European beachgrass has changed beach topography, creating steep foredunes where none were present prior to its introduction, and altering dune formation to promote dunes that are parallel to the coast, whereas under native grasses, dunes formed roughly perpendicular to the coast.

European beachgrass directly threatens native plant communities, including Leymus mollis dominated foredunes and dune mat communities, as well as the endangered Menzies’ wallflower (Erysimum menziesii) and other rare dune species.

European beachgrass forms a dense cover that appears to exclude many native taxa. Plant species diversity on beaches dominated by European beachgrass is much less than that of beaches dominated by native beachgrass. As European beachgrass cover increases, the cover of native plant species decreases significantly.

Information from the California Invasive Plant Council - where efforts have been ongoing for 20 years to correct the folly of planting European Beachgrass along the West Coast.