During the past three to four decades, parallel expansions of populations of non-indigenousrhizomatous grasses have occurred in aquatic and estuarine habitats around the nation.Among these expansions are Spartina alterniflora invasions in the salt marshes of thePacific Northwest (Callaway and Josselyn, 1992), take-over of large sections of theriparian ecosystems in Southern California by Arundo donax (Bell, 1997) and Phragmitesaustralis invasions in the upper regions of salt marshes in the mid-Atlantic states(Hellings and Gallagher, 1992).
