floods. This is why the US Army Corps of Engineers has been clearing arundo reeds from the River, using pesticides like Monsanto’s controversial Roundup.

Appleton is here with students from Cal State Northridge to suggest a different approach.

Cal State Northridge students Genevieve Hilburn and Stephen Crews gather arundo to create musical instruments. (Photo by Spencer Robins/KCET)

The shoots they harvest will become flutes, percussion instruments and sculptures, to be used in a performance of original music and dance at CSUN’s all-day festival April 5th. The project, called “Future Currents” and organized by CSUN’s Younes and Soraya Nazarian Center for the Performing Arts (“The Soraya”), is meant to bring CSUN’s arts students into the conversation around the city’s, county’s and state’s various river “revitalization” projects. In the words of the Soraya’s director Thor Steingraber, the point is to “raise our hand and say the arts have a place at that table.”

The lead artists for the project are Appleton, a sculptor, and choreographer Lynn Neumann. Appleton is a community activist as a well as an artist. He’s lived near the river for 18 years and has played an active role in the planning process for the river’s redevelopment. (He also owns and operates LA River Kayak Safari.) Neumann’s dance work has long been focused on ecological issues; one of her most well-known pieces was a long-term project that helped clean plastic trash off Coney Island beaches. The two artists have been working with CSUN students for months to create dance, music and sculptural pieces for the April 5th performance.

A trellis made out of arundo, an invasive reed species harvested out of the L.A. River. (Photo by Spencer Robins/KCET)

The project’s leaders are careful to say that it doesn’t have an agenda — it doesn’t advance a particular vision for the river’s future. The point is for teachers and students to make art and share it with the public. But part of what the students are learning to do is use this artistic practice to direct the public’s attention in ways that could shape river policy.

That makes them part of a long tradition. Arguably, it’s only because of artists that the idea of “revitalizing” the LA River (or just the idea of the river, period) is in the public consciousness at all. In 1986, Lewis MacAdams and several artist friends cut through a chain-link fence on the river’s edge, walked down the channel, and asked for the river’s permission to “speak for it in the human realm.” MacAdams went on to found Friends of the Los Angeles River, whose “40-year art project” is to draw attention to the possibility of a renewed river. CSUN alum Judith Baca’s Great Wall of Los Angeles is another model — pedagogical and creative — for “Future Currents”: Baca designed the massive mural, which depicts “the history of ethnic peoples of California from prehistoric times to the 1950s,” and hundreds of young Angelenos painted it. The question is, now that the River is squarely a matter of public and political concern, will artistic projects like these continue to play a role in determining its future?

A drumstick made of arundo gets some percussion practice on a rock. (Photo by Spencer Robins/KCET)

One thing art can do is call attention to material questions about the river that might otherwise pass below public notice. For example: what to do with the rocks? In the fall, Appleton noticed that the Army Corps of Engineers, which controls the river’s concrete channel, was removing boulders from it. They didn’t give the public any notice, but Appleton made calls and learned that the rocks were being shipped to a landfill far outside the city. Appleton was shocked — he described himself as “emotionally attached” to the rocks, which he believes were carried into the river by streams flowing from the San Gabriel Mountains. (Locally sourced rocks, in other words.) So, he spent two weeks calling the Mayor’s office, the Army Corps, the firm in charge of designing the G2 parcel — while Neumann considered choreographing a human-chain dance project to remove the rocks by hand. In the end, they convinced the City to ask the Corps to store the rocks at the river-adjacent Taylor Yard instead, where they can be used as landscape when the Yard eventually becomes a park.

Think of it as a pre-art project — gathering material for a future creation. Neumann wants people to think of lots of river issues that way. “There’s gonna be a lot of concrete coming out of that river,” as the city’s revitalization plans go forward. “That’s a usable material! So what happens to it?”

Learn more about the ecosystems in Los Angeles in “Earth Focus” Urban Ark.

The arundo raises other questions, which would have been easy to overlook. One is how to value the plants and animals that live in the river now. Neumann points out that even deciding what to count as native or nonnative in a place as human-impacted as the L.A. river is complex. “At this point, what’s native? How far back do you look?” Arundo is probably destructive enough to other plants that it should be removed, but even so, once a species has been labeled “invasive,” it’s easy to think of it as having no value. In fact, says Steingraber, “arundo is an ancient reed with an ancient purpose”: native to the Mediterranean, it has been used for thousands of years to make wind instruments like the Turkish ney. The ney will be a central part of the Future Currents performance: L.A. musician Danny Shamoun will play ney music alongside original works by CSUN students. By following this kind of tradition, says Neumann, “we’re trying to show that arundo is a very useful material. It might be harmful in this particular environment, but it could be harvested and put to good use.”

The other issue is that thinking of nonnative plants like arundo in purely negative terms could have real, destructive consequences. Valuing only native vegetation has led the Corps to remove successful nonnative habitat in the past, and strictly speaking the Army Corps’ policy is that, for the sake of flood control, “the channel is designed to be maintained free of vegetation.” It’s only due to their “limited funds” that the Corps focuses on removing nonnative plants. But Appleton argues “this whole River movement is based on people’s direct, often surprising experience of the natural environment that’s there. Planning that contemplates removing this habitat” — or that removes arundo using methods with potential environmental side effects — “would run counter to the public will and the original desires of the whole project” of renewing the river.

By contrast, finding value in arundo speaks to another, quieter history. People living along the river in Frogtown (people whose place there might be threatened by the gentrification that river revitalization could bring) have been making use of arundo for years. Several homes there have garden trellises made from the dried-out reed. Harvesting and making makes for a very different kind of relationship with place. Appleton hopes the Future Currents project will encourage more of this intimate, hands-on thinking — that it will “expand the ownership of the river” beyond the planners and help people think of the river “as our own backyard. “Lewis Macadams said the L.A. River was a forty-year art project. We’re trying to keep the project going.”

This story was first published by KCET on March 27, 2019. You can find the original report here.

L.A.’s Trees are Dying but is City Hall Doing Enough to Save Them?

LOS ANGELES – For months, Encino resident Shelley Billik filled up 5-gallon water bottles, drove out to White Oak Avenue and watered the newly planted trees herself. The city of Los Angeles, she said, planted dozens of trees along the median, but without a maintenance plan or irrigation system to care for them.

“There’s no way physically I could do 72 trees, but I can irrigate these young trees because they are not getting anything,” Billik told SoCal Connected. “I want to make sure they don’t die.”

Unfortunately, Billik’s effort turned out to be for naught. The younger trees were no match for the weekend’s heavy rains, which knocked the saplings to the ground, uprooting some.

“The young ones may have been planted poorly,” she said. “Plus, they shouldn’t be staked any longer. Those stakes are rotten.”

According to a recent study, Los Angeles is failing when it comes to its trees. City leadership, the report said, places little value on its “urban forest,” leaving it lacking in visionary management and planning, and well behind in funding to plant and maintain trees and replace those dying from the effects of climate change, drought and insect infestations.

Trees are important not only for beautifying neighborhoods, but cleaning the air, reducing heat, combating climate change, and even improving mental health.

The recent report, “First Step, Developing an Urban Forest Management Plan for the City of Los Angeles,” written by the Dudek consulting firm, said the city’s yearly budget of $27 per tree on public grounds is 140 to 212 percent less than what is spent in New York City, San Francisco and Melbourne, Australia. Los Angeles, the report said, needs an estimated budget increase of $40 to $50 million “to manage the urban forest at a sustainable level.”

A plan is needed quickly, the study said, because trees are particularly vulnerable. The dreaded invasive shot hole borer, an insect the size of a rice grain, has the potential to kill 27 million trees – nearly 40 percent – of the trees in Los Angeles, Orange, Riverside, and San Bernardino counties. Already, 129 million trees have died in California since 2010 because of climate change, drought and the bark beetle, the study said.

“We could lose probably a million trees,” Jerrold Turney, a Los Angeles County plant pathologist told SoCal Connected. “Entire neighborhoods will go from streets that are shaded by tall trees to full sun.”

This young tree was knocked over by January’s storms. The 20 largest cities in the Los Angeles basin experienced an annual 1.2 percent decrease in tree cover from 2000 to 2009. (Photo courtesy Shelley Billik)

Humans haven’t helped. The 20 largest cities in the Los Angeles basin experienced an annual 1.2 percent decrease in tree cover from 2000 to 2009. A USC study, “Urban Forestry & Urban Greening,” found that Los Angeles’ tree cover is disappearing, from 14 percent to as much as 55 percent in some single-family neighborhoods.

“What happened is that houses that were maybe 1,000 square-feet on a 5,000-square-foot lot are being turned into a 4,000-square-foot house on a 5,000-square-foot lot,” USC architecture associate professor Travis Longcore told SoCal Connected. “With that goes a dramatic decrease in tree cover. So if you were at 21 percent tree cover in a neighborhood at the beginning of the 2000s, you might be down to 11 at the end.”

Something must be done, experts say. Los Angeles has no tree czar and, according to the Dudek report, lags way behind where it should be in its urban forestry management. The city, the report said, “does not know enough about its trees,” lacks in reliable information about its trees in public parks and street and has no idea what is needed for the future. The city lacks in short and long-term goals for its programs, without even proper computer software to track them, the report said.

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That must change, the report said, with city leaders prioritizing trees with adequate funding, staffing, maintenance and goals for the future. Otherwise, Los Angeles faces the potential for a “catastrophic tree canopy cover loss.”

“If the City is willing to invest now towards creating a more sustainable urban forest, the city’s trees will be healthier, more diverse, and better cared for and the urban forest better equipped to respond to the various environmental threats,” the study said.

The city’s 2018-19 budget, however, allocates just $2 million for tree maintenance and its urban forestry program, along with $4.4 million for tree trimming, or about $40 million below the amount its consultant, Dudek, recommended it needs.

The city does require developers and residents to replace any trees they destroy through construction. Laws require residents to buy new trees for each tree cut down to make room for building. Residents pay $267 per tree, or about a tenth of what developers do.

But if there’s no room to plant those new saplings on the same site, the trees are expected to be planted elsewhere. Purchased trees are shipped to a nursery for safekeeping until they receive their final landing spot.

Often, they die waiting.

At a City Council meeting in May 2018, Los Angeles Council Member Paul Krekorian called that situation a “failure,” a result of a lack of any real strategic urban forestry planning.

A City of Los Angeles tag on this tree is part the plan to protect and preserve the urban canopy. (Photo courtesy Shelley Billik)

During that meeting, some council members called for major changes as they adopted a method to replace trees destroyed during construction. Instead of buying actual trees that soon die without a forever home, homeowners and developers can pay a fee to go into a fund that, in theory, will eventually buy trees to be planted somewhere.

Through Jan. 11, the “in lieu” fund as it is called, has collected $115,212. The fund has purchased 86 trees to replace 69 that were removed, said Elena Stern, a spokeswoman for the Bureau of Public Works.

The Bureau of Street Services, meanwhile, is also hiring 55 new employees this year “to perform more tree trimmings, remove dead trees, plant new trees and enforce regulations to protect and preserve trees,” Stern said.

“Critical to these new hires, is the creation of a new position, the Citywide Tree Policy Coordinator, who will ensure that the city’s focus on the entire tree canopy is synchronized, from streets to parks, city properties, and private development,” Stern said.

The coordinator, Stern said, will work with the nonprofit organization, City Plants, to “deliver a road map for a Citywide Urban Forest Management Plan.”

Tamarisk wars: Non-native trees are demonized, but are they really the enemy?

LONGMONT, Colorado – About a dozen people crouched in the tall grass of an open field, moving slowly and deliberately through mud that squished underfoot. Some carried huge, serrated knives called hori-hori, a Japanese tool made specifically for weeding. Others wielded gardening shears, saws or chemical sprays as their weapons of choice.

Their enemy was the tamarisk, a tree with a prehistoric look – tall, with scaly leaves and tiny pink flowers. It looks delicate, but the kind of delicate that makes it indestructible, as if it might bounce right back up after a dinosaur stepped on it.

“We’re going to be going really slow with a fine-toothed comb and trying to find every single last tamarisk that we can,” said Jim Krick, a natural resources specialist with city of Longmont. “Every tamarisk that grows up into an adult plant is going to put thousands more seeds out there.”

Weeding projects like this one, organized by a group called Wildlands Restoration Volunteers, are happening across the West.

The tamarisk, which was brought to the U.S. from Eurasia in the late 1800s for erosion control, windbreaks and decoration, is much detested. Since its introduction, tamarisk – also known as salt cedar – has been blamed for choking waterways, hogging water and salting the earth as its range expands, driving out such native trees as cottonwood and willows. In Palisade, Colorado, a state lab is breeding beetles whose sole purpose is to destroy tamarisk. At one point, the University of Nevada published a poster about the plant titled WANTED – Dead, Not Alive!

“There’s been a concerted effort to demonize tamarisk,” said Matt Chew, a historian of invasion biology at Arizona State University’s School of Life Sciences. But he thinks this war is aimed at the wrong enemy.

The tree, he said, is a scapegoat for our struggle with something much bigger and messier than weedy fields: our relationship with water in the West.

The tamarisk has a reputation for hogging water – but is it warranted?

“This is one of the constant counts against tamarisk – that it’s wasting water,” Chew said. “That particular idea got started in the late 1930s and early 1940s for a very particular reason.”

Back then, Chew says, the Phelps Dodge Corp. wanted to expand its copper mine in Arizona, but it didn’t have the water it needed for the additional mining and processing. All the water rights to a nearby creek and river had been allocated.

“What they needed was an excuse to say there was more water in the rivers so that Phelps Dodge could have more water,” Chew said. “So, where are they going to get more water?”

Phelps Dodge inspected nearby water sources and found lots of tamarisk growing along the banks, Chew said. Mine officials rationalized that if they could prove the tamarisk was draining river water, he said, the mine could potentially get the rights to the “extra” water available by killing tamarisk.

“Phelps Dodge did a bunch of experiments which were later picked up by the Agriculture Department,” Chew said, adding that Phelps Dodge ended up getting its water rights through other means, but the tamarisk’s image was destroyed.

As Chew writes in the Journal of the History of Biology, “with water shortages, economic development during the Depression and copper mining for national defense during World War Two, federal hydrologists moved quickly to recast tamarisks as water-wasting foreign monsters.”

Since then, researchers have shown that the tree doesn’t use more water than native riparian vegetation, including cottonwoods.

To make matters worse, big changes were occurring in the 1930s and ’40s in the way that water was being moved through the West. Dams and diversions were changing the patterns of flooding, patterns that used to be in sync with the reproductive cycle of more sensitive native plants, such as cottonwoods.

“To some extent, the way we were managing Western rivers actually created a giant tamarisk housing project,” Chew said.

If the tamarisk is a monster, he said, it’s because we created it.

“If you want good, old-fashioned 17th-century riparian areas in the western U.S.,” Chew said, “you can’t take all the water out of the river. You can’t have big irrigated fields. You can’t have huge cities.”

Anna Sher, an invasive species biologist at the University of Denver and author of the book “Tamarix: A Case Study of Ecological Change in the American West,” agrees that Tamarix (the species’ genus) isn’t all bad.

Yes, Tamarix can create saltier surface soil that retards other vegetation, and its dense wood can fuel more intense fires. Sher even has heard that a boater drowned in Arizona because rescuers couldn’t get through the dense thickets of tamarisk crowding the shore in time to help him.

But, she says, “I certainly do not hate this plant.”

It provides nesting spots for the Southwestern willow flycatcher, for example, and she says it’s entirely possible for the trees to be a part of the landscape without completely taking over.

“It’s only behaving badly because of the way that we’ve managed our rivers,” Sher said.

Although the way we manage our rivers isn’t going to change anytime soon, Sher sees hope for restoring the landscape. It’s called the Field of Dreams hypothesis.

“The Field of Dreams hypothesis predicts that when you remove the invasive species, there’s an opportunity for the desirable species to come in,” she said.

Initially, Sher and other ecologists suspected the hypothesis was a pipe dream.

“But after doing surveys of hundreds of sites throughout the American Southwest, we can see that, on average, native species will come back and they’ll come back proportionally to how much tamarisk has been removed,” she said. “More tamarisk taken out, more native plants can come in.”

There are two conditions required for successful restoration. First, there has to be enough water in the rivers and streams to supply the new vegetation. Second, the public has to remain open to what native plants might come back. They might not be the cottonwoods and willows people hope for.

“It’s a new game now with Tamarix here and with the water needs that we have now,” Sher said, and humans will have to get used to plants that can handle the landscape as we’ve shaped it.

Those plants might be drought-adapted shrubs and grasses instead of picnic-worthy trees. And they will most certainly have a tamarisk or two as neighbors.

This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, Yellowstone Public Radio in Montana, KUER in Salt Lake City and KRCC and KUNC in Colorado.