most competitive in shallow warm water and L. major more competitive
in deeper colder water given sufficient light availability.
The ability of E. canadensis to sustain a high trait performance
over a range of treatments suggests high phenotypic plasticity of
this species. On the other hand the strong negative response of
L. major at high temperature suggests less phenotypic plasticity
at the high temperature. It has often been suggested that invasive
terrestrial plant species possess high phenotypic plasticity (e.g.
Sultan, 2001; Pigliucci, 2005) and this has also been confirmed in
empirical studies (e.g. Rice and Mack, 1991; Niinemets et al., 2003;
Funk, 2008). This implies that E. canadensis is more a generalist