“Over time, an invasive plant [Garlic Mustard] loses its toxic edge”

9/1/09 | Diana Yates, Life Sciences Editor | 217-333-5802; diya@illinois.edu

CHAMPAIGN, lll. – “Like most invasive plants introduced to the U.S. from Europe and other places, garlic mustard first found it easy to dominate the natives. A new study indicates that eventually, however, its primary weapon – a fungus-killing toxin injected into the soil – becomes less potent.

Garlic mustard produces glucosinolates, pungent compounds that leach into the soil and kill off many soil fungi, especially those native to North America. | Photo by L. Brian Stauffer

The study, in Proceedings of the National Academy of Sciences, is one of the first to show that evolutionary forces can alter the very attributes that give an invasive plant its advantage. In fact, the study suggests the plant’s defenses are undermined by its own success.

Garlic mustard comes from a family of smelly, sharp-tasting plants that includes cabbage, radish, horseradish and wasabi. Unlike most plants, which rely on soil fungi to supplement them with phosphorous, nitrogen and water, garlic mustard gets by without the extra help, said Richard Lankau, a postdoctoral researcher at the Illinois Natural History Survey (INHS) at the University of Illinois. Lankau led the study with INHS plant ecologist Greg Spyreas.

“For whatever reason, these plants just don’t hook up with the soil fungus,” Lankau said. Instead, garlic mustard produces glucosinolates, pungent compounds that leach into the soil and kill off many soil fungi, especially those native to North America. This weakens the native plants. As a result, garlic mustard now grows in dense patches in many North American woodlands, its preferred habitat. Those patches are often devoid of native plants.

Lankau began the new study with a seemingly obvious question: Once garlic mustard has vanquished most of its competitors, why would it invest as much in maintaining its toxic arsenal? He predicted – correctly, it turns out – that levels of glucosinolates in the plant would diminish over time.

“When you’re in a situation where the only thing you’re competing with is other garlic mustard, it may be that making lots of this chemical is not a very good idea,” he said.

Thanks to a study of historic herbarium records conducted by co-author Victoria Nuzzo, of Natural Area Consultants, N.Y., the researchers had access to a 140-year record of the age of garlic mustard populations across the eastern half of the U.S. The team collected garlic mustard seeds from 44 locations, grew them in a greenhouse and tested glucosinolate levels in each. Those tests found that older populations – those that have been present in an area for more than 30 years – produced lower levels of the fungicidal compounds than those that got their start less than two decades ago, Lankau said.

Genetic studies suggested that these patterns were the result of natural selection. That is, the plants that produced less of the toxin were more likely to survive and reproduce in older populations. 

The researchers then grew the garlic mustard in soil from native woodlands. After a time, they removed these plants and potted native trees in the same soil. The trees did best in pots that had held plants from older populations of garlic mustard, indicating, again, that the plants’ toxin output had diminished over time, killing less of the fungus on which the native plants relied.

To determine if the decline in glucosinolate production was allowing native plants to return to areas previously dominated by garlic mustard in the wild, the researchers turned to a unique data set available in Illinois. The Critical Trends Assessment Program (CTAP) is a
long-term initiative funded by the state Department of Natural Resources and administered by the INHS that monitors the status of plants, birds and insects across the state every five years. The CTAP began in 1997, and so data from the first two sampling periods were used (1997-2001 and 2002-2007)

Because CTAP includes data on plant abundance, including garlic mustard and native plants from across the state, the researchers were able to determine if native plants were declining or advancing in the presence of garlic mustard. Again, they found that older populations of garlic mustard – though still problematic – posed less of a threat to native plants than the newer ones did.

While this study focused on only one plant, the results indicate that some invasive plants evolve in ways that may make them more manageable over time, Spyreas said. This suggests that conservation efforts might be more effective if they focus on the most recently invaded areas, which – in the case of garlic mustard, at least – is probably where the most damage occurs.

This study was funded by the Agriculture and Food Research Initiative at the U.S. Department of Agriculture and by the Illinois Department of Natural Resources. The research team also included Adam Davis, of the Agricultural Research Service at the USDA.”

For more on this story, please click here to check out the News Bureau Website from Illinois University

Editor’s note: To contact Rick Lankau, e-mail ralankau@illinois.edu. To reach Greg Spyreas, call 217-819-2059; e-mail spyreas@illinois.edu. The paper, “Evolutionary limits ameliorate the negative impact of an invasive plant,” is available online.

Huron Arbor Cluster Wins Cluster Cup!

For the second year in a row, the Huron Arbor Cluster has won the 2010 Garlic Mustard Challenge’s Cluster Cup!  They crossed the finish line with 58,327 pounds of garlic mustard!

With a big push at the end, the West Michigan Cluster came in Second Place with 51,259 pounds of garlic mustard.  The Headwaters Cluster, with 36,740 pounds, just barely held on to Third Place while the Out-of-Cluster Area group rallied at the last minute finshing in Fourth with 35,575 pounds of garlic mustard.

The final tally in the Stewardship Network’s 2010 Garlic Mustard Challenge was 243,216 pounds of collectively pulled and reported garlic mustard!!

Thank you to EVERYONE involved in the 2010 Challenge, our collective efforts, big and small, really made a difference in beloved natural areas across the Great Lakes and beyond!!

Check out more Cluster Standings here…

Garlic Mustard a real-life Sci-Fi Story?

Need to fight off the back-at-work blues?  Read this article about little green aliens… and then think about all of the good we are collectively doing across the region fighting back!

“Baby-boomers and twenty-something sci-fi freaks may remember the 60s cult-classic film, The Day of the Triffids, about an invasion of flesh-eating plants from outer space.

In truth, Benzie County [Michigan] could create its own reality show with an invasive alien species from the flora world Garlic Mustard. The tenacious immigrant from Europe, Garlic Mustard, Alliaria petiolata, poses a serious threat to our North American woods, including some of its beloved plants such as the trillium and trout lily.

If we like this area and wild flowers in it, something has to be done to get rid of the garlic mustard plant, says park ranger Bill Herd of Sleeping Bear Dunes National Lakeshore. Right now, it is biggest threat to the park.

Herd says it showed up in this region about five years ago. What makes this unique is it’s the one invasive plant that thrives in the shade of the forest floor. It is green under the snow, giving it a head start in the spring. It replaces native plants before they come up, and is even a threat to tree seedlings, threatening future forests. It’s conceivable that morel hunting will only be a story this generation tells their children of something they did before garlic mustard wiped out the northern Michigan’s favorite mushroom.

Just how concerned should we be? What is the prognosis for eliminating this plant? Herd says there are now nature preserves in several New England States that are now more than 80% garlic mustard. There are forests with no natural plants-just dense colonies of garlic mustard.

Plant biologists agree this plant could be one of the most harmful and difficult to control of all the invasive plants in the region. The seeds germinate easily. Its presence and infestation means a drastic ecological impact for native species. It changes the soil composition of the forest floor. Morels and tree-seedlings will have a hard time sprouting and growing as this plant inserts itself on the forest floor. The plant was first documented in North American around 1868. Although, it was used as a cooking herb because of its garlic-like scent, it is unclear if was deliberately or accidentally introduced by its seeds from European travelers. Now it is found in 30 U.S. states and at least three Canadian provinces. The seeds are easily spread by humans, birds, rodents and deer.

The battle is being lost to regional area infestations, including Benzie, Lake and Wexford Counties. The insidious take-over may be breeding in those back forty acres that are seldom hiked on.

Hand-pulling, herbicides and fire are the management techniques used. The simplest and most effective is hand-pulling, which could turn the losing battle around if all citizens were aware of the situation and assumed a vigilante force against this “alien flesh-eating” plant of our forest floors.

We’re aware of this problem and we’re going to do everything we can, says Josh Mills, Frankfort City Superintendent. But it’s going to take a lot of community effort. Mary Schmitt, Frankfort resident, is a perfect example of the community effort initiative that Mills was referring to. After attending a meeting at the township hall in Benzonia last month, she learned about the seriousness of the problem. She met the presenter, Jerry Solanics, who is another citizen police, who works with Manistee and Benzie counties on educating others about identification and how to participate in management. I appointed myself block captain Schmitt says, and I went up and down Leelanau Avenue with Jerry and knocked on doors and handed out flyers with information and photographs of the plant. Schmitt says most people know about it but don’t know what to do about it. And, she points out that some people just aren’t physically able to get out and pull it. She says she spent an afternoon with three students from Benzie High School pulling the invader from neighbors yards who weren’t able. I thanked them for taking the time to come and do this, she said, and one of the young men replied that it was better than staying home and watching.” -Great Lakes Wiki

Week 12: We’ve Smashed the Goal of 150,000 lbs… Now Let’s Party!

In Week 12, there was no letting up in the reports streaming in, eventhough we had already surpassed 100 tons last week!  Collectively across the Great Lakes Region, people have pulled and reported an astonishing 217,696 lbs of garlic mustard!

In the Cluster Competition, the Huron Arbor Cluster has solidified their lead at 53,062 lbs!  West Michigan Cluster is hanging out in 2nd place with an impressive 46,274 lbs, while the Headwaters Cluster is in 3rd with an inspiring 35,870 lbs of garlic mustard!

There is only one week left in the Stewardship Network’s 2010 Garlic Mustard Challenge!  Make sure to encourage anyone who has not yet reported to report their garlic mustard- help your Cluster finish strong! Friday, July 9th at 5:00 p.m. EST is the deadline for reports!!

Now that we have collectively pulled an insane amount of garlic mustard- let’s party! We hope you and anyone else involved in garlic mustard pulling (or anyone that just wants to come and network!) will join us for a End of Challenge Celebration and Award Ceremony!   More information below…

End of Challenge Celebration and Award Ceremony (Awarding of the Cluster Cup to the Winning Cluster!!)
When: Friday, July 9th, 2010  /  7:00 p.m. – 10:00 p.m. ish
Where: Sandhill Shelter, Lake Lansing North Park  /  Haslett, Michigan (just east of East Lansing)
It’s a potluck, so please bring a garlic mustard inspired dish to pass! (could be garlicky, mustardy, both, or actually made with some garlic mustard)
RSVP Here

Never Know What You’ll Stumble Upon When Pulling Garlic Mustard

Sometimes we can get a little caught up in our mission to rid areas of invasives, that we forget to breathe a little and see the forest for well, more than just its garlic mustard.  Susan Miller in the Raisin Cluster learned a great lesson from her experiences pulling garlic mustard… always bring along a camera!

I found this lovely little indigo bunting nest deep in the garlic mustard (in Napoleon Twp). A couple weeks before, I’d nearly tripped over a newborn fawn in the woods, while pulling GM, so I’d vowed to keep a camera in my pocket. It’s possible the chicks in the nest are cowbirds (they look big!) but I don’t really know. I left their patch of garlic mustard for cover. One of the benefits of garlic mustard pulls is the wonderful things one finds while in the woods.

Susan Miller, Private Landowner

Join Us! End of 2010 Challenge Celebration and Awarding of Cluster Cup

It’s nearing the end of the Stewardship Network’s 2010 Garlic Mustard Challenge!  Since everyone went above and beyond the call of duty and pulled over 100 tons of garlic mustard, it’s time to party!

Please join us!
End of Challenge Celebration & Awarding of the Cluster Cup
Friday, July 9th, 2010  /   7:00 p.m. – 10:00p.m. ish
Come just for some or stay for it all!
Lake Lansing North Park, Haslett, Michigan (just east of East Lansing)

RSVP Here

We hope you’lll join us! Bring a garlic mustard insprired dish to pass (garlicky, mustardy, both, or actually made from garlic mustard!), enjoy swapping tales from the field, listen in on garlic mustard presentations from researchers and land managers, groove to live percussion music from Juice, and meet others who’ve toiled all spring pulling garlic mustard just like you!  And don’t forget, we’ll be awarding the Cluster Cup to the Winning Cluster and the Mid-Michigan Cluster will be awarding their own “Golden Bag” Award! RSVP Today!

RRIP IT UP! (Rapid Response Invasive Plant Intervention Team – Upper Peninsula)

Rrrrrip it up!  This newly formed invasive task force team in Michigan’s Upper Peninsula has some big plans for removing and mapping garlic mustard in the UP.  In addition to actual on-the-ground invasive weed removal, they plan in the near future to map both infestations of garlic mustard across the peninsula and garlic mustard “free” zones.  RRIP IT UP is an effort being coordinated by the Upper Peninsula Resource Conservation and Development Council, ran as a collaborative project between a number of different organizations in the UP, and like the Stewardship Network’s 2010 Garlic Mustard Challenge, is being generously sponsored by the Sustain Our Great Lake Program.

Please click here to learn more about the Rapid Response Invasive Plant Intervention Team – Upper Peninsula!

Nearly 2 Billion Seeds Saved from Being Spread 2010 Field Season

Ok, so I want to preface this by saying, these are rough numbers, there are SO many factors and variables that would go into producing a completely accurate number.  But I just wanted to give you some scope on the difference that we are all making.  Here was my attempt at calculating just how many garlic mustard seeds we have all prevented from being spread during the 2010 Garlic Mutard Challenge so far…2,064,239,100 seeds!

That seems like an insance number, right?  Well it is!  To make this number seem even more magnanimous, imagine this-

Keep in mind that many seeds don’t even make it to seedlings or then rosettes in the first place, and only 60-90% of seedlings make it through summer droughts.  So, using conservative numbers, from what we’ve all pulled this year, we have collecitvely saved a potential 2,554,495,786,250 seeds from spreading in 2011!

Yikes, all that math is making my brain hurt!   But all of that math should make you think twice about overlooking a patch of garlic mustard or not stopping for the 2 seconds it takes to brush off your boots when entering or leaving a natural area. 

I’m usually the first one to start running the other way when the idea of math is brought up- but I really wanted to bring home the difference that we are all making! Think about the impact that your action of just pulling one stalk or just one bag or a 1/2 bag or 50 bags of garlic mustard is having on natural areas for future generations!

Week 11: Hold on to your Hats! We’re Over 100 Tons!

That’s right!  Collectively, we’ve pulled 208,509 lbs of garlic mustard! During week 11 of the Stewardship Network’s Garlic Mustard Challenge, the Southwest Corner Cluster reported nearly 10,000 lbs in just a few reports from only a handful of events- that’s a lot of pulling!!

To celebrate the end of the Challenge on July 9th, the Stewardship Network is hosting a 2010 Garlic Mustard Challenge Celebration at Lake Lansing North Park.  Join us as we award the winning Cluster with the Cluster Cup, listen in on a few garlic mustard presentations, swap field stories, listen to live music performance from Juice, and eat lots of garlic mustard inspired dishes to pass (garlicky, mustardy, both, or actually made with garlic mustard plant!).  We really hope you’ll join us!  RSVP here

Check out Cluster Competition…

“7 Man Roll”

Unfortunately there are many, many other invasive plant species out there posing similar threats to native biodiversity across the country.  I’m sure you’ve all had your fair share of struggles when it comes to removing garlic mustard from natural areas.  But, all I can say is thank goodness garlic mustard isn’t viney!

Check out this video of volunteers in Fairfax, Virginia trying to remove the invasive weed Mile-a-Minute.  Seems like the only way is to adopt the “7 man roll…”

http://www.fairfaxcounty.gov/parks/resources/ima/