Biol Invasions (2016) 18:2421–2431 DOI 10.1007/s10530-016-1132-3 PHRAGMITES INVASION Phragmites australis as a model organism for studying plant invasions Laura A. Meyerson . James T. Cronin . Petr Pysˇek Received: 18 December 2015 / Accepted: 24 March 2016 / Published online: 26 April 2016 Ó Springer International Publishing Switzerland 2016 Abstract The cosmopolitan reed grass Phragmites Third, it grows abundantly in a wide range of australis (Poaceae) is an intensively studied species ecological systems and plant communities, allowing globally with a substantial focus in the last two a broad range of research questions to be addressed. decades on its invasive populations. Here we argue We formalize the designation of P. australis as a that P. australis meets the criteria to serve as a model model organism for plant invasions in order to organism for studying plant invasions. First, as a encourage and standardize collaborative research on dominant species in globally important wetland habi- multiple spatial scales that will help to integrate tats, it has generated significant pre-existing research, studies on the ecology and evolution of P. australis demonstrating a high potential for funding. Second, invasive populations, their response to global envi- this plant is easy to grow and use in experiments. ronmental change, and implications for biological security. Such an integrative framework can serve as guidance for studying invasive plant species at the Guest editors: Laura A. Meyerson and Kristin Saltonstall/ population level and global spatial scale. Phragmites invasion. Keywords Genome size Á Global climate change Á L. A. Meyerson (&) Global research network Á Herbivory Á Hybridization Á The University of Rhode Island, Kingston, RI 02881, Ploidy level USA e-mail: [email protected] J. T. Cronin Introduction Louisiana State University, Baton Rouge, LA 70803, USA P. Pysˇek Phragmites australis (Cav.) Trin. ex Steud. (formerly Institute of Botany, The Czech Academy of Sciences, P. communis, common reed, Poaceae family) has been Za´mek 1, 252 43 Pru˚honice, Czech Republic mentioned as a model organism for plant invasions by a number of researchers because of its near global P. Pysˇek Department of Ecology, Faculty of Science, Charles distribution (Clevering and Lissner 1999), well-known University in Prague, Vinicˇna´ 7, 128 44 Prague, Czech invasion history in North America (Saltonstall 2002), Republic ease of detection using aerial or satellite imagery (Bhattarai and Cronin 2014), high genetic and kary- P. Pysˇek Centre for Invasion Biology, University of Stellenbosch, ological diversity (Meyerson et al. 2016), occurrence Matieland 7602, South Africa as multiple lineages and genotypes along latitudinal or 123 2422 L. A. Meyerson et al. climatic gradients (Cronin et al. 2015; Hughes et al. literature on P. australis. Instead, it is meant to be a 2016), and for its array of traits that are easily concise argument, with key examples, for why P. measured and highly variable depending on genotype australis makes is a good model species. and/or environmental conditions (e.g., Meyerson et al. 2000a, b; Achenbach et al. 2013; Mozdzer et al. 2013; Guo et al. 2013). Here we formalize the recognition of Substantial research, tools and knowledge exist P. australis as a model organism for plant invasions by for Phragmites australis adapting the criteria outlined by Kueffer et al. (2013) who suggested that using model systems in invasion Phragmites australis is arguably among the world’s science could facilitate and strengthen global collab- most studied plants and is cited by Pysˇek et al. (2008) oration and allow investigators to address fundamental as the third most studied plant species over the period questions in invasion science through integrative 1980–2006 and by Hulme et al. (2013) as being among research. the five most studied invasive species globally. There The use of model organisms in plant research, such is a wealth of information on its ecophysology and as Arabidopsis thaliana, is well established and highly population dynamics from the native European range valued because a useful model organism is easily where it has been subject of intensive research effort manipulated, genetically tractable, and about which and international projects since 1970s (Dykyjova´ et al. much is already known, thus allowing researchers to 1973; Tscharntke 1992;Cˇ ´ızˇkova´ et al. 1996; Brix rapidly accumulate comprehensive knowledge of the 1999). Its introduction and invasion history is rela- whole plant. Model plant species allow researchers to tively well known, especially in North America test hypotheses quickly and efficiently thereby func- (Chambers et al. 1999; Saltonstall 2002). Numerous tioning as a reference system for other plant systems recent reviews have synthesized the ecology, evolu- and more quickly advancing empirical science—a tion, management (Hazelton et al. 2014), costs (Martin particularly important undertaking for invasion ecol- and Blossey 2013), and benefits (Kiviat 2013) of this ogy and research that seeks to predict the effects of species. The Web of Science database yielded 4142 global change. Our interpretation of a model species published papers for the search term ‘‘Phragmites’’ follows that of Kueffer et al. (2013), who suggested and 3503 for Phragmites australis as the ‘‘topic’’ from that invasion science can profit from in-depth research 1950 to 2016 (Fig. 1). More generally, Google Scholar of invasions of particular taxa (‘model organisms’) or returned[25,000 hits for the search term ‘‘Phragmites at a particular site (‘model ecosystems’), and from the australis’’ indicating a broad exchange of knowledge integration of diverse information on such taxa or through news outlets, management and academic sites. Developing model systems in invasion science literature. has become increasingly possible due to recent One strong argument for P. australis to qualify as accumulation of comprehensive datasets on selected a suitable model species is that this plant is invasive species and research focused on particular researched by an order of magnitude more inten- model systems will help to identify processes relevant sively than other notorious plant invaders and for understanding invasions, and identifying their candidate model species (Table 1). Although not all underlying mechanisms the information that is available refers to its invasion, Kueffer et al. (2013) adapted the following criteria the research so far has accumulated a solid knowl- for identifying model organisms in invasion science: a edge base from a variety of disciplines. A brief model organism should (1) be characterized by the inspection of the 1033 case studies returned by the existence of substantial pre-existing research, tools WoS search reveals that in addition to the most and knowledge; (2) readily lend itself to research and represented research areas such as environmental use in experiments; (3) represent a wide range of sciences, ecology and conservation (43 %), plants systems and species; and (4) facilitate high versatility sciences (36 % of all papers), and marine and for research and funding. We assert that P. australis freshwater biology (28 %) are well represented. readily meets all these criteria and we provide More practically oriented fields like engineering evidence to support each point below. This is not (9 %), agriculture (6 %), microbiology and biotech- meant to be an exhaustive review of the published nology (6 %) or research in water resources (5 %) 123 Phragmites australis as a model organism for studying plant invasions 2423 Fig. 1 Number of publications over time for journal articles (n = 1019, Web of Science Core Collection, Title: Phragmites with Phragmites australis as the main research topic, as australis OR Phragmites communis, 18 December 2015) indicated by the species name used in the paper title are also a part of the literature on P. australis. 2016, this issue; Meyerson et al. 2010a, b, 2012). More Another feature that makes P. australis a strong recently, the full plastid genome of P. australis has candidate for a model species is that it is represented been published on the NCBI website (http://www. on all continents except Antarctica, and both native ncbi.nlm.nih.gov/bioproject/174737). and invasive populations have very broad geographic The great research intensity makes P. australis ranges. Other prospective model invasive species rather exceptional among invasive species in that listed in the Table 1 are geographically limited in there is a large body of literature from its native one way or another, making them rather difficult, if range (e.g. Brix 1999). As shown recently in a not impossible, to use to address questions related to thorough comparison of 26 plant species considered global macroecological patterns or, e.g., global among the world worst invaders, data from native change. ranges are generally rather scarce (Parker et al. Phragmites australis is an easily recognizable plant 2013). Phragmites australis is widely studied in both species whose lineages and subspecies in North its native and introduced ranges for its ability to America can often be distinguished based on mor- rapidly colonize new areas (Chambers et al. 1999) phology but sometimes require genetic confirmation. and efficiently uptake nutrients (Brix 1994; Meyer- The genetic and morphological tools to rapidly son et al. 1999, 2000a, b). Comparisons of native identify the origin and genotypes of P. australis were and invasive populations