Phragmites workshop



AGENDA

Phragmites Workshop

Cornell University, Ithaca, New York

Date: October 15-16, 2007

Location: Auditorium,

Boyce Thompson Institute, Tower Road,

Cornell Campus, Ithaca NY 14853

15 October 2007

9:00AM Registration opens

9:15AM Welcome, logistics, opening remarks

Bernd Blossey, Cornell University

Session 1: History of invasion and control of invasive Phragmites

9:30AM Arrival and spread of invasive Phragmites in North America: Piecing together past and present distributions

Bernd Blossey, Department of Natural Resources, Cornell University

10:00AM The spread of the exotic genotype of common reed in Québec: a biogeographical and genetic study

Claude Lavoie1, François Belzile2, Benjamin Lelong1, Yvon Jodoin1, Marie-Claire LeBlanc1, Julie Labbé1 and Sylvie de Blois3

1 Centre de recherché en aménagement et développement, Université de Laval, Quebec

2 Departement de phytologie, Université de Laval, Quebec

3 Plant Science Department, McGill University, Montreal, QC and McGill School of Environment, McGill University, Montreal, QC

10:30AM A history of dealing with invasive and native Phragmites on National Wildlife Refuges

Joseph McCauley, US Fish and Wildlife Service, Rappahannock NWR, Virginia

11:00AM The Use of GIS in a Phragmites Control Project on Private Lands around Back Bay, Virginia

Dorie S. Stolley, U.S. Fish and Wildlife Service, Back Bay National Wildlife Refuge

11:15AM The Montezuma National Wildlife Refuge: From purple loosestrife to Phragmites management

Tom Jasikoff and Linda Ziemba, Montezuma NWR, Seneca Falls, NY

11:30AM Distributional patterns of native and introduced populations of Phragmites in mid-atlantic tidal marshes with landscape implications for their management.

Robert Meadows, Delaware Division of Fish & Wildlife, Newark, DE 19702

11:45PM Phragmites management on transportation corridors: A Brighter Future?

Kyle Williams, Ed Frantz, NY DOT, Albany, NY

12:15PM Lunch break

1:30PM Native and introduced Phragmites in WA state: an approach to area wide management

Greg Haubrich, Washington State Department of Agriculture, Yakima, WA 1:30PM

2:00PM Managing Phragmites australis in Virginia

Paul Clarke and Rick Myers, Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond, VA

2:30PM Test applications of habitat and renovate herbicides for Phragmites control

Glenn Sullivan1 and Steven Wilson1, 1 Allied Biological Inc. Hackettstown, NJ

3:00PM Outreach, education, and treatment: a community-wide Phragmites control program. A video presentation and discussion of issues related to control and protection of Phragmites on Beaver Island, MI.

Barbara Lucas, the Beaver Island Association

3:30PM Planting of native woody plants as a technique for controlling and replacing Phragmites

Michael D. Byer, Gateway National Recreation Area, U. S. National Park Service

4:00PM Coffee break

Session 2: Impacts of Phragmites spp. on native organisms

4:30PM Phragmites australis dynamics in invasion corridors and wetlands

Sylvie de Blois1,2, Karyne Benjamin1, Mathieu Maheu-Giroux1, and Jacques Brisson3

1 Plant Science Department, McGill University, Montreal, QC

2 McGill School of Environment, McGill University, Montreal, QC

3 Université de Montréal, Institut de recherche en biologie végétale, Montreal, QC

5:00PM Interspecific competition between common reed and cattails

Jaques Brisson, Marie-Éve Bellavance, Étienne Paradis and Bastien Fontaine, Institut de recherche en biologie végétale, Université de Montréal, Montreal, QC

5:30PM adjourn

6:30PM Dinner on your own at local restaurants or as groups

16 October 2006

Session 2: Impacts of Phragmites spp. on native organisms (continued)

8:30AM Impact of native and introduced Phragmites on amphibians

Jillian Cohen1, John Maerz 1,2, and Bernd Blossey1,

1 Department of Natural Resources, Cornell University

2 Warnell School of Forestry, University of Georgia, Athens, GA

Session 3: Biology and ecology of native and introduced Phragmites haplotypes

9:00AM Sexual Reproduction in non-native common reed, Phragmites australis

Amy Campbell, The Ohio State University, Dept. of Evolution, Ecology and Organismal Biology, Columbus, OH 43210

9:30AM Phenology of native and introduced Phragmites haplotypes

Mia Park and Bernd Blossey, Department of Natural Resources, Cornell University

10:00 Coffee break

10:30PM Photosynthetic differences between native and non-native Phragmites australis haplotypes

Tom Mozdzer and Joseph Zieman, Department of Environmental Sciences, University of Virginia, Charlottesville, VA

11:000AM Comparative physiological ecology of native and introduced Phragmites

Australis: Previous and proposed work to identify traits associated with

invasions

Eric Hazelton, University of Southern ME

11:30AM Evidence for intraspecific hybridization of native and introduced subspecies of Phragmites australis in North America

Laura Meyerson and Emma White, Natural Resources Science, University of Rhode Island, Kingston, RI 02881

12:00PM Lunch break

1:00PM Indirect effects of North American herbivores on native and exotic Phragmites interactions

Adam Lambert1 and Richard Casagrande2

1 University of California, Eastern CT State University

2 Plant Sciences Department University of RI

Session 4: Development of biological control of Phragmites spp.

1:15PM A history of Phragmites biocontrol efforts

Richard Casagrande1, Bernd Blossey2, Lisa Tewksbury1 and Patrick Häfliger3,

1 Department of Plant Sciences, University of Rhode Island, Kingston, RI

2 Department of Natural Resources, Cornell University

3 CABI Europe-Switzerland, Delémont, Switzerland

1:45PM Phragmites biocontrol research in Europe: candidates, their ecology and impact

Patrick Häfliger, CABI Europe-Switzerland, Delémont, Switzerland

2:15AM Current proposed host specificity test plant list

Lisa Tewksbury, Department of Plant Sciences, University of Rhode Island, Kingston, RI

2:45PM Planned steps in the development of biological control in North America

Bernd Blossey, Cornell University

3:00PM Discussion: Phragmites biocontrol : a bright future or a scary scenario?

Questions to address:

How do we treat hybrids?

How much host specificity is sufficient?

How to deal with uncertainty?

Can an endangered species status of native Phragmites be anticipated?

Is the no-action scenario (retain status quo) acceptable?

Other research needs, monitoring protocols?

5:00PM Adjourn

Arrival and spread of invasive Phragmites in North America: Piecing together past and present distributions

Bernd Blossey, Department of Natural Resources, Cornell University

Abstract: Evidence from sloth diet and sediment cores suggests that the genus Phragmites has been present in North America for thousands of years. The arrival of European genotypes, first chronicled by Kristin Saltonstall in her seminal paper, has changed the abundance and distribution of the species in North America dramatically. Range expansions into the previously Phragmites-free southeast, and into new habitats not previously occupied by native Phragmites coincide with replacement of native stands by the introduced more competitive haplotype. At present, introduced Phragmites occurs throughout much of the US and southern Canada with the largest populations and most frequent occurrences in the East. Extensive introduced populations also occur in the Pacific Northwest and certain interior drainages (such as the Platte River in NE) but much of the Midwest shows a mix of native and introduced populations. Native population show genetic substructuring and have distinct regional morphological differences, while the introduced haplotype is morphologically identical across the North American range.

The spread of the exotic genotype of common reed in Québec: a Biogeographical and genetic study

Claude Lavoie1, François Belzile2, Benjamin Lelong1, Yvon Jodoin1, Marie-Claire LeBlanc1, Julie Labbé1 and Sylvie de Blois3.

1Centre de recherche en aménagement et développement or 2Département de phytologie, Université Laval, Québec, Québec, G1K 7P4, Canada ; 3Departement of Plant Science and School of Environment, McGill University, 21,111 Lakeshore, Sainte-Anne-de-Bellevue, Québec, H9X 3V9, Canada.

Corresponding Author : claude.lavoie@esad.ulaval.ca

Abstract: We reconstructed the spread of the common reed (Phragmites australis) in Québec, where large-scale invasion of this plant species has been reported since the 1960’s. For this reconstruction, we used historical data (herbarium specimens, aerial photographs) and conducted large-scale surveys along roads and rivers. All specimens were genetically differentiated using molecular tools to identify the genotype (native or exotic). The exotic genotype (haplotype M) has been present in Québec since at least 1916, but it was rare prior to the 1970’s. The exotic genotype spread inland only after the beginning of the 1970’s. In less than 20 years, a complete shift occurred, from the dominance of native genotypes to the dominance of the exotic genotype. Today, more than 95% of common reed colonies found in Québec are dominated by the haplotype M. The development of the highway network in the 1960’s and 1970’s strongly contributed to the inland expansion of the exotic genotype. The exotic common reed is also invading lakeshores. Recent genetic analyses strongly suggest that the common reed established along the shores of large lakes originated from seeds, which will seriously complicate the management of this invader in the future.

A history of dealing with invasive and native Phragmites on National Wildlife Refuges

Joseph McCauley, Manager, Eastern Virginia Rivers National Wildlife Refuge Complex, Warsaw, Virginia

Abstract: National wildlife refuges have been attempting to control invasive stands of Phragmites australis for decades to improve habitat for waterfowl and other wetland-dependent fish and wildlife. Application of approved herbicides (glyphosate and imazapyr), often in combination with prescribed burning or mowing, has been the primary control method. In the Northeast Region, refuges have taken a coordinated approach over the past three years to reduce the costs of aerial applications, which in 2006 averaged $127 per acre. On the Rappahannock River, care is taken to protect stands of Phragmites australis americanus from impact during control operations. We continue to seek ways to reduce costs and increase efficiency in controlling invasive stands, while supporting ongoing research into a viable biological control program.

The Use of GIS in a Phragmites Control Project on Private Lands around Back Bay, Virginia

Dorie S. Stolley, U.S. Fish and Wildlife Service, Back Bay National Wildlife Refuge

Abstract: In an effort to conduct Phragmites control on a landscape level, Back Bay National Wildlife Refuge recruited partners and private landowners to participate in a two-year endeavor commencing in 2007 to treat Phragmites in the watershed of Back Bay, Virginia Beach, Virginia. GIS was an important tool for planning, mapping, and monitoring, and for the application of herbicide by helicopter. GIS-related items used included the software ArcINFO 9.2 and ArcPad 6.3, a Trimble GeoXT GPS unit, orthophotography, digital raster graphics, private property and Refuge boundary shapefiles, National Wetlands Inventory data and AgNAV capability onboard the helicopter. Seven private landowners were recruited, their Phragmites stands were mapped, photopoints were established and 448 acres were treated with glyphosate. Planning is underway to conduct prescribed burns on most of the acreage; a few acres will be mowed instead due to logistical and safety constraints.

Montezuma National Wildlife Refuge: From purple loosestrife to Phragmites management

Tom Jasikoff, Refuge Manager and Linda Chorba Ziemba, Wildlife Biologist

Abstract: Due to successful biological control efforts initiated in the late 1990’s, to control purple loosestrife at the Montezuma National Wildlife Refuge, management emphasis has shifted to address Phragmites. Conventional techniques including herbicide application followed by mowing or burning have proven successful at controlling existing stands of Phragmites. The refuge also is experimenting with preventative techniques such as native wetland plant establishment.

Distributional patterns of native and introduced populations of phragmites in mid-Atlantic tidal marshes with landscape implications for their management

Robert E. Meadows, Delaware Division of Fish & Wildlife, 2430 Old County Road, Newark, DE 19702 robert.meadows@state.de.us

Abstract: Starting in the fall of 2002, major tidal tributaries in the mid-Atlantic were surveyed for native and introduced populations of Phragmites to document their size, position, and density. These surveys found native populations to be quite common on the eastern shore of Maryland in Chesapeake Bay but uncommon in Delaware Bay, due most likely to differences in historic agricultural practices. All native populations were located in freshwater and oligohaline habitats, typically occurring along the creek edge. Introduced populations were found in freshwater through polyhaline habitats and were more widely distributed, ranging from the creek edge across the marsh plain to the marsh-upland interface. A consistent distributional pattern was noted in most watersheds where introduced populations dominated the lower drainage with native populations being confined to the upper tidal reach where introduced populations were less common. A similar pattern was documented in Delaware and has lead to implementation of the “Native Reserve Program”, a landscape approach to invasive species control, focusing initially on the upper basin where the vegetation is still dominated by natives and introduced species, like Phragmites, remain uncommon. This control effort works progressively downstream with the ultimately goal of eliminating introduced Phragmites totally from the drainage.

Phragmites Management on Transportation Corridors: A Brighter Future?

Kyle Williams, Ecologist, NYSDOT Environmental Analysis Bureau

Abstract: Transportation corridors provide prime conduits for the introduction and spread of invasive species. The degree of disturbance, the nature of their use and the “unnatural connections” transportation corridors provide, all contribute to favor plant invaders such as non-native phragmites. In addition to harming the environment and economy, phragmites, due to it’s rapid, dense and tall growth, impacts driver safety by blocking signs, clogging drainage systems and limiting sight distances. Over the past decade, the NYS Department of Transportation has tried several approaches to managing existing phragmites populations and preventing additional introductions. Most of these attempts, however well intentioned, have been expensive, unsuccessful or impractical on a large-scale. This presentation will discuss NYSDOT’s general approach for invasive species management and highlite management efforts directed towards non-native phragmites, including herbicide application, black plastic barriers, excavation, mowing and disposal. The presentation will conclude with a discussion of future management direction including recent research for the development of an effective biocontrol program.

Native and introduced Phragmites in WA State: an approach to area wide management

Greg Haubrich, Washington State Department of Agriculture, Yakima, CA

Abstract: Phragmites australis was first collected in Washington State in 1882 near White Salmon in Klickitat County. It was generally considered to be a native plant that co-existed peacefully in wetlands. In the mid 1990’s there were reports that Phragmites was behaving aggressively in some areas of Washington State. The Army Corps of Engineers reported that it was spreading rapidly in the Snake River system in eastern Washington. This concern was being echoed by a number of county noxious weed control boards in both eastern and western Washington. In 1998 the Army Corps made a formal request to list introduced Phragmites on the Washington State Noxious Weed List. The species was placed on the State Monitor List while the Washington State Noxious Weed Control Board (WSNWCB) gathered evidence on whether or not it was a native plant. Subsequently research by Dr. Kristin Saltonstall determined that there were native and introduced haplotypes in North America. However there was a hesitancy to list the species as a noxious weed until the native haplotype could be distinguished from the introduced haplotype. Dr. Bernd Blossey developed a list of morphological characteristics to enable field identification of the native and introduced types. In 2003 the WSNWCB listed Phragmites as a Class “C” noxious weed. Washington uses a tiered weed list and Class “C” noxious weeds are a county option for control. Placing it on the state weed list also allowed the Washington State Department of Agriculture (WSDA) to issue permit coverage for chemical control in riparian areas. In 2003 WSDA received a grant from the Washington Department of Ecology to document and map populations of both native and introduced types in Washington State. Samples were collected from each population and submitted to Dr. Blossey for confirmation of field identification. The resultant survey data has allowed the WSNWCB to propose upgrading introduced Phragmites from a Class “C” to a Class “B” designation. As a Class “B” there is a state mandate for control in certain areas. This allows for aggressive control in eliminating outlying populations while working to contain and reduce the larger populations.

Managing Phragmites australis in Virginia

Paul Clarke¹ and Rick Myers¹. ¹Virginia Department of Conservation and Recreation, Division of Natural Heritage, 217 Governor Street, Richmond, VA 23219.

Abstract: Common reed, Phragmites australis, has been expanding into a variety of previously unoccupied wetland habitats throughout Virginia. This invasion by a non-native haplotype of Phragmites is a major concern due to the loss in plant and faunal diversity, and changes in ecosystem structure. These and other negative impacts from Phragmites are being realized across a diverse group of landowners and wetland managers throughout Virginia as well as the eastern United States. Consequently, efforts to control Phragmites and to promote the continued ecological function of those wetlands threatened by Phragmites have grown to include a suite of partners and multi-tiered strategies as diverse as the habitats impacted by Phragmites. With the frustration involved with spending limited conservation dollars to control Phragmites while not adequately understanding Phragmites rates of spread, or whether or not our control efforts were minimizing the statewide threat from Phragmites, we collectively adopted a strategy “from the sky down”. Land managers and private landowners affected by Phragmites have implemented broad and diverse management strategies including: “old-school” landscape-scale mapping with helicopters and GPS, state-of-the-art web-based technology to support private landowners, public forums for landowners and realtor associations, incorporation of private interest groups and local municipalities, a coordination group for effective communication and information sharing, creative funding sources, herbicide treatments utilizing imazapyr and glyphosate, and monitoring for herbicide efficacy and non-Phragmites response to treatments. Invasive species management involving the magnitude of Phragmites, whether addressed from a local natural area perspective, or from a statewide perspective, is best addressed with a strategy involving many tiers of action and many partners.

Test Applications of Habitat and Renovate Herbicides for Phragmites Control

Glenn Sullivan, Christopher Doyle, Brian Janoski, Jeff Horn, Allied Biological, Inc.

Abstract: Glyphosate has been widely used for control of invasive common reed (Phragmites australis). For glyphosate to work properly, the herbicide must be applied to mature plants in the late-Summer or Fall, allowing the herbicide to be effectively translocated to the rhizome. This application period requirement results in a short application window and a prolonged period between applications and/or re-vegetation. The aquatic herbicides Habitat (imazapyr) and Renovate (triclopyr) are reported to offer phragmites control at an earlier growth phase. To provide some first-hand experience, Allied Biological conducted test plot applications of both Habitat and Renovate, using spray and wicking application methods, to a freshwater stand of phragmites in Sussex County, NJ. Results of these test applications indicted various levels of control. These results will be discussed and compared to other field applications of the products.

Outreach, education, and treatment: a community-wide Phragmites control program

Barbara Lucas, the Beaver Island Association

Video Presentation and Discussion of issues related to control and protection of Phragmites on Beaver Island, MI

Planting of Native Woody Plants as a Technique for Controlling and Replacing Phragmites

Michael D. Byer, Gateway National Recreation Area, U. S. National Park Service

Abstract: One way to control invasive plants is to replace them with desirable, native plants. In fact, this is probably part of most successful control projects, since simply eliminating the invasives creates a biological vacuum that will soon be filled either by a resurgence of the original invasive, or by one or more other invasive species. At Floyd Bennett Field and Deadhorse Bay, Gateway NRA, Brooklyn, NY, we weed-whacked monocultures of the exotic, invasive form of Phragmites australis in small areas along visitor trails, and planted native trees and shrubs appropriate to the soils and hydrology. Over ten years later, the crowns of these woody plants have overtopped Phragmites and formed a closed canopy in some areas that suppresses growth of the invasive grass sufficiently to render it ineffective as a competitor. The work is very labor-intensive, as whacking must be repeated annually until the desired plants overtop Phragmites. Weed-blocker fabric and/or replacement of the top 30 cm of soil with “clean” topsoil are helpful.

Phragmites australis dynamics in invasion corridors and wetlands

Sylvie de Blois1,2, Karyne Benjamin1, Mathieu Maheu-Giroux1, and Jacques Brisson3

1 Plant Science Department, McGill University, Montreal, QC

2 McGill School of Environment, McGill University, Montreal, QC

3 Université de Montréal, Institut de recherche en biologie végétale, Montreal, QC

Email: sylvie.deblois@mcgill.ca

Abstract: Most historical reconstructions of invasion patterns of P. australis have been done in wetland patches. Here we report on a study of recent invasion patterns (1985-2002) in linear habitat corridors (roadside and agricultural ditches) of the St. Lawrence valley using aerial photographs. We discuss the challenges of mapping an emergent macrophyte in narrow habitats at the landscape scale. Our results show rapid colonization of two periurban landscapes in less than 20 years with roadside habitats appearing to serve as invasion foci. In Quebec, linear wetlands are almost exclusively colonized by the introduced haplotype while the native one is found in only a few refuges. Although there is historical evidence at the regional level showing a change in the relative abundance of the two haplotypes, there is little understanding of the current dynamics of mixed stands which could provide useful information for management. We therefore also present an ongoing investigation of the spatial distribution of the exotic and native haplotypes and of their relative effect on plant diversity in a large wetland reserve in southern Quebec. Preliminary results suggest similar plant species richness in plots dominated by either type, but also show a decline in the abundance of associated plant species in plots dominated by the exotic type. The exotic haplotype, unlike the native one, appears to benefit from human perturbations (management, residential zone, etc.).

Interspecific competition between common reed and cattails

Jacques Brisson, Marie-Ève Bellavance, Étienne Paradis and Bastien Fontaine

Institut de recherche en biologie végétale, Université de Montréal. 4101 East, Sherbrroke St. Montreal (Qc), H1X 2B2. Canada.

Corresponding author : jacques.brisson@umontreal.ca

Abstract: In Quebec, common reed commonly forms dense monospecific stands in alternance with cattails stands (Typha latifolia, Typha angustifolia, and Typha xglauca), with intense interspecific competition at the contact zone between stands. We used a combination of field observations and mesocosm experiments to determine the effect of competitive interactions with cattails on reed dynamics. Common reed is faster than cattail at colonizing unvegetated sites. When two colonies meet, common reed is always gaining ground, at the expense of cattail, but this progression varies annually, probably in response to climatic conditions. A controlled competition experiment at high plant density shows that both common reed and cattail density and biomass are negatively affected under compeittive pressure. The detrimental effect of competition, however, is stronger on cattail. All these observations demonstrate the competitive superiority of common reed in ditch conditions. We are currently doing competition mesocosms experiment under different salinity levels to evaluate the effect of road de-icing on reed-cattail dynamics in roadside ditches.

Impact of native and introduced Phragmites on amphibians

Jillian Cohen1, John Maerz2, and Bernd Blossey1

1Department of Natural Resources, Cornell University

2Warnell School of Forestry, University of Georgia, Athens, GA

Abstract: We studied larval performance of three native amphibians in habitats dominated by native and introduced plant communities in three wetlands complexes in upstate New York from May to August 2007. We hypothesized that introduced plants will decompose more slowly, reducing algal productivity and therefore amphibian metamorph biomass. We established a total of 64 cages, five of which were located in stands of introduced Phragmites australis. We were able to locate native P. australis at one of our study sites, but in quantities too small to set cages in. We collected water samples from each cage in June and August, filtering out and preserving zooplankton and algae for later analysis. We also preserved water for phenolic analysis. We have data on the proportion of

amphibian species surviving to metamorphosis in each cage, as well as the mean metamorph biomass of each amphibian species across plant species. These data indicate that P. australis provides relatively poor habitat for two amphibian species, and mediocre habitat for a third. The data also show tremendous variation among regions, plant species, among cages within a treatment, as well as among the amphibian species, and do not indicate generalizable differences in how native and introduced plants affect larval amphibians.

Sexual reproduction in non-native common reed, Phragmites australis

Amy Campbell, The Ohio State University, Dept. of Evolution, Ecology and Organismal Biology, Columbus, OH

Abstract: I investigated seed viability, germinability and dormancy of the non-native common reed, Phragmites australis (Cav.) Trin. ex Steudel growing in four freshwater wetlands on the south shore of Lake Erie, Ohio, USA.  In June of 2006, I located a total of 24 sampling sites in three hydrologic zones:  upland (never inundated), water line (moist soil), and standing water throughout the growing season.  In November of 2006, I collected panicles from current-year Phragmites shoots at each of these sites.  I tested seed viability using a tetrazoleum test. I then germinated seeds over 12 days to obtain percent germination per site.  I found that seeds from all sites were mostly viable. Across hydrologic zones, seeds had low germination percentages (6 to 25%) when exposed to a constant temperature of 25 (C.  Germination percentages improved substantially (90 to 100%) for all sites when the seeds were exposed to a diurnal temperature fluctuation of 10-30 (C.  These results suggest that seeds may play a larger role in the spread of Phragmites australis than previously thought.

Phenology of native and introduced Phragmites haplotypes

Mia Park and Bernd Blossey, Department of Natural Resources, Cornell University

Abstract: Plant community structure is determined by combined influences of inherent plant traits and external forces (e.g. herbivores); however, rarely are the two explicitly integrated in studies of plant invaders. We investigated whether above-ground growth phenology and increased stem height contribute to success of invasive Phragmites australis in North America, using non-invasive Phragmites australis americanus as phylogenetic control. We recorded influence of attack by a stem-galling introduced specialists and an introduced generalist aphid on expression of plant traits in two venues. In the garden but not the field, nonnative Phragmites leaves lived on average a month longer. Consistent across sites, vertical leaf age structure of nonnative Phragmites demonstrated a potential for greater resource gain in dense canopy conditions. We found significant differences in plant height in the field, which were mediated by galling rather than origin. Galling influenced vertical age structure of leaves but not their seasonal senescence patterns. Aphids had no significant effect on traits measured. Differences in leaf phenology between native and non-native Phragmites may contribute to the competitive superiority of nonnative Phragmites. Introduced herbivores caused higher herbivore damage on native P. australis americanus and may facilitate replacement of the endemic subspecies by nonnative Phragmites.

Photosynthetic differences between native and non-native Phragmites australis haplotypes

Thomas J. Mozdzer and Joseph C. Zieman, University of Virginia, Department of Environmental Sciences, 291 McCormick Rd, Charlottesville, VA, 22904

Abstract: The common reed, Phragmites australis, has been a native component of North American wetlands for thousands of years.  However, the introduction of a non-native haplotype of P. australis over a century ago has resulted in its well documented expansion into a variety of North American wetlands.  To determine if the invasive nature of the non-native haplotype could be attributed to physiological differences, we investigated if eco-physiological differences exist between native and non-native P. australis haplotypes.  Photosynthetic parameters were measured on native (type F) and non-native (type M) P. australis haplotypes on both greenhouse-grown plants and in-situ on plants in a tidal marsh near Easton, MD using infrared gas analysis (IRGA) and pulse amplitude modified (PAM) flourometry.  Field measurements were conducted monthly for two years from June through August.  Photosynthetic pigments were also quantified on greenhouse-grown and field plants using standard spectrophotometric techniques. Significant differences were observed between native and non-native P. australis haplotypes in both field and greenhouse grown plants.  Non-native P. australis contained significantly greater concentrations of chlorophyll a and chlorophyll b than native P. australis plants.  Additionally, non-native P. australis plants demonstrated superior photosynthetic potential with significantly greater values of Amax.  These results demonstrate that native P. australis plants are physiologically different from the non-native invader, and suggest that the expansion of non-native P. australis into previously unoccupied habitats may be facilitated by its greater photosynthetic potential.

Comparative Physiological Ecology of Native and Introduced Phragmites australis: Previous and Proposed Work to Identify Traits Associated with Invasions

Eric L. G. Hazelton, Theresa A. Theodose, Thomas J. Knight

Abstract: The Phragmites australis complex offers a study system with minimal phylogenetic effects, allowing us to determine strategies that may confer competitive advantages to invasive plants. Here, we review present work on the partitioning of glutamine synthetase in P. australis as it compares to other salt marsh grasses. In a single-population pilot study, one of the current authors (E.H.) recorded non-significant differences in GS partitioning between the haplotypes, a trait that is often associated with increased photosynthetic rates, growth rates and nitrogen use efficiency. While non-significant, this study’s results may have been affected by pseudoreplication (indicated by power analysis) and a larger, multi-population follow-up is underway. We propose using geographically diverse populations of P. australis as a model system for additional trait-level comparisons, increasing our knowledge of traits associated with invasive plants.

Evidence for Intraspecific Hybridization of Native and Introduced Subspecies of Phragmites australis in North America

Laura A. Meyerson and Emma White, University of Rhode Island, Kingston, RI 02881

Abstract: Interspecific hybridization can lead to the extinction of native floral and faunal gene pools and may result in increased aggressiveness in some hybrid forms relative to their parental lineages. While hybridization between native and introduced species can dilute the native gene pool, interbreeding among subspecies is not currently recognized as a serious threat to native species. Phragmites australis offers the opportunity to investigate intraspecific hybridization as both native and introduced lineages occur in North America. Despite range overlaps, hybridization has not been detected between the native and introduced lineages. One hypothesis holds that a phenological barrier precludes cross-pollination between native and introduced populations. However, hybridization should be possible given that native and introduced Phragmites strains are classified as subspecies. Results to date indicate a substantial overlap in the timing of anthesis in multiple paired populations of native and introduced Phragmites. Furthermore, in hand pollination studies, 87% of putative intraspecific hybrid crosses produced seed and 62% had rates of seed set of over 50%, a very high success rate for this species. Microsatellite analyses of both seeds and seedlings produced from the crosses indicate that native and introduced Phragmites can hybridize.

Indirect effects of North American herbivores on native and exotic Phragmites interactions

Adam M. Lambert, Department of Biology, Eastern Connecticut State University, Willimantic, CT, lambertA@easternct.edu, and Riparian Invasives Research Lab, University of California, Santa Barbara

Abstract: Five native and 21 European herbivores use native and exotic Phragmites genotypes as a food resource in North America. Native and exotic Phragmites genotypes show differential susceptibility to these herbivores, with several exotic herbivores having a greater negative impact on native Phragmites genotypes. In the Northeast, shoot flies (Lipara sp.) and aphids (Hyalopterus pruni) have significantly higher populations on native Phragmites genotypes, inflicting substantial tissue damage and reducing flowering rates. In the Southwest, aphids are the primary herbivores where they reduce native Phragmites above-and belowground growth. Experimental evidence suggests that aphids may play an indirect, but major role in reducing the competitive ability of native Phragmites genotypes.

A history of Phragmites biocontrol efforts

Richard Casagrande1, Bernd Blossey2, Lisa Tewksbury1 and Patrick Häfliger3,

1Department of Plant Sciences, University of Rhode Island, Kingston, RI

2Department of Natural Resources, Cornell University

3CABI Europe-Switzerland, Delemont, Switzerland

Abstract: This project was initiated in 1998 when, realizing the similarities between problems with P. australis and purple loosestrife, Casagrande and Blossey joined forces with colleagues at CABI Bioscience (Delémont, Switzerland) to address phragmites biological control. This project has involved several components including three major themes:

1) Locating native and exotic phragmites populations throughout North America.

2) Determining the identity and impact of existing insect natural enemies on native and exotic phragmites in North America.

3) Evaluating European natural enemies for potential use in biological control in North America.

Work has progressed to a point where we are now conducting host range testing for promising natural enemies.

Phragmites biocontrol research in Europe: candidates, their ecology and impact

Patrick Hafliger, CABI Europe-Switzerland, Delemont, Switzerland

Abstract: During a two year survey in Europe nine herbivore species were identified as potential biological control agents and five of them were selected for detailed studies. The noctuid moth Archanara geminipuncta seems to be the most promising potential biological control agent. It can occur in high densities and has a high impact on P. australis stems. The shoot fly Platycephala planifrons also causes big damage to stems of P. australis. However, its capability to reach high infestation levels seems to be restricted. Therefore, we are focussing now on A. geminipuncta and three other closely related noctuid species for host-specificity testing. So far, we know that A. geminipuncta can develop on the native North American subspecies. However, there seem to be some preference for the introduced European reed and we found increased mortality of eggs laid on P. australis americanus.

Current proposed host specificity test plant list

Lisa Tewksbury, Department of Plant Sciences, University of Rhode Island, Kingston, RI

Abstract: Patrick Häfliger has evaluated European insect herbivores on phragmites at CABI Europe in Switzerland, and we are now able to begin conducting host range testing of four potential biological control agents. A preliminary test plant list of approximately 50 species was created utilizing the guidelines created by TAG (Technical Advisory Group for Biological Control Agents of Weeds). This preliminary list was distributed on the Cornell invasive plants web site and by email through the Invasive Plant Newsbriefs (New England Invasive Plant Group) to solicit comments. An amended list will be submitted to the TAG for review, and host range testing will begin this spring.

Planned steps in the development of biological control in North America

Bernd Blossey, Department of Natural Resources, Cornell University

Abstract: After nearly a decade of research into the potential for biocontrol to aid in managing invasive Phragmites australis, we are now ready to engage in the second phase of extensive host specificity testing with an increased emphasis on safety of native genotypes. Parallel to these investigations to be conducted in Switzerland and Rhode Island, we will engage in research to further assess ecological and economic ecosystem impacts of native and introduced Phragmites. In addition, we will conduct surveys to assess stakeholder attitudes towards biological control and develop and test standardized long-term monitoring protocols and mass rearing techniques. Developed protocols should allow participation by non-academic audiences to disseminate and streamline delivery of information rapidly among those interested implement biological control (if approved).

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