Blade for blade, which grass wins duel of the dunes?

Byline: Winston Ross The Register-Guard

FLORENCE - One of the signatures of an Oregon beach is the "foredune," that long lump of sand that lines much of the coast and makes for a breathless scramble to reach the water itself.

What most people don't know is that the foredune is a creation of human engineering, the byproduct of 100 years' growth in beachgrass. There are two kinds of it: American and European, and their effects on the surrounding ecosystem have been debated for decades.

Some say the beachgrass is an invasive species that crowds out native plants and eats up the open sand that provides nesting habitat for endangered birds such as the Western snowy plover. Others sing beachgrass' praises, claiming the plant has helped stabilize shifting sands that would otherwise bury roadways and train tracks, and inundate homes.

Researchers at Oregon State University weighed in on that debate Tuesday after studying the two varieties of beachgrass. They say it appears the American brand - the "native" grass - is actually more invasive than the kind imported from Europe, and it's threatening the protection that the foredune offers seaside homeowners.

"It has a different ability to hold onto sand," said Sally Hacker, an assistant professor of zoology at the university. Hacker and another assistant professor of zoology, Eric Seabloom, have been studying the grasses over the past year and a half. "What we think is it doesn't hold the sand quite as well as the European version."

As Hacker and her colleagues continue the work, they hope to learn more about what separates the two kinds of grass, and what implications that could have for their continued planting in some places and removal in others along the coast.

So far, the researchers have learned that the American brand of beachgrass is slowly taking over the Oregon Coast and places as far north as Long Beach, Wash. The foredunes created by the grass - the plant keeps sand from moving inland, causing the sand to pile up on itself - are only about half as tall as the ones created by European beachgrass, Hacker and Seabloom found.

"There's a strong correlation between the height of the dune and the kind of beachgrass there," Hacker said. "We think it might have something to do with the spacing of the blades."

European beachgrass has been planted along the Oregon and Washington coasts since the turn of the 20th century, before there was a foredune, when the sand was free to roam where it pleased.

The American variety, imported from the East Coast, started showing up in the 1930s, Hacker said, mostly at sites along the Columbia River, and has spent the past 70 years working its way north.

The most pressing question is how the American and European beachgrass affect the environment differently, Hacker said.

One of the ways the researchers will try to determine that is by planting the two species together, "to see who's going to win."

Florence resident and former Mayor Wilber Ternyik is one of the architects of Oregon's prolific beachgrass population, having planted much of it himself over the past several decades. He says both varieties play an important role.

The American beachgrass works better on the ocean side of the foredune, he said. "It grows five feet tall. But it's not as dependable."

The Oregon State scientists are also studying oceanographic models to figure out how much protection is lost when European grass gets edged out by the American kind.