Phragmites australis - (Cav.) Trin. ex Steud.
Common Reed
Other Common Names: common reed
Synonym(s): Phragmites communis Trin.
Taxonomic Status: Accepted
Related ITIS Name(s): Phragmites australis (Cav.) Trin. ex Steud. (TSN 41072)
Spanish Common Names: Cana de Indio
Unique Identifier: ELEMENT_GLOBAL.2.134146
Element Code: PMPOA4V010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Grass Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Cyperales Poaceae Phragmites
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Concept Reference
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Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Phragmites australis
Taxonomic Comments: Generally accepted as an essentially cosmopolitan species; the name Phragmites communis is used for this plant in most older North American literature. LEM 6Jun01.
Conservation Status
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NatureServe Status

Global Status: G5
Global Status Last Reviewed: 16May2016
Global Status Last Changed: 28Apr1988
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Reasons: Nearly cosmopolitan as a presumably native plant in marshes and other wetland habitats on all continents except Antarctica. Additionally, at least in North America, non-native genotypes may have become established in areas not previously supporting Phragmites.
Nation: United States
National Status: N5?
Nation: Canada
National Status: N5 (10Oct2016)

U.S. & Canada State/Province Status
United States Alabama (SNR), Arizona (SNR), California (SNR), Colorado (SNR), Connecticut (SU), Delaware (SU), District of Columbia (SNR), Florida (SNR), Georgia (SNA), Idaho (SNR), Illinois (S3S4), Indiana (SNR), Iowa (S4), Kansas (SNR), Kentucky (SNA), Louisiana (SNR), Maine (SNR), Maryland (SNR), Massachusetts (SNR), Michigan (SNR), Minnesota (SNR), Mississippi (SNR), Missouri (SNR), Montana (S4), Nebraska (SNR), Nevada (SNR), New Hampshire (SNR), New Jersey (S5), New Mexico (SNR), New York (SNR), North Carolina (S3), North Dakota (SNR), Ohio (SNR), Oklahoma (SNR), Oregon (SNR), Pennsylvania (SNA), Rhode Island (SNA), South Carolina (SNR), South Dakota (SNR), Tennessee (SNR), Texas (SNR), Utah (SNR), Vermont (SNR), Virginia (SNR), Washington (SNR), West Virginia (SNA), Wisconsin (SNR), Wyoming (S2S3)
Canada Alberta (S3), British Columbia (SNR), Manitoba (S5), New Brunswick (S4), Newfoundland Island (SNR), Northwest Territories (SNR), Nova Scotia (S4), Ontario (S4?), Prince Edward Island (S3?), Quebec (SNA), Saskatchewan (S5)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent Comments: Phragmites australis is found on every continent except Antarctica and may have the widest distribution of any flowering plant (Tucker 1990). It is common in and near freshwater, brackish and alkaline wetlands in the temperate zones world-wide. It may also be found in some tropical wetlands but is absent from the Amazon Basin and central Africa. It is widespread in the United states, typically growing in marshes, swamps, fens, and prairie potholes, usually inhabiting the marsh-upland interface where it may form continuous belts (Roman et al. 1984).

Because Phragmites has invaded and formed near-monotypic stands in some North American wetlands only in recent decades there has been some debate as to whether it is indigenous to this continent or not. Convincing evidence that it was here long before European contact is now available from at least two sources. Niering and Warren (1977) found remains of Phragmites in cores of 3000 year old peat from tidal marshes in Connecticut. Identifiable Phragmites remains dating from 600 to 900 A.D. and constituting parts of a twined mat and other woven objects were found during archaeological investigations of Anasazi sites in southwestern Colorado (Kane & Gross 1986; Breternitz et al. 1986).

There is some suspicion that although the species itself is indigenous to North America, new, more invasive genotype(s) were introduced from the Old World (Metzler and Rosza 1987). Hauber et al. (1991) found that invasive Phragmites populations in the Mississippi River Delta differed genetically from a more stable population near New Orleans. They also examined populations elsewhere on the Gulf coast, from extreme southern Texas to the Florida panhandle, and found no genetic differences between those populations and the one near New Orleans (Hauber, pers. comm. 1992). This increased their suspicion that the invasive biotypes were introduced to the Delta from somewhere outside the Gulf relatively recently.

Phragmites is frequently regarded as an aggressive, unwanted invader in the East and Upper Midwest. It has also earned this reputation in the Mississippi River Delta of southern Louisiana, where over the last 50 years, it has displaced species that provided valuable forage for wildlife, particularly migratory waterfowl (Hauber 1991). In other parts of coastal Louisiana, however, it is feared that Phragmites is declining as a result of increasing saltwater intrusion in the brackish marshes it occupies. Phragmites is apparently decreasing in Texas as well due to invasion of its habitat by the alien grass ARUNDO DONAX (Poole, pers. comm. 1985). Similarly, Phragmites is present in the Pacific states but is not regarded as a problem there. In fact, throughout the western U.S. there is some concern over decreases in the species' habitat and losses of populations.

Number of Occurrences: 81 to >300
Number of Occurrences Comments: Perhaps the most widespread plant species on Earth, with numerous large, presumably native stands on all continents except Antarctica. In addition, at least in North America, novel (Eurasian?) genotypes have become widely established along the Atlantic Coast and in scattered inland sites where Phragmites was not previously known historically (Kristin Saltonstall, presentation to Botanical Society of Washington, 5 June 2001).

Population Size Comments: Often but not always community dominant in larger occurrences (some of these non-native), but at lower density in some habitats. Intensely cloning, so genetic diversity at sites is much lower (Saltonstall, unpubl., 2001).

Overall Threat Impact Comments: IMPACTS (THREATS POSED BY THIS SPECIES)

Phragmites can be regarded as a stable, natural component of a wetland community if the habitat is pristine and the population does not appear to be expanding. Many native populations of Phragmites are "benign" and pose little or no threat to other species and should be left intact. Examples of areas with stable, native populations include sea-level fens in Delaware and Virginia and along Mattagota Stream in Maine (Rawinski 1985, pers. comm. 1992). In Europe, a healthy reed belt is defined as a "homogeneous, dense or sparse stand with no gaps in its inner parts, with an evenly formed lakeside borderline without aisles, shaping a uniform fringe or large lobes, stalk length decreasing gradually at the lakeside border, but all stalks of one stand of similar height; at the landside edge the reeds are replaced by sedge or woodland communities or by unfertilized grasslands" (Ostendorp 1989).

Stable populations may be difficult to distinguish from invasive populations, but one should examine such factors as site disturbance and the earliest collection dates of the species to arrive at a determination. If available, old and recent aerial photos can be compared to determine whether stands in a given area are expanding or not (Klockner, pers. comm. 1985).

Phragmites is a problem when and where stands appear to be spreading while other species typical the of the community are diminishing. Disturbances or stresses such as pollution, alteration of the natural hydrologic regime, dredging, and increased sedimentation favor invasion and continued spread of Phragmites (Roman et al. 1984). Other factors that may have favored recent invasion and spread of Phragmites include increases in soil salinity (from fresh to brackish) and/or nutrient concentrations, especially nitrate, and the introduction of a more invasive genotype(s) from the Old World (McNabb and Batterson 1991; Metzler and Rosza 1987, see GLOBAL RANGE section for further discussion).

Michael Lefor asserts that one reason for the general spread of Phragmites has been the destabilization of the landscape (pers. comm. 1993). In urban landscapes water is apt to collect in larger volumes and pass through more quickly (flashily) than formerly. This tends to destabilize substrates leaving bare soil open for colonization. Watersheds throughout eastern North America are flashier due to the proliferation of paved surfaces, lawns and roofs and the fact that upstream wetlands are largely filled with post-settlement/post agricultural sediments from initial land-clearing operations.

Many Atlantic coast wetland systems have been invaded by Phragmites as a result of tidal restrictions imposed by roads, water impoundments, dikes and tide gates. Tide gates have been installed in order to drain marshes to harvest salt hay, to control mosquito breeding and, most recently, to protect coastal development from flooding during storms. This alteration of marsh systems may favor Phragmites invasion by reducing tidal action and soil water salinity and lowering water tables.

Phragmites invasions may threaten wildlife because they alter the structure and function (wildlife support) of relatively diverse Spartina marshes (Roman et al. 1984). This is a problem on many of the eastern coastal National Fish and Wildlife Refuges including: Brigantine in NJ; Prime Hook and Bombay Hook in DE; Tinicum in PA; Chincoteague in VA; and Trustom Pond in RI.

Plant species and communities threatened by Phragmites are listed in the Monitoring section. Some of these instances are described below:

1. Massachusetts, a brackish pondlet near Horseneck Beach supports the state rare plant MYRIOPHYLLUM PINNATUM (Walter) BSP, which Phragmites is threatening by reducing the available open water and shading aquatic vegetation (Sorrie, pers. comm. 1985).

2. Maryland, at Nassawango Creek, a rare coastal plain peatland community is threatened by Phragmites (Klockner, pers. comm. 1985).

3. Ohio, at the Arcola Creek wetland, phragmites is threatening the state endangered plant CAREX AQUATILIS Wahlenb. (Young, pers. comm. 1985).

Phragmites invasions also increase the potential for marsh fires during the winter when the above ground portions of the plant die and dry out (Reimer 1973). Dense congregations of redwing blackbirds, which nest in Phragmites stands preferentially, increase chances of airplane accidents nearby. The monitoring and control of mosquito breeding is nearly impossible in dense Phragmites stands (Hellings and Gallagher 1992). In addition, Phragmites invasions can also have adverse aesthetic impacts. In Boston's Back Bay Fens, dense stands have obscured vistas intended by the park's designer, Frederick Law Olmstead (Penko, pers. comm. 1993).

As noted above Phragmites is not considered a threat in the West or most areas in the Gulf states.

Short-term Trend: Increase of >10%
Short-term Trend Comments: Increasing overall in North America, although decreasing at some sites, and some historically known genotypes of New England now possibly extirpated by introduction of more vigorous alien genotypes there (Saltonstall, unpubl., 2001).

Other NatureServe Conservation Status Information

Distribution
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Global Range: Phragmites australis is found on every continent except Antarctica and may have the widest distribution of any flowering plant (Tucker 1990). It is common in and near freshwater, brackish and alkaline wetlands in the temperate zones world-wide. It may also be found in some tropical wetlands but is absent from the Amazon Basin and central Africa. It is widespread in the United states, typically growing in marshes, swamps, fens, and prairie potholes, usually inhabiting the marsh-upland interface where it may form continuous belts (Roman et al. 1984).

Because Phragmites has invaded and formed near-monotypic stands in some North American wetlands only in recent decades there has been some debate as to whether it is indigenous to this continent or not. Convincing evidence that it was here long before European contact is now available from at least two sources. Niering and Warren (1977) found remains of Phragmites in cores of 3000 year old peat from tidal marshes in Connecticut. Identifiable Phragmites remains dating from 600 to 900 A.D. and constituting parts of a twined mat and other woven objects were found during archaeological investigations of Anasazi sites in southwestern Colorado (Kane & Gross 1986; Breternitz et al. 1986).

There is some suspicion that although the species itself is indigenous to North America, new, more invasive genotype(s) were introduced from the Old World (Metzler and Rosza 1987). Hauber et al. (1991) found that invasive Phragmites populations in the Mississippi River Delta differed genetically from a more stable population near New Orleans. They also examined populations elsewhere on the Gulf coast, from extreme southern Texas to the Florida panhandle, and found no genetic differences between those populations and the one near New Orleans (Hauber, pers. comm. 1992). This increased their suspicion that the invasive biotypes were introduced to the Delta from somewhere outside the Gulf relatively recently.

Phragmites is frequently regarded as an aggressive, unwanted invader in the East and Upper Midwest. It has also earned this reputation in the Mississippi River Delta of southern Louisiana, where over the last 50 years, it has displaced species that provided valuable forage for wildlife, particularly migratory waterfowl (Hauber 1991). In other parts of coastal Louisiana, however, it is feared that Phragmites is declining as a result of increasing saltwater intrusion in the brackish marshes it occupies. Phragmites is apparently decreasing in Texas as well due to invasion of its habitat by the alien grass ARUNDO DONAX (Poole, pers. comm. 1985). Similarly, Phragmites is present in the Pacific states but is not regarded as a problem there. In fact, throughout the western U.S. there is some concern over decreases in the species' habitat and losses of populations.

U.S. States and Canadian Provinces
Color legend for Distribution Map
NOTE: The distribution shown may be incomplete, particularly for some rapidly spreading exotic species.

U.S. & Canada State/Province Distribution
United States AL, AZ, CA, CO, CTexotic, DC, DE, FL, GAexotic, IA, ID, IL, IN, KS, KYexotic, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PAexotic, RIexotic, SC, SD, TN, TX, UT, VA, VT, WA, WI, WVexotic, WY
Canada AB, BC, MB, NB, NF, NS, NT, ONnative and exotic, PE, QCexotic, SK

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
CT Litchfield (09005)*, Middlesex (09007)*, New London (09011)*
DE Kent (10001), New Castle (10003), Sussex (10005)
MA Barnstable (25001), Berkshire (25003), Dukes (25007), Essex (25009), Middlesex (25017)
OH Champaign (39021), Erie (39043), Lake (39085), Lucas (39095), Seneca (39147), Summit (39153)
PA Crawford (42039), Erie (42049), Susquehanna (42115)
VT Addison (50001), Chittenden (50007)*, Franklin (50011), Grand Isle (50013), Orleans (50019), Washington (50023)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Concord (01070005)+, Lower Connecticut (01080205)+*, Charles (01090001)+, Cape Cod (01090002)+, Housatonic (01100005)+
02 Brandywine-Christina (02040205)+, Broadkill-Smyrna (02040207)+, Chincoteague (02040303)+, Upper Susquehanna (02050101)+
04 Blanchard (04100008)+, Lower Maumee (04100009)+, Cedar-Portage (04100010)+, Sandusky (04100011)+, Ashtabula-Chagrin (04110003)+, Winooski River (04150403)+*, Lake Champlain (04150408)+, St. Francois River (04150500)+
05 Middle Allegheny-Tionesta (05010003)+, Shenango (05030102)+, Tuscarawas (05040001)+, Upper Great Miami (05080001)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: Phragmites australis is a large perennial rhizomatous grass, or reed. The name Phragmites is derived from the Greek word for fence, phragma, in reference to its fence-like growth along streams.
Technical Description: Phragmites australis is a rhizomatous grass, or reed, with broad, flat leaf blades and large terminal infloresences. The roots are fibrous and there are three stem types: fleshy, ribbed, jointed horizontal rhizomes found 0.2 to 0.5 m underground and which can renew a stand; above-ground vertical rhizomes, which bear the aerial shoots; and erect aerial shoots which photosynthesize and bear the inflorescences (Haslam 1968). The erect shoots, or culms, arise from stout, creeping rhizomes and generally grow 1.5 to 4 m high. However, colonies with culms up to 7 m tall have been reported in Boston's Back Bay Fens (Penko, pers. comm. 1993) and the Danube Delta (Pallis). The leaf sheaths are somewhat loose and overlapping; the blades are flat and glabrous, up to 60 cm. long, 0.8-6 cm wide, tapering to a spiny point. The inflorescence is a feathery panicle, somewhat nodding, 15-50 cm long, whitish, tannish, brownish or purplish, rather dense, with slender, ascending branches. The rachillas (unbranched central axes of the spikelets) are clothed with long, silky hairs which contribute to the inflorescence's woolly appearance. The spikelets are numerous, 1.0-1.7 cm. long with 3-7 flowers apiece. The glumes are unequal in size, lanceolate, acute. The 1st glume is 2.5-5 mm long and the 2nd glume 5-7 mm long. The lemmas are narrow, long-acuminate; that of the lowest floret (flower and enclosing bracts) is somewhat longer so that its tip reaches those of the uppermost florets but it is empty or subtends a staminate (male) flower. The other florets are perfect (male+female) with paleas one half to two thirds the length of their lemmas. The perfect florets have three stamens and an ellipsoid ovary with two short stigmas topped with feathery stigmas. The hairs of the rachilla extend beyond the florets The above description was taken from Tucker (1990), Fernald (1950) and Ricciuti (1983).

Excellent illustrations of the species may be found in Mason (1957). Illustrations are also present in Hitchcock and Chase (1950), Gleason (1950) and a number of other regional floras.

The species base chromosome number is 12 (Tucker 1990). However, Haslam (1972) reported diploid numbers of 36, 48, 84 and 96 while anueploids with 2n = 42, 44, 46, 49, 50, 51, 52, 54, and 56 have also been reported (Gorenflot et al. 1972; Bjork 1967; Rodewald- Rudescu 1974). Clearly the species is extremely variable in chromosome compliment but no correlation between chromosome number, habitat and/or geography was found in a survey of 40 European populations (Raicu et al. 1972).

This species was long known as Phragmites communis (L.) Trin. However, P. australis is the earliest available valid name and therefore the correct name (Clayton 1968). Other synonyms that have been used for this species are Phragmites communis variety berlandieri (Fourn.) Fern. and Phragmites phragmites (L.) Karst. (Kartesz and Kartesz 1980).

CARRIZO (Mexico) Hitchcock and Chase (1950) state that in the southwestern United States this species and a similar grass, Arundo donax L., are referred to by the name CARRIZO. Neither species is now present on The Nature Conservancy's Carrizo Plain Preserve in California.

The species is sometimes called REED GRASS but this name is also used for a number of species in other genera, including Arundo donax. In the popular press it is occasionally incorrectly referred to as PAMPAS GRASS, a name more properly applied to Cortaderia selloana (Schultes) Asch. & Graebner.

Diagnostic Characteristics: Members of the genus Phragmites are superficially similar to Arundo. Sterile specimens of P. australis are sometimes misidentified as Arundo donax, a grass introduced to North America from Asia and now troublesome in natural areas, especially in California. The genera can be distinguished when in flower because the glumes of Phragmites are glabrous while those of Arundo are covered with soft, whitish hairs 6-8 mm long. In addition, the glumes are much shorter than the lemmas in Phragmites.
Duration: PERENNIAL
Reproduction Comments: Phragmites is typically the dominant species on areas that it occupies. It is capable of vigorous vegetative reproduction and often forms dense, virtually monospecific stands. Hara et al. (1993) classify sparse stands as those with densities of less than 100 culms m-2 and dense stands as those with densities of up to about 200 culms m-2 in wet areas or up to 300 culms m-2 in dry areas. Mammalian and avian numbers and diversity in the dense stands are typically low (Jones and Lehman 1987). Newly opened sites may be colonized by seed or by rhizome fragments carried to the area by humans in soils and on machinery during construction or naturally in floodwaters.

The plants generally flower and set seed between July and September and may produce great quantities of seed. In the northeast, seeds are dispersed between November and January. However, in some cases, most or all of the seed produced is not viable (Tucker 1990). The seeds are normally dispersed by wind but may be transported by birds such as red-winged blackbirds that nest among the reeds (Haslam 1972). Following seed set, nutrients are translocated down into the rhizomes and the above- ground portions of the plant die back for the season (Haslam 1968).

Temperature, salinity and water levels affect seed germination. Water depths of more than 5 cm and salinities above 20 ppt (2%) prevent germination (Kim et al. 1985; Tucker 1990). Germination is not affected by salinities below 10 ppt (1%) but declines at higher salinities. Percentage germination increases with increasing temperature from 16 to 25 oC while the time required to germinate decreases from 25 to 10 days over the same temperature range. Barry Truitt (pers. comm. 1992) has observed that areas covered by thick mats of wrack washed up during storms and high water events are frequently colonized by Phragmites on the Virginia Coast Reserve. It is not clear whether it establishes from rhizome pieces washed in with the wrack or from seed that blows in later.

Once a new stand of Phragmites takes hold it spreads, predominantly through vegetative reproduction. Individual rhizomes live for 3 to 6 years and buds develop at the base of the vertical type late in the summer each year. These buds mature and typically grow about 1 meter (up to 10 m in newly colonized, nutrient-rich areas) horizontally before terminating in an upward apex and going dormant until spring. The apex then grows upward into a vertical rhizome which in turn produces buds that will form more vertical rhizomes. Vertical rhizomes also produce horizontal rhizome buds, completing the vegetative cycle. These rhizomes provide the plant with a large absorbent surface that brings the plant nutrients from the aquatic medium (Chuchova and Arbuzoba 1970). The aerial shoots arise from the rhizomes. They are most vigorous at the periphery of a stand where they arise from horizontal rhizomes, as opposed to old verticals (Haslam 1972).

Known Pests: APHIDS
Ecology Comments: Salinity and depth to the water table are among the factors which control the distribution and performance of Phragmites. Maximum salinity tolerances vary from population to population; reported maxima range from 12 ppt (1.2%) in Britain to 29 ppt in New York state to 40 ppt on the Red Sea coast (Hocking et al. 1983). Dense stands normally lose more water through evapotranspiration than is supplied by rain (Haslam 1970). However, rhizomes can reach down almost 2 meters below ground, their roots penetrating even deeper, allowing the plant to reach low lying ground water (Haslam 1970). Killing frosts may knock the plants back temporarily but can ultimately increase stand densities by stimulating bud development (Haslam 1968).

Phragmites has a low tolerance for wave and current action which can break its culms (vertical stems) and impede bud formation in the rhizomes (Haslam 1970). It can survive, and in fact thrive, in stagnant waters where the sediments are poorly aerated at best (Haslam 1970). Air spaces in the above-ground stems and in the rhizomes themselves assure the underground parts of the plant with a relatively fresh supply of air. This characteristic and the species' salinity tolerance allow it to grow where few others can survive (Haslam 1970). In addition the build up of litter from the aerial shoots within stands prevents or discourages other species from germinating and becoming established (Haslam 1971a). The rhizomes and adventitious roots themselves form dense mats that further discourage competitors. These characteristics are what enable Phragmites to spread, push other species out and form monotypic stands.

Such stands may alter the wetlands they colonize, eliminating habitat for valued animal species. On the other hand, the abundant cover of litter in Phragmites stands may provide habitat for some small mammals, insects and reptiles. The aerial stems provide nesting sites for several species of birds, and Song Sparrows have been seen eating Phragmites' seeds (Klockner, pers. comm. 1985). Muskrats (ONDATRA ZIBETHICUS) use Phragmites for emergency cover when low lying marshes are swept by storm tides and for food when better habitats are overpopulated (Lynch et al. 1947).

Studies conducted in Europe indicate that gall-forming and stem- boring insects may significantly reduce growth of Phragmites (Durska 1970; Pokorny 1971). Skuhravy (1978) estimated that roughly one-third of the stems in a stand may be damaged reducing stand productivity by 10-20%. Mook and van der Toorn (1982) found yields were reduced by 25 to 60% in stands heavily infested with lepidopteran stem- or rhizome-borers. Hayden (1947) suggested that aphids (HYALOPTERUS PRUNI) heavily damaged a Phragmites stand in Iowa. On the other hand work in Europe by Pintera (1971) indicated that although high densities of aphids may bring about reductions in Phragmites shoot height and leaf area they had little effect on shoot weight. Like other emergent macrophytes, Phragmites has tough leaves and appears to suffer little grazing by leaf-chewing insects (Penko 1985).

As mentioned above, there is great concern about recent declines in Phragmites in Europe where the species is still used for thatch. In fact, the journal Aquatic Botany devoted an entire issue (volume 35 no.1, September 1989) to this subject. Factors believed responsible for the declines include habitat destruction and manipulation of hydrologic regimes by humans, grazing, sedimentation and decreased water quality (eutrophication) (Ostendorp 1989).

Detailed reviews of the ecology and physiological ecology of Phragmites are provided by Haslam (1972; 1973) and Hocking et al. (1983) and an extensive bibliography is provided by van der Merff et al. (1987).

Palustrine Habitat(s): Bog/fen, FORESTED WETLAND
Terrestrial Habitat(s): Grassland/herbaceous, Urban/edificarian
Habitat Comments: Phragmites is especially common in alkaline and brackish (slightly saline) environments (Haslam 1972, 1971b), and can also thrive in highly acidic wetlands (Rawinski, pers. comm. 1985). However, Phragmites does not require, nor even prefer these habitats to freshwater areas. Its growth is greater in fresh water but it may be outcompeted in these areas by other species that cannot tolerate brackish, alkaline or acidic waters. It is often found in association with other wetland plants including species from the following genera: SPARTINA, CAREX, NYMPHAEA, TYPHA, GLYCERIA, JUNCUS, MYRICA, TRIGLOCHIN, CALAMAGROSTIS, GALIUM, and PHALARIS (Howard et al. 1978).

Phragmites occurs in disturbed areas as well as pristine sites. It is especially common along railroad tracks, roadside ditches, and piles of dredge spoil, wherever even slight depressions hold water (Ricciuti 1983). Penko (pers. comm. 1993) has observed stunted Phragmites growing on acidic tailings (Ph 2.9) from an abandoned copper mine in Vermont. Various types of human manipulation and/or disturbance are thought to promote Phragmites (Roman et al. 1984). For example, restriction of the tidal inundation of a marsh may result in a lowering of the water table, which may in turn favor Phragmites. Likewise, sedimentation may promote the spread of Phragmites by elevating a marsh's substrate surface and effectively reducing the frequency of tidal inundation (Klockner, pers. comm. 1985).

A number of explanations have been proposed to account for the recent dramatic increases in Phragmites populations in the northeastern and Great Lakes States. As noted above, habitat manipulations and disturbances caused by humans are thought to have a role. In some areas Phragmites may also have been promoted by the increases in soil salinity which result when de- icing salt washes off roads and into nearby ditches and wetlands (McNabb and Batterson 1991). On the other hand, bare patches of road sand washed into ditches and wetlands may be of greater importance. Phragmites seeds are shed from November through January and so may be among the first propagules to reach these sites. If the seeds germinate and become established the young plants will usually persist for at least two years in a small, rather inconspicuous stage, resembling many other grasses. Later, perhaps after the input of nutrients, they may take off and assume the tall growth form that makes the species easily identifiable . Increases in soil nutrient concentrations, may come from runoff from farms and urban areas. It has also been suggested increases in nutrient concentrations, especially nitrates, are primarily responsible for increases in Phragmites populations. Ironically, eutrophication and increases in nitrate levels are sometimes blamed for the decline of Phragmites populations in Europe (Den Hartog et al. 1989).

Economic Attributes Not yet assessed
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Management Summary
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Stewardship Overview: Communities that have stable Phragmites populations present but have been exposed to disturbance should be closely monitored. Management is necessary when evidence indicates that Phragmites has spread, or is spreading and threatening the integrity of rare communities, invading the habitat of rare plants or animals or interfering with the wildlife support function of refuges. Cutting, burning, application of herbicides (in particular Rodeo), or water management schemes are possible control measures. The measure(s) used will depend on a number of factors including the size and location of the infestation, the presence of sensitive rare species and the work-force available.
Restoration Potential: Areas that have been invaded by Phragmites have excellent potential for recovery. Management programs have proven that phragmites can be controlled, and natural vegetation will return. However, monitoring is imperative because Phragmites tends to reinvade and control techniques may need to be applied several times or, perhaps, in perpetuity. It is also important to note that some areas have been so heavily manipulated and degraded that it may be impossible to eliminate Phragmites from them. For example, it may be especially difficult to control Phragmites in freshwater impoundments that were previously salt marshes.
Management Requirements: Invasive populations of Phragmites must be managed in order to protect rare plants that it might outcompete, valued animals whose habitat it might dominate and degrade, and healthy ecosystems that it might greatly alter.

BIOLOGICAL CONTROL: Biological control does not appear to be an option at this time. No organisms which significantly damage Phragmites australis but do not feed on other plant species have been identified. In addition, some of the arthropods that feed on Phragmites are killed by winter fires and thus would likely be eliminated from the systems where prescribed fires are used. Coots, nutria, and muskrats may feed on Phragmites but appear to have limited impacts on its populations (Cross and Fleming 1989).

BURNING: Prescribed burning has

BURNING: Prescribed burning does not reduce the growing ability of Phragmites unless root burn occurs. Root burn seldom occurs, however, because the rhizomes are usually covered by a layer of soil, mud and/or water. Fires in Phragmites stands are dangerous because this species can cause spot-fires over 100 feet away (Beall 1984). Burning does remove accumulated Phragmites leaf litter, giving the seeds of other species area to germinate.

CHEMICAL: Rodeo TM, a water solution of the isopropylamine salt of glyphosate is commonly used for Phragmites control. This herbicide is not, however, selective and will kill grasses and broadleaved plants alike. Toxicity tests indicate that it is virtually non-toxic to all aquatic animals tested. It should be noted that many of these tests were performed by or for Monsanto, the company which manufactures Rodeo.

Rodeo must be mixed with water and a surfactant which allows it to stick to and subsequently be absorbed by the plant (Beall 1984). Instructions for application are on the Rodeo label.

Application of Rodeo must take place after the tasseling stage when the plant is supplying nutrients to the rhizome.

CUTTING: Cutting has been used successfully to control phragmites. Since it is a grass, cutting several times during a season, at the wrong times, may increase stand density (Osterbrock 1984). However, if cut just before the end of July, most of the food reserves produced that season are removed with the aerial portion of the plant, reducing the plant's vigor. This regime may eliminate a colony if carried out annually for several years. Care must be taken to remove cut shoots to prevent their sprouting and forming stolons (Osterbrock 1984).

GRAZING, DREDGING, AND DRAINING: Grazing, dredging, and draining are other methods that have often been used to reduce stand vigor (Howard, Rhodes and Simmers 1978). However, draining and dredging are not appropriate for use on most preserves (Osterbrock, 1984).

Grazing may trample the rhizomes and reduce vigor but the results are limited (Cross and Fleming 1989). Van Deursen and Drost (1990) found that cattle consumed 67-98% of above-ground biomass; in a four year study, they found that reed populations may reach new equilibria under grazing regimes.

MANIPULATION OF WATER LEVEL AND SALINITY: Reintroduced tidal action and salinity can reduce Phragmites vigor and restore the community's integrity.

MOWING, DISKING, AND PULLING: Beall (1984) discourages mowing and disking. Mowing only affects the above ground portion of the plant, so mowing would have to occur annually. To remove the rhizome, disking could be employed. However, discing could potentially result in an increase of Phragmites since pieces of the rhizome can produce new plants. Cross and Fleming (1989) describe successful mowing regimes of several year duration during the summer (August and September) and disking in summer or fall.

Monitoring Requirements: Phragmites populations require close monitoring in order to determine whether they are increasing in area or not. Populations that are growing may quickly threaten or even eliminate rare elements. Monitoring provides the data needed in order to decide if control measures are necessary. If and when a control program is begun it is important to monitor targeted populations so that the program's effectiveness can be determined. If it is possible to leave untreated control areas without jeopardizing the success of the control program these should be monitored as well for comparison. It is imperative to continue monitoring even if a control program succeeds initially because Phragmites may reinvade and the sooner this is detected the easier it will be to combat.

To assess if a Phragmites colony is spreading, quantitative measurements should be made of percentage of aerial cover, stem density and culm height, especially at the periphery of the stand. Annual data should be compared to detect if the colony is expanding and the stand gaining vigor. Inventories of the vegetation in and near the colony should also be carried out in order to determine whether declines in species diversity are occurring.

In Europe, reed declines have been documented by comparing areas covered by Phragmites colonies on up-to-date maps or aerial photographs with older sources, monitoring permanent quadrats within or at the border of the reed belt and mapping the stubble fields left after die-back (Ostendorp 1989). In lakes (Stark and Dienst 1989), wooden poles 5 m apart were connected with string and the numbers of reed stalks directly below the strings were counted each year in the spring.


Management Programs: BURNING: Prescribed burning has been used with success after chemical treatment at The Brigantine National Wildlife Refuge, NJ (Beall 1984) and in Delaware (Lehman, pers. comm. 1992). Occasional burning has been used in Delaware in conjunction with intensive spraying and water level management. This helps remove old canes and allows other vegetation to grow (Daly, pers. comm. 1991).

According to Cross and Fleming (1989), late summer burns may be effective, but winter and spring burning may in fact increase the densities of spring crops.

CHEMICAL: At the Brigantine National Wildlife Refuge, Rodeo was applied aerially after the plants tasseled in late August. The application resulted in a 90% success. The following February, a fast moving prescribed burn was carried out to remove litter, exposing the seed bed for re-establishment of marsh vegetation.

Aerial spraying has been used since 1983 in many Delaware state wildlife refuges (Lehman, pers. comm. 1992). Using Rodeo, the state sprays freshwater and brackish impoundments, brackish marshes, and salt marshes from early September to early October; this is combined with winter burns between the first and second year of spraying.

In more fragile situations where Phragmites is threatening a rare plant or community, aerial spray techniques are inappropriate because such large-scale application could kill the community that the entire operation was designed to protect. Glyphosate can be applied to specific plants and areas by hand with a backpack sprayer. Wayne Klockner of The Nature Conservancy's Maryland Field Office has been successful in eliminating most Phragmites at the Nassawango preserve by applying glyphosate by hand with a backpack sprayer (Klockner, pers. comm. 1985).

CUTTING: In the Arcola Creek Preserve in Ohio, cutting reduced the vigor of the Phragmites colony.

Cutting an area 25' x 25' to waist height with a hedge clippers and the applying one drop of Roundup with a syringe with a large needle into the top of the plant in a brackish- freshwater marsh was begun in Constitution Marsh in New York in 1991 (Keene, pers. comm. 1991). Initial results indicate 90% eradication.

MANIPULATION OF WATER LEVEL AND SALINITY: A self-regulating tide gate which reintroduced saltwater tidal action was used to help restore a diked marsh in Fairfield, Connecticut (Thomas Steinke pers. comm. 1992; Bongiorno et al. 1984); plant density declined dramatically the following year.

Flooding can be used to control Phragmites when 3 feet of water covers the rhizome for an extended period during the growing season, usually four months (Beall 1984). However, many areas can not be flooded to such depths. Furthermore, flooding could destroy the communities or plants targeted for protection.

Open Marsh Water Management (OMWM) has been used as a method to control Phragmites (Niniviaggi, pers. comm. 1991; Rozsa, pers. comm. 1992).

Monitoring Programs: The programs listed below used various methods to control Phragmites populations and are monitoring the success of these actions including the degree of recovery of native species and the longevity of the control.

CONNECTICUT Monitoring phragmites reduction and replacement vegetation after reintroducing tidal flow, using transects and line intercept. Contact: Charles T. Roman, William Niering, Scott Warren Dept of Botany Connecticut College New London, CT 06320

Monitoring Phragmites reaction to reintroduction of tidal flow and salinity. Contact: Tom Steinke Fairfield Conservation Commission, Independence Hall 725 Old Post Road Fairfield, CT 06430 203-256-3071

Annual cutting of perimeter of one-acre stand and monitoring with aerial photos on five-year basis; herbicide application on small patch at edge of salt marsh. Contact: Beth Lapin The Nature Conservancy 55 High Street Middletown, CT 06457 203-344-0716

DELAWARE Aerial spraying of RodeoTM (glyphosate) and water management plan using stoplogs and vegetation analyses of replacement species. Contact: Paul Daly Bombay Hook National Wildlife Refuge RD #1 Box 147 Smyrna, DE 19977 302-653-9345

Monitoring the ecological factors (water table level, PH, salinity) governing the growth of Phragmites in 4 habitats; 1) open high salt marsh, 2) open low salt marsh, 3) brackish water impoundment, 4) freshwater impoundment. Investigating Phragmites control with glyphosate. Contact: Wayne Lehman and Bill Jones Delaware Division of Fish and Wildlife P.O. Box 1401 Dover, DE 19903 302-653-2079.

MASSACHUSETTS Cutting three times in one season, followed by opening of tidal flood gate. Contact: Mike Wheelwright Department of Public Works Town of Quincy Quincy, MA 02169 617-773-1380 x210 Contact: Ross Dobberteen Lelito Environmental Consultants 2 Bourbon St. #102 Peabody, MA 01960 508-535-7861

MARYLAND Nassawango Creek, A Nature Conservancy Preserve RodeoTM (glyphosate) applied with backpack sprayer. Contact: Wayne Klockner The Nature Conservancy Chevy Chase Center Office Building 35 Wisconsin Circle, Suite 304 Chevy Chase Maryland 20815 301-656-8073

Spraying with RodeoTM (glyphosate), burning. Contact: Steve Ailstock Environmental Center Anne Arundel Community College Arnold, MD

NEW JERSEY Aerial spraying with RodeoTM (glyphosate), prescribed burn to remove litter. Contact: David Beall Edwin B. Forsythe National Wildlife Refuge Brigantine Division PO Box 72, Great Creek RD Oceanville, NJ 08231 609-652-1665

Pulling rhizomes, chemical spray. Contact: Liz Johnson The Nature Conservancy 17 Fairmont Road Pottersville, NJ 07979 908-439-3007 NEW YORK:

Using water level manipulation and burning. Contact: Bob Parris Wertheim NWR P.O. Box 21 Smith Road Shirley, NY 11967 516-286-0485

PENNSYLVANIA Chemical application. Contact: Dick Nugent Tinicum Environmental Center Scott Plaza 2 Philadelphia, PA 19113 215-521-0663

OHIO Arcola Creek Wetland, Morgan Marsh Controlling Phragmites by cutting. Contact: Terry Seidel The Nature Conservancy Ohio Field Office 1504 West 1st Ave. Columbus, Ohio 43212 614-486-6789

VIRGINIA RodeoTM (glyphosate) application and monitoring program. Contact: Irvin Ailes Chincoteague National Wildlife Refuge Chincoteague, VA 23336 804-336-6122

Winter burns. Contact: Marilyn Ailes Public Works Office Building Q29 Aegis Combat System Center Wallops Island, VA 23337 804-824-2082

Management Research Programs: LOUISIANA Aerial photographs of the Mississippi River Delta indicated that different stands of Phragmites had different infrared signatures. Isozyme analyses were performed on samples from these stands in order to determine whether they differed genetically and constituted different clones. Two distinct clones were found and both differed from stands elsewhere on the Gulf coast. Additional isozymal work is planned on populations from elsewhere on the Gulf coast and, if time allows, from populations in the eastern and Great Lakes states as well

For research on population biology and control methods refer to BIOLOGICAL MONITORING PROGRAMS section.

Management Research Needs: Research on the following facets of Phragmites invasions and basic biology are needed: 1. what types and levels of disturbance and stress induce Phragmites to invade and/or dominate an area?; 2. how effective are various control programs and what conditions promote or allow Phragmites to reinvade areas from which it has been removed?; 3. if Phragmites does reinvade how long does this process take?; 4. are there ways to alleviate or mitigate for the stresses that induce the spread of Phragmites?; 5. can the use of competitive plantings of TYPHA or other desirable species be used to control Phragmites.
Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank)
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Disclaimer: While I-Rank information is available over NatureServe Explorer, NatureServe is not actively developing or maintaining these data. Species with I-RANKs do not represent a random sample of species exotic in the United States; available assessments may be biased toward those species with higher-than-average impact.

I-Rank: High
Rounded I-Rank: High
I-Rank Reasons Summary: Phragmites invasions increase the potential for marsh fires, form dense mats that discourage competitors in a layering effect, and alter the wetlands they colonize, eliminating habitat for other species. Rhizomes and roots form dense mats and monotypic stands. The species can become nearly monospecific in areas and negatively affect native plants and wildlife. Phragmites occurs in disturbed areas as well as pristine sites and is known to negatively affect several rare plants throughout its range. Although the species itself is indigenous to North America and extremely widespread, new, more invasive genotype(s) were introduced from the Old World and it is these that are of the greatest concern as invasives. Phragmites is not considered a threat in the West or most areas in the Gulf states. It is a problem when and where stands appear to be spreading while other species typical the of the community are diminishing. The portion of the native population that has become invasive (particularly in brackish coastal marshes of the northeastern U.S. and along streambanks and roadside ditches in inland wetlands, including alkaline swamps; also brackish marshes and freshwater tidal marshes in the Chesapeake Bay) may have become hybridized with a non-native genotype (perhaps from Eurasia) to form the highly invasive and problematic variety currently degrading native wetlands. Long distance dispersal potential is high as this species has adapted to disperse along human utilized water corridors including those inhospitable to many plants such as roadside ditches. Many reproductive characters assist this species in being highly invasive. Areas invaded by Phragmites often have excellent potential for recovery but a combination of control measures is often necessary over several years. Negative impacts on native species can be high even when control is properly monitored.
Subrank I - Ecological Impact: High
Subrank II - Current Distribution/Abundance: High
Subrank III - Trend in Distribution/Abundance: High
Subrank IV - Management Difficulty: High/Medium
I-Rank Review Date: 26Jun2006
Evaluator: J. Cordeiro
Native anywhere in the U.S?
Native Range: Phragmites australis is found on every continent except Antarctica and may have the widest distribution of any flowering plant (Tucker, 1990).

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Screening Questions

S-1. Established outside cultivation as a non-native? YES
Comments: The portion of this native species that has become invasive (particularly in brackish coastal marshes of the northeastern U.S. and along streambanks and roadside ditches in inland wetlands, including alkaline swamps; also brackish marshes and freshwater tidal marshes in the Chesapeake Bay) may have become hybridized with a non-native genotype (perhaps from Eurasia) to form the highly invasive and problematic variety currently degrading native wetlands (Chambers et al., 1999; Marks et al., 1994; Richburg et al., 2001; Saltonstall, 2003). A low-cost restriction fragment length polymorphism (RFLP) assay was recently developed (Saltonstall, 2003) to distinguish native, non-native, and Gulf Coast type populations of Phragmites from each other.

S-2. Present in conservation areas or other native species habitat? Yes
Comments: Phragmites is especially common in alkaline and brackish (slightly saline) environments (Haslam 1972, 1971b), and can also thrive in highly acidic wetlands (Rawinski, pers. comm. 1985). However, Phragmites does not require, nor even prefer these habitats to freshwater areas. Its growth is greater in fresh water but it may be outcompeted in these areas by other species that cannot tolerate brackish, alkaline or acidic waters. It is widespread in the United states, typically growing in marshes, swamps, fens, and prairie potholes, usually inhabiting the marsh-upland interface where it may form continuous belts (Roman et al. 1984).

Subrank I - Ecological Impact: High

1. Impact on Ecosystem Processes and System-wide Parameters:Moderate significance
Comments: Phragmites invasions increase the potential for marsh fires during the winter when the above ground portions of the plant die and dry out (Reimer, 1973). Rhizomes and roots form dense mats that discourage competitors in a layering effect (Marks et al., 2001) and pushing out other species to form monotypic stands. Stands may alter the wetlands they colonize, eliminating habitat for other species. Dense colonies produce a large litter biomass that increases sediment accretion and bottom aggradation, leading to progressive drying out of littoral zones.

2. Impact on Ecological Community Structure:High significance
Comments: Phragmites occurs in disturbed areas as well as pristine sites. Rhizomes and roots form dense mats that discourage competitors in a layering effect (Marks et al., 2001) and pushing out other species to form monotypic stands. Because of its wide impacts on ecological systems and communities, it is assumed that when Phragmites invades a natural area with species or communities of conservation concern, alteration of the habitat will have a trickle down effect in terms of impact. Phragmites invasions may threaten wildlife because they alter the structure and function (wildlife support) of relatively diverse Spartina marshes (Roman et al. 1984). This is a problem on many of the eastern coastal National Fish and Wildlife Refuges including: Brigantine in NJ; Prime Hook and Bombay Hook in DE; Tinicum in PA; Chincoteague in VA; and Trustom Pond in RI. Richburg et al. (2001) found a population of Phragmites that had invaded an adjacent highway bog in Massachusetts sometime after the 1950s had recently become very dense and highly invasive dominating at the expense of other species in most plots surveyed. Impacts to several state listed rare plant and animal species is unknown but likely deleterious. Richburg et al. (2001) demonstrated that Phragmites negatively impacts the graminoid fen as indicated by lower cover valued for many of the previously common fen plant species; thereby impacting impacts on both the species themselves and the structure of the community. Because individual plants reach 1 to 5 meters in height, Phragmites is one of the tallest marsh plants, conferring at a competetive advantage for light over other platns (Lindsay, 2000; Hudon, 2004). In a study on the St. Lawrence River, this species (as well as a few other aquatic wetland invasive plant species) was found to expand aggressively to a point of almost monospecific dominance during periods of low water levels (be they natural or artificial) as the plants monopolize light and space better than less aggressive species (Hudon, 2004).

3. Impact on Ecological Community Composition:High significance
Comments: Phragmites is frequently regarded as an aggressive, unwanted invader in the East and Upper Midwest. It has also earned this reputation in the Mississippi River Delta of southern Louisiana, where over the last 50 years, it has displaced species that provided valuable forage for wildlife, particularly migratory waterfowl (Hauber 1991). In other parts of coastal Louisiana, however, it is feared that Phragmites is declining as a result of increasing saltwater intrusion in the brackish marshes it occupies. Phragmites is apparently decreasing in Texas as well due to invasion of its habitat by the alien grass Arundo donax (Poole, pers. comm. 1985). Similarly, Phragmites is present in the Pacific states but is not regarded as a problem there. In fact, throughout the western U.S. there is some concern over decreases in the species' habitat and losses of populations. Phragmites often grows in near monotypic stands and effectively out-competes other vegetation (Marks et al., 2001). It also offers poor-quality habitats for larval and juvenile fish (Meyer et al., 2001). It further reduces avian diversity by limiting available nesting and feeding habitat for waterfowl (Chambers et al., 1999). Because it has lower nutritive value than other aquatic wetland plants, it unifies faunal food quality and thus the structure of food webs that may be supported by wetlands.

4. Impact on Individual Native Plant or Animal Species:High significance
Comments: Phragmites is often found in association with other wetland plants including species from the following genera: Spartina, Carex, Nymphaea, Typha, Clyceria, Juncus, Myrica, Triglochin, Calamagrostis, Galium, and Phalaris (Howard et al. 1978).

Dense congregations of redwing blackbirds, which nest in Phragmites stands preferentially, increase chances of airplane accidents nearby. The monitoring and control of mosquito breeding is nearly impossible in dense Phragmites stands (Hellings and Gallagher 1992). Phragmites often grows in near monotypic stands and effectively out-competes other vegetation (Marks et al., 2001).

Richburg et al. (2001) found a population of Phragmites that had invaded an adjacent highway bog in Massachusetts sometime after the 1950s had recently become very dense and highly invasive dominating at the expense of other species in most plots surveyed. Impacts to several state listed rare plant and animal species is unknown but likely deleterious. Richburg et al. (2001) demonstrated that Phragmites negatively impacts the graminoid fen as indicated by lower cover valued for many of the previously common fen plant species; thereby impacting impacts on both the species themselves and the structure of the community. Negative impacts on marsh nekton animals (Fundulus heteroclitus, Palaemonetes pugio, Callinectes sapidus, Uca minax) have not been demonstrated as these animals are using Phragmites dominated wetlands in the Huydson River, New York (Hanson et al., 2002).


5. Conservation Significance of the Communities and Native Species Threatened:High/Moderate significance
Comments: Phragmites occurs in disturbed areas as well as pristine sites. Because of its wide impacts on ecological systems and communities, it is assumed that when Phragmites invades a natural area with species or communities of conservation concern, alteration of the habitat will have a trickle down effect in terms of impact. Some plant species and communities threatened by Phragmites include:

1. Massachusetts, a brackish pondlet near Horseneck Beach supports the state rare plant Myriophyllum pinnatum (Walter) BSP, which Phragmites is threatening by reducing the available open water and shading aquatic vegetation (Sorrie, pers. comm. 1985).

2. Maryland, at Nassawango Creek, a rare coastal plain peatland community is threatened by Phragmites (Klockner, pers. comm. 1985).

3. Ohio, at the Arcola Creek wetland, phragmites is threatening the state endangered plant Carex aquatilis Wahlenb. (Young, pers. comm. 1985).


Subrank II. Current Distribution and Abundance: High

6. Current Range Size in Nation:High significance
Comments: Crow and Hellquist (2000b) list western hemisphere range as Quebec west to British Columbia, south to Florida, Texas, California, and Mexico; and in Central America, but it is found on every continent except Antarctica and may have the widest distribution of any flowering plant (Marks et al., 2001). Because Phragmites has invaded and formed near-monotypic stands in some North American wetlands only in recent decades there has been some debate as to whether it is indigenous to this continent or not. Convincing evidence that it was here long before European contact is now available from at least two sources. Niering and Warren (1977) (cited in Marks et al., 2001) found remains of Phragmites in cores of 3000 year old peat from tidal marshes in Connecticut. Identifiable Phragmites remains dating from 600 to 900 A.D. and constituting parts of a twined mat and other woven objects were found during archaeological investigations of Anasazi sites in southwestern Colorado (Kane and Gross, 1986; Breternitz et al., 1986; both cited in Marks et al., 2001).

Although the species itself is indigenous to North America, new, more invasive genotype(s) were introduced from the Old World and it is these that are of the greatest concern as invasives (see under Prop. Having Negative Impacts).


7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:High/Moderate significance
Comments: Phragmites is not considered a threat in the West or most areas in the Gulf states. Phragmites can be regarded as a stable, natural component of a wetland community if the habitat is pristine and the population does not appear to be expanding. Many native populations of Phragmites are "benign" and pose little or no threat to other species and should be left intact. Recent studies suggest Phragmites marshes may function as viable wetland habitat (Marks et el., 2001; Warrent et al., 2001; Hanson et al., 2001). Examples of areas with stable, native populations include sea-level fens in Delaware and Virginia and along Mattagota Stream in Maine (Rawinski 1985, pers. comm. 1992). In Europe, a healthy reed belt is defined as a "homogeneous, dense or sparse stand with no gaps in its inner parts, with an evenly formed lakeside borderline without aisles, shaping a uniform fringe or large lobes, stalk length decreasing gradually at the lakeside border, but all stalks of one stand of similar height; at the landside edge the reeds are replaced by sedge or woodland communities or by unfertilized grasslands" (Ostendorp 1989).

Phragmites is a problem when and where stands appear to be spreading while other species typical the of the community are diminishing. Disturbances or stresses such as pollution, alteration of the natural hydrologic regime, dredging, and increased sedimentation favor invasion and continued spread of Phragmites (Roman et al. 1984).

The portion of the native population that has become invasive (particularly in brackish coastal marshes of the northeastern U.S. and along streambanks and roadside ditches in inland wetlands, including alkaline swamps; also brackish marshes and freshwater tidal marshes in the Chesapeake Bay) may have become hybridized with a non-native genotype (perhaps from Eurasia) to form the highly invasive and problematic variety currently degrading native wetlands (Amsberry et al., 2000; Chambers et al., 1999; Marks et al., 1994; Richburg et al., 2001; Saltonstall, 2002; 2003). A low-cost restriction fragment length polymorphism (RFLP) assay was recently developed (Saltonstall, 2003) to distinguish native, non-native, and Gulf Coast type populations of Phragmites from each other.

Stable populations are difficult to distinguish from invasive ones but factors such as site disturbance and earliest collection dates should be utilized to arrive at a determination. Different invasive gentotypes are known from the Mississippi River Delta and Gulf Coast region (Hauber et al., 1991; Saltonstall, 2003), New England (where native genotypes are likely extinct) and the northeast Atlantic coast (Saltonstall, 2002; 2003), the tidal marshes of the upper Chesapeake Bay region (Rice et al., 2000) and the U.S. and Canadian Great Lakes (Hudon et al., 2005). Saltonstall (2002) demonstrated rapid replacement of native lineages by invasive ones in marshes of Connecticut and Massachusetts by 1940. This invasion is on a scale comparable (if not greater than) other known wetland invaders such as purple loosestrife and salt ceader, but appears to still be in a phase of expansion into new areas.


8. Proportion of Nation's Biogeographic Units Invaded:Moderate significance
Comments: It is conservatively estimated that over 25 ecoregions have been invaded by the invasive strain of Phragmites with almost all ecoregions having some form (either native or non-native) strains present (Cordeiro, pers. obs. March 2006 based on TNC, 2001). Different invasive gentotypes are known from the Mississippi River Delta and Gulf Coast region (Hauber et al., 1991; Saltonstall, 2003), New England (where native genotypes are likely extinct) and the northeast Atlantic coast (Saltonstall, 2002; 2003), the tidal marshes of the upper Chesapeake Bay region (Rice et al., 2000) and the U.S. and Canadian Great Lakes (Hudon et al., 2005).

9. Diversity of Habitats or Ecological Systems Invaded in Nation:High significance
Comments: Phragmites is especially common in alkaline and brackish (slightly saline) environments (Haslam 1972, 1971b), and can also thrive in highly acidic wetlands (Rawinski, pers. comm. 1985). However, Phragmites does not require, nor even prefer these habitats to freshwater areas. Its growth is greater in fresh water but it may be outcompeted in these areas by other species that cannot tolerate brackish, alkaline or acidic waters. It is often found in association with other wetland plants including species from the following genera: Spartina, Carex, Nymphaea, Typha, Clyceria, Juncus, Myrica, Triglochin, Calamagrostis, Galium, and Phalaris (Howard et al. 1978).

Phragmites occurs in disturbed areas as well as pristine sites. It is especially common along railroad tracks, roadside ditches, and piles of dredge spoil, wherever even slight depressions hold water (Ricciuti 1983). Penko (pers. comm. 1993) has observed stunted Phragmites growing on acidic tailings (Ph 2.9) from an abandoned copper mine in Vermont. Various types of human manipulation and/or disturbance are thought to promote Phragmites (Roman et al. 1984). For example, restriction of the tidal inundation of a marsh may result in a lowering of the water table, which may in turn favor Phragmites. Likewise, sedimentation may promote the spread of Phragmites by elevating a marsh's substrate surface and effectively reducing the frequency of tidal inundation (Klockner, pers. comm. 1985).

A number of explanations have been proposed to account for the recent dramatic increases in Phragmites populations in the northeastern and Great Lakes States. As noted above, habitat manipulations and disturbances caused by humans are thought to have a role. In some areas Phragmites may also have been promoted by the increases in soil salinity which result when de- icing salt washes off roads and into nearby ditches and wetlands (McNabb and Batterson 1991). On the other hand, bare patches of road sand washed into ditches and wetlands may be of greater importance. Phragmites seeds are shed from November through January and so may be among the first propagules to reach these sites. If the seeds germinate and become established the young plants will usually persist for at least two years in a small, rather inconspicuous stage, resembling many other grasses. Later, perhaps after the input of nutrients, they may take off and assume the tall growth form that makes the species easily identifiable. Increases in soil nutrient concentrations, may come from runoff from farms and urban areas. It has also been suggested increases in nutrient concentrations, especially nitrates, are primarily responsible for increases in Phragmites populations. Ironically, eutrophication and increases in nitrate levels are sometimes blamed for the decline of Phragmites populations in Europe (Den Hartog et al. 1989).


Subrank III. Trend in Distribution and Abundance: High

10. Current Trend in Total Range within Nation:High significance
Comments: Phragmites range is increasing dramatically overall in North America in the past 150 years (Saltonstall, 2002), although locally decreasing at some sites (much like some Eurasian populations). A portion of the native population that has become invasive (particularly in brackish coastal marshes of the northeastern U.S. and along streambanks and roadside ditches in inland wetlands, including alkaline swamps; also brackish marshes and freshwater tidal marshes in the Chesapeake Bay) may have become hybridized with a non-native genotype (perhaps from Eurasia) to form the highly invasive and problematic variety currently degrading native wetlands (Chambers et al., 1999; Marks et al., 1994; Richburg et al., 2001; Saltonstall, 2002; 2003). This introduced type has displaced native types as well as expanded to regions previously not known to have Phragmites. Different invasive gentotypes are known to be increasing in the Mississippi River Delta and Gulf Coast region (Hauber et al., 1991; Saltonstall, 2003), New England (where native genotypes are nearly extinct) and the northeast Atlantic coast (Saltonstall, 2002; 2003), and the tidal marshes of the upper Chesapeake Bay region (Rice et al., 2000). Great Lakes populations have also increased dramatically recently (Hudon et al., 2005; Marks et al., 2001). Hudon et al. (2005) documented tremendous increase in the number of colonized sites along the St. Lawrence River since 1980.

11. Proportion of Potential Range Currently Occupied:Medium/Low significance
Comments: Approximately 11 native North American strains have shown little change in their distribution between historic and modern samples from the Midwest to the Pacific Coast, but the 3 native haplotypes found in historical samples from southern and central New England appear to be extirpated in that area since the introduction of the non-native strains leaving only non-native strains today (Saltonstall, 2002; 2003). Similar extinctions have appeared locally along the Atlantic coast southwards from New England. Saltonstall (2002) demonstrated rapid replacement of native lineages by invasive ones in marshes of Connecticut and Massachusetts by 1940. This invasion is on a scale comparable (if not greater than) other known wetland invaders such as purple loosestrife and salt ceader, but appears to still be in a phase of expansion into new areas.

12. Long-distance Dispersal Potential within Nation:High significance
Comments: Long distance dispersal potential is high as this species has adapted to disperse along human utilized water corridors including those inhospitable to many plants such as roadside ditches. Rivers of all sizes (including temporary creeks) allow for dispersal across large distances, particularly through disturbed areas. Farnsworth et al. (2003) demonstrated that this species, when compared to other common native wetland species as well as three other invasive species, shows a high degree of invasiveness in terms of height growth and emergence time, biomass per ramet, standing leaf area, total leaf area per plant, standing crop, and total foliar chlorophyll. Ditches along highway corridors have been shown to serve as migration corridors for invasive wetland plants (Richburg et al., 2001; Wilcox, 1989).

13. Local Range Expansion or Change in Abundance:High significance
Comments: Phragmites is a problem when and where stands appear to be spreading while other species typical the of the community are diminishing. Disturbances or stresses such as pollution, alteration of the natural hydrologic regime, dredging, and increased sedimentation favor invasion and continued spread of Phragmites (Roman et al. 1984). Certain factors that may have favored recent invasion and spread of Phragmites include increases in soil salinity (from fresh to brackish) and/or nutrient concentrations, especially nitrate, and the introduction of a more invasive genotype(s) from the Old World (McNabb and Batterson 1991; Metzler and Rosza 1987).

Many Atlantic coast wetland systems have been invaded by Phragmites as a result of tidal restrictions imposed by roads, water impoundments, dikes and tide gates. Tide gates have been installed in order to drain marshes to harvest salt hay, to control mosquito breeding and, most recently, to protect coastal development from flooding during storms. This alteration of marsh systems may favor Phragmites invasion by reducing tidal action and soil water salinity and lowering water tables. Farnsworth et al. (2003) demonstrated that this species, when compared to other common native wetland species as well as three other invasive species, shows a high degree of invasiveness in terms of height growth and emergence time, biomass per ramet, standing leaf area, total leaf area per plant, standing crop, and total foliar chlorophyll.

This portion of the native population that has become invasive (particularly in brackish coastal marshes of the northeastern U.S. and along streambanks and roadside ditches in inland wetlands, including alkaline swamps; also brackish marshes and freshwater tidal marshes in the Chesapeake Bay) may have become hybridized with a non-native genotype (perhaps from Eurasia) to form the highly invasive and problematic variety currently degrading native wetlands (Chambers et al., 1999; Marks et al., 1994; Richburg et al., 2001; Saltonstall, 2003). A low-cost restriction fragment length polymorphism (RFLP) assay was recently developed (Saltonstall, 2003) to distinguish native, non-native, and Gulf Coast type populations of Phragmites from each other.

Different invasive gentotypes are known from the Mississippi River Delta and Gulf Coast region (Hauber et al., 1991; Saltonstall, 2003), New England (where native strains are extirpated) and the northeast Atlantic coast (Saltonstall, 2002; 2003), and the tidal marshes of the upper Chesapeake Bay region (Rice et al., 2000). Saltonstall (2002) demonstrated rapid replacement of native lineages by invasive ones in marshes of Connecticut and Massachusetts by 1940.


14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Moderate significance
Comments: This species is listed as an "invasive plant of major concern" in Czarapata (2005). Disturbances or stresses such as pollution, alteration of the natural hydrologic regime, dredging, and increased sedimentation favor invasion and continued spread of Phragmites (Roman et al. 1984). Certain factors that may have favored recent invasion and spread of Phragmites include increases in soil salinity (from fresh to brackish) and/or nutrient concentrations, especially nitrate, and the introduction of a more invasive genotype(s) from the Old World (McNabb and Batterson 1991; Metzler and Rosza 1987).

Farnsworth et al. (2003) demonstrated that this species, when compared to other common native wetland species as well as three other invasive species, shows a high degree of invasiveness in terms of height growth and emergence time, biomass per ramet, standing leaf area, total leaf area per plant, standing crop, and total foliar chlorophyll. Ditches along highway corridors have been shown to serve as migration corridors for invasive wetland plants (Richburg et al., 2001; Wilcox, 1989). Salinity tolerance is a limiting factor in distribution of this species although it has a fairly high tolerance (12 ppt in Britain, 29 ppt in New York, 40 ppt on the Red Sea Coast) (Hocking et al., 1983) because air spaces in above ground stems and rhizomes assure underground parts have a fresh water supply. Under favorable conditions, germination begins 1 day after sowing and may reach nearly 100 percent (Ekstam and Forseby, 1999). Saltonstall (2002) demonstrated rapid replacement of native lineages by invasive ones in marshes of Connecticut and Massachusetts by 1940. This invasion is on a scale comparable (if not greater than) other known wetland invaders such as purple loosestrife and salt ceader, but appears to still be in a phase of expansion into new areas.


15. Similar Habitats Invaded Elsewhere:Moderate significance
Comments: Ironically, eutrophication and increases in nitrate levels are sometimes blamed for the decline of Phragmites populations in Europe (Den Hartog et al. 1989). Phragmites can be found in tropical wetlands but is absent from such habitats in the U.S. and the Amazon basin, thus far (Marks et al., 2001). Recently, it has developted a tolerance for invading lowland marsh habitats by initially establishing itself in the high marsh then expanding into the less favorable lower marsh habitat (Amsberry et al., 2000).

16. Reproductive Characteristics:High significance
Comments: Phragmites is capable of vigorous reproduction forming monospecific stands and newly opened sites may be colonized by seed (uncommon) or rhizome fragments carried by humans in soils or on machinery or naturally in floodwaters. Once Phragmites has colonized a site, new stands spread predominantly through vegetative reproduction rather than by seed (Hudon et al., 2005). Phragmites seeds are shed from November through January and so may be among the first propagules to reach certain sites. If the seeds germinate and become established the young plants will usually persist for at least two years in a small, rather inconspicuous stage, resembling many other grasses. Under favorable conditions, germination begins 1 day after sowing and may reach nearly 100 percent (Ekstam and Forseby, 1999). Later, perhaps after the input of nutrients, they may take off and assume the tall growth form that makes the species easily identifiable. Phragmites colonization typically is driven mainly be vegetative growth of rhizomes as seedlings are rarely observed in the field despite the annual flowering, large seed production, and germination potential. Alvarez et al. (2005) confirmed this attributing it to rare occurrence of the regeneration window of the reed, but found that when suitable conditions were created, reed could efficiently colonize empty space sexually by seedling establishment. Examining reedbed dynamics in a marsh in southern France over 25 years, Alvarez et al. (2005) determined reedbed dynamics were a combination of slow (long-term) vegetative growth (esp. during stable water levels) with a few phases of seedling establishment (esp. during spring drawdown events). Note that in most systems, spring drawdowns are very rare so sexual colonization during such times usually does not occur.

Subrank IV. General Management Difficulty: High/Medium

17. General Management Difficulty:High/Moderate significance
Comments: Invasive populations of Phragmites must be managed in order to protect rare plants that it might outcompete, valued animals whose habitat it might dominate and degrade, and healthy ecosystems that it might greatly alter. Areas invaded by Phragmites often have excellent potential for recovery but a combination of control measures is often necessary, such as spraying followed by burning followed by spraying over 3-5 years (Rice, 2005).

Various control measures (chemical- spraying, wicking, sulfide treatments; mechanical- water management, disking, bulldozing, dredging, seasonal mowing, cutting, plastic barriers, perimeter ditching, burning, shading; biological- various insects) have been reviewed and their merits and shortcomings outlined (see Czarapata, 2005; Perry and Stanhope, 2002; Marks et al., 2001; Norris et al., 2002). For most, management is difficult and time consuming often requiring repeated effort and a combination of different management actions. Some management actions utilized in the past have been shown to actually benefit renewed Phragmites growth and colonization. For example, common reed (Phragmites australis) comprised 91% of the biomass in a marsh along Lake Manitoba (Thompson and Shay, 1989). Portions of the marsh were burned by headfires in August at peak growth, in October after dormancy was established, or in May before growth began; and all three burn dates increased shoot density in the summer after the burns. Aboveground biomass of common reed declined on the summer burns, was unchanged by the fall burns, and was increased by the spring burning.


18. Minimum Time Commitment:Moderate significance
Comments: Areas invaded by Phragmites often have excellent potential for recovery but a combination of control measures is often necessary, such as spraying followed by burning followed by spraying over 3-5 years (Rice, 2005). Management programs have proven that Phragmites can be controlled, and natural vegetation will return. However, monitoring is imperative because Phragmites tends to reinvade and control techniques may need to be applied several times or, perhaps, in perpetuity. It is also important to note that some areas have been so heavily manipulated and degraded that it may be impossible to eliminate Phragmites from them. For example, it may be especially difficult to control Phragmites in freshwater impoundments that were previously salt marshes. For most, management is difficult and time consuming often requiring repeated effort and a combination of different managment actions. Some management actions utilized in the past have been shown to actually benefit renewed Phragmites growth and colonization (see Perry and Stanhope, 2002; Marks et al., 2001; Norris et al., 2002).

19. Impacts of Management on Native Species:High/Moderate significance
Comments: Various control measures (chemical- spraying, wicking, sulfide treatments; mechanical- water management, disking, bulldozing, dredging, seasonal mowing, cutting, plastic barriers, perimeter ditching, burning, shading; biological- various insects) have been reviewed and their merits and shortcomings outlined (see Czarapata, 2005; Perry and Stanhope, 2002; Marks et al., 2001; Norris et al., 2002). Impacts on native species vary by control measure but most impact non-target plant and animal species to varying degrees. For example, control by flooding followed by burning to remove will affect all species in an area. Using a wick applicator herbicide treatment is more appropriate in areas with native vegetation persisting within a common reed grass clone as it allows for selective treatment, particularly when colored dye is added to the herbicide (Czarapata, 2005). Biological control seems to have the most promising potential for Phragmites control as there are over 100 insect species known to attack Phragmites in Europe and about 50% of these are Phragmites specialists (Norris et al., 2002; Perry and Stanhope, 2002).

20. Accessibility of Invaded Areas:Low significance/Insignificant
Comments: It appears most to all areas are easily accessible, as for most aquatic plants outside unusual habitats such as caves or high elevation streams or ponds. Because this species occurs in a wide variety of aquatic wetland habitats, some areas may have access problems.

Other Considerations: Assessment of the invasiveness of Phragmites australis is based on the non-native strains of the species introduced in the United States only.
Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 12May1993
NatureServe Conservation Status Factors Author: Marianne Marks (original version), Beth Lapin & John Randall (1993 update), Larry Morse (minor updates 2001).
Management Information Edition Date: 12May1993
Management Information Edition Author: Marianne Marks (original version), Beth Lapin & John Randall (1993 update)
Element Ecology & Life History Edition Date: 12May1993
Element Ecology & Life History Author(s): Marianne Marks (original version), Beth Lapin & John Randall (1993 update)

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

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Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

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