ISSN 1188-603X

No. 418 December 3, 2009 Victoria, B.C.
Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2


Eric Snyder, Biodiversity Conservation Biologist, Biodiversity Section, Ontario Ministry of Natural Resources, 300 Water Street, Peterborough, Ontario K9J 8M5


This is a note on what appears to be the first observation of the invasive European lineage of Common Reed (Phragmites australis (Cav.) Trin. ex Steud subsp. australis) in the Canadian Prairie Provinces. To place this observation in context, I commence with a very brief summary of the literature on the known distribution of invasive Common Reed in Canada. I then provide the details of recent observations made in Winnipeg, Manitoba. In conclusion, I offer a few remarks on the potential impacts of invasive Common Reed in the Canadian Prairies.

Canadian Distribution

Less than a decade ago, it came to be recognized that two subspecies of the arundineceous grass, Phragmites australis (Cav.) Trin. ex Steud., occur in Canada. One of these, the endemic North American Common Reed, has very recently been classified as Phragmites australis (Cav.) Trin. ex Steud. subsp. americanus Saltonstall, P.M. Peterson and Soreng (Saltonstall et al. 2004). The other, which has been shown to be of Eurasian origin, has been referred to Phragmites australis (Cav.) Trin. ex Steud. subsp. australis (Catling 2006, 2007a). It is often called European Common Reed or invasive Common Reed. Several field characters have been identified by means of which these two subspecies can be differentiated (Catling et al. 2007; cf. Catling et al. 2003, Catling 2007a, Robichaud and Catling 2003).

Knowledge of the respective distributions of the two subspecies in Canada has progressed at almost the same pace as the understanding of how to differentiate them. The native Common Reed has been found to occur in all Canadian provinces and territories except the Yukon, Nunavut and Newfoundland and Labrador (CBIF 2007). The invasive Common Reed was initially recognized in southern Ontario and Quebec. It was then confirmed to be in the British Columbia interior, a small number of stands having established within the Okanagan Valley (Martin 2003, Schueler et al. 2003). Finally, its distribution in the Maritime Provinces was described, where it occurs at Stephenville in Newfoundland, Beaver Dam and Sackville in New Brunswick, and several localities in Nova Scotia (Catling et al. 2004). The best representation of its distribution in these provinces is probably that given by the Google Earth map which can be generated from the CBIF (2007) Phragmites of Canada database. (See in this issue: Catling and Mitrow, Canadian Phragmites Database Update Notes for Use.)

Observations in Winnipeg

What is the situation in the Canadian Prairie Provinces? The endemic North American Common Reed is widespread in the eastern prairie and boreal zones of Manitoba, Saskatchewan and Alberta (CBIF 2007). Until recently, the invasive Common Reed has been unknown from these areas. (See in this issue: Catling and Mitrow, Where is the Invasive Alien Phragmites Going in Canada.) However, on 15 October 2009, I observed a stand of over a hundred plants growing in the city of Winnipeg, Manitoba.

As is often the case in other provinces, the stand was found in a roadside ditch within an urbanized commercial area. It was discovered in the Fort Garry section of the city, on the western side of Route 90, north of Route 155: 49.8263 N. 97.2066 W. UTM coordinates are 14U 0628984 5520862 (WGS 84).

Most of the plants had inflorescences and approximately twenty five had reached anthesis. Unlike native plants, observed the same day between Winnipeg and the Ontario border, these plants were not yet senescing.

I was able to document this occurrence with both photographs and specimens. The former have been accessioned in the National Vascular Plant Herbarium (DAO) and the latter will be in the near future.

A second stand of invasive Common Reed is suspected on the south side of Highway 17, approximately ten minutes drive east of Winnipeg where road construction was taking place on the date of observation. Traffic conditions did not permit a closer investigation of this occurrence.


The introduced Common Reed has been recognized as a top priority invasive alien plant of natural habitats in Canada (Catling 2005). It is known to displace native wetland vegetation in the Great Lakes and Saint Lawrence River regions of this country (Gilbert et al. 2009, Lavoie et al. 2003, Wilcox et al. 2003). Similar impacts may be expected in prairie wetlands, including potholes, deltas and fens. This in turn might have significant impacts on the waterfowl species that depend on these habitats.

To prevent these outcomes, reconnaissance should be undertaken along the roadside ditches of major highways and high traffic routes in urban areas of southern Manitoba to assess the extent of the invasion. It may still be possible to eliminate invasive Common Reed stands as they develop. Without a well-organized control program, the grass became a serious problem in eastern North America within a decade.


Dr. Paul Catling very kindly provided remarks on the first draft of this article and assisted in arrangements for its publication in BEN - Botanical Electronic News.

Literature Cited

Blossey, B. 2002.
Replacement of native North American Phragmites australis by introduced invasive genotypes.BEN - Botanical Electronic News 284.
Canadian Biodiversity Information Facility (CBIF). 2007.
Phragmites of Canada. Database in Species Access: Canadian specimen information network. Accessible at
Catling, P. M. 2005.
New "top of the list" invasive plants of natural habitats in Canada. BEN - Botanical Electronic News 345.
Catling, P. M. 2006.
Notes on the lectotypification of Phragmites berlandieri and identification of North American Phragmites. BEN - Botanical Electronic News 366.
Catling, P. M. 2007a.
Additional notes on the identification of alien Phragmites in Canada. BEN - Botanical Electronic News 370.
Catling, P. M. 2007b.
Canadian Phragmites database notes for use. BEN - Botanical Electronic News 370.
Catling, P. M., G. Mitrow, L. Black and S. Carbyn. 2004.
Status of the alien race of Common Reed (Phragmites australis) in the Canadian Maritime Provinces. BEN - Botanical Electronic News 324.
Catling, P. M., G. Mitrow and L. Black. 2007.
Analysis of stem color for grouping Phragmites taxa in eastern Ontario and an evaluation of lower glume and ligule length for separating stem color groups. Rhodora 109(938): 125-136.
Catling, P.M., F.W. Schueler, L. Robichaud, and B. Blossey. 2003.
More on Phragmites - native and introduced races. Bull. Can. Bot. Assoc. 36(1): 4-7.
Gilbert, J. M. L. Bennett, F. Letourneau, K. McLean, R. Drouin and B. Locke. 2009.
McLean Marsh Pilot Project: Managing the Invasive alien species Phragmites australisssp. australis (Common Reed) in a Lake Erie coastal wetland, Rondeau Bay, Ontario. Ontario Ministry of Natural Resources, Lake Erie Management Unit OMNR #52528
Lavoie, C., M. Jean, F. Delisle and G. Letourneau. 2003.
Exotic plant species of the St. Lawrence River wetlands: a spatial and historical analysis. Journal of Biogeography 30: 537-549.
Martin, M. 2003.
Common Reed (Phragmites australis) in the Okanagan Valley, British Columbia, Canada. BEN - Botanical Electronic News 318.
Robichaud, L. and P. M. Catling. 2003.
Potential value of glume length in differentiating native and alien races of Common Reed, Phragmites australis. BEN - Botanical Electronic News 310.
Saltonstall, K. 2002.
Cryptic invasion by non-native genotype of the common reed, Phragmites australis, into North America. Proc Natl. Acad. U.S.A. 99: 2445-2449.
Saltonstall, K., Peterson, P. M. and Soreng, R. J. 2004.
Recognition of Phragmites australis subsp. americanus (Poaceae: Arundinoideae) in North America: evidence from morphological and genetic analysis. Sida 21(2): 683-692.
Schueler, F. W., A. Karstad and J. H. Schueler. 2003.
Non-native Phragmites communis in British Columbia. BEN - Botanical Electronic News 315.
Wilcox, K. L., S. A. Petrie, L. A. Maynard & S. W. Meyer. 2003.
Historical distribution and abundance of Phragmites australis at Long Point, Lake Erie, Ontario. Journal of Great Lakes Research 29(4): 664-680.


From: Gisèle Mitrow & Paul M. Catling, Agriculture and Agri-Food Canada, Environmental Health, Biodiversity, Saunders Bldg., Central Experimental Farm, Ottawa, Ontario K1A 0C6 Canada

We frequently receive requests for information on Phragmites in Canada. Useful major published compilations have been produced by Haslam (1958) and Mal and Narine (2004), but this was in advance of the realization that the rapid invasion of Phragmites was a result of a foreign genotype rather than simply the spread of the native genotype. As Phragmites australis subsp. australis has spread through eastern North America, it has attracted much attention and the number of articles and reports that mention it has increased sharply. Consequently much recent work that compares the two genotypes or concerns the invasive genotype (subsp. australis) is not included in the synthesis of Mal and Narine (2004). A few other websites listed below are very informative, but none of these has all the content of a list that we recently developed to assist those with questions. Most of the questions we receive relate to identification, ecology, distribution and control and our list covers primarily those areas. Since the older literature is available elsewhere (e.g. Mal and Narine 2004), our list begins in 2000 with the exception of a few valuable older reviews. This list is based on: (1) a library search of Biosis (biological abstracts), CAB abstracts and Agricola (agricultural on-line access); (2) documents found through a Google search of websites; and (3) reports and articles that have been sent to us. It has been developed especially for Canada but includes research based in other parts of the world that can be applied to Canada. To access the list, available here as an appendix to this issue of BEN: This list will continue to grow and we expect to release updates in the future. Therefore we will be pleased to be informed of additions. Since much useful information is available on the web, we have listed several valuable websites below along with the two major reviews.


List of recent references for Phragmites in Canada

Other major sources:

Chesapeake Bay Program
Cornell University
Ecology and management of Invasive Plants Program
Environment Canada
Common Reed, Phragmites australis. Fact sheet in the "Monitoring the State of the St. Lawrence " series. Exotic plant species of the St. Lawrence River wetlands Haslam, S.M. 1972.
Biological flora of the British Isles, no. 128. Phragmites communis Trin. (Arundo Phragmites L.,? Phragmites australis (Cav.) Trin. ex Steudel). Journal of Ecology 60(2): 585-610.
Laval University
Laboratoire de recherche sur les plantes envahissantes (LAREPE) Research Laboratory on Invasive Plants
Mal T.K. & L. Narine. 2004.
The biology of Canadian weeds. 129. Phragmites australis (Cav.)Trin. ex Steud. Can. J. Plant Sci. 84: 365-396
Michigan Beaver Island
Nature Conservancy, Element Stewardship Abstract
United States Forest Service, Fire Effects Information System
USDA Natural Resources Conservation Service
Wisconsin Wetland Association


From: Hana Čížková & Jan Kvet, University of South Bohemia, České Budejovice, Czech Republic (HČ + JK), Czech Academy of Sciences, Institute of Systems Biology and Ecology, Trebon, Czech Republic (JK) e-mail: &

Phragmites australis has been extensively studied by European and Asian scientists since the time of the International Biological Programme (IBP) in the 1960s and 1970s. The management and use of Phragmites-dominated wetlands is summarized by Gopal and Mazing (1990) and Haslam et al. (1998). Main production-ecological features are given by Květ et al. (1998). Both earlier and IBP studies brought the first information on ecotypic variation of Phragmites australis (Björk 1967, van der Toorn 1972).

The recent history of Phragmites australis subsp. australis in Europe encompasses examples of both decline and spread. First indications of decline were described by Klötzli (1971, 1974). A thorough description of its symptoms was given by Ostendorp (1989), and the knowledge acquired until the late 1980s is presented in Den Hartog (1989). Both national and international projects were carried out in the 1990s with the aim to elucidate mechanisms of the decline (Van der Putten 1997, Brix 1999). Although the reed decline had always site-specific features, some general mechanisms seem to emerge. First, declining populations always occurred on sites with stabilized water levels and fairly deep water columns (at least 0.5 m), which prevented generative reproduction (Rea 1996). The vegetatively maintained reed stands coped with this situation usually fairly well until an additional stress event occurred (e.g., strong mechanical damage or a flood event associated with a further marked increase of the water column). Eutrophication of wetland habitats probably predisposed the reed plants to decline because of a strengthened oxygen deficiency in the sediment (Šantrůčková et al. 2001), followed by damage to root and rhizome tips by toxic products of microbial metabolism (Armstrong et al. 1996).

The genetic research of declining reed populations in German lakes pointed to their low genetic diversity (Koppitz et al. 1997). It was suggested that in originally diverse populations, only such clones would persist that would be able to survive under the particular site conditions; and this would be reflected by a reduced genetic variability within the given population. The resulting populations, consisting of only a few large monoclonal stands, were supposed to be more susceptible to rapid changes in environmental conditions such as eutrophication, because the low genetic diversity would not provide the stands with a sufficient phenotypic plasticity needed for successful adaptation. Indirect support to the above hypothesis was provided by a study of genetic diversity of populations of different age, which showed that the genetic diversity decreased with the population age (Čurn et al. 2007).

Reed expansion has been observed at some other European sites (Güsewell et al. 2000, Čížková, unpublished results, and personal communications of nature conservation managers of sedge meadows along the Labe (Elbe) River, Czech Republic). These sites provide waterlogged or shallowly flooded habitats that were originally oligotrophic, but have recently been exposed to a higher nutrient supply. Under such conditions, the competitive ability of the common reed seems to be supported at the expense of species of the original sedge-dominated vegetation.


Research papers on Phragmites australis in Europe and Asia


Armstrong, J., Armstrong, W., Armstrong, I.B., Pittaway, G.R. 1996.
Senescence, and phytotoxin, insect, fungal and mechanical damage: factors reducing convective gas-flows in Phragmites australis. Aquatic Botany 54: 211-226.
Björk, S. 1967.
Ecologic investigations of Phragmites communis. Folia Limnologica Scandinavica 14: 1-248.
Brix, H. 1999.
The European Research Project for Reed Dieback and Progression (EUREED). Limnologica 29: 5-10.
Čurn, V., Kubátová, B., Vávřová, P., Křiváčková-Suchá, O., Čížková, H. 2007.
Phenotypic and genotypic variation of Phragmites australis: Comparison of populations in two human-made lakes of different age and history. Aquatic Botany 86: 321-330.
Gopal, B., Masing, V. 1990.
7. Biology and ecology. Pp. 91-239 in: Patten, B.C. et al. (eds.): Wetlands and Continental Shallow Water Bodies, Vol. 1. SPB Academic Publishing bv., The Hague, The Netherlands,
Güsewell, S., LeNédic, C., Buttler, A. 2000.
Dynamics of common reed (Phragmites australis Trin.) in Swiss fens with different management. Wetlands Ecology and Management 8: 375-389.
Hartog, C. den (ed.) 1989.
Reed and Reed Decline in Europe. Aquatic Botany (Special Issue) 35(1): 1-132.
Haslam, S.M., Klötzli, F., Sukopp, H., Szczepaňski, A. 1998.
8. The management of wetlands. Pp. 405-464 in: Westlake, D.F., Květ, J., Szczepanski, A. The Production Ecology of Wetlands. Cambridge Univ. Press, Cambridge, U.K.
Klötzli, F. 1971.
Biogenous influence on aquatic macrophytes, especially Phragmites communis. Hidrobiologia (Bucuresti) 12: 107-111.
Klötzli, F. 1974.
Über die Belastbarkeit und Produktion in Schilfröhrichten. Verhandlungen der Gesellschaft für Ekologie, Saarbrücken 1973: 237-247.
Koppitz, H., Kühl, H., Hesse, K., Kohl, J.-G. 1997.
Some aspects of the importance of genetic diversity in Phragmites australis (Cav.) Trin. ex Steudel for the development of reed stands. Bot. Acta 110: 217-223.
Květ, J., Westlake, D.F., Dykyjová, D., Marshall, E.J.P., Ondok, J.P. 1998.
2. Primary production in wetlands. Pp. 78-168 in: Westlake, D.F., Květ, J., Szczepanski, A. The Production Ecology of Wetlands. Cambridge Univ. Press, Cambridge, U.K.
Ostendorp, W. 1989.
'Die-back' of reeds a critical review of literature. Aquatic Botany 35: 5-26. Rea, N. 1996.
Water levels and Phragmites: Decline from lack of regeneration or dieback from shoot death. Folia Gebotanica et Phytotaxonomica 31: 85-90.
Šantrůčková, H., Picek, T., Šimek, M., Bauer, V., Kopecký, J., Pechar, L., Lukavská, J., Čížková, H. 2001.
Decomposition processes in soil of a healthy and a declining Phragmites australis stand. Aquatic Botany 69: 217-234.
Toorn, J. van der 1972.
Variability of Phragmites australis (Cav.) Trin. Ex Steudel in realtion to the environment. Van Zee tot Land 48: 1-122.
Van der Putten, W. H. 1997.
Die-back of Phragmites australis in European wetlands: an overview of the European research programme on reed die-back and progression 1993-1994. Aquatic Botany 59: 263-275.


From: Paul M. Catling and Gisèle Mitrow, Agriculture and AgriFood Canada, Environmental Health, Biodiversity, Saunders Bldg., Central Experimental Farm, Ottawa, Ontario K1A 0C6 Canada

The GBIF website ( including the "Phragmites of Canada" databasae allows some niche modelling using climate data with the niche modeling library "openModeler" ( To determine the potential distribution, i.e. to predict spread, of the alien invasive Phragmites australis subsp. australis in Canada, we produced a map (approximation based on models) of the presence of climate similar to the climate already occupied by Phragmites australis subsp. australis in eastern Canada. Such maps are easily produced using instructions provided elsewhere in this issue. The procedure used a lax bioclimatic envelope algorithm called "envelope score":

Basically we assume that the plant could occupy all parts of Canada with climate equivalent to places where it already occurs. This area is the "fundamental niche". For many native species, dispersal capability, barriers, competition, pathogens, and other factors (e.g. MacArthur 1972) spatially reduce the fundamental niche to a "realized niche". For alien invasives on the other hand, dispersal is usually effective, competition is less severe and natural controls are fewer (at least for a period of time) so that the fundamental niche may correspond to the potential realized niche. Thus the assumption of potential range of an invasive plant being determined by climate and soil is not unreasonable. In the present case of Phragmites australis subsp. australis, edaphic factors appear to be less important to spread than usual because it has a broad tolerance of soil moisture ranging from continuously inundated to periodically very dry. Although it may prefer alkaline substrates, it can spread in extensive regions of acid soil along roadside ditches that are alkaline due to the use of de-icing salt. In fact there is good evidence that the major expansion of Phragmites australis subsp. australis in eastern Canada has been by fragmentation along roads (Catling & Carbyn 2006, Lelong et al. 2005, 2007). It does well in calcareous (CaCO3) and saline (NaCl) subtrates ranging from pure organic material to pure clay, beach sand, or rock and various combinations. Consequently we assume that climate will be much more important than soils in determining the potential distribution and within climate, its broad moisture tolerance suggests that temperature will be the ultimate factor. The lack of importance of precipitation is reinforced by the abundance of water throughout most of southern Canada and the fact that much of the spread of the plant is by rhizome fragments with roots and buds rather than seeds (Catling & Carbyn 2006) which may be more prone to the effects of periodic drought.

OpenModeller reads the corresponding environmental values for each occurrence point. The data points then become samples representing the environmental conditions at each location. An algorithm is then used to find a representation of the species niche in the environmental space. In the present case, for each environmental variable the envelope score algorithm finds the minimum and maximum at all occurrence sites. During model projection, the probability of occurrences is determined as: p = layers within min-max threshold / number of layers. We used 12 temperature layers (because Phragmites australis subsp. australis is capable of dealing with much variation in water availability in eastern Canada as noted above). The 20 climate layers included annual mean temperature, mean diurnal range, isothermality, temperature seasonality, maximum temperature of warmest month, minimum temperature of coldest month, temperature annual range, mean temperature of wettest quarter, mean temperature of driest quarter, mean temperature of warmest quarter, mean temperature of coldest quarter, annual precipitation, precipitation of wettest month, precipitation of driest month, precipitation seasonality, precipitation of wettest quarter, precipitation of driest quarter, precipitation of warmest quarter, precipitation of coldest quarter. This square km climate grid data (Hijmans et al. 2005) is provided by WorldClim (

Currently Phragmites australis subsp. australis is frequent in the southern parts of Ontario and Quebec with isolated occurrences in BC (Martin 2003, Schueler et al. 2003), the maritime provinces (Catling et al. 2004), and northwestern Ontario ( The potential distribution map using only temperature suggested a much more extensive distribution in Canada including a large area of the prairie ecozone in the southern prairie provinces [Note: no sooner is a prediction made than it comes true see article by E. Snyder in this issue, Ed.], and much of lower elevation of the montane cordillera ecozone in central BC as well as western parts of the Boreal Plains ecozone (for Canadian ecozones see ). This map also suggests extensive colonization of parts of the Canadian Shield ecozone and the Atlantic Maritime Ecozone, although impact on natural habitat and agriculture in this region may be less due to acidic substrates. These results provide a picture of potential distribution that is supported by other models (in preparation) including other environmental measures such as growing degree days.

The potential distribution of Phragmites australis subsp. australis in Canada is very alarming because the potential environmental damage is very substantial. Prairie wetlands for example, are host to a large native biodiversity that includes waterfowl of great economic importance. Wild rice may be extensively displaced. Substantial costs to agriculture may occur as a result of invasion of irrigation systems in the western prairie region. Sport fishing may be impacted by general decline in wetland biodiversity in parts of southern and northwestern Ontario. Invasion of maritime salt marsh in eastern Canada will also likely be accompanied by substantial biodiversity loss. Prediction allows some hope for containment since it allows preparation. Control can protect biodiversity until either natural enemies catch up and/or until biocontrol agents become effective.

Literature Cited

Catling, P.M. and S. Carbyn. 2006.
Recent Invasion, current status and invasion pathway of European Common Reed (Phragmites australis (Cav.) Trin. ex Steud. var. australis) in the Southern Ottawa District. Canadian Field-Naturalist 120(3): 207-312.
Catling, P. M., G. Mitrow, L. Black and S. Carbyn. 2004.
Status of the alien race of Common Reed in the Canadian Maritime Provinces. BEN - Botanical Electronic News 324.
Hijmans, R.J., S.E. Cameron, J.L. Parra, P.G. Jones and A. Jarvis, 2005.
Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology 25: 1965-1978.
Lelong, B., C. Lavoie, Y. Jodoin and F. Belzile. 2005.
The invasive common reed (Phragmites australis) along roads in Quebec (Canada): a genetic and biogeographical analysis. Road Ecology Centre Scholarship Repository, John Muir Institute of the Environment, University of California.
Lelong, B., C. Lavoie, Y. Jodoin and F. Belzile. 2007.
Expansion pathways of the exotic common reed (Phragmites australis): a historical and genetic analysis. Diversity and Distributions 13: 430-437.
MacArthur, R.H. 1972.
Geographical ecology: patterns in the distribution of species. Harper and Row, New York.
Martin, M. 2003.
Common Reed (Phragmites australis) in the Okanagan Valley, British Columbia, Canada. BEN - Botanical Electronic News 318.
Muñoz, M.E.S., R. Giovanni, M.F. Siqueira, T. Sutton, P. Brewer, R.S. Pereira, D.A.L. Canhos, and V.P Canhos. 2009.
OpenModeller: a generic approach to species' potential distribution modelling. GeoInformatica. DOI: 10.1007/s10707-009-0090-7.
Schueler, F.W., A. Karstad and J.H. Schueler. 2003.
Non-native Phragmites communis in British Columbia. BEN - Botanical Electronic News 315.

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