July 17, 2006
Earth versus 'the swamp thing'
Shoreline parks closing today and tomorrow as officials battle cordgrass
/Daily Review (Hayward)
SAN LEANDRO — Like a mutant B-movie swamp thing that only gets bigger if you pelt it with machine gun fire, the invasive cordgrass known as Spartina alterniflora is a very tough weed to kill.
"It's just really, really good at surviving," said Erik Grijalva, field manager for the San Francisco Estuary Invasive Spartina Project. "It takes over the mudflats first and then begins to spread out into the established marshlands."
Today and tomorrow, Grijalva and a coalition of East Bay officials are attempting their latest of many efforts to rid the Bay of a non-native plant that smothers native life.
More than a decade of similar efforts have proved futile. But this time, several agencies are teaming up in a way they have not before to cover a seven-mile stretch of Hayward, San Leandro and Oakland in two days. They are bringing in a helicopter that will race up and down the marshlands at low tide, spraying a low-toxic herbicide from 10 to 15 feet in the air.
"This is kind of a seminal year for Spartina control," Grijalva said as he walked with knee-high boots last week along Bunker Marsh at the San Leandro shoreline.
Several shoreline parks and trail systems will be closed down and blocked off for the two days.
"We're trying to accommodate the public as best we can, but we've got to get this thing done," said Mark Taylor, who supervises the Hayward shoreline for the East Bay Regional Park District.
A species of Atlantic coast cordgrass, Spartina alterniflora, has been causing problems on the Bay since the U.S. Army Corp of Engineers planted the intertidal grass to reduce erosion in Alameda flood control channels in the 1970s, Grijalva said.The Atlantic plant later mixed with a native Pacific coast cordgrass, Spartina foliosa, creating a "supervigorous hybrid" that breeds easily and has become hard to defeat, furthering the infestation, he said.
Competing against the low-lying pickleweed and orange-colored dodder of the native Bay shoreline, the invader weeds grow together in huge island clumps that spread quickly and change the composition of local mudflats and tidal marshes. Along with affecting the wildlife, the changed landscape can contribute to flooding and mosquito problems.
Endangered birds such as the California clapper rail seem to enjoy foraging on the hybrid weed, but the plant ends up destroying the open mudflats on which the birds depend.
"It's kind of junk food for the clapper rail," Grijalva said. "They wind up starving and drowning and the like."
And while sending a flotilla of helicopters never seems to work on those B-movie monsters, researchers believe an aerial attack is the cheapest and easiest way to kill large patches of unwanted Spartina.
"It's the most cost-effective way to do it," Taylor said.
Formed by the California Coastal Conservancy in 2000, the Invasive Spartina Project has picked up hundreds of thousands of dollars in conservation grants to help slow the tide of a Spartina infestation that affects all sides of the San Francisco Bay.
This week's effort will cover 320 acres of the Hayward area shoreline managed by the East Bay park district, including Coggswell Marsh and Roberts Landing at the mouth of San Lorenzo Creek. The city of San Leandro is pitching in with money to help out with about 112 acres of city-owned shoreline.
"The city spent a lot of money and time getting the marshlands restored in the 1990s. It was a huge project," said Delmarie Snodgrass, manager of the San Leandro Marina. She said it would be a waste of all those efforts if the plants were allowed to destroy what the city has worked hard to preserve.
Several acres of the Oakland shoreline at Arrowhead Marsh also are scheduled to be sprayed this morning.
Snodgrass said the herbicide being used, Imazapyr, is not considered harmful to humans and other animals and does little damage to native plants. But local officials are putting up signs and blocking off access points to the shore today and tomorrow anyway.
Although the weather is expected to be perfect for spraying, the wrong temperature or wind speed this morning could postpone the project until the end of the month.
One of the biggest challenges for the eradication effort is getting past all of the obstacles along the East Bay shoreline, from homes to golf courses or sewer plants.
Housing developments such as Heron Bay in San Leandro jut into Spartina-infested tidal marshes; the aircraft, from contractor Alpine Helicopters, is obligated to stay 400 meters from civilization.
In September, after the clapper rail breeding season has ended, crews will travel by boat and trudge through mud to reach the areas that could not be hit by helicopter spraying.