Weeding Out a Killer : Replanting Aims to Restore Habitat Overrun by Arundo

Using a stick of dried arundo grass as his measuring tool, 7-year-old Andrew Krasowski got on his knees to mark a spot every three feet. That way, his dad would know just where to plant the mule fat and willow branches.

Mike Krasowski, his wife, Jo, and Andrew were part of a team of volunteers who offered their elbow grease Saturday to help restore the Arroyo Simi in Moorpark to its natural state.

It was part of an effort, led by the Moorpark chapter of the Environmental Coalition, to replant five acres of shoreline habitat with native vegetation along a meandering stretch of the flood channel running through the city.

Once sprouting a variety of willow bushes and other native vegetation, the arroyo has become congested with arundo, a weed which--if left unchecked--could choke out all other vegetation, said Environmental Coalition member Roseann Mikos.

The hearty arundo grass, which lines many of Southern California’s flood channels and rivers, was originally introduced to prevent erosion, but has had unforeseen consequences.

“The arundo grass overpowers the roots of native plants that belong there,” Mikos said. “And it’s no good for wildlife. The animals that would want to live there can’t--it’s not their natural habitat.”

The first phase of the restoration was completed last October, when work crews cut down several tons of the dense growing, bamboo-like grass, which can grow up to 30 feet tall.

By noon Saturday, about 40 volunteers--including a Moorpark Cub Scout pack, high school students and Environmental Coalition members--were scattered along the gently flowing flood channel for the next phase.

Taking instructions from project manager Mikos, work crews picked up trash that littered the area and commenced the replanting, which is scheduled to continue through March.

First they created holes by driving into the ground one-inch-think “rebar,” a steel pipe commonly used for reinforcement. Then they pushed 20-inch cuttings--trimmed from existing native plants in the area--into the moist ground and firmly packed the surrounding soil.

“We’re out here because we wanted to help save the riverbed,” said Mike Krasowski, 42, of Moorpark. “Driving by here, I’d rather see a little bit of nature than cement.”

Margaret and John Kirnig of Moorpark searched for the elusive red willow--which they hoped to use to make cuttings--along the banks of the arroyo, where the chirping of songbirds mixed with the drone of passing cars on the freeway.

“This is a perfect day to be out here,” said Margaret Kirnig, who was enjoying the sunny weather and cool breeze.

Along with the cuttings from native plants, about 200 sycamore and cottonwood trees--purchased with grant money--will eventually be planted along the five-acre stretch of arroyo.

The Moorpark portion of the Arroyo Simi was chosen for replanting because its banks are lined with the least amount of concrete, Mikos said, and offers the best hope for a return of natural habitat--if the arundo grass can be stopped.

“The arundo grass is like Freddy Krueger from ‘Nightmare On Elm Street,’ ” said California Department of Transportation biologist Paul Caron as he prepared willow branches for planting. “It just keeps coming back.

“But by replanting, we’re giving the native vegetation a chance to dominate,” said Caron, who was helping supervise the effort for Caltrans, which owns the land.

A return of native vegetation will attract and maintain bigger populations of songbirds, snowy egrets, herons and the endangered least Bell’s vireo, Caron said. Hawks and owls are also expected to return to the area.

Besides the weekend volunteer efforts, California Conservation Corps crews and students from local schools will be assisting during weekdays, Mikos said.

Mikos said the replanting must be accomplished by the end of March, the end of seasonal rain and the beginning of the nesting season.

“This is an ideal place to encourage nesting, and we don’t want to be here when the birds try to nest,” she said.