Oh noes! Giant thistle weeds a coming consequence of climate change, but another study says “maybe not”

Yellow starthistle is indeed a problem in western states, but the problem preceded “climate change” by decades.  See the end of the press release for more.

Purdue News

Climate change allows invasive weed to outcompete local species

May 31, 2011

WEST LAFAYETTE, Ind. – Yellow starthistle already causes millions of dollars in damage to pastures in western states each year, and as climate changes, land managers can expect the problem with that weed and others to escalate.

When exposed to increased carbon dioxide, precipitation, nitrogen and temperature – all expected results of climate change – yellow starthistle in some cases grew to six times its normal size while the other grassland species remained relatively unchanged, according to a Purdue University study published in the early online edition of the journal Ecological Applications. The plants were compared with those grown under ambient conditions.

“The rest of the grassland didn’t respond much to changes in conditions except nitrogen,” said Jeff Dukes, a Purdue associate professor of forestry and natural resources and the study’s lead author. “We’re likely to see these carbon dioxide concentrations in the second half of this century. Our results suggest that yellow starthistle will be a very happy camper in the coming decades.”

The study is one of the first comparing the growth of invasive species versus their local competitors under future climate scenarios. Dukes believes the results indicate problems land managers and crop growers could see in the coming decades, and not just with yellow starthistle.

“Plants are going to respond in a number of ways to climate change. Sometimes, the species we depend on will benefit, but other times, it will be the weedy, problematic species that benefit most, and there can be economic and ecological damages associated that people should be aware of,” Dukes said. “These problems with yellow starthistle aren’t going to go away on their own. If anything it’s going to become more of a problem than it is now.”

Yellow starthistle is a significant weed in the West, especially in California, where it has a longer growing season than native plants and depletes ground moisture, affecting water supplies.

Yellow starthistle

Image via Wikipedia

“It reduces the quality of the area for animal forage, is toxic to horses and when it forms spines, cattle don’t want to eat it,” Dukes said. “Many consider yellow starthistle to be the worst grassland weed in the West.”

The decreased pasture production, lost water, and control costs associated with yellow starthistle cause economic impacts in many western states. Experts suggest that in Idaho alone, the weed may cause more than $12 million a year in economic damage and that yellow starthistle reduces pasture values by 6 percent to 7 percent across the state of California.

Dukes said all plants increased in size as expected when exposed to more nitrogen. But yellow starthistle was especially responsive to increased carbon dioxide.

That might be in part because the weed can gain access to more soil resources, Dukes said. Grassland plants’ stomata, small porelike openings on the leaves, don’t have to be open as wide to take in carbon dioxide when there is a larger concentration in the air. Those smaller stomata allow less water to escape, and the extra water in the soil could favor yellow starthistle. The added carbon dioxide also changed the mix of species competing with the weed and may have allowed it to grow a more effective root system.

“It was an impressive increase in growth,” Dukes said. “It was one of the largest responses to elevated carbon dioxide ever observed.”

Biological control species introduced to control yellow starthistle have not been effective enough, and Dukes said it is becoming urgent that better controls be developed to address invasive species that could cause significant damage to pasture, cropland and wildlands.

The National Science Foundation and the David and Lucile Packard Foundation funded the research, which was carried out in collaboration with researchers at the University of Massachusetts Boston, Stanford University and the Carnegie Institution for Science.

Writer: Brian Wallheimer, 765-496-2050, bwallhei@purdue.edu

Source: Jeff Dukes, 765-496-1446, jsdukes@purdue.edu

==========================================================================

From Wikipedia: it seems the spread of this weed preceded the global warming issue by decades:

After the turn of the 20th century, Spain, France, Italy, and perhaps Turkestan were also likely sources of the invasion’s seed. Since its introduction to California in the mid-nineteenth century, it has become a large-scale invasive species (noxious weed or invasive exotic) throughout twenty three states. It currently dominates over 15,000,000 acres (61,000 km2) in California alone.

By 1970, yellow star-thistle had reached 23 U.S. states. According to the USDA Forest Service, as of 2006 the plant has been reported present in 41 of the 48 contiguous U.S. states, with the only exceptions being Maine, Vermont, and five of the Deep South states (Arkansas, Louisiana, Mississippi, Alabama, and Georgia). The plant is considered an invasive species in six of the 41 states: California, Oregon, Washington, Idaho, Utah, and New Jersey.

Also, here’s an article from 2004, by a US Forest Service expert on Yellow Starthistle, called Explosion in Slow Motion. Not a peep about climate change or global warming being a contributing factor.

Oh but wait, there’s more, just two years ago we read that climate change may actually get rid of star thistle and other noxious weeds.

From The Nature Files: An upside to climate change?

They’re the five “dirty words” of the West — cheatgrass; spotted knapweed; yellow starthistle; tamarisk; and leafy spurge — but the battle against these pervasive troublemakers could receive a boost from an unlikely ally, climate change. Scientists from Princeton University have determined that climate change will very likely cause massive die-offs of these invasive plants across the West, creating unprecedented opportunities to restore millions of acres of infected wilderness to native vegetation.

The findings, released this month in the journal Global Change Biology, will help land managers develop long-term invasive plant recovery projects. The restorative potential comes at a price however, as the model used in the study also predicts that some populations of invasive plants may simply shift their ranges to new areas — yellow starthistle will likely move from its current range in California, Oregon and Washington to a new ranges in California and Nevada for example.

Here’s the press release and link to paper:

Public release date: 27-Jan-2009

Climate change’s impact on invasive plants in Western US may create restoration opportunities

Princeton, NJ – January 27, 2009 – A new study by researchers at Princeton University’s Woodrow Wilson School of Public and International Affairs has found that global climate change may lead to the retreat of some invasive plant species in the western United States, which could create unprecedented ecological restoration opportunities across millions of acres throughout America. At the same time, global warming may enable other invasive plants to spread more widely.

The study, “Climate change and plant invasions: restoration opportunities ahead?”, was co-authored by Bethany Bradley, a biogeographer, Michael Oppenheimer, a geoscientist, and David Wilcove, a conservation biologist, at Princeton’s Woodrow Wilson School, and is published in the journal Global Change Biology.

The article is accessible online at http://www3.interscience.wiley.com/journal/121521769/abstract.

The researchers assessed the relationship between climate change and the distribution of five prominent invasive plants in the western United States – known colloquially as the “kudzus of the West” – cheatgrass; spotted knapweed; yellow starthistle; tamarisk; and leafy spurge. Such plants are defined as invasive because they were brought into this country from other lands and now dominate and alter ecosystems in ways that threaten native wildlife, agriculture, and ranching. All have greatly expanded their ranges in recent decades in the western U.S., causing millions of dollars in damage to farmlands and rangelands. Invasive plants are increasingly expensive to control, and it is widely believed that global warming will make the problem worse.

But Bradley and her co-authors find that global warming may also reduce the competitiveness of some invasive plants if conditions become climatically unsuitable to the weeds, “creating opportunities for restoration in areas currently dominated by intractable invasive species,” according to the study.

full PR article here

So we have dueling model outputs. It might be better to simply say “we don’t know”. Pass the Roundup.

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51 thoughts on “Oh noes! Giant thistle weeds a coming consequence of climate change, but another study says “maybe not”

  1. I guess none of the researchers are Scots. If this weed/plant is actually thistle, then Scots will be ecstatic! They will take it as a sign of the return of Scot hegemony. And why not? Aren’t we seeing the return of the Medieval Warm Period and Viking hegemony?

    Also, who cares? Because some weed/plant grows in the Western US I am supposed to embrace higher taxes on my energy use? Next thing, I will be taxed because Kudzu is just about everywhere and Asian Carp are headed up the Mississippi to the Great Lakes. No, I am not paying.

  2. “When exposed to increased carbon dioxide, precipitation, nitrogen and temperature – all expected results of climate change – yellow starthistle in some cases grew to six times its normal size while the other grassland species remained relatively unchanged, according to a Purdue University study published in the early online edition of the journal Ecological Applications.”

    Well duh! Of course only nasty naughty weedy plants thrive in a CO2-rich, warm, wet climate. Conversely, all things bright and beautiful shrivel up and die a slow agonising death.

  3. We must shutdown all international trade and movement of people or goods to prevent these invasive species from destroying our way of life /sarc . In particular, isolate California, with special emphasis on San Francisco, LA, and Berkeley. A moat with gators is recommended around those areas.

  4. But Milerepa http://en.wikipedia.org/wiki/Milarepa lived the last years of his life on only thistle tea. But then again that was the MWP so maybe there is something to it. Though I doubt it got that warm in the mountains of Tibet. Does Mann have a tree from that area we can check?

  5. > When exposed to increased carbon dioxide, precipitation, nitrogen and temperature – all expected results of climate change.

    Well, two brownie points for saying “carbon dioxide” instead of “carbon”, but that makes the fertilizer-speak for “nitrogen” just sound very weird. The atmosphere is already 79% nitrogen. Of course, he meant bio-available nitrogen as ammonium or nitrate, and I don’t think I’ve heard about climate change impacts on them.

    Lessee, http://www.ec.gc.ca/pcmar-cabmp/default.asp?lang=En&n=ACBFF19F-1 shows no change in nitrate aerosols except for bigger outliers.

    http://iopscience.iop.org/1755-1315/6/8/082017 is titled “Climate change factors increase ammonium, amino acids, DON and DOC in soil solution in a subarctic birch forest in northern Sweden”

    http://authors.library.caltech.edu/13194/ says “Climate change alone is predicted to lead to decreases in levels of sulfate and ammonium in the southeast U.S. but increases in the Midwest and northeast U.S. Nitrate concentrations are projected to decrease across the U.S. as a result of climate change alone.”

    Glad to clear that up.

  6. If grazing animals eat only what they like, and don’t eat the weeds, of course the weeds will prosper and take over.

  7. So there are two more entries to add to the ‘Things Global Warming Will Cause’ site:

    – Giant thistleweed runs rampant
    – Extinction of giant thistleweed

    Form an orderly queue at the door, and your own personal grounds for climate hysteria will be assigned to you at random.

  8. “It’s worse than we thought”.

    Two points, first, this quote: “When exposed to increased carbon dioxide, precipitation, nitrogen and temperature – all expected results of climate change – yellow starthistle in some cases grew to six times its normal size while the other grassland species remained relatively unchanged…” from the Purdue study.

    I thought global warming was going to cause LESS precipitation here in the West. That’s what we’ve been told for over a decade. Oops, record snowfall in the Rockies, guess they had to change that.

    Second, I grew up on a farm. We always fought thistles. They will grow faster than surrounding grasses irregardless of temperature. They spread so well because cattle, sheep, horses and other foraging animals don’t eat them, leaving them to seed and spread.

  9. How come certain rodents demand protection, but “weeds” should not be allowed to thrive?

  10. “…but the battle against these pervasive troublemakers could receive a boost from an unlikely ally, climate change. Scientists from Princeton University have determined that climate change will very likely cause massive die-offs of these invasive plants across the West, creating unprecedented opportunities to restore millions of acres of infected wilderness to native vegetation….”

    That was pretty funny. How much climate change are they anticipating?

  11. Sounds like a plot line for a sequel to “Attack of the Killer Tomatoes”. I can see it now: The killer thistles grow to gigantic sizes and crush the Giant Windmill Beings from outer space.

  12. Aren’t these weeds originally from the Siberian Steppes? And haven’t they already been out-competing local plants? And ANY plant will thrive with “increased carbon dioxide, precipitation, nitrogen”

  13. When exposed to increased carbon dioxide, [etc] …… expected results of climate change ……

    Nice to see that acknowledgment in an academic paper. So many seem to dispute the relationship.

  14. “The study is one of the first comparing the growth of invasive species versus their local competitors under future climate scenarios. ”

    Oh golly! I’m mighty impressed! A whole new industry is born…..really, have these so-called researchers nothing better to do than to waste money doing the obvious?

  15. Aren’t we all invasive weeds according to the UN.
    They’d love to use Round Up on us, or just round us up!

  16. The Yellow Starthistle thrives when it’s competion is removed. It doesn’t get along too well with the natural grasses and reeds. Unfortunately, most of the natural grasses have been removed/plowed under.
    It’s also easy to pull up, and if you get rid of it before it goes to seed, it doesn’t come back.
    It gets spread along highways where hay is transported.
    Fire won’t do anything to eradicate it, and if you weed whack it, you’re screwed.
    Pull it up.

  17. “They’re the five “dirty words” of the West — cheatgrass; spotted knapweed; yellow starthistle; tamarisk; and leafy spurge –“

    A hillside of blooming yellow star thistle is beautiful – from a distance.
    Dirty words? I don’t know. Consider: Gore, UN, Big Jim, tax, and it’s worse than we thought – there’s five dirties for you!

  18. “…under future climate scenarios.”
    Boo!…boo from the “future climate scenarios.”

  19. Why is it that global warming is good for ‘bad’ things and bad for ‘good’ things?

    Polar bears = good
    Rats = bad

  20. Invasive plants are increasingly expensive to control, and it is widely believed that global warming will make the problem worse.

    Oh noes!!

  21. Garbage in, garbage out. What are the odds that this was funded with specially earmarked “climate change study” grants?

  22. How odd that this thistle is taking over pasture land. Forbs (non-grassy flowering plants) are very easy to control or even eradicate with proper cultural practices.

    First, practice intensive, rotational grazing. Put your livestock in a limited pasture and leave them there until they’ve eaten all they can. Then move them to the next pasture. If you put cattle in when the thistle have not yet formed a seed-head, they’ll eat it just fine, and the thistle won’t reseed itself. It may take a couple of treatments a year for two or three years.

    Second, run sheep or goats with your cattle. In spite of the old sheepherder vs cattleman wars, sheep and cattle do not compete for graze. Cattle prefer grasses, and sheep and goats prefer forbs. If you intensively graze with sheep, it may require only a single treatment to pretty much wipe out this weed. (It should be noted that sheep and goats exhibit a strong liking for the yellow starthistle.)

    And, a note from the Sheep Industry News,

    Targeted grazing to control yellow starthistle is strongly recommended for sheep and goats, less so for cattle. Goats are probably the most effective livestock to use for grazing of yellow starthistle because they will readily eat the plant in all growth stages. Grazing reduces plant vigor and plant size and suppresses flower production. Effective control depends on the prevention of flower and seed production, which can be achieved by grazing at least twice a year over several years. Yellow starthistle is highly toxic to horses.

    cheers,

    gary

  23. Addendum to my previous post: I knew I had seen more info on this. See Livestock Grazing Guidelines for Control Noxious Weed in the Western United States
    By
    Jason C. Davison
    Forage and Alternative Crops Specialist, University of Nevada Cooperative Extension
    Ed Smith
    Natural Resource Specialist, University of Nevada Cooperative Extension
    Linda M. Wilson
    Invasive Plant Ecologist, Plant, Soil and Entomological Sciences, University of Idaho
    .

    If the Purdue academics don’t understand intensive grazing’s benefits to grass production and weed control, they should consider their own lawns and the effects there, i.e. regular mowing.

    cheers,

    gary

  24. Somehow we never hear about studies that show increase growth of beneficial plant due to higher CO2 and temperature.

  25. I just want to know if the “Pods” from the critically acclaimed documentary “Invasion of the Body Snatchers” are going to be helped by increased sea-O-two.

  26. Honeybees love star thistle. The resulting honey is a sustainable, alternative, biofuel potentially subsidized by the federal government. When stored in my pantry, it sequesters hydrocarbons thereby saving the planet. Plus it chokes horses, thus serving to control the expansion of the wild mustangs that threaten native plants.

  27. I remember first seeing Start Thistle in my area (S.E. Wash. State) in the 1980s, but for the past several years I have noticed its decline in the gardens and horse pastures around our place. There is some kind of caterpillar that is eating them.

  28. I’m surprised nobody has yet referenced the Genesis song: Return of the Giant Hogweed.

    Turn and run!
    Nothing can stop them,
    Around every river and canal their power is growing.
    Stamp them out!
    We must destroy them,
    They infiltrate each city with their thick dark warning odour.

    http://www.songmeanings.net/songs/view/1617/

    You can see a cover version done at

    Hogweed, thistleweed — it’s close enough for government work.

  29. A sixth invasive species to add to the list is puncturevine, aka goathead, devil weed, and many other names. It has sharp spines that will penetrate almost anything. It was imported from Europe or Africa and does well in dry, nutrient poor dirt. It’s a real problem in Idaho, capable of puncturing bike tires, lawnmower tires, etc. They penetrate shoes, and my dog hates them. The seed can lay dormant for 20 years, so it’s hard to get rid of. Since it loves adversity, it will probably do well with more CO2 and less water, should that come to pass. Some people think it increases sex drive, but all I have experienced is pain.

  30. Back in the old stone age, I was responsible for the pasture up keep on my family’s property – maintaining fences primarily. But working at abating star thistle was another chore. The chief method I used was limited by what I could reach with a hose. I watered the pasture and encouraged manuring by the cattle and horses. Star thistle doesn’t compete very well against a healthy population of perennial grasses and forbes. It likes dry land, disturbed soils, and generally marginal areas. It prospers in western pastures because we generally don’t irrigate them and grazing animals break up the surface soil, offer a strong foot hold to annual grasses and thistles, and gradually reduce the density of preferred forage. That leaves the thistle to prosper. It is bitter tasting, and cattle and horses usually avoid it. If they don’t, it can be toxic.

  31. slp says: “How come certain rodents demand protection, but “weeds” should not be allowed to thrive?”

    Because they are weeds, silly. But not to worry. In California, we had supposedly endangered native species called (among other varieties) the Santa Cruz tarweed. When people questioned the need for protecting a weed, academics declared that henceforth the Santa Cruz tarweed was to be called “Santa Cruz tarplant.” Seriously.

    But it’s worse than you thought. In California (and some other states), we have a crime called “plant molestation.” Strike from your minds those naughty images of (Northern) Californians performing botodomy in a field of, say, jack-in-the-pulpits. It simply means doing anything that might damage a plant, such as feeling or plucking its flowers, leaves, pistils, stamens, etc. You could get in serious trouble for molesting a tarweed!

    (As far as I know, no one has tried to smoke one, but anything is possible in California. Obviously.)

  32. Charlie Foxtrot says:
    May 31, 2011 at 9:15 pm

    “Some people think it increases sex drive, but all I have experienced is pain.”

    Charlie, maybe you didn’t put it in the right place.

  33. Crop it, burn it and produce electricity. (Have I said something like that before?).

  34. We have giant weeds here in Ottawa now because the provincial government banned perfectly safe herbicides. grrrr###

  35. “The rest of the grassland didn’t respond much to changes in conditions except nitrogen,” ……
    really?
    ah?
    so wouldnt that mean that the massive undergrowth and fires they like to terrify people about may also not occur? that fodder and crops will adjust as they always do?
    the variance in plain ordinary seeds survival and adaption is amazing we dont need no Gm to save us either. they love the carbon fallacy, makes business.
    unless its Australia, or course, where cows that kept undergrowth down, got banned for not being a green idea.
    whats worse, some bush eaten -wild life alive.
    or
    fires and many dead animals and people
    Must be THE Year of the thistle then:-)
    cos Aus also has many species that havent been seen in many years appearing madly in our paddocks, nasty spiny evil buggers. Big too.
    and gee, the PPM is 390 and theyre growing on sand ,mud, pasture , fallowed, and cropping grounds, with and without nitrogen or insane PPM Co2 fakery trials

  36. Time for those weed picking/ bug destroying solar powered robots we saw in the movie “Runaway”.
    Someone want to fund my IPO?

  37. How do the ‘good’ plants tell if it’s ‘good’ CO2 (natural) or ‘bad’ CO2 (man-made) so that they know if they should use it or not?

  38. I had an abundance of Thistle growing in our yard. Originally I thought it was due to my not so motivated teen-age son, but now I wonder if I have been a victim of Anthropogenic Global Warming.

    The thistle crop was enormous, with no less than ten plants. The only thing is they had purple flowers, not yellow. Does that count? Can I get compensation?

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