Phragmites Identification, Ecology, and Management

Noelle OrloffMontana State University

Montana Weed Control Association Annual Conference January 13, 2016

Outline

• Phragmites history, competitive interactions, and impacts

• Identification – native versus exotic

• Management options

• What next in Montana?

Phragmites australis - history

• Global distribution• Oldest U.S. samples are from sloth poop in AZ

cave from 40,000 years ago! • Dozens of genetic lineages• Lineage native to North America is subspecies

americanus (Saltonstall 2004)

Chesapeake Bay Program

Phragmites is a “cryptic invader”

From Saltonstall, K. 2002. Cryptic invasion by a non-native genotype of the common reed, Phragmites australis, into North America. Proceedings of the National Academy of Sciences of the United States of America 99(4):2445-2449.

Chesapeake Bay Program

Phragmites australis - biology

• Large statured grass• Reproduces by seeds, rhizomes, or stolons• Clonal species• Hollow stems• Large, plume like flowers can have a golden or

purple hue• Inhabits a variety of wetland soils

• Genetic variability = ability to colonize various habitats

• Differences in response to elevated resources (eutrophication and elevated CO2)

• Morphological and trait differences between native and exotic….

Keys to non-native Phragmites success

Keys to non-native Phragmites success

Trait and Morphological Differences

• Trait differences in invasion ecology. Is an invasive species better at photosynthesizing? Does it grow faster? Grow earlier? Etc?

• One weakness of this approach is you are often comparing plants that are really different from one another. Not with Phragmites!

• Example: Mozdzer et al 2013.

Meta-analysis of field studies about Phragmites growth

From Mozdzer, T.J, Brisson, J., and E.L.G. Hazelton. 2013. Physiological ecology and functional traits of North American native and Eurasian introduced Phragmites australis lineages. Annals of Botany

Smithsonian Environmental Research Center

From Mozdzer, T.J, Brisson, J., and E.L.G. Hazelton. 2013. Physiological ecology and functional traits of North American native and Eurasian introduced Phragmites australis lineages. Annals of Botany

Meta-analysis of lab studies about Phragmites traits

Impacts of Phragmites

• Continentally, exotic is increasing while native is decreasing.

• Does the exotic “outcompete” the native?– Yes according to personal observations.– No evidence according to published studies.

• Other processes that can have this outcome:– Exotic better at colonizing disturbed areas?– Exotic can colonize a wider variety of habitats?

Impacts of Phragmites

• Often associated with:– Decreased plant diversity– Declines/changes in fish and wildlife habitat– Changes in biogeochemical cycles

• Data supporting these impacts is often weak or lacking, seems to be ongoing debate

• Some point to ecosystem services rather than negative impacts

• Hybridization?

Status in Montana

• Found in 2014• 2 locations near Havre• Listed as noxious weed in

2015• Unknown if there are

other populations• Unknown if it is adapted

to Montana climateTerry Turner

Outline

• Phragmites history, competitive interactions, and impacts

• Identification – native versus exotic

• Management options

• What next in Montana?

Do you have native or exotic Phragmites?

• Identification is tricky!

• Observe a combination of features

• Observe multiple stems

• Get help if you need it!

Terry TurnerTerry Turner

Do you have native or exotic Phragmites?

Leaf sheath, stem color, stem texture

Native Introduced

Photo credit: Lindsay and Scott Namestnik, handlensandbinoculars@blogspot.com.

Introduced

Do you have native or exotic Phragmites?

Ligule length and appearance

Native> 1.0 mm, more likely to look shredded

< 1.0 mm, more likely to be intact

Photo credit: Anton Reznicek, University of Michigan Herbarium.

Do you have native or exotic Phragmites?

Glume length

Native IntroducedUpper 4.5-7.5 mmLower < 4 mm

Upper 5-11mmLower > 4 mm

Photo credit: Anton Reznicek, University of Michigan Herbarium.

Native• Mixed plant communities

• Stem density may be lower

• Stems less likely to persist

Introduced• More likely monoculture

• Stem density can be very high (10 stems/ft2)

• Stems more likely to persist to next season

Is it native or exotic Phragmites?

Stem density and persistence

• Can be very difficult to determine if you have native or exotic Phragmites. Genetic testing is possible.

Do you have native or exotic Phragmites?

Genetic testing

Chesapeake Bay Program

Outline

• Phragmites history, competitive interactions, and impacts

• Identification – native versus exotic

• Management options

• What next in Montana?

Phragmites Management – Small patches

• Considered very difficult to control, so repeated management is necessary.

• Integrated approaches are important and will be site-specific. Often herbicide combined with mowing, discing, or prescribed fire.

Michigan State University Extension

Phragmites Management - Herbicide• Herbicides are common tool for managers

(94%) and often tested by researchers (79%)• Glyphosate vs. Imazapyr• Glyphosate

– Fewer non-target effects– End of growing season vs. early summer

• Imazapyr– More effective for Phragmites control– Non-target effects more of a concern- soil activity

*From Hazelton, L.G., T.J. Mozdzer, D.M. Burdick, K.M. Kettenring, and D.F. Whigham. 2014. Phragmites australis management in the United States: 40 years of methods and outcomes. Annals of Botany and references therein.

“Management efforts should focus on restoring native plant communities, rather than

eradicating Phragmites stands*”

*From Hazelton, L.G., T.J. Mozdzer, D.M. Burdick, K.M. Kettenring, and D.F. Whigham. 2014. Phragmites australis management in the United States: 40 years of methods and outcomes. Annals of Botany.

Photo credit: USFWS Mountain-Prairie

Outline

• Phragmites history, competitive interactions, and impacts

• Identification – native versus exotic

• Management options

• What next in Montana?

Montana – next step

• Keep your eye out for suspected non-native Phragmites populations

• Helpful ID materials available from NPS, Michigan State Extension

Terry Turner

For assistance identifying unknown plants such as Phragmites, one option is to send samples to the Schutter Diagnostic lab at Montana State University. Please refer to this website for instructions on submitting samples, and to download a form: http://diagnostics.montana.edu/Plant/index2.html

Mailing address: Noelle OrloffSchutter Diagnostic Lab119 Plant BioScience BuildingPO Box 173150Bozeman, MT 59717-3150406-994-6297

Thank you! Questions?