One of a kind: a single Presidio manzanita remains in the wild and its location is a closely guarded secret.
Battered by incessant winds, the manzanita grows only a few inches high but stretches nearly seven meters in diameter. Its leathery leaves are nearly round and measure less than an inch across. Delicate white urn-shaped blossoms with a hint of pink emerge in winter.
The Presidio, a former Army base and now part of Golden Gate National Recreation Area, protects the last of this manzanita subspecies, along with the remaining patches of the shrub's habitat--serpentine maritime chaparral. The Presidio manzanita is endemic to serpentine soil, which is high in magnesium and toxic to most plants.
The California Department of Fish and Game declared the Presidio manzanita endangered in 1978; the next year, the U.S. Fish and Wildlife Service (USFWS) added it to the federal endangered species list. USFWS finalized a recovery plan for the manzanita in 1984. One year later, an Army road project modified a slope that comprised some of the plant's best remaining habitat. The Army was responsible for protecting the species before October 1994, when the Presidio was transferred to the National Park Service.
Under the Park Service's stewardship, the last Presidio manzanita is flourishing. Despite the agency's efforts, says park biologist Colette Hunter, the species is probably "doomed." With only one individual remaining in the wild, the plant appears incapable of self-pollinating or producing viable seeds. Even so, the park staff has implemented elements of the recovery plan to focus on protecting the plant, expanding the stand, and restoring its habitat.
With the help of volunteers, the park carries out an aggressive campaign to eliminate non-native flora from the immediate area. An agreement reached in the wake of the Army's road project led to the removal of four exotic Monterey pines that shaded the manzanita. With the removal of two more of the pines in the last year, the Presidio manzanita has been restored to full sunlight and protected from the hazard of faring trees.
In an effort to avoid disturbing the plant, most preservation work occurs around its perimeter, says Sharon Farrell, leader of the park's efforts to protect the manzanita's habitat.
The Park Service's approach to the last wild Presidio manzanita is a marked change from an ambitious plan begun a decade ago. In 1987, 180 cuttings were taken from the parent plant and over the next two years, 65 rooted cuttings were planted throughout the Presidio. A survey conducted this summer found that 21 of the clones survive; some of them have grown to a diameter of two meters. Genetically identical to the parent, the clones are equally vulnerable to pests and disease, but they may survive to provide a genetic record. Nevertheless, when the parent plant--which is at least 45 years old--dies, the species will be considered extinct in the wild.
"We've already lost the battle for the Presidio manzanita," says Peter Holleran, a park volunteer, "but it has become a totem for endangered species, a reminder that we need to work on habitat restoration before it's too late."
KATHERINE HEINRICH is assistant editor of National Parks.
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|Title Annotation:||rare plant at the Golden Gate National Recreation Area, CA|
|Author:||Heinrich, Katherine M.|
|Date:||Nov 1, 1996|
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