Monday, October 17, 2011

"Non-invasive" cultivar? Buyer beware

October 2011 Issue of BioScience

Read the full article (PDF)

Cultivars of popular ornamental woody plants that are being sold in theUnited States as non-invasive are probably anything but, according to an analysis by botanical researchers published in the October issue of BioScience. Tiffany M. Knight of Washington University in St. Louis, Missouri, and her coauthors at the Chicago Botanic Garden write that the claims of environmental safety are in most cases based on misleading demographic evidence that greatly underestimates the plants' invasive potential. What is more, the offspring of cultivars do not usually "breed true" and may be more fecund than their parents, especially if they cross with plants from nearby feral populations.

Many invasive plants were once ornamental cultivars, because the characteristics that the "green" industry looks for are the same ones that make a plant potentially invasive-being adaptable to wide range of conditions, forming dense stands good for erosion control, and having a long flowering period, for example. In recent years the nursery and horticultural industries have responded by creating cultivars of top-selling plants that produce reduced numbers of viable seed and are advertized as "safe to natural areas." Such cultivars of Japanese barberry, buckthorn, and burning bush are now widely sold, as they avoid bans on growing invasive species.

Yet simple population modeling demonstrates that reductions of even 95 percent in the number of viable seed will leave a long-lived species quite capable of spreading-and many of the new cultivars do not achieve even that much of a reduction. More sophisticated modeling would likely reveal even stronger invasive potential of the "safe" cultivars. Knight and her coauthors conclude that only completely sterile cultivars can be consideredtruly safe without further testing, and that other types should be tested for breeding true and having a low growth rate before they are sold as non-invasive.

Thursday, October 13, 2011

Citizens for Conservation - Invasive Species Flyers

The Citizens for Conservation Community Education Committee has produced several great lfyers on invasive species. You can find links to these flyers at:

Northeast Illinois Invasive Plant Partnership Helps Communities with Invasive Plants

Original article found at:

Northeast Illinois Invasive Plant Partnership Helps Communities with Invasive Plants

By Cathy McGlynn

Regional Invasive Plant Organization Celebrates Anniversary

Glencoe, IL (October 11, 2011) – A newly established regional organization recently celebrated its one year anniversary. Partners in the Northeast Illinois Invasive Plant Partnership (NIIPP) prevent and detect new invasions, control and manage existing invasive plants, and educate people about how to reduce intentional introductions and unintentional transport of invasive plants. The first annual meeting took place in September at the Morton Arboretum.
“NIIPP has fostered collaborations among organizations that have not worked together before and will continue to develop relationships that will promote control and management of invasive plants on both sides of property boundaries.” Cathy McGlynn, Coordinator, Northeast Illinois Invasive Plants Partnership

At the meeting, Illinois Department of Transportation District 1 presented its plan for coordinated control and management of invasive plants in rights of way and the Illinois Department of Natural Resources provided information about its new Conservation Corps. These and additional presentations can be found at
NIIPP works in conjunction with the New Invaders Watch Program (NIWP), an early detection and rapid response program that trains natural areas managers, volunteer stewards, and other interested people to identify twenty-one invasive plants that are currently rare in this region ( Many of these trainees register to become monitors for NIWP and report populations of new invaders so that landowners can be made aware of potential invaders in the vicinity of their properties. Since the beginning of this program in 2003 more than 1500 people have been trained. NIIPP also works with River to River CWMA ( to send out statewide alerts about the arrival of new invaders and most recently sent out an alert about Japanese Stiltgrass (Microstegium vimineum), a recent arrival to the Northeastern Illinois region

In addition to NIWP trainings in the natural resource community, NIIPP is collaborating on several outreach and education programs about more established invaders as well as aquatic and ornamental invasive species. In May of this year 18 NIIPP partners organized more than 31 garlic mustard pulls as part of the US Forest Service Garlic Mustard Challenge and handily won the challenge by pulling 52,000 lbs. of garlic mustard and raising public awareness about invasive plants during Illinois Invasive Species Awareness Month. In addition, IL-IN Sea Grant and NIIPP are working to develop and establish a statewide Clean Boats, Clean Waters program ( that educates boaters, anglers, and recreational watercraft users about aquatic invasive species and how not unintentionally transport them from water body to water body. The Midwest Invasive Plant Network, Chicago Botanic Garden, The Nature Conservancy, Chicago Department of the Environment, and NIIPP are collaborating on an education and outreach campaign about intentional introductions of ornamental plants that have the potential to escape from landscaped areas and invade natural areas. Our target audience is green industry (garden centers and nurseries) and its consumers. Development of the program will begin this fall.

The Northeast Illinois Invasive Plant Partnership intends to work toward the prevention and control of new plant invasions, control and manage current invasions, support informed management decisions, and raise public awareness concerning the threat posed by invasive plants. NIIPP’s goal is to minimize the adverse impacts invasive plants have on our open lands and waters in northeast Illinois, especially on native habitats and their native plants and wildlife. NIIPP is poised to expand the reach of its efforts in the coming year, bringing a regional plan to fruition.

Eight years ago the idea of a regional cooperative weed management area started to take form in the minds of natural areas managers in Northeast Illinois. In 2010, as a result of federal funding from the Great Lakes Restoration Initiative, the Northeast Illinois Invasive Plant Partnership (NIIPP) began, turning a regional coordinated effort to address the issue of invasive plants into a reality. The plan for regional cooperative weed management areas (CWMAs) first began in the Western United States. CWMAs are local organizations that integrate all invasive plant management resources across jurisdictional boundaries in order to benefit entire communities. In the case of NIIPP, our partners are all interested landowners, land managers (private, city, county, state, and federal), non-profits, private entities, industry, special districts, and the public in the Northeast Illinois. During the past year we have been joined by 46 partners including the United States Forest Service, Illinois Department of Natural Resources, Illinois Department of Transportation District 1, Fermilab Natural Areas, Forest Preserve Districts of Boone County, DuPage County, Kendall County, Lake County, Will County, and Winnebago County; Villages of Algonquin, Lincolnshire, and Glenview; Midwest Groundcovers, LLC., Integrated Lakes Management, and Tallgrass Restoration. These and many other partners have been instrumental in our success this year. They have controlled and managed thousands of acres of invasive plants and restored many native habitats. And they will continue their efforts to protect and preserve native biodiversity and habitats.To learn more about NIIPP please visit our website at

Friday, October 7, 2011

New kudzu identification guide from Illinois DNR

The Illinois Department of Natural Resources recently published an identification guide to kudzu. This full color guide gives descriptions and photographs of both kudzu and potential look-a-likes. You can find an electronic version of the guide on the CWMA's website at:

Wednesday, October 5, 2011

New invasive species videos from the National Park Service

As part of the Great Lakes Restoration, the National Parks Service created four short 5 minute videos discussing the impact of invasive species on people and communities as well as what the general public can do to prevent their spread.
Although set in the national parks they are useful to anyone in an educational setting.

LITTLE THINGS big problems -- Emerald Ash Borer

LITTLE THINGS big problems -- Spotted Knapweed

LITTLE THINGS big problems -- Invasive Plants In Our Parks

LITTLE THINGS big problems -- Aquatic Invaders

Monday, October 3, 2011

Two recent stories on ecosystem impacts of invasion

Two recent stories surfaced about invasive plants and how far reaching their impacts on ecosystems can be.

The first story comes from a recent journal article by Watling et al. In this article, the researchers were looking at bush honeysuckle and how invasions lead to a decrease in amphibian diversity (both richness and eveness). Basically what happened was the slightly cooler temperatures under the honeysuckle lead to the native green frog flourishing, which it then was able to outcompete the other native amphibians, leading to domianance by one species and lower diversity overall. You can find their research in Biological Conservation.

The second story came from NPR's 'Living on Earth' series and it was about invasive plants in Montana's grasslands. The stiff thatch of the invaders, such as spotted knapweed and leafy spurge, has provided structure for a couple of native spiders to build more and larger webs than they would be able to in native prairie. This has led to more insect prey being caught, allowing the spiders to reproduce more and thus build more webs and feed on more insects. They sum up their point very well by saying "The native spiders are thriving because of the new exotic plants. They can eat more insects, and these insects can then no longer keep the growth of certain plants in check, and on and on. You alter one piece of the ecosystem, and the whole web changes." You can read the transcript or listen to the audio of the story on the Living on Earth website .

Both of these stories really do illustrate a point that is often overlooked when considering invasive plants. Their presence in a new environment can have impacts that are unforseen and not restricted to direct competitors. With a cursory glance, one might even think these invaders are having a positive impact on their surroundings (both situations lead to an increase in the populations of native species), but a closer look reveals their ability to throw things out of balance and faciliitate a larger-scale collapse in diversity. I think the authors of the honeysuckle article put it best when they labelled honeysuckle as having the ability to be an "Invasive Ecosystem Engineer", which they describe in the below excerpt:

"Invasive species can have far-reaching impacts on ecosystems. Although some invasive species interact with native taxa primarily through one or few biotic or abiotic pathways (e.g., competition, allelopathy), habitat-forming invasive species may act as ecosystem engineers with the potential to affect many organisms through multiple different pathways. Although the impacts of invasive species are often framed in terms of trophic interactions between organisms (e.g., species that interact as competitors or as predators and prey), an emerging perspective emphasizes the ability of invasive plants to change habitat structure or quality, i.e., to act as ecosystem engineers. Invasive ecosystem engineers may have widespread effects on native species that do not directly consume or compete with the invader. Identifying these non-trophic effects is important because they may be pervasive, yet cryptic consequences of invasion, especially given the extensive realized and potential distribution of many species in invaded landscapes."