Biological Flora of the British Isles:Phragmites australis

Abstract

Summary1. This account presents comprehensive information on the biology of Phragmites australis (Cav.) Trin. ex Steud. (P. communis Trin.; common reed) that is relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors and to the abiotic environment, plant structure and physiology, phenology, floral and seed characters, herbivores and diseases, as well as history including invasive spread in other regions, and conservation. 2. Phragmites australis is a cosmopolitan species native to the British flora and widespread in lowland habitats throughout, from the Shetland archipelago to southern England. It is widespread throughout Ireland and is native in the Channel Islands. Native populations occur naturally in temperate zones and on every continent except Antarctica. Some populations in Australia and North America have been introduced from elsewhere and have become naturalized, and in North America, some of these are known to be invasive where they compete with native local populations of P. australis. Typical habitats in Britain range from shallow still water along waterbody edges to marshlands, saltmarshes and drier habitat on slopes up to 470 m above sea level. Additional habitats outside Britain are springs in arid areas, riverine lowlands (À5 m above sea level) and groundwater seepage points up to 3600 m above sea level. Although it occurs on a wide range of substrates and can tolerate pH from 2Á5 to 9Á8, in Britain it prefers pH >4Á5 and elsewhere it thrives in mildly acidic to mildly basic conditions (pH 5Á5-7Á5). The species plays a pivotal role in the successional transition from open water to woodland. 3. Phragmites australis is a tall, helophytic, wind-pollinated grass with annual shoots up to 5 m above-ground level from an extensive system of rhizomes and stolons. A single silky inflorescence develops at the end of each fertile stem and produces 500-2000 seeds. The plant is highly variable genetically and morphologically. 4. Expansion of established populations is mainly through clonal growth of the horizontal rhizome system and ground-surface stolons, while new populations can establish from rhizomes, stem fragments and seeds. Shoots generally emerge in spring, with timing determined primarily by physiology that is mediated by external conditions (e.g. local climate including frost).*Nomenclature of vascular plants follows Stace (2010). This account supersedes that of Phragmites communis by Haslam (1972).

Small genome separates native and invasive populations in an ecologically important cosmopolitan grass

“…In Europe, P. australis is considered to be the most competitive of all wetland plants, with a great ecological amplitude that extends from lime‐ and acid‐oligotrophic to eutrophic waters (Ellenberg , Rodwell , Packer et al. ). The species is monodominant in wetlands over extensive areas of land, commonly covering several square kilometers (Ellenberg ), indicating that its expansive behavior in the native range was, during post‐glacial colonization (e.g., in UK; Pigott and Pigott , Ingrouille ), even more pronounced than that of the invasive populations in North America (Packer et al.…”

Competition among native and invasive Phragmites australis populations: An experimental test of the effects of invasion status, genome size, and ploidy level

“…ex Steud. (common reed, Poaceae; Figure ) is tall, helophytic, wind‐pollinated perennial grass with shoots up to 4 m tall, forming an extensive system of rhizomes and stolons (runners), with a single inflorescence developing on each fertile stem, producing 500–2,000 seeds (Packer et al, ), but not all shoots are fertile every year and not all seeds fully develop. The species is highly productive (Bittmann, ; see Packer et al, , for a review) and exhibits great genetic, karyological, and morphological variation.…”

“…(common reed, Poaceae; Figure ) is tall, helophytic, wind‐pollinated perennial grass with shoots up to 4 m tall, forming an extensive system of rhizomes and stolons (runners), with a single inflorescence developing on each fertile stem, producing 500–2,000 seeds (Packer et al, ), but not all shoots are fertile every year and not all seeds fully develop. The species is highly productive (Bittmann, ; see Packer et al, , for a review) and exhibits great genetic, karyological, and morphological variation. It belongs to one of the most ploidy‐variable invasive species known, with published cytotypes from 3x to 22x, based on x = 12 (te Beest et al, ), and there is marked intraspecific variation in genome size (Suda et al, ), as well as phylogeographic genetic diversity within the species and the whole genus (Lambertini et al, ; Meyerson, Cronin, Bhattarai, et al, ; Meyerson et al, ; Saltonstall, ).…”

“…Recently, it is increasingly recognized that addressing invasions at the intraspecific level can provide novel insights into mechanisms underlying plant invasiveness, by comparing particular invading populations and addressing more subtle differences in their performance when trait differences associated with species level are held constant (Cronin, Bhattarai, Allen, & Meyerson, ; Pyšek et al, ). One system that provides opportunities to focus on organizational levels below the species rank, such as subspecies, populations, or individual genotypes, is a dominant species of wetlands all over the world Phragmites australis (common reed, Poaceae; Meyerson & Cronin, ; Meyerson, Lambert, & Saltonstall, ; Packer, Meyerson, Skálová, Pyšek, & Kueffer, ). This grass makes an ideal model system to study invasions by particular populations representing distinct genotypes, with native and invasive populations coexisting within the same geographic range (Eller et al, ; Meyerson, Cronin, & Pyšek, ; Packer et al, ; Pyšek et al, ).…”

“…One system that provides opportunities to focus on organizational levels below the species rank, such as subspecies, populations, or individual genotypes, is a dominant species of wetlands all over the world Phragmites australis (common reed, Poaceae; Meyerson & Cronin, ; Meyerson, Lambert, & Saltonstall, ; Packer, Meyerson, Skálová, Pyšek, & Kueffer, ). This grass makes an ideal model system to study invasions by particular populations representing distinct genotypes, with native and invasive populations coexisting within the same geographic range (Eller et al, ; Meyerson, Cronin, & Pyšek, ; Packer et al, ; Pyšek et al, ). Although the analogous situation has been described for other tall grass‐like species and grasses, such as in the Typha genus (Ciotir & Freeland, ) or for Phalaris arundinacea (Lavergne, Muenke, & Molofsky, ), respectively, and some forbs (e.g., Myriophyllum spicatum ; Zuellig & Thum, ), the common reed invasion in the North America is by far best researched with a great body of accumulated information providing a broad background for ongoing studies (Chambers, Meyerson, & Saltonstal., ; Eller et al, ; Meyerson, Cronin, & Pyšek, ; Packer et al, ).…”