Our Invasive Phragmites

Our Invasive Phragmites: Great Salt Lake Phragmites Courtesy & Copyright Karin Kettenring
Great Salt Lake Phragmites
Courtesy & Copyright Karin Kettenring
Those unfamiliar with the history of the Utah’s wetlands may see Phragmites and say, “What a beautiful, elegant plant! It looks so graceful blowing along the shore.”

However, the plant’s attractiveness and ability to absorb pollutants may not compensate for its negative impacts.

Phragmites is an invasive perennial grass that now thrives in much of the wetlands around the Great Salt Lake and other marshes in northern Utah. It grows in dense clusters and normally reaches 5 to 10 feet in height. If the conditions are right it can reach 15 feet.

The patches of grass are so dense that wetland managers are called out each year to rescue duck hunters – who are lost in the Phragmites.

Karin Kettenring, associate professor of wetland ecology in the Department of Watershed Sciences at USU and her research team have been studying Utah Phragmites for the past decade.

Kettenring explains why Phragmites is a concern, “We fear it is fundamentally changing the habitat of Great Salt Lake wetlands which are renowned for being a home for migratory birds including waterfowl and shore birds.”

The exotic grass most likely started in the Great Salt Lake wetlands after the flooding of 1983. The flood washed out the marshes. When the water levels receded, the salty water had destroyed all the native vegetation in the wetlands. Phragmites then moved in. By 2011, the exotic grass had spread over 24,000 acres.

Mowing Phragmites Courtesy & Copyright Karin Kettenring
Mowing Phragmites
Courtesy & Copyright Karin Kettenring
Scientists believe humans inadvertently brought Phragmites to Utah, since birds don’t migrate East and West, and the birds usually don’t eat the seeds. Someone’s boat may have transported the seeds into Utah. They sat dormant in the soil until the conditions were perfect, then the spread of Phragmites began.

Today an average small patch of Phragmites, about 20 feet square, can spread a couple yards a year just from the stems it sends out above and below the ground. However, research has shown it’s not the stems that cause the most reproduction – but the seeds.

Karin_Kettenring-in-the-Great-Salt-Lake-Wetlands Courtesy & Copyright Karin Kettenring
Karin_Kettenring-in-the-Great-Salt-Lake-Wetlands
Courtesy & Copyright Karin Kettenring
Karen Mock, associate professor in the Department of Wildland Resources and a long-term collaborator on this project helped Kettenring with the genetic work.

They tested the genetics of a lot of Phragmites pulled from the same patches and found many different genotypes – proving the plants came from different seeds, not the stems of neighboring plants.

With these results, Kettenring’s lab discovered the best way to control the invasive grass is to first control the seed production by mowing the grass mid-summer to keep it from spreading. Then in the fall spraying the area with herbicide three years in a row. An herbicide approved for use in wetlands can be used – such as Rodeo.

If the Phragmites has been there only a few years then the seeds of the native vegetation will still be in the soil, and they’ll come back on their own.

However, if the Phragmites has been there for a long time then re-seeding of native plants will be necessary.

To determine the best way to re-seed wetlands, Kettenring partnered with Utah Division of Wildlife Resources, Utah Division of Forestry, Fire & State Lands and David England – one of Kettenring’s past graduate students. England has spent extensive time in the lab determining how to help seeds germinate.

Emily Martin, Kettenring’s current graduate student will also help with the UDWR reseeding as she searches for techniques to make seeding more effective.

Ultimately their goal is to restore native plant communities to keep Phragmites from coming back and restore habitat for important migratory birds.

This is Shauna Leavitt and I’m Wild About Utah.

Credits:
Photos: Courtesy & Copyright Karin Kettenring
Audio: Courtesy and Copyright Kevin Colver
Text: Shauna Leavitt

Sources & Additional Reading

How to control Phragmites
Kettenring, Karin, Rupp, Larry, Whitesides, Ralph, Hazelton, Eric, Phragmites Control at the Urban/Rural Interface, 2014, https://works.bepress.com/karin_kettenring/92/

Extensive readings about Phragmites:
https://works.bepress.com/karin_kettenring/

Video: USU researchers mowing Phragmites in the Great Salt Lake wetlands. The passenger is Chad Cranney a past graduate student of Karin Kettenring’s:
https://bft.usu.edu/rqcq9

*****

Larese-Casanova, Mark, Phragmites-Utah’s Grassy Invader, Wild About Utah, August 23, 2012, https://wildaboututah.org/phragmites-utahs-grassy-invader/

Common Reed, Phragmites australis. National Invasive Species Information Center, USDA National Agricultural Library, https://www.invasivespeciesinfo.gov/aquatics/commonreed.shtml

Phragmites Factsheet, US Fish & Wildlife Service, https://www.fws.gov/GOMCP/pdfs/phragmitesQA_factsheet.pdf

Phragmites Phragmites australis, Aquatic Invasive Species, Utah Division of Wildlife Resources, Sept 17, 2013, https://wildlife.utah.gov/habitat/ans/phragmites.php

Phragmites Phragmites australis, Plants Database, USDA Natural Resources Conservation Service(NRCS), https://plants.usda.gov/core/profile?symbol=phau7

Phragmites-Utah’s Grassy Invader

Invasive Phragmites
Phragmites australis
Photo Courtesy
Plant Conservation Alliance
Alien Plant Working Group
As found on
nps.gov/plants/alien/fact/phau1.htm
Photographers credited on Factsheet

Invasive Phragmites vs. Native

Photo Courtesy
Plant Conservation Alliance
Alien Plant Working Group
As found on
nps.gov/plants/alien/fact/phau1.htm
See guide to distinguish
Invasive from Native plants
Photographers credited on Factsheet

Hi, this is Mark Larese-Casanova from the Utah Master Naturalist Program at Utah State University Extension.

When exploring wetlands, streambanks, and the shores of Great Salt Lake this time of year, it’s common to see tall grasses, over ten feet high, blowing in the breeze. While it is very abundant, the common reed known as Phragmites australis is anything but normal.

Phragmites was introduced from Europe over a century ago, and is now found in all 50 states and on every continent except Antarctica. It can grow to more than 15 feet in height, with long blade-like leaves. It flowers from July to October, producing dense, feathery clusters of small flowers that are purple while flowering and turn light brown after producing seeds. Each stem can produce up to 2,000 wind-dispersed seeds that are particularly effective at colonizing new areas. Because of this, Phragmites can take over a disturbed area quickly and prevent native plants, such as bulrush and cattail, from becoming established.

Like other invasive plants, Phragmites is successful at outcompeting native plants. Once a plant is established from seed, Phragmites spreads quickly through rhizomes, or underground stems, that can produce many additional stalks. While Phragmites may start growing among other wetland plants, it quickly outcompetes them for nutrients and sunlight. However, the native “Phragmites australis subspecies americanus” does not grow nearly as dense or tall, and tends to not be invasive.

Because introduced Phragmites can quickly grow into solid stands, it can greatly reduce plant diversity in wetlands, ultimately reducing the quality of wildlife habitat. Wetlands along the shore of Great Salt Lake are particularly important habitat for many migratory birds species, some of which occur here in the largest populations in North America or the world. The rapid takeover by Phragmites in these wetlands could eventually have dramatic impacts to the entire Great Salt Lake ecosystem.

In order to combat this threat, wetland managers have tried several methods for controlling or removing Phragmites, including spraying with herbicide, burning, livestock grazing, and mowing. Dr. Karin Kettenring, a Utah State University researcher, and her graduate students are currently studying the effects of several of these Phragmites control methods along the shores of Great Salt Lake. By experimenting with the timing of mowing and herbicide treatment, as well as covering mowed Phragmites with heavy black plastic, Dr. Kettenring and her team hope to find the most effective combination of treatments. With the continual conversion of native wetland habitats to a monoculture of Phragmites, Dr. Kettenring’s research is of particular importance to maintaining the health of the Great Salt Lake ecosystem- one of our state’s greatest natural wonders.

For Wild About Utah, I’m Mark Larese-Casanova.

Credits:
Images: Courtesy & Copyright
            Jil M. Swearingen, National Park Service, Center for Urban Ecology, Washington, DC
            Dr. Kristin Saltonstall, Adjunct Research Scientist, Horn Point Laboratory,
                  University of Maryland Center for Environmental Science, Solomon, MD
            Robert Meadows, Environmental Scientist, North DE Wetland Rehabilitation Program,
                  DE Mosquito Control Section, Newark, DE
            As found on http://www.nps.gov/plants/alien/fact/phau1.htm
Text:     Mark Larese-Casanova, Utah Master Naturalist Program at Utah State University Extension.


Additional Reading:

Evans K, Martinson W (2008) Utah’s featured birds and viewing sites: a conservation platform for Important Bird Areas and Bird Habitat Conservation Areas. Salt Lake City, Utah

Kulmatiski A, Beard KH, Meyerson LA, Gibson JR, Mock KE (2010) Nonnative Phragmites australis invasion into Utah wetlands. Western North American Naturalist 70:541-552

Long, A.L., C.M.U. Neale, and K.M. Kettenring. 2012. Management of Phragmites in the Great Salt Lake watershed. Final report to the Utah Department of Natural Resources, Division of Forestry, Fire & State Lands. 15 pp.