Washington's Coast
Washington State Department of Ecology

BEACHES
ANIMALS
 
PLANTS
spruce
spartina
beachgrass
dune plants
Foredune at Ocean Shores
European beachgrass Changing the beach

American beachgrass and European beachgrass were originally planted to stabilize dunes. Both exotic species have changed sand movement, plant communities, and animal habitats along Washington's southwest coast.
  • High foredunes front the beach
    Beachgrass has changed dune structure by forming a high foredune, unlike the lower mounds created by native species. As sand builds up, so does the beachgrass. Beachgrass traps sand, then sends out strong vertical and horizontal rhizomes, creating a wall of vegetation.
  • Beachgrass displaces native plants and invertebrates
    Studies show that areas filled with beachgrass, rather than native dunegrass, have fewer species of plants and sand dune arthropods.
  • Beachgrass invades endangered shorebird nesting areas
    By 1988, spreading beachgrass threatened Snowy Plover nesting areas at Leadbetter Point. Beachgrass has also invaded Snowy Plover nesting habitat at Damon Point.
Foredune heights created by beachgrass
American beachgrass forms a foredune about 9 feet in height. European beachgrass creates a foredune about 14 feet in height -- 60 percent higher than American beachgrass.
 
 
American beachgrass American beachgrass, Ammophila breviligulata, is native to the East Coast and Great Lakes. In the Pacific Northwest, American beachgrass is an exotic grass that spreads agressively and now dominates the coastal foredunes of Washington.
European beachgrass
European beachgrass, Ammophila arenaria, a native of Europe, was first planted in 1896 to stablilize sand in California. It spread quickly along Washington's coast, both by natural means and cultivation. European beachgrass was planted at Twin Harbors State Park, Grays Harbor North Jetty, and other locations.
Dunegrass, Elymus mollis
Dunegrass, Elymus mollis, was the dominant grass along Washington's dunes before the arrival of European and American beachgrass. Dunegrass can be found on offshore seabird islands and in patches on dunes.
American beachgrass
  • Planted on the Clatsop peninsula
    In a program of dune stabilization, American beachgrass was planted on the Clatsop peninsula in Oregon during the late 1930s and early 40s. Between 1940 and the early 1970s, American beachgrass spread up the southwest coast of Washington. Plant fragments most likely spread north, carried by winter currents.
  • Now dominates most Washington dunes
    Between 1940 and the early 1970s, American beachgrass spread along the entire foredunes of the Long Beach peninsula. American beachgrass now fronts most foredunes, from the mouth of the Columbia River to the mouth of the Copalis River.
Sources: E. Seabloom, Ammophila, breviligulata Fern, American Beachgrass on the Foredunes of the Washington Coast, 1991, Washington State Department of Ecology; Washington State Recovery Plan for the Snowy Plover, Washington State Department of Fish and Wildlife, 1995.
 
Image courtesy of The Coos Bay Bureau of Land Management.

Botanical News, American Beachgrass Research and distribution.


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