Phragmites Identification, Ecology, and Management

Transcription

1 Phragmites Identification, Ecology, and Management Noelle Orloff Montana State University Montana Weed Control Association Annual Conference January 13, 2016

2 Outline Phragmites history, competitive interactions, and impacts Identification native versus exotic Management options What next in Montana?

3 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

4 Phragmites is a cryptic invader From Saltonstall, K 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):

5 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 Chesapeake Bay Program

6 Keys to non-native Phragmites success Genetic variability = ability to colonize various habitats Differences in response to elevated resources (eutrophication and elevated CO 2 ) Morphological and trait differences between native and exotic.

7 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.

8 Meta-analysis of field studies about Phragmites growth From Mozdzer, T.J, Brisson, J., and E.L.G. Hazelton Physiological ecology and functional traits of North American native and Eurasian introduced Phragmites australis lineages. Annals of Botany

9 Smithsonian Environmental Research Center

10 Meta-analysis of lab studies about Phragmites traits From Mozdzer, T.J, Brisson, J., and E.L.G. Hazelton Physiological ecology and functional traits of North American native and Eurasian introduced Phragmites australis lineages. Annals of Botany

11 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?

12 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?

13 Status in Montana Found in locations near Havre Listed as noxious weed in 2015 Unknown if there are other populations Unknown if it is adapted to Montana climate Terry Turner

14 Outline Phragmites history, competitive interactions, and impacts Identification native versus exotic Management options What next in Montana?

15 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 Turner

16 Do you have native or exotic Phragmites? Leaf sheath, stem color, stem texture Native Introduced Photo credit: Lindsay and Scott Namestnik,

17 Do you have native or exotic Phragmites? Ligule length and appearance Native > 1.0 mm, more likely to look shredded Introduced < 1.0 mm, more likely to be intact Photo credit: Anton Reznicek, University of Michigan Herbarium.

18 Do you have native or exotic Phragmites? Glume length Introduced Upper mm Lower < 4 mm Native Upper 5-11mm Lower > 4 mm Photo credit: Anton Reznicek, University of Michigan Herbarium.

19 Is it native or exotic Phragmites? Stem density and persistence Native Mixed plant communities Introduced More likely monoculture Stem density may be lower Stem density can be very high (10 stems/ft 2 ) Stems less likely to persist Stems more likely to persist to next season

20 Do you have native or exotic Phragmites? Genetic testing Can be very difficult to determine if you have native or exotic Phragmites. Genetic testing is possible. Chesapeake Bay Program

21 Outline Phragmites history, competitive interactions, and impacts Identification native versus exotic Management options What next in Montana?

22 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

23 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 Phragmites australis management in the United States: 40 years of methods and outcomes. Annals of Botany and references therein.

24 Management efforts should focus on restoring native plant communities, rather than eradicating Phragmites stands* Photo credit: USFWS Mountain-Prairie *From Hazelton, L.G., T.J. Mozdzer, D.M. Burdick, K.M. Kettenring, and D.F. Whigham Phragmites australis management in the United States: 40 years of methods and outcomes. Annals of Botany.

25 Outline Phragmites history, competitive interactions, and impacts Identification native versus exotic Management options What next in Montana?

26 Montana next step Keep your eye out for suspected non-native Phragmites populations Helpful ID materials available from NPS, Michigan State Extension Terry Turner

27 Thank you! Questions? 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: Mailing address: Noelle Orloff Schutter Diagnostic Lab 119 Plant BioScience Building PO Box Bozeman, MT