Posts filed under ‘Stories from the field’
“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.”
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.
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
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
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.
“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…”
Garlic Mustard Free, It’s the Way to Be!
Last year we compiled a list of Garlic Mustard “Free” locations across the region at the end of the Challenge. These are locations that have been monitored to some extent and have been found to have zero second year garlic mustard plants! And we’re doing it again this year- tell us about your Garlic Mustard “Free” property!
During the Stewardship Network’s Garlic Mustard Challenge, one of our goals obviously was to pull 150,000 lbs of garlic mustard- and then once we shattered that goal, see just how much we could collectively pull before July 9th!
But, the goal doesn’t end at however many pounds of garlic mustard we can pull- it’s the idea that getting rid of garlic mustard makes way for the return of beloved native wildflowers and plants, brings the local ecosystem closer into balance, and increases the overall quality of the natural area for everyone.
That’s where the Garlic Mustard Free locations come in. Not only do we want to see how many pounds of garlic mustard we can collectively pull, but how many natural areas near and dear to our hearts we can win back from the clutches of garlic mustard and other invasive species. How many acres can we reclaim from the degrading biological and aesthetic effects of monocultures?
Big or small, every piece of garlic mustard ‘free’ land is another step towards brining the Great Lakes Region- and beyond- back into balance.
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Join the list below! To join the list, email the property name, approximate location (county or city), and estimated acreage to staff@stewardshipnetwork.org
Berberian Woods, Oakland County, MI (Six Rivers Regional Land Conservancy)
Bradford Dickinson White Preserve, Kent County, MI (Land Conservancy of West Michigan)
Castle Park Preserve, Allegan County, MI (Land Conservancy of West Michigan)
Coldwater River, Kent County, MI (Michigan Nature Association)
DePersia South Highlands, Ottawa County, MI (Land Conservancy of West Michigan)
Dunes Pines Nature Preserve, Allegan County, MI (Land Conservancy of West Michigan)
Frances Broehl Memorial #1, Lenawee County, MI (Michigan Nature Association)
Maas Family Nature Preserve, Kent County, MI (Land Conservancy of West Michigan)
Minnie Swarek Nature Preserve, Ottawa County, MI (Land Conservancy of West Michigan)
Prairie Ronde Savanna, St. Joseph County,MI (Michigan Nature Association)
Tippy Dam, Manistee County, MI
Trillium Ravine, Berrien County, MI (Michigan Nature Association)
Wege Natural Area, Kent County, MI (Land Conservancy of West Michigan)
Between Maple Road and Liberty Road, surrounded by Pine Lake Co-Op, Ann Arbor, MI
Garlic Mustard Competitions Across the United States
Feel isolated in your work to get rid of garlic mustard? Well you’re not!
Garlic mustard awareness is popping up all over the US, inspiring on-the-ground action and competition! If you’ve “Googled”* 2010 Garlic Mustard Challenge, you may have noticed that there are other garlic mustard pulling competitions going on in the Eastern United States not affiliated with our collaborative 2010 Stewardship Network Garlic Mustard Challenge.
The word is out on garlic mustard- people are taking action and having fun while they pull! Think about the difference these Challenges across the country are making actually on-the-ground in the natural areas where pulls are taking place and in the communities where awareness is spreading about the threat of invasive species on beloved natural areas everywhere. That’s a lot of difference!!
2010 Garlic Mustard Challenge in Maryland
Montgomery County Parks
*(for those less up to speed with new computer lingo, google (verb) = search the internet via the search engine “Google”)
The Difference Volunteer Programs Can Make
“A few days after Garlic Mustard Weed Out Day (Ann Arbor, MI), I received a call from someone who said she had never heard of that garlic plant before she volunteered with us for weed out day and had a few more questions. She said that she and her kids had a great time pulling out this plant that they now know to be a plant out of place. When they got home they realized it was all over their yard too! She put her kids to work right away to get it out of their yard. Now she has a big pile of it and doesn’t know what to do with it. Touched by the impact we had made, I gladly shared with her some different techniques for disposal.
She then said she wanted to thank us for the opportunity to volunteer and get free tickets to Disney (“Give a Day, Get a Disney Day” Program). As luck would have it, she has a friend who lives near Disney that they can stay with while they visit the park. With emotion in her voice, she explained that as a single mother of 5 kids, she would have never been able to afford to provide her children with that kind of trip without the generous offer of her friend, of Disney, and of Natural Area Preservation.”
Tina Roselle, City of Ann Arbor Natural Area Preservation
Garlic Mustard that’s too old to pull…
Wondering what garlic mustard looks like when it’s too ripe to pull? Well, City of Ann Arbor Natural Area Preservation was generous enough to provide us with some pictures of garlic mustard that is too old and ripe to pull, and should be left alone.
“Manchester residents work to put squeeze on garlic mustard”
By Stacy Laskovich Swann
Jackson News
The Latest Community, Education, & Governemnt News, Blogs, Photos, and Videos
May 24, 2010, 12:05PM
It’s an invasive plant that prevents the growth of wildflowers, saplings and other plant species.
It has white flowers with four petals that form a cross.
Its thicket of doom can wreak havoc on land everywhere.
Manchester residents are joining the fight against the persistent weeds called garlic mustard.
The weeds choke out native wildflowers, taking over space and sunlight. They also excrete chemicals through their roots, further preventing wildflower growth. Sapling growth is similarly limited by crops of garlic mustard.
The Sharon Hills preserve in Manchester has been particularly hit hard by the plant, and while the early spring has caused the garlic mustard to seed and flower earlier than usual, the often inclement weather has thwarted volunteer pull efforts.
Volunteers are encouraged to look at pictures of garlic mustard before pulling if they are not familiar with the plant. More information about invasive plant life and the Garlic Mustard Challenge 2010 can be found at www.stewardshipnetwork.org or by calling the Legacy Land Conservancy, which serves Jackson and Washtenaw counties, at 734-302-LAND (5263).
“We have a lot of work left to do at Sharon Hills,” said Suzie Heiney, communications and development director for the Legacy Land Conservancy in Ann Arbor. Only Heiney and one other volunteer showed up for a pull at Sharon Hills earlier this month on a day that was cold and rainy.
“It was still very worthwhile,” Heiney said. “We focused on areas that are cleaner so that the garlic mustard does not spread to any endangered plant life in the preserve.”
The Stewardship Network serves as a connection between preservation groups and helps put out the call for volunteers, filling in gaps where help is needed.
Their Garlic Mustard Challenge encourages people to collaboratively remove, or pull, at least 100,000 pounds of garlic mustard between mid-April and mid-June. Groups can report the number and size of their bags by visiting www.stewardshipnetwork.org and clicking on Garlic Mustard Challenge 2010. As of mid-May, 65,647 pounds have been reported.
The website warns groups to use their best judgment when tackling garlic mustard plants.
Because of the early spring, plants have been flowering early and will go to seed earlier than usual. When garlic mustard dries, the seeds begin to pop when pulled, and that can do more harm than good.
“Garlic mustard seeds love disturbed soil,” Heiney said. So the more the grounds are flooded or hiked on, the easier it is for the plant to spread.
Continued volunteer efforts are encouraged and appreciated, especially at the Sharon Hills Preserve in Manchester, Heiney said.
“If people live nearby and are interested, we would love to have them come out and help,” Heiney said.
