Advertisement
YOU ARE HERE: LAT HomeCollectionsVolunteers

Next L.A. | Public Places

Returning the Natives

Students Help Reestablish Original Species on Ballona Dunes

March 11, 1997|JANE SPILLER | SPECIAL TO THE TIMES

The natives versus the invaders--in this battle it should be easy to know which side to be on.

On a recent morning on the Ballona Dunes in Playa del Rey, 15 enthusiastic youngsters in work gloves pulled out more than their weight in ice plant, piling it high enough to play king of the mountain. They were third-graders from Turningpoint School in Culver City on a field trip to join the volunteer effort to remove exotic plants that have taken over the sand dunes and to help reestablish native species.

Somehow, 30 hands wielding trowels cooperated to dig two holes and plant two willow trees propagated from cuttings of trees on the site. The students took home one-gallon cans seeded with lupine, a native plant that they will care for and return to the site for replanting.

On the dunes that morning, purple spires of lupine bloomed on silvery green bushes. Great egrets flew over from the tidal inlet, folding their long white wings as they settled down on the sand. Meadow larks were singing. Half a dozen stick nests built by great blue herons were silhouetted in the limbs of a cottonwood tree. By the time the chicks are hatched, the tree will be covered with leaves.

The eight acres of dunes are all that remain of a primary dune area that was leveled and carted away in the 1930s, '40s and '50s as houses were built facing the beach. Since that time exotic plants have taken over.

The most common nonnative invasive plant is the ice plant--formally known as the Hottentot fig--a visitor from South Africa with succulent triangular leaves. It was brought over as a drought-tolerant ornamental ground cover. Ice plant and other common exotic plants--pampas grass, ripgut broome, myoporum and castor beans--have few natural enemies here, so they overwhelm native species. They send out roots that steal water and spread leaves that shade the soil and lower the ground temperature so that other seeds won't germinate. As they destroy the habitat that supports native microorganisms, insects, birds and animals, they wipe out links in the local food chain.

Ice plant is an escape artist with a tendency to migrate from gardens and hillsides and spread. New plants can grow from pieces that break off.

And sometimes ice plant gets help in spreading. "You have a hillside at home?" I heard a parent say to a third-grader. "Maybe you want to take the ice plant home and plant it there. That's what ice plant's good for, to keep hills from coming down in the rains." Myths die hard.

"Historically ice plant has been used to hold slopes, but in Laguna Hills, Palos Verdes and elsewhere you see whole hillsides with ice plant that have ripped off," said John Rieger, a restoration ecologist who worked on the plan for the dunes. Ice plant has a shallow root system and 95% of its weight is in succulent leaves that pull it down hill. Rieger said other plants are more suitable for hillside planting, such as coastal sage scrub, which can be seen on the steep slopes of the Westchester bluffs to the east. The native plants have deep roots and less mass above ground.

"If we put more effort into exploring our native species or noninvasive species we'd be much farther ahead in resolving a lot of issues such as water conservation, erosion, sloughing, sedimentation--all those issues are connected," he said.

Even small choices on what to plant in the garden can have big consequences for survival of native species, experts say. Gardeners who cannot resist planting invasive exotics unwittingly threaten native plants with extinction--and extinction is happening at an accelerating pace.

"I have roses in my front yard," Rieger said, "but also natives all around my house." The roses are not native, but they stay put.

Fencing of the dunes property to protect it from people and dogs, and three years of volunteer effort by the Friends of the Ballona Wetlands, are showing results.

Just pulling weeds taps into a dormant native seed bank. After weeding a small area of about 10 feet, volunteers have found 200 native plants sprouting.

The next goal is to increase biodiversity on the dunes, which Rieger said is the key to a healthy ecosystem. There are now only about eight native plant species here. The plan is to increase that to 20.

The property is open to the public for workdays and nature walks. Call the Friends of the Ballona Wetlands at (213) 436-0983 for information.

Public Places writer Jane Spiller welcomes suggestions and comments. Contact her c/o NEXT LA or at Jane.Spiller@latimes.com

Advertisement
Los Angeles Times Articles
|
|
|