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the Silent Invasion
ENVIRONMENTAL IMPACT
ECONOMIC CRISIS
THE RIPPLE EFFECT
PATHS OF INVASION
UNINTENDED CONSEQUENCES
Gorse at the Oregon Coast

Many invasive species are beautiful to look at. Think of the vibrant green foliage of English ivy, the lovely flowers of blooming yellow star thistle or the striking mustard color of gorse set against an ocean backdrop. And yet invasive plants and animals rival climate change and habitat destruction as the biggest threats to Oregon's environment. Part of their success lies in the fact that our sense of what's beautiful often trumps our understanding of what's native and natural. Green grass is better than mud, right? Not so in the case of invasive spartina. And those mesmerizing flocks of starlings? Not so great when you're a farmer trying to save a crop from being devoured by these invaders.

Understanding the threat invasive species pose to our native plants and wildlife requires thinking about beauty in new ways. Green isn't always good. Colorful flowers are a poor indicator of landscape health. Understanding invasive species also means restoring "native common sense"— knowing what belongs and doesn't belong in the places we live, even if what belongs may not be as 'showy' as the invaders fighting to take over.

Spartina: The Grass That Kills

Spartina is one of those beautiful invaders that's so successful because it looks like it belongs. Green fields of waving grass in Willapa Bay look natural, but what native birds, fish and wildlife need is mud. Plain, simple, gooey, mud. It all has to do with what they grew up with. Along the east coast of the United states, shorebirds are perfectly adapted to feeding within dense stands of native spartina (spartina alternaflora). But along the west coast, shorebirds that use places like Willapa and Humbolt Bay feed on the insects and crustaceans that live in wide open and grass free mudflats. When this east coast shoregrass showed up, the birds journeying on a long, difficult migration struggled to find food because the natural mudflats were overrun with grass. So next time you're in Willapa remember—mud good, grass bad.

A Timeline of the Willapa spartina Invasion

Late 1800's
Spartina (S. Alternaflora) arrives in Willapa Bay with a load of imported oysters. It grows slowly at first as it tries to get established.
1950's
Spartina is now noticeably spreading in bay.
1984
Scientists estimate that 300 acres are infested.
1995
A law enacted by Washington Legislature directs funding to three agencies: DNR, Washington Department of Fish and Wildlife (WDFW), and Washington State Department of Agriculture (WSDA) as the state lead, to begin a control program.
1997
Approximately 11,000 to 15,000 acres are now infested. This amounts to 25-32 percent of Willapa's intertidal mudflat acreage.
Late 1990's
Early efforts to control Spartina are limited in their effectiveness. Crews struggle to find the best combinations of method (mechanical and chemical) for control.
1996
First experimental, limited use of new herbicide called Amazapyr
2000
A joint federal and state control program begins in Willapa. More effective chemical and mechanical control methods being used.
2004
Amazapyr authorized to be used across Willapa Bay. Control efforts begin to see some real success as Spartina retreats.
2003
8,500 acres still infested. A Massive control is effort underway.
2007
Approximately 1,100 acres considered infested.
2008
Plan is to spray every Spartina seedling left in Willapa Bay.
The future?
Though Spartina has retreated significantly, many researchers believe spartina control will need to continue due to resilience of the weed and because new spartina seed may continue to float in from other infested areas along the west coast.

Timeline compiled from research provided by Friends of Willapa Bay, Washington Dept. of Natural Resources, Willapa National Wildlife Refuge, and from Kim Patten at the Washington State University.

Controlling Spartina in Oregon

Crews apply herbicides to spartina during
the height of the counterattack against spartina
in Willapa Bay, Washington.

One of the only known infestations of Spartina in Oregon so far is on the Nature Conservancy's Cox Island preserve along the Siuslaw river. The invader is Spartina patens, a slightly different variety of cordgrass than the Spartina alternaflora found at Willapa. It's invasive just the same. Fortunately, when Nature Conservancy crews detected the invader, they acted. Crews used a non-chemical approach to killing the grass. They covered it up with thick black fabric, cutting off all sunlight and preventing its growth and spread. It seems to have worked. With spartina, as with all invasive species, early detection is the key to reducing the potential for ecological and economic damage.

© 2014 Oregon Public Broadcasting.