| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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habitats Restoring (Dune) Community Values One hundred and forty years ago, W. P. Blake wrote of a San Francisco dominated by a complex of sand dunes stretching from Ocean Beach south of Lake Merced nearly to Fort Point and east all the way to what is now the bottom of Market Street. Each spring, the peninsula would go berserk with blossoming wildflowers, changing color every couple of weeks as a succession of Franciscan wallflower, Indian paintbrush, purple cobweb thistle, and mock heather took turns luring pollinating insects and birds into their realms. The dunes remained colorful attractants for pollinators and the animals that preyed on them for ten months out of the year, remarkable considering that the area gets only about 20 inches of rain. At the turn of the century, there were as many as 22 square miles of dunes filling what are now San Francisco's Sunset, Western Addition, and Richmond districts, Golden Gate Park, and much of the Presidio. This was one of the most extensive dune complexes on the California coast. You'd never know it now. By the mid-1950s all but a few score acres of dunes--the best around Baker Beach--were gone. Well, not exactly gone. Perhaps "asleep" would be a better word. "Those dunes are still there," says Marc Albert, a National Park Service biologist working at the Lobos Creek dune restoration project at the Presidio. "If you dig your foot into the duff throughout much of the Presidio, you get to sand pretty quickly." The Golden Gate National Recreation Area--which took over management of the Presidio when the U.S. Army transferred it to the Park Service in 1994--has been trying to wake up portions of those ancient dunes. Unfortunately, it is not just a matter of pulling exotic vegetative covers off the slumbering sand. Rather, those scientists restoring the dunes must recreate a complex and interactive web of associations and relationships. To do this, they are squeezing events that took hundreds or thousands of years into a decade or less. So that the dunes work as an ecosystem, they are planting patches in each of the natural stages of dune succession: annuals, sub-shrubs, late successional scrub, and coast live oak woodland. Two years ago, when the dunes project was launched, its project manager, Joe Cannon, first had to recreate the rolling sand hills that characterize dune topography. In his way were about a dozen cypress trees, a seldom-used baseball diamond, and a public relations nightmare. To Cannon and the others working on the project, the restoration was obviously an improvement. But the value of dunes was not as clear to everyone. Getting rid of the trees was a harsh initiation: from the Headwaters Forest to the Presidio, if you want people to hate you, cut down the trees they love. It doesn't matter much whether they are thousand-year-old redwoods or decades-old exotics, people will go to great extents to save them. Most vocal were the joggers and hikers accustomed to passing through the site and the property owners whose homes were just across Lobos Creek. The latter had bought their homes next to cypress, planted by the Army in the 1890s, and they didn't want their trees ripped out and replaced by what they saw as a monotonous, lifeless, experimental sandbox. But after a great deal of explanation, and haggling, the trees did come down, the iceplant was removed, the ball park was dug out, and in 1995 the first three acres of the restoration site were planted with thousands of native annuals, perennials, and shrubs. From the beginning, budget constraints had forced Cannon and the Presidio Natural Resources Staff to the conclusion that they could not afford to do the work with paid employees. They decided instead to rely on community volunteers for everything from running the nursery to planting and weeding the dunes. "This basically economic decision turned out to have all kinds of positive ramifications," says Cannon. On the January Saturday that I joined a dozen other volunteers at the dunes, the advantages of this approach were obvious. Not only do volunteers work for free, and not only do they put their hearts into the work in a way few professionals could do for long, but they also provide a vital educational and personal link to the community. "The volunteer program gets all kinds of people involved who wouldn't ordinarily be," says Peter Holloran, president of the Yerba Buena Chapter of the California Native Plant Society and a long-time volunteer at the Presidio. This includes middle school and high school students, corporate and community group volunteers, as well as drunk drivers and other convicts doing community service in reparation for their crimes. Anthropologist Anne Whittey conducted a six-month study of volunteers doing restoration work at the Presidio. Her report, to be published this summer in Restoration & Management Notes, the journal of the Society for Ecological Restoration, suggests that working with plants--especially in restoration, where damage done to the landscape is being remedied--weaves volunteers into the wider community of living things. "I am finding that the larger ecological system is the primary context in which life is meaningful," she says. "And through my interviews I can see that whether they are aware of it on a conscious level or not, the volunteers become more and more open to this meaning as they spend time working within this larger context." Psychobabble? Wisdom? Both? I don't know. But the volunteers clearly enjoy the work and they come in numbers that pose practical challenges for the program administrators. "This is the only program that I know of that has more volunteers than it knows what to do with," says Holloran.
Even after the politics have been sorted out, recreating a dune community is tricky business, especially where there are no models of intact habitat to mimic. "We want this to be a native habitat restoration, not just a revegetation," says Cannon. This approach is necessary partly because these 13 acres of dunes will be surrounded by non-dune habitat, so Cannon can't just prepare the terrain and let the vegetation move back on its own. The native plants will have to be reintroduced one at a time. And constant vigilance must be kept against the reinvasion of iceplant, radish, sheep sorrel, and grasses such as rip-gut brome and wild oats, all aliens that could overrun the dune community before it gets a foothold. "The dunes at Baker Beach are our best approximation of what should be here," says Cannon. "But they've had a lot of perturbations and are far from pristine. Since we don't have a model of what we're trying to make, we have to study the system to see how it works." To do this Cannon and Holloran studied the remaining fragments of coastal dunes from Monterey to Humboldt County, noting the plant associations and geological and weather forces at work. "The big challenge is to get a dynamic system," says Holloran, "where you have not only these perennials that will become shrubs, but also all the annuals that need openings, where there are no shrubs. The processes in the past that created that--aeolian sand movement and sand deposition from other unstabilized dunes--are no longer present here." The Lobos Dunes have been cut off from those forces by remaining Presidio forest and houses that line the creek and the hillside to the west of the site. Until the creek corridor to Ocean Beach is cleared of trees--a plan of Cannon's that may take decades if it is politically tenable at all--Cannon and his volunteer will have to fabricate those habitat-creating disturbances to approximate the conditions of living dunes. "We laugh about bringing in `the stochastic bulldozer,'" says Holloran. "We're trying to approximate nature as best we can, but our hands are all over this piece of property," Cannon says. "We'll be creating a new community, not exactly reproducing a natural one. But given the constraints we work under, that's all we can do here." The volunteer crew I am working with, after weeding a patch of dune, plants seedlings of dune knotweed, coastal buckwheat, deerweed, yarrow, and wild strawberries. "It's important to plant these right," Cannon says as he shows us how to dig with hand picks and tap the seedlings free of their containers. "A lot of work has gone into getting these seedlings to this point. Students collected the seeds from wild plants, volunteers planted them and raised them in our nursery, where we've been tending them in preparation for this moment." In the three hours we work, we planted about a quarter of an acre. It didn't yet look much like a plant community, but the group seemed satisfied anyway. I know that I was savoring my expectations for the spring, when the roots we put in would begin to take hold and the plants show their true colors. The last Xerces blue butterfly was seen on this very site in 1941. It was a beautiful and delicate endemic; I have seen a specimen of Xerces blue in the Academy's entomology collection. No matter how successful this restoration is, that butterfly will never grace these hills again. But there are other species that might. One is the rare Pheres blue butterfly, which also lived in San Francisco. Its only known occurrence now is at Point Reyes National Seashore. Perhaps one day decades from now it will alight on one of the shrubs we've put in this morning, finding the same nectar its ancestors found in these plants tens of thousands of years ago. Gordy Slack is an Associate Editor of California Wild. |
Spring 1997
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