Bushwhacked: Tamarisk, a water-guzzling alien, is wreaking havoc in the West — Colorado Springs Independent

April 29, 2015

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.”[…]

Southwestern Willow flycatcher

Southwestern Willow flycatcher

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.

More tamarisk control coverage here and here.


@TODAYshow: Goldfish have taken over a lake in Boulder, Colorado

April 9, 2015


Been seeing tamarisk beetle kills in S. Nev. Updated map also shows ’em converging on New Mexico

February 27, 2015

2014 Tamarisk leaf beetle distribution map via the Tamarisk Coalition

2014 Tamarisk leaf beetle distribution map via the Tamarisk Coalition

From the Tamarisk Coalition website:

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.

More tamarisk control coverage here.


Bureau of Reclamation: This map shows where invasive mussels have infested or been detected in our reservoirs or facilities

February 26, 2015

More invasive species coverage here.


2015 Colorado legislation: HB15-1006 (Invasive Phreatophyte Grant Program) makes it out of committee #coleg

February 3, 2015

Tamarisk

Tamarisk


Click here to read the bill.

From The Grand Junction Daily Sentinel (Charles Ashby):

A House panel (House Committee on Agriculture, Livestock, & Natural Resources) unanimously approved a bill Monday to help local communities get rid of invasive species such as tamarisk and Russian olive trees because they drink up precious water.

While it may seem like that’s a good idea, not everyone was enamored with the measure, HB1006, as drafted, because it doesn’t go far enough.

It isn’t good enough just to get rid of the invasive plants, called phreatophytes. Native phreatophytes, such as cottonwoods and aspen, must be used to replace them to guard against erosion and maintain the animal habitat, those opponents said.

“Simply eradicating existing phreatophytes under the term ‘invasive’ implies that we’re going to have additional problems with flooding, with sedimentation, that we’re going to have some of the same problems that led us into the issues we have with tamarisk,” Jennifer Bolton, a lobbyist for the Audubon Society, told the House Agriculture, Livestock & Natural Resources Committee.

But other supporters, including the bill’s sponsor, Rep. Don Coram, R-Montrose, said the measure is tied to the state’s existing laws dealing with noxious plants.

As a result, the Colorado Department of Agriculture is required to consider the entire health of a watershed, and not merely taking out a few noxious weeds here and there.

Chris Treece, external affairs director for the Colorado River Water Conservation District, said he’s not worried both of those things won’t occur.

“The clear purpose of this bill is to provide the resources to those who have the expertise, who have the programs set up, and would allow for the exercise of those programs,” Treece told the committee. “All of those programs … prioritize the proper removal, the proper weed control, the proper rehabilitation and restoration of the riparian area.”

Regardless, the committee tacked an amendment onto the bill to ensure that awarded grants include not only removing invasive species, but also encouraging the growth of native ones.

Coram also amended the bill to ensure that the funding for the grants — $5 million a year in each of the next five years — will come from severance tax revenues and not from the state’s general fund.

While some Western Slope lawmakers balked at that idea, given recent protestations against a proposal to use severance tax money to help offset any taxpayer refunds, Coram said these grants are for water projects, and that’s where some of the severance tax revenues are intended to be used.

The bill heads to the House Appropriations Committee for more debate.

More invasive species coverage here.


Grand Junction to hire Colorado Youth Corps Association youth to remove tamarisk #ColoradoRiver

January 13, 2015
Tamarisk

Tamarisk

From The Grand Junction Daily Sentinel:

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 traciw@gjcity.org.

For information about the youth corps, call Jeff Roberts with the Western Colorado Conservation Corps at 241-1027 or email jroberts@mesapartners.org.

More tamarisk control coverage here.


The BBC looks at Didymo (rock snot)

January 1, 2015
Didymosphenia

Didymosphenia

From the BBC (Larry O’Hanlon):

It began with a few small strange patches of slime, clinging to the rocks of the Heber River in Canada. Within a year, the patches had become thick, blooming mats. Within a few years the mats had grown into a giant brownish-yellow snot. And within a few decades this snot had spread around the world, clogging up rivers as far away as South America, Europe and Australasia.

This snot, which is still flourishing today, is caused by a microscopic alga, a diatom that goes by its scientific name Didymosphenia geminata. It has become so notorious it has its own moniker, Didymo. People have been blamed for the sudden, global explosion of this tiny organism, unwittingly carrying the algae from river to river on fishing gear, boats and kayaks. The huge snots it forms have wreaked havoc in waterways, forcing governments and environmental organisations to initiate huge and costly clean-up operations.
But underlying the snots’ strange appearance is an even stranger story. About Didymo itself, about what it is, and how it behaves.

Scientists are now discovering that the sudden appearance of Didymo may not have been so sudden after all.

Its blooms aren’t really blooms – instead they are more of an elixir-induced metamorphosis. And Didymo seems to ignore the usual rules followed by invasive species. It even appears likely that this little diatom may not even be a significant problem itself; instead the brownish-yellow snot it forms may be a symptom of greater changes underway in freshwater systems around the world.

Malignant morphs

The diatom was first spotted in 1988, a few patches of alga within Heber River, in Vancouver Island, British Columbia. By 1989, several kilometres of river were covered in thick mats of the stuff, a surprise since the rare alga was not thought to grow this way. Today, Didymo coats the rocks of streams and rivers around the globe, from Quebec in Canada, Colorado and South Dakota in the US, Poland and Norway in Europe, even reaching Iceland, Chile and New Zealand.

Normally diatoms or other algae bloom when water is rich in nutrients, feeding an explosive increase in reproduction. This has a massive detrimental impact on freshwater systems. After diatoms increase in huge numbers, they also die in huge numbers, creating a surge in decay that depletes oxygen in the water. That suffocates freshwater animals such as insects, crustaceans and fish. Algal blooms essentially create an aquatic apocalypse.

But intriguingly, none of this applies to Didymo. When it creates huge snots, it’s not actually reproducing, scientists have discovered. Instead, it’s morphing, from something benign to something malignant. Each single-celled organism exudes long stringy stalks of mucous that entangle, creating the mats and snots that coat rocks.

“We usually think of massive cell division in a bloom,” says ecologist Cathy Kilroy, of New Zealand’s National Institute of Water and Atmospheric Research Ltd, in Christchurch. “That’s not the case here.”
The water conditions which cause this transformation are also unexpected. “Most algal blooms are attributed to too much nutrients,” explains diatom researcher Sarah Spaulding, of the US Geological Survey in Colorado.
“This is the first time it’s attributed to too little nutrient.”

Didymo, it turns out, only turns malignant when waters are very low in phosphorus, a nutrient often associated with pollution by detergents and fertilisers. It’s this paucity of phosphorous that causes the stringy stalks to grow, not the alga trying to reproduce, says Kilroy, whose experiments helped establish the connection…

Ever-present?

Didymo is also pulling a second surprise on scientists. For decades, it was thought that people spread the diatom around the world, the alga hitching a ride on the tackle, nets and wading boots of fishermen, and boats and boating equipment. To counter the threat, river users have been encouraged to clean their gear between visits.

But Didymo may not have been spread across the globe after all. It may have been there all along, believe Brad Taylor of Dartmouth College in Hanover, New Hampshire, US and Max Bothwell of Environment Canada’s Pacific Biological Station in Nanaimo, BC.

The two diatom researchers have just published a study in the journal BioScience. It reveals fossil and historical evidence that Didymo has long existed on every continent except Africa, Antarctica and Australia. Fossilised forms of Didymo, for example, can be found in at least 11 countries in Europe, across North America and Asia, and in South America.

“The idea that D. geminata is a recently introduced species or a native species expanding its range has been accepted and promoted,” say the scientists in their study. But that idea is wrong, they argue. And it explains why legislation banning certain types of wading gear, thought to help spread algae, has had no impact on the spread of Didymo’s brown snot into new rivers. Because Didymo was already there…

Catastrophic or not?

However, to fishermen and boaters wrestling with Didymo’s brown, or sometimes yellow or green snots, its origins are academic. They want to know what it’s doing to the waterways, whether it’s hurting fish or invertebrates such as the insects on which fish depend.

Even here though, the diatom continues to surprise. Research has shown that the alga boosts numbers of small insects, such as midges and gnats, while reducing numbers of larger insects, such as mayflies, stoneflies and caddisflies. “That seems to be a universal change in these streams,” says fisheries biologist Daniel James of the US Fish and Wildlife Service in the Black Hills of South Dakota, where Didymo appeared in 2002.

James’s research has focused on the diets of freshwater fish, and whether they have less to eat due to the presence of brown snots. But the reduction in larger insects hasn’t so far caused a problem, as the fish are just eating more of the smaller insects.

While the fish of South Dakota seem unaffected by Didymo, which covers around a third of the riverbeds studied by James, he cautions that may not be so in other places, such as in New Zealand. There the snots can blanket the whole river.

However, on the whole, Didymo doesn’t yet seem to have caused the ecological catastrophe that so many feared. “At first there was a huge concern about how Didymo was going to affect fish,” says James. “But it’s more of an annoyance.”

It can cause some problems for irrigation systems, says Kilroy. But its biggest impact seems to be aesthetic. “The main effect of Didymo is how it changed the appearance of rivers and streams,” she says. “It’s not toxic. It really doesn’t do anything really awful.”

The real invaders

So what then, is the real meaning of the Didymo phenomenon worldwide? The true significance of the brown snot taking over the world’s rivers may not be the snot itself, but what it tells us about our own, human impact on freshwater ecosystems.

Bothwell, Taylor and Kilroy have collaborated on new research recently published in the journal Diatom Research. They propose a few mechanisms by which humans may have altered the world’s rivers, creating the opportunity for Didymo.

First, the burning of fossil fuels such as oil and coal has increased the amount of nitrogen compounds on the atmosphere. That nitrogen causes soil organisms to better use phosphorous in the soil, meaning less phosphorous runs into rivers and streams. That creates the more phosphorus-free water beloved by Didymo.

A second mechanism, which has the same effect as the first, is the increasing addition of nitrogen-rich fertilisers to soils by agriculture and forest managers.

A third involves climate change, and the way it changes the timing of growing seasons and melting of snow. This might somehow also reduce the amount of phosphorous entering freshwater ecosystems, the researchers say, again creating the environment in which Didymo brown snots can flourish.

It could be that different mechanisms are the cause of Didymo blooms in different places around the world, or that they are working in synergy.

But whichever turn out to be at work, the research seems to suggest that we have met the invaders, and they are not brown snot-causing Didymo diatoms. They are us.

More invasive species coverage here.


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