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Emerging Issues Surrounding Invasion and Control of Phragmites australis in Wisconsinís Wetlands:
A Survey of Wetland Professionals
Click here for printable PDF version
Phragmites australis, a relatively new invader of Wisconsinís wetlands, is rapidly expanding its range in Wisconsin to the detriment of native wetland communities. Many wetland managers, restoration practitioners, researchers and other wetland professionals in Wisconsin and the Great Lakes region have knowledge about Phragmites invasion and control through on-the-ground experience. However, much of this knowledge has not been published, and thus far there has not been a means to make this collective Phragmites expertise available such that wetland professionals can build on the experience of others in the wetland community.
Wisconsin Wetlands Association has begun to address this need by surveying wetland professionals in Wisconsin. In 2004, WWA coordinated a written survey of wetland professionals about Phragmites invasion and control, and also coordinated a Phragmites working group at its January 2005 Wetland Science Forum. More than 35 wetland professionals participated in these discussions (click here for a graph showing types of professionals who participated). Discussions focused on Phragmites topics such as monitoring and mapping; prevention, early detection and rapid response; native versus non-native populations, competition with natives and other invasive plants, and control techniques.
This webpage is a compilation of contributions of Phragmites experience and informal insights made by wetland professionals through our written survey and working group discussion. Contributions are organized by topic and include observations, research needs, and opinions regarding priorities for dealing with Phragmites in Wisconsinís wetlands. WWA encourages wetland researchers, consultants, land managers and others working in wetlands to continue to share the results of new Phragmites work with us and the rest of the wetland community. The goal of this working document is to provide a means for Phragmites information exchange that allows wetland professionals to learn from and build upon one anotherís on-the-ground experience battling Phragmites in Wisconsinís wetlands.
| Acknowledgements: Thanks to all of the wetland professionals who contributed to this effort (click here for a list of participants). Special thanks to Kelly Kearns for advising on the survey development and facilitating the working group discussion. Finally, thank you to Wisconsin Coastal Management Program and National Oceanic and Atmospheric Administration for grant funds that supported this project. || |
Please note that the information submitted by wetland professionals and compiled below has not been confirmed by Wisconsin Wetlands Association. This is intended as a working document and will be continually updated with new Phragmites information as it is submitted by wetland professionals.
PHRAGMITES INVASION ECOLOGY
Observations - Invasion Ecology
Research Needs - Invasion Ecology
- In Wisconsin, Phragmites is most commonly found in disturbed areas with altered hydrology or sedimentation such as roadside ditches, wetlands downhill from active farm fields, and farmed wetlands that have been left fallow.
- Phragmites is now also being observed in interior wetlands in Wisconsin (not just roadside ditches, powerline cuts, etc.). It is not clear how it is spreading to sites that are not obviously disturbed.
- While Phragmites usually grows in sunny, open areas, it has been observed growing in the shade (e.g. Ridges Sanctuary).
- Low water levels in Lake Michigan have facilitated invasion along the shoreline of Green Bay.
- At Ridges Sanctuary, Phragmites has not spread rapidly into thick monotypic cattail stands. However, when water levels are down, Phragmites has slowly started to spread into areas where cattail organics have accumulated.
- Phragmites spreads rapidly on exposed, moist soils, but does not appear to spread readily on sites that have dense, established vegetation.
- Phragmites exhibits different growth patterns/forms in different areas (circular clumps of stems versus scattered stems).
- Phragmites is still intentionally planted for boat covers and wildlife cover (some nurseries still recommend it).
- In some areas, duck hunters transplant Phragmites for duck blinds (largely in September).
- In calcareous fens and sedge meadows of the Lower Minnesota River valley, Phragmites poses a greater threat than either reed canary grass or purple loosestrife. Unlike other invaders, Phragmites does not require soil disturbance to invade and dominate fen and sedge meadow communities. It spreads rapidly via rhizomes and chokes out 95 percent of fen and sedge meadow species over the course of a 5- to 10- year period. The loss of calcareous fen species includes threatened and special concern species such as white ladyís slippers and common valerian. None of the MN-listed species persist once a canopy of Phragmites develops.
- Some municipal reed bed systems in Wisconsin still use non-native Phragmites to dewater sewage sludge. Permits for these facilities require monitoring and safeguards to minimize the chance of spread. WDNR would like to get native ecotype rootstock propagated for use in these beds, but currently native stock is not available in sufficient quantities to require its use. The DNR staff who permit these systems and the company that installs them are open to ideas on ways to safeguard against Phragmites spread from municipal reed bed sites.
- Survey Result: Only 3/4 of survey participants were aware of the fact that Phragmites is being used by municpal water treatment facilities to dewater sewage slude.
- What are the most common vectors for the spread of Phragmites?
- How does Phragmites spread to interior wetlands where there is no obvious disturbance such as roads, powerline cuts, etc.?
- Under what conditions does Phragmites invade most aggressively? Under what conditions is it not as successful?
- Does road salt runoff facilitate the spread of Phragmites along roadside corridors?
- Does roadside mowing exacerbate the spread of Phragmites?
- What conditions determine the growth pattern/form that Phragmites will take (e.g. circular clumps of stems versus scattered stems) at a given infestation site?
- How long do Phragmites seeds remain viable in the seed bank?
- Under what conditions does Phragmites reproduce vegetatively versus through seed germination?
MONITORING AND MAPPING
Resources - Monitoring and Mapping
Observations - Monitoring and Mapping
- Great Lakes Indian Fish and Wildlife Commission (GLIFWC) maintains an online GIS-database of all invasive plant species in the region. GLIFWC is willing to receive and post submissions of monitoring data for Phragmites or other invasives. Submission of invasives monitoring data should include location, size of stand (acres), density of stems (optional) and information about ownership of the land.
- Phragmites voucher specimens may be sent to the herbarium at UW-Madison or UW-Stevens Point.
Research Needs - Monitoring and Mapping
- Click here for a graph of the types of monitoring data that wetland professionals are collecting.
- In Door County, Phragmites has been observed growing in a variety of wetland types including bedrock beaches, swales at the Ridges Sanctuary, sand beaches, sedge meadows, exposed lake bed when Lake Michigan water levels dropped, bog communities, shallow marshes, roadsides, and stream banks. Some Phragmites mapping work for Door County has been completed by Gary Fewless and colleagues at UW-Green Bay.
- Steve Eggers (U.S. Army Corps of Engineers) has monitored the rate of Phragmites invasion into a calcareous fen plant community in MN (Savage Fen Scientific and Natural Area, Dakota County) using both on-the-ground surveys and interpretation of aerial photography from the 1930s to present day. The ground survey consisted of a baseline established in 1992 at the edge of a Phragmites colony and calcareous fen community. On an annual basis, he has monitored the rate (distance) and number of new Phragmites plants that have spread into the calcareous fen community.
- Wisconsin Wetlands Association involved citizen volunteers in surveying invasive plants in wetlands in 2002 & 2003. While many volunteers conducted purple loosestrife surveys (data are posted on the GLIFWC website mentioned above), few collected Phragmites survey data for reasons unknown.
- Jim Meeker (Edgewood College) is monitoring Phragmites populations in Bark Bay Slough, Lake Superior.
- Other reported Phragmites monitoring locations include: Bay Beach Wildlife Sanctuary (Brown Co.), Merrimac Preserve (Sauk Co), southwest portion of Green Bay shoreline, Savage Fen Scientific and Natural Area (Dakota Co., MN), mitigation sites in northeast Chicago and northwest Indiana, and aerial surveys of Lake Co., IL.
Opinions/Priorities - Monitoring and Mapping
- Can Phragmites be identified and mapped using remote sensing techniques (aerial photos or satellite imagery)?
- Click here for a graph of monitoring priorities suggested by survey participants.
- In Door County and Green Bay, Phragmites invasion is so extensive that resources should be focused on control efforts rather than monitoring and mapping.
- The wetland community is on the cusp of public understanding and support for Phragmites prevention and control. Shoreline landowners are having such difficulty with Phragmites infestations on their properties that they are starting to seek help with their control efforts. The wetland community needs to continue to inform landowners and prepare them to watch for new infestations.
NATIVE VERSUS NON-NATIVE POPULATIONS
Resources - Native vs. Non-native Populations
Observations - Native vs. Non-native Populations
- Online Morphological Key: Use this key to distinguish native from non-native Phragmites (provided by the Ecology and Management of Invasive Plants Program, Cornell University)
- Phragmites Diagnostic Service: Submit your specimen for identification as native or non-native (provided by the Ecology and Management of Invasive Plants Program, Cornell University)
Research Needs - Native vs. Non-native Populations
- Native Phragmites stands don't expand as quickly as non-native stands.
- Native Phragmites stands are typically less dense than non-native stands and have been observed growing mixed with sedge meadow species.
- Native Phragmites grows in drier conditions than non-native.
- Native stands and non-native stands of Phragmites can grow side by side. Some wetland professionals have observed Phragmites populations with native characteristics on the invasion front and non-native characteristics in the interior of the stand.
- Non-native Phragmites has greater seed germination rates than native Phragmites.
- Non-native Phragmites is harder to control with herbicide than native Phragmites, possibly because it has longer rhizomes.
- Ridges Sanctuary is working to eliminate both native and non-native Phragmites.
Opinions/Priorities - Native vs. Non-native Populations
- Do native and non-native Phragmites exhibit different allelopathic effects?
- What is the most accurate yet straightforward field indicator test to distinguish native from non-native Phragmites (for use by both conservation professionals and the general public)?
- Wetland professionals have experienced mixed success using the morphologic key to distinguish native and non-native Phragmites. Because of the potential for hybridization, some wetland professionals question whether morphologic characters can provide accurate identification.
- Wetland managers should eliminate both non-native and native Phragmites stands if enough resources are available. When resources are limiting, control efforts should focus on non-native stands.
- The state should identify and maintain stocks of native Phragmites genotypes for research purposes.
- The state should locate native Phragmites populations that can be used as a reed source for municipal reed bed systems for dewatering sewage sludge (current stock is non-native and is brought to Wisconsin from the east coast).
COMPETITION WITH NATIVES AND OTHER INVASIVES
Observations - Competition
Research Needs - Competition
- Phragmites can outcompete purple loosestrife when water levels change.
- Phragmites has outcompeted purple loosestrife in roadsides around Green Bay. Tower Bridge Drive was formerly surrounded by purple loosestrife, but this area is now infested with dense stands of Phragmites.
- Native Phragmites may outcompete reed canary grass in drier conditions.
- Phragmites has been observed spreading into infestations of reed canary grass.
- At Ridges Sanctuary in Door County, Phragmites has not spread rapidly into areas with thick monotypic cattail stands.
- At some sites where Phragmites control measures have been successful, jewelweed has replaced Phragmites.
- How does Phragmites alter its environment and what are the effects of such alterations on native plants?
Observations on Effectiveness of Herbicides
NOTE: Chemical control of aquatic plants requires a permit from WDNR. To learn more about Wisconsin's Aquatic Plant Management and Protection Program and permit requirements, visit WDNR's website.
Observations on Effectiveness of Other Control Techniques
- Click here for a graph of herbicides employed by survey participants.
- In general, late summer application of herbicides is most effective at killing Phragmites plants because this is when fluids flow down plant stems to their roots.
- HABITAT: The new herbicide Habitat seems expensive at about $700 for 2.5 gallons, but it is highly concentrated (2.5 gal is about 1000 gal once mixed). Mark Martin (WDNR) conducted test sprays of Habitat at Pickerel Pond in 2004 and will assess the results in 2005 in acre-sized test plots.
- RODEO-Cut Stem Treatment: Rodeo has been very effective in Phragmites control at some sites when applied as a cut stem herbicide. Mark Martin (WDNR) has had success controlling Phragmites by treating stems with Rodeo in August (bundle, cut, and dab stems with herbicide). This technique was about 98% effective in the first year and remaining stems were eliminated in the second year.
- RODEO-Foliar Treatment: Rodeo wicked on leaves was 99% effective at one control site. Additional treatment was necessary after several years when Phragmites began to recover.
- VANTAGE: Some wetland professionals report little success with the herbicide Vantage as a Phragmites control treatment.
Research Needs/Future Research - Control Techniques
- Click here for a graph of control methods employed by survey participants.
- PLASTIC COVERING: Phragmites control on a small scale was achieved at Ridges Sanctuary by covering a stand with black plastic. The plastic had to be weighted down and thick so that Phragmites shoots would not lift up or poke through the plastic.
- BURNING: Andy Nelson (Northern Environmental) has had success with burning Phragmites in part because the native plant community was stimulated at control sites.
- BURNING: Wetland professionals report that burning as a Phragmites control technique is generally ineffective unless combined with other control techniques. For example, herbicide application in the fall followed by burning in the spring has been effective at some sites.
- MOWING: Frequent mowing of the beach at Baileys Harbor in Door County successfully eliminated Phragmites, but this control technique also adversely affects many other wetland species.
- EXCAVATION: Art Kitchen (USFWS) has successfully used excavation as a control technique. Phragmites root systems were excavated to a depth of at least 1 ft and buried in a ditch 4 ft deep. Though this technique was successful, it is also expensive.
- COMBO: A combination of multiple mowings and Round Up sprayings was successful at Ridges Sanctuary only when the area was quickly tilled and resown with replacement species (cover crop of annual rye and prairie mix).
- COMBO: A combination of herbicide spraying (late summer), burning (mid to late fall), and spraying again and overseeding with native species (the following growing season) was reported as successful at one Phragmites control site.
- COMBO: Cut stem herbicide application followed by burning has been reported as successful in the first 1-2 years of treatment.
Opinions/Priorities - Control Techniques
- Under what conditions (water level, season, etc.) are various control techniques and combinations of techniques effective? How does one select control technique(s) given particular site-specific conditions?
- What combinations of control techniques are effective?
- Can flooding be effective as a control measure? The Nature Conservancy plans to experiment with flooding as a control technique in Carlsville (Door County).
- Can burning be used as an effective management technique?
- Can consistent mowing be used as an effective management technique?
- Could altering ditch mowing/cleaning techniques help control and prevent the spread of roadside Phragmites populations?
- Is there a safe and effective and safe biocontrol agent for Phragmites?
- What is the relative effectiveness of different herbicides that do not impact sedges and forbs (grass-specific herbicides)?
- Along coastal shorelines, efforts to eliminate Phragmites should include plans for replacing the erosion control function that Phragmites stands currently provide.
- At sites where the native seed bank is lacking, efforts to eliminate Phragmites should include plans for reestablishment of native plant communities to prevent other invasive plant species from taking over.
WETLAND CONSULTANTS WITH PHRAGMITES EXPERTISE
Looking to hire a professional to assist with a Phragmites control project? Below is a list of firms that offer invasive plant control services with expertise in Phragmites control. Please note that these listings do not equate to WWA endorsements of particular firms. We recommend that you ask for references and information on Phragmites projects completed by firms under your consideration.
Does your firm offer invasive plant control services with expertise in Phragmites control techniques? WWA will maintain a list of consultant contacts here to connect those in need of such services with experienced professionals. To have your firm listed, email WWA at programs [at] wisconsinwetlands.org.
NEW SUBMISSIONS OF PHRAGMITES INFORMATION
Are you conducting research on Phragmites? Experimenting with different Phragmites control techniques on your property? Conducting wetland restoration on a site infested with Phragmites? If you have gained on-the-ground experience with Phragmites, please consider sharing what you have learned with the wetland community by submitting information for inclusion on this webpage. Simply complete the form below and email it to WWA at programs [at] wisconsinwetlands.org.
PHRAGMITES FIELD GUIDE
Do you need assistance with identifying Phragmites in the field and with distinguishing native from non-native strains? Wisconsin Wetlands Association has produced a Phragmites field guide brochure that includes photos and descriptions of key identification characters. Order copies of Wisconsin Wetlands Association's Phragmites field guide brochure by emailing or calling WWA (608-250-9971).
ONLINE PHRAGMITES RESOURCES
- Upper Green Bay River Basin Partnership Team's Phragmites webpages
- Common Reed (Phragmites australis) Response to Mowing and Herbicide Application. Jeffrey Derr. Invasive Plant Science and Management, 2008 1:12-16.
- The Michigan Landowners' Guide to Phragmites Control
- Ducks Unlimited guide book on the control and management of invasive phragmites Phragmites
- Presentation on identification of native and non-native Phragmites developed by Plant Conservation Alliance
- Ecology and Management of Invasive Plants Program, Cornell University (includes a morphological key for distinguishing native vs. non-native Phragmites)
- Recent Research on Phragmites australis in North America: Implications for Management. Proceedings of the Aquatic Invaders of the Delaware Estuary Symposium, Malvern, Pennsylvania, May 20, 2003, pp. 12-15.
- Bibliography of Phragmites References by the Cooperative Wildlife Research Laboratory of Southern Illinois University
- Global Invasive Species Database
- The Nature Conservancyís Invasive Species Initiative
- Natural Resources Conservation Serviceís Invasive Plants Profile
- UW Green Bay Herbarium
- Cryptic invasion by a non-native genotype of the common reed, Phragmites australis, into North America (PDF download). 2002. Kristin Saltonstall. Proceedings of the National Academy of Sciences: 99(4): 2445-2449
- WI DNRís Non-native plants webpages
- Research at University of Delaware on Phragmites control by genetically engineering native species to be "Phragmites blockers"
- New Phragmites research at the University Laval in Quebec including a paper on the role of seed dispersal in Phragmites invasion
- Seasonal Abundance and Species Richness of Birds in Common Reed Habitats in Lake Erie by Meyer et al (2010) in the Journal of Wildlife Management that recommends restoration of meadow marsh habitat through reduction of Phragmites in Great Lakes wetlands where providing habitat for breeding marsh-nesting birds is an objective.
- Great Lakes Phragmites Collaborative, established to facilitate communication among stakeholders across the region and to serve as a resource center for information on Phragmites biology, management and research.
GRAPHS OF SURVEY RESULTS
View tallied results from a subset of the Phragmites survey questions below.
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