Presidio's plant, wildlife is making a comeback
ENVIRONMENT With stewardship, native species thrive
Published 4:00 am, Sunday, May 27, 2012
Biologists tiptoed between the tiny pink blooms scattered across a windy bluff below Inspiration Point in the Presidio of San Francisco on a recent weekday, trying their hardest not to step on endangered species.
It was a difficult task. Rare plants poked up like benevolent weeds along the grasslands on this rocky serpentine hillside.
There, next to the California poppies, was the federally endangered Presidio clarkia with its pink blossoms. Cuttings from the last known wild Franciscan manzanita in the world were right next to the footpath. The Marin Western Flax, a federally threatened species, was underfoot near the rocks.
"The clarkia here is a great example of how, with stewardship and care, we can restore native habitat," said Michael Chassé, a natural resource management specialist for the Golden Gate National Recreation Area, as he busily counted plants within a designated research area. "We've seen a tenfold increase in the number of individual plants. And it's not just clarkia. It's poppies and many other plants."
The Presidio has become a model for native plant species and habitat restoration since 1994, when the U.S. military turned the land over to the National Park Service and later created the Presidio Trust to oversee 80 percent of the park.
Invasive trees and plants, culverts, decrepit buildings, dumpsites and military detritus have been removed over the past decade. Biologists, ecologists and volunteers have, in turn, opened underground springs, brought creeks and waterways out from culverts to the surface, restored wetlands and cultivated native plant species once thought to be extinct.
Now, the fruits of their labor are beginning to show. Butterflies, hummingbirds, coyotes, a large population of frogs and, at El Polin Spring, 12 ducklings have repopulated the urban park.
"There are a lot of native species that have disappeared from the San Francisco area because of development, and with restoration they are starting to come back," said Teri Thomas, the director of conservation, stewardship and research for the Presidio Trust. "Often when we do restorations, we get plants growing that we didn't expect, either from seeds buried deep in the native soil or after being blown in."
The most remarkable thing, at least to the botanists and biologists, is the sheer number of rare species now living in the Presidio. Chassé said 10 plant species in the entire 74,000-acre recreation area are listed as threatened or endangered under the U.S. Endangered Species Act. Four are now growing in the Presidio, including the clarkia.
Discovered in 1956
Clarkia franciscana, as it is known in scientific circles, was discovered in 1956 growing in a 50-by 50-foot area in an old quarry at the Presidio, according to botanists. By 1969, after motorcycle riding decimated the site, the plant was reported to be extinct. Fortunately, a botanist had collected seeds, which were grown by James Roof, then the director of the Tilden Botanical Garden. They were planted below Inspiration Point, where the motorcycle tracks are still visible, in 1972.
By 1994, 6,000 clarkias were counted. In 2011, there were 100,000, said Shelley Estelle, a biological science technician for the Presidio Trust. Another remnant population has since been found in the East Bay hills, she said.
One plant that isn't listed under the Endangered Species Act is the Franciscan manzanita, which was believed to be extinct in the wild for more than 60 years until it was discovered in the Presidio in 2009. The ground-hugging shrub has been moved to an undisclosed location, but cuttings were recently taken from it and are being planted throughout the park.
"There's 10 of them spread out here," said Estelle, pointing to several small green plants among the shrubbery at Inspiration Point. The U.S. Fish and Wildlife Service has recommended listing the plant as endangered.
Presidio manzanita is another rare species that is uniquely adapted to San Francisco's natural sand dunes, wind and fog. Also known as Raven's manzanita, it was rediscovered in the 1950s by world-renowned botanist Peter Raven after being gone for half a century. There is now only one specimen left in the wild and it, too, is in a secret location in the Presidio.
"We are looking into other areas on the coastal bluffs where there is good enough habitat for us to expand these species and help them recover," said Chassé, who is in charge of coastal plant restoration and works closely with the Presidio Trust.
No place in the Presidio has seen a more rapid recovery than the restored sand dunes and coastal habitat off Battery Caulfield Road, on the southern edge of the Presidio. The trust removed debris from a former dump and then covered an old merchant marine graveyard with 25,000 cubic yards of excavated sand from the M.H. de Young Memorial Museum construction project in Golden Gate Park.
Thousands of native plants, grasses and annual flowers, including the federally endangered San Francisco Lessingia, were planted on the dunes over the past year.
The flowering yellow Lessingia, which was down to about 100 individual plants in the early 1990s, is thriving. There are now between 200,000 and 300,000 in the Presidio and another small population on San Bruno Mountain, said Lew Stringer, a restoration ecologist for the trust.
"This is a botanical wonderland of rare and endangered species," said Stringer, as he pointed out different plants and told about the butterflies and bees that use them as hosts or harvest their nectar.
He then walked over to a seasonal pond that, for the first time this year, is hopping with bug-size baby western chorus frogs, a tree frog that, when they all get together, can make quite a racket. The native chorus frogs, which had disappeared from the Presidio many years ago, were spotted again next to the Crissy Field marsh three years ago.
"There's a lot of life here that's hard to see," Stringer said. "It's mostly small life now, but its building back up."
Rare dune plants
Some of the rare and endangered flowers and plants that are growing in the Presidio can be seen at: links.sfgate.com/ZLKE.
To see a video of the ducklings at El Polin, go to: links.sfgate.com/ZLKK.
Peter Fimrite is a San Francisco Chronicle staff writer. firstname.lastname@example.org