Note to McGlynn’s article “Native and invasive plant interactions in wetlands and the minimal role of invasiveness” in Biological Invasions (2009) 11:1929–1939

Abstract

In the recent article, ‘‘Native and invasive plant interactions in wetlands and the minimal role of invasiveness’’ (McGlynn 2009), the author compared the effects of two invasive plants on native wetland communities in freshwater tidal wetlands in the Hudson River Valley in the United States (US). The author investigated whether Lythrum salicaria L. (purple loosestrife) and Phragmites australis (Cav.) Trin ex Steudel (common reed) affect species richness, composition and abundance in native wetland communities dominated by Typha angustifolia L. (narrowleaf cattail) and Typha latifolia L. (broadleaf cattail). The author compared plots where the two invasive wetland plants occurred with plots where they did not occur to measure the effect of two invasive wetland species. Two aspects of this study raise particular concern: first, the erroneous assignment of native and invasive status to two plant species investigated in this study, and, second, the implications of this error for the conclusions drawn. In the methods section, the author claims that ‘‘P. australis (Family Poaceae) is a native of the US, but it is not native to the Hudson River Valley’’ (McGlynn 2009). In fact, two distinct subspecies of P. australis exist in the US: P. australis subspecies australis and P. australis subspecies americanus. P. australis subspecies australis is native to Eurasia and was introduced to the US, where it has aggressively invaded many wetlands in recent decades. P. australis subspecies americanus, on the other hand, is endemic to the US (Saltonstall 2002, 2003a, b, c; Saltonstall et al. 2004). Although no P. australis subspecies americanus populations are known to exist currently in the Hudson River Valley, records from the Vassar College Herbarium indicate that this subspecies was present there in the late 1800 s (B. Blossey, personal communication). Because of the different origins and invasive characteristics of the two subspecies of P. australis, it is essential to distinguish between these subspecies when working with P. australis in the US. Also in the methods section, the author claims that ‘‘T. angustifolia and T. latifolia (Typhaceae) are considered native to the Hudson Valley’’ (McGlynn 2009). It is correct that T. latifoila is native to the US (Grace and Harrison 1986; Shih and Finkelstein 2008; Smith 2004; USDA 2010). However, until recently, T. angustifolia was widely considered to be native to Europe and introduced to the US (Galatowitsch et al. 1999; Gleason and Cronquist 1995; Grace and Harrison 1986; Selbo and Snow 2004; Smith 2000, 2004; Stuckey and Salamon 1987; USDA 2010; Zedler and Kercher 2004). However, recent findings suggest that T. angustifolia also may have been in the US prior to European settlement, but this earlier US origin remains uncertain (Shih and Finkelstein 2008). F. B. Eichiner (&) Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, NY 14853, USA e-mail: fbe2@cornell.edu