From the Grand Junction Free Press (Gigi Richards):
It’s a beautiful sunny afternoon and you’re on the Riverfront Trail, pedaling your bicycle along the Colorado River, and suddenly there are orange caution signs and the pavement turns to gravel. What happened? Is the path being improved, or new utilities being installed? Probably not. Most of the time, when you see gouges in the river bank leaving the paved bike path unsupported, or even missing, the Colorado River is responsible.
Flooding rivers have a lot of power to do an amazing amount of work. A flooded river can move gravel, and larger stones, reshaping the riverbanks. The work that rivers do is beneficial, such as maintaining spawning gravels and side channels for native fish to flourish, and depositing nutrients on the floodplain. However, sometimes that swift current, chewing away at the banks, undermines man-made structures that are located in the floodplain, like bike paths.
Back in the late 1800s, Westerners were frustrated with losing valuable farm and ranch land to fast moving rivers and decided to do something about it. A common strategy for protecting a river’s bank from erosion was to dump junk along the bank – large chunks of concrete, rubble, bricks, and old cars. Another strategy was to plant tamarisk, an invasive plant, along the streams to help stabilize the riverbanks.
Tamarisk, a remarkable plant, has colonized many rivers in the Southwest and has become a nuisance. The list of tamarisk’s vices is a long one. Dense tamarisk stands have stabilized the banks and locked these rivers into a single-thread channel, an unnaturally stable position. Tamarisk’s deep taproot allows a thicket of tamarisk to extend farther from the river than native riparian forest, which may take more water from the river. It forms a monoculture, out-competing native plants and leaving behind a salty duff on the ground that’s not conducive to the growth of other plants. It resists all attempts to remove it, being resilient in the face of floods, droughts and fires.
In the last five years, efforts to remove tamarisk have ramped up as restoration of our river corridors and preserving water have become higher priorities. But what does the removal of this bank stabilizing plant mean for our managed river systems? If we remove tamarisk will the rivers erode their banks with renewed vigor?
The answer is not so straightforward, and like many questions related to the functioning of natural systems, “it depends.” The bank material, the removal method, the vagaries of weather, and the presence of upstream dams all affect whether tamarisk removal will result in increased bank erosion or not. Some studies have shown dramatic channel change following tamarisk removal, for example on the Rio Puerco, New Mexico, and other studies show little, such as in the Canyon de Chelly in Arizona.
Ongoing research, conducted by Colorado Mesa University and the Tamarisk Coalition, into this question will help us understand some of the complexity of the interaction between tamarisk removal, and the potential destabilizing response of the river. Over the last two years, the Colorado River channel has been surveyed prior to tamarisk removal at three sites in the Grand Valley. The river will be resurveyed, after the next high spring snowmelt, and changes in the channel will be studied. In addition, historic aerial photographs are being analyzed to understand how the river has moved historically in areas where tamarisk was removed and where riparian vegetation remains.
As population grows demands on our water supply will increase. We strive to support healthy watershed and riparian areas and tamarisk removal efforts will continue. Better understanding of how rivers respond to tamarisk removal will be useful in designing effective riparian restoration and tamarisk removal efforts. So, when you come across gravel sections along the bike path, you can appreciate the hardworking Colorado River, doing its job, moving sediment and eroding its banks, whether tamarisk removal played a role, or not.
From the Grand Junction Free Presss (Shannon Hatch):
Have you noticed anything missing in the Grand Valley lately? Perhaps you’ve been out biking on the Colorado Riverfront Trail, walking along Connected Lakes, playing disc golf at Matchett Park, rafting the Colorado River, or driving along Monument Road and thought — hmmm — something is different here. I think there used to be more trees. Why did someone remove them? Is something going to take their place?
Recently, a number of organizations and individuals, including Colorado Parks & Wildlife, City of Grand Junction, Mesa County, Natural Resources Conservation Service, Tamarisk Coalition, and various private landowners have been undertaking a variety of riverside restoration projects along the Colorado River and its associated washes, from Palisade to Fruita. Much of this work is being completed under the umbrella of the Desert Rivers Collaborative (DRC), a public-private partnership dedicated to improving habitat along the Colorado and Gunnison Rivers in Mesa and Delta counties.
One of the main focal points of the DRC is the management of invasive plant species, including tamarisk (also known as salt cedar) and Russian olive, which can degrade the ability of areas along rivers and streams to provide essential habitat and resources for humans and wildlife alike. Tamarisk and Russian olive’s dense growth patterns can block access for recreation and agriculture, create hazards for river runners, invade popular campsites, channelize waterways, and, in the case of tamarisk, facilitate increased wildfires. Both species displace native vegetation, which negatively impacts fish and wildlife habitat, and water usage by these plants can also be substantial, most notably in areas where these species displace less thirsty plants, such as sagebrush and rabbitbrush.
Visually, as many of you may have noticed, initial removal of tamarisk and Russian olive can be quite dramatic. Due to the scope and densities of infestations, heavy equipment is often utilized to mulch trees across large acreages, leaving behind areas that some have likened to a “bomb blast” zone. And then there’s the issue of secondary weeds: some of our valley’s finest — including kochia, whitetop, Russian thistle, cheatgrass and perennial pepperweed — take a liking to these recently disturbed sites, often setting up shop in high-density.
Restoring habitat along rivers and streams is typically a multi-staged event, with initial removal merely the first act. In addition to on-going monitoring and maintenance, treatment of tamarisk and Russian olive resprouts, secondary weed spraying, and revegetation with native plants are also key components, and ones that often require a phased approach. For example, in order to avoid damage to desired plant species, revegetation activities may need to be put on hold until completion of herbaceous weed spraying, a process that can last several growing seasons.
Fortunately, landowners and managers in the Grand Valley are no strangers to the hard work and ongoing attention that these projects require. And thanks to more flexible grant funding, managers are now able to better plan for the myriad steps, often required over a multi-year time frame, needed to achieve restoration success. ˆ
As an example, 24 acres of tamarisk and Russian olive were treated at the Connected Lakes Section of James M. Robb Colorado River State Park in the winter of 2013. Resprouts and secondary weeds were sprayed at various stages in 2014. Revegetation with native plants, including grasses, forbs, cottonwoods, willows, and various shrubs, occurred earlier this year, with monitoring and maintenance an ongoing priority. In a testament to the importance of monitoring, Pete Firmin, park manager, noted that 15 cottonwood trees were lost in a single weekend to beaver activity, prompting changes in how the trees were protected. Pete also noted that “patience and planning are important in restoration work. Throughout the process we encourage the public to visit these sites and talk with the area manager about the ongoing plans for the land.”
While some of your favorite areas in town may currently be looking a bit bare, rest assured that restoration actions to improve these riparian habitats for the betterment of the community are underway. The legacy of invasive species impacts can’t be erased overnight, but with time, great improvements in the structure, function, accessibility, and enjoyment of these areas can be realized.
If you are interested in touring local restoration sites up-close and personal, consider joining Tamarisk Coalition on their annual Raft-the-River trip on Aug. 23. Rimrock Adventure guides and hand-picked local river experts will provide an informative, fun float down the Colorado River with après dinner, drinks, live music, and prizes to boot. For more information on the raft trip or to learn more about local restoration projects, please contact Tamarisk Coalition at 970-256-7400 or visit http://www.tamariskcoalition.org.
Shannon Hatch is restoration coordinator for the Tamarisk Coalition. This is part of a series of articles coordinated by the Water Center at Colorado Mesa University in cooperation with the Colorado and Gunnison Basin Roundtables to raise awareness about water needs, uses and policies in our region. To learn more about the basin roundtables and statewide water planning, and to let the roundtables know what you think, go to http://www.coloradomesa.edu/WaterCenter. You can also find the Water Center at http://www.Facebook.com/WaterCenter.CMU or http://www.Twitter.com/WaterCenterCMU.
House Bill 1006 creates the Invasive Phreatophyte Grant Program.
Governor John Hickenlooper signed the bill at a ceremony in Montrose on Tuesday…
Republican Representative Don Coram of Montrose sponsored the bill.
He called the invasive plants ‘water thieves’ that menace riparian areas.
“I truly believe the eradication of phreatophytes is the first tool in the Colorado Water Plan,” Coram said at the signing ceremony.
Coram said these plants are a problem in his district and across the state.
“If you travel the Colorado River [and] the Dolores River for example, it’s a thicket in many areas that you can’t even walk through, but it’s also a water quality issue because the tree sucks up the water and it drops salt so nothing else really [can] grow,” he said.
The water conservation board will oversee the program and distribute grants for projects. The program is set to end in 2018.
From the Colorado Springs Post Independent (Pam Zubeck):
Because of the plant’s resistance to heat and drought, the Army Corps of Engineers used it in the mid-19th century to stabilize riverbanks against erosion. Then, during the severe drought of the 1930s on the Great Plains, farmers deployed it and its companion, invasive Russian olive, to provide windbreaks.
In the decades since, the story has shifted. Tamarisk, which can grow to 20 feet tall, has proliferated with a vengeance, colonizing thousands of miles of riparian corridors in the West, including those along the Front Range. It guzzles water, squeezes out any competitors, and sterilizes wetlands by leaving soils parched with salinity — hence its other name, saltcedar.
Besides being hard to destroy, a single plant’s blossoms produce thousands of seeds, which easily take root. Tamarisk, by one account, has multiplied 150-fold in just 100 years and now occupies up to 1.5 million acres in the western United States.
Even as water resources are taxed amid drought conditions, this ever-spreading exotic drinks freely via taproots that can reach 50 feet into the ground. One analysis put its consumption of water along the Arkansas River between Pueblo and the Kansas state line as enough to serve 376,000 people annually.
The body of research on the plant is massive and growing. Many have taken up the cause of eradication: government agencies, nonprofits and thousands of volunteers, as well as scientists and researchers, including a Colorado College botany professor and his students. Congress even adopted a law in 2006 ordering the Interior and Agriculture departments to get involved, though significant funding was never allocated.
Some new strategies for controlling tamarisk — including deployment of an insect, which has grown controversial due to its destruction of habitat for an endangered species — show promise. But the war on tamarisk is far from over, and warming temperatures due to climate change could help it spread farther by creating hospitable conditions in new areas.
Its role as villain may be relatively new, but tamarisk has fully embraced the part by being very hard to vanquish.
According to the Global Invasive Species Database, there are three varieties of tamarisk on Earth: tamarix aphylla (shrub), tamarix parviflora (tree) and tamarix ramosissima (tree, shrub). The last type prevails in the American West, in a spread the database refers to as “a massive invasion.”[…]
Eradication efforts began on the local level sporadically in the 1940s, but didn’t get traction on a wider scale until the 1990s, when a project on the Rio Grande River south of Albuquerque was undertaken.
About 15 years ago, the Tamarisk Coalition was formed. Today it works with more than 100 partners to restore riparian lands overrun with tamarisk through education and removal projects.
Some of those were undertaken along the Dolores and Colorado rivers with the help of Troy Schnurr, a ranger with the Bureau of Land Management in Grand Junction. The stretch Schnurr and others worked on isn’t accessible by heavy equipment, so crews had to raft down the river, work by hand with chainsaws and apply herbicides to stumps.
The project covered 25 miles and took 15 years.
“It can be overwhelming when you start,” Schnurr says. “There’s a lot of repair work, reseeding, replacement because the tamarisk has been there so long. That plant’s gonna be around for quite a while.”
Shelly Simmons, assistant district forester with the Colorado State Forest Service, explains it like this.
“What happens is resprouting,” she says. “Tamarisk has an aggressive root system. Once it does get established, you’re going to have to watch it for five years and treat it for regrowth. It’s rare if you get 100 percent control the first time you try to control it.”
Simmons works with volunteers, land owners and various agencies, including conservation districts, attacking tamarisk in the Purgatoire basin, Chico Creek, Fountain Creek, Huerfano Creek and the main stem of the Arkansas River.
“There’s been a lot of workshops in the Lower Arkansas Valley over the years,” she says. “We focus on riparian restoration, so we’ve had a lot of land managers and land owners attend those workshops. If a landowner feels they have the equipment and the means, they can undertake projects on their own land.” That was the case in an area along the Arkansas east of Pueblo and south of Highway 50, where tamarisk was cut and piled into heaps several years ago…
The act did result in a peer-reviewed assessment of tamarisk, though, completed in 2010 by the U.S. Geological Survey. That assessment puts a lot of stock in saltcedar leaf beetles (Diorhabda elongata), citing a study area in Nevada that showed a 65 percent mortality rate in saltcedar five years after the beetle was unleashed there. The beetles “consume saltcedar leaves, depleting root energy reserves until they are exhausted and the plant dies,” the assessment says.
These beetles came to Colorado about a decade ago, Beaugh says. Initially imported from Asia where the plant originated, the beetles are collected from areas on the Western Slope, where they’re well-established, and housed at the Palisade Insectary, run by the Colorado Department of Agriculture’s Biological Pest Control Program. From there, they’re shipped around the state, including to the Arkansas River corridor and Fountain Creek.
They arrive in cardboard jugs that resemble ice cream containers. Simmons says workers perch the cartons amid tamarisk bushes, and simply open the lids. The beetles, 1,500 per jug, crawl out and go to work. About 10,000 beetles are released per site, Simmons says, ideally “where tamarisk trees are younger and more succulent.”
A Colorado Agriculture Department newsletter says the beetle had settled into the Arkansas Basin by 2012, where some sites have been defoliated multiple times and up to 60 percent of the target tamarisk trees have been killed. The state has taken to calling the beetle “a valuable management tool.”
It also lies at the heart of the CC professor’s latest research. Heschel wants to know how the beetle affects tamarisk’s consumption of water; data to date suggest that in some cases, a tamarisk plant under siege only gets more aggressive.
“When the beetle attacks tamarisk,” Heschel says, “tamarisk tends to increase its water use to compensate for getting attacked.”
The study, which includes one site just south of the Fountain Creek Regional Park Nature Center, also looks at whether tamarisk that survive the beetle attack somehow become even heartier and more thirsty. “Is that what we’re accidentally doing?” Heschel says. “I don’t know the answer to that.”[…]
Use of the beetle, however, is being curtailed in some other states due to its potential to destroy habitat for the endangered southwestern willow flycatcher. In September 2013, the Center for Biological Diversity, and the Maricopa Audubon Society, in Arizona, filed a lawsuit against the U.S. Department of Agriculture, alleging the beetles were destroying the songbird’s nesting areas. The lawsuit, according to the Los Angeles Times, accused the department’s Animal and Plant Inspection Service of failing to protect the flycatcher, which nests in tamarisk thickets. The case is pending before a federal judge.
Robin Silver with the Center for Biological Diversity says while the lawsuit points to problems in Utah, Arizona and Nevada, the beetles also have invaded nesting areas in southwest and south central Colorado. “[Federal agriculture officials] said, ‘Don’t worry, because the native plants will come back,'” Silver says. But he argues that “unless you change the hydrology, you’ll end up with nothing” in the way of vegetation after tamarisk has been removed. “The only chance you have,” he says, “is to get out ahead of the beetles and change some of the hydrology for plant recovery. [Officials] don’t want to do that because it costs money.”
Patrick Shafroth, a research ecologist with the USGS at the Fort Collins Science Center, agrees that restoration is crucial in determining what vegetation comes next in the context of tamarisk control. As stated in a 2011 paper by USGS and other researchers about consequences of using the beetle, “Conditions in many areas now occupied by tamarisk have been so altered anthropogenically that recolonization by native willows and cottonwoods is unlikely without intensive restoration efforts.”
Considering the sky-high cost and massive efforts to restore large areas affected by the beetle, the paper says, “widespread tamarisk mortality will likely result in a net loss in riparian habitat for at least a decade or more.”[…]
And then there’s the wild card of climate change. Despite all attempts to rid rivers and streams of tamarisk, the hearty plant could get a leg up from rising temperatures. While Shafroth considers the question of climate change’s influence “uncertain,” the 2010 USGS assessment and other scholarly works say it could foster tamarisk’s proliferation, given that it thrives in hot, dry weather, and parts of Colorado remain in moderate to severe drought conditions.
From the assessment: “Further expansion of saltcedar northward (and to higher elevations) is likely to occur due to climate warming.”
All of which makes Shafroth wonder if this scoundrel of the West is a cause, or merely a symptom, of the real problem.
Each year, with the help of numerous partners across eleven states and Mexico, TC produces an annual distribution map that notes the presence and absence of Diorhabda spp. from sampling sites across the west. These data in no way represent all locations where the tamarisk beetle may exist, but give a broad perspective of beetle dispersal, providing land managers with information that may help with their integrated pest management plans, restoration strategies, and funding opportunities. If you would like to participate in the program, or help fill any “gaps” you may see in current data on the map, please visit our tamarisk beetle monitoring program page.
For 2014, TC would like to thank more than 30 partners directly involved in providing this year’s data, and more than 60 that have provided data during the span of TC’s involvement in tracking beetle locations across the west. This year showed rapid population expansion in Kansas, Oklahoma, and eastern New Mexico, with a slowing of spread along the Rio Grande in New Mexico, and a “stall” in southern Arizona. This decreased expansion, as compared to movement the last few years, is most likely indicative of the Northern Tamarisk Beetle (Diorhabda carinulata) reaching the southern limits of its physiological constraints along the Colorado, Little Colorado, and Rio Grande. There are three other species of tamarisk beetle in North America, and this year was the first time that all four species were recorded in a single state, New Mexico.
The production of the Annual Tamarisk Beetle Distribution Map is generously funded by a grant from the Walton Family Foundation.
The city of Grand Junction will use the $15,000 it recently received from Great Outdoors Colorado (GOCO) to remove tamarisk and Russian olive from the undeveloped Matchett Park area.
Because the GOCO funds were awarded as part of a Colorado Youth Corps Association program, the city will hire 10 youth ages 14 to 25 to complete the work, which is expected to take two weeks and to begin this spring.
The brush must be removed before moving forward with the master plan for the Indian Wash area, according to city officials.
Mesa County is one of 14 counties throughout the state in which Colorado Youth Corps Association programs will take place this spring and summer.
The projects, which will employ 200 youth from across the state, will enhance Colorado’s trails, parks, open spaces and wildlife habitat.
The overarching goal is to employ youth and young adults to work on critical outdoor recreation and land conservation projects in partnership with local governments and open space agencies.
All projects throughout the state will be completed with GOCO funds, portions of which come from Colorado Lottery proceeds.
For information about the Matchett Park project, call Traci Wieland at 254-3846 or email firstname.lastname@example.org.
For information about the youth corps, call Jeff Roberts with the Western Colorado Conservation Corps at 241-1027 or email email@example.com.
Introduced in the 19th century to protect railroad bridge abutments, praised for its ability to protect riverbanks from erosion, vilified for alleged water-sucking ways while simultaneously defended as wildlife habitat, the story of the Eurasian tamarisk – also known as salt cedar – is a textbook example of unintended consequences.
The beetle, introduced in small populations in an attempt to control the tamarisk, is the latest example. Brought from Europe to Utah and Colorado a decade ago, along with small populations in Texas, the beetle has run amok, spreading far beyond the narrow range biologists predicted.
After initial beetle arrival in 2012, the beetle rapidly spread uninvited up and down New Mexico’s rivers.
“Last year was really the year of the beetle,” said Oglesby, an attorney at a University of New Mexico water policy think tank and board member of the Tamarisk Coalition, a nonprofit tracking the beetle’s spread. “It came charging down the Jemez. It came charging down the Rio Grande, and now it’s charging up the Pecos as well.”
The beetles lay their eggs on tamarisks, with their larval offspring eating the leaves, quickly turning green patches of trees brown. Depending on local conditions, they often do not kill the tree outright, leaving it bristling with dead growth that nevertheless can sprout new leaves the following year.
Getting rid of tamarisk always has been an article of faith along Western rivers, but the dying trees along rivers’ edges in New Mexico and around the West are raising new questions – about fire risk and lost habitat for birds and other creatures that have made their homes in the artificial forests…
Oglesby saw the entire panoply of the tree’s history on display as he and a group of colleagues kayaked down the Rio Grande north of Albuquerque one recent fall afternoon.
Tamarisk swarmed over the river’s banks, crowding out native vegetation. In some areas, humans had intervened at great expense to clear them, creating an open bosque cottonwood forest.
But everywhere the scrubby tamarisk remained, there were signs of beetles chomping their way through them.
Formed to pursue habitat restoration along Western rivers, the Colorado-based Tamarisk Coalition now has become the de facto chronicler of the beetle’s spread. The group’s 2014 monitoring efforts are not yet complete, said Ben Bloodworth, who is overseeing the effort for the group.
But preliminary reports suggest that the beetle has become firmly established in Bernalillo and Valencia counties, and that a second population of beetles introduced in Texas has made its way through Las Cruces and is moving north up the Rio Grande.
The first beetle introductions, in Colorado and Utah, were approved by the U.S. Department of Agriculture, with the belief that the beetle’s impacts would be local.
Once it became clear the beetle was spreading much farther than expected, the agency stopped the program, but the beetle has continued to spread, undeterred…
For now, action in the middle Rio Grande is limited to monitoring the beetle’s progress. “People are just waiting and watching,” Oglesby said.
More Tamarisk control coverage here here and here.