Hidden Habitats

Before Europeans settled in what we now know as San Francisco, the peninsula was home to a wide variety of unique habitats. Native plant communities had specialized adaptations that allowed them to tolerate extreme environmental conditions and disturbances, including harsh soils, desiccating winds, periodic fires, and seasonal flooding. These are some of the historical habitat types that occurred in San Francisco.

Sand dunes

Sand dunes, or ‘sand hills’ as early settlers called them, were prominent in San Francisco, and they supported a wide variety of plant communities uniquely adapted to grow in the dunes’ harsh conditions. The balance between disturbance and stability in dune systems made these communities both fragile and diverse. Some dunes were relatively stable and supported dune scrub comprised of shrubby plants like yellow bush lupine (Lupinus arboreus), coastal sagewort (Artemisia pycnocephala), and California goldenbush (Ericameria ericoides). The westernmost part of the peninsula, however, was characterized by a vast expanse of sparsely vegetated sand dunes that were constantly shifting from the forceful winds. For example, San Francisco’s Outside Lands, referring to today’s Richmond and Sunset Districts, earned its name in the 19th century. The region was dominated by vast sand dunes that were considered an uninhabitable wasteland by early settlers. Today, most of San Francisco’s sand dunes have been lost to development, but you can now find restored dune communities at the Presidio.

“Brush covered the land, or rather sand hills, between Kearny and Dupont Streets, near Sacramento. In fact, the winds swept across a series of sand hills with such force that at times the sand was driven in clouds along the main traveled roads. I noticed that horse shoes and pieces of metal lying on the surface were smooth and brightly burnished by the attritions of the sand.”

-Edward E. Chever, 1849 in Through the Straits of Magellan.

Sand dunes and dune scrub at Lands End ca. 1910. Photo courtesy of OpenSFHistory/wnp14.2414.jpg
Mixed serpentine grassland and chaparral in the Presidio. Photo courtesy of Lew Stringer.


Maritime chaparral occurred on the rocky, nutrient-poor soils of San Francisco, where specialized adaptations to drought and heat are essential. Chaparral plants, such as manzanita (Arctostaphylos spp.), ceanothus (Ceanothus spp.), and hollyleaf cherry (Prunus ilicifolia), have tough, evergreen leaves that help them conserve water and tolerate hot, dry summers. Chaparral is adapated to periodic fires, and the seeds of many chaparral plants, such as blueblossom (Ceanothus thyrsiflorus) and some manzanita species, in fact require fire or exposure to charred wood to germinate.

"The appearance of San Francisco at night, from the water, is unlike anything I ever beheld... Seated on the slopes of its three hills, the tents pitched among the chapparal [sic] to the very summits, it gleams like an amphitheatre of fire."

-Bayard Taylor and Thomas Butler King, 1850 in Eldorado, or, Adventures in the Path of Empire


In early San Francisco, coast live oak (Quercus agrifolia) often had a stunted growth form as a result of the constant winds and the dry, nutrient-poor soils of the peninsula. It was often described as ‘scrubby oak’ by early settlers, who relied on the oaks for firewood. These “dwarf” coast live oaks typically grew among a dense matrix of low-lying shrubs and grasses.

The stand of dwarf coast live oaks visible in this 1899 photo can still be found today at the National AIDS Memorial Grove in Golden Gate Park. Similar dwarf coast live oak woodlands also persist at Fort Ord near Monterey and the Elfin Forest Natural Area near Morro Bay.

1902: “As for Black Point … a very paradise of live-oak and scrub-oak, and of oak that had gone mad in the whirlwinds and sandstorms that revelled there.”

-Charles Warren Stoddard, 1902 in San Francisco Memoirs: 1852-1899

“This open -space, bounded on the south and east by a narrow ravine coming down about where Sacramento street now lies, beyond which is—I beg pardon, was—a wilderness of green, uninviting shrubbery, the well known dwarf scrub oak, unrelieved by a single habitation, unmarked by a single sign of road or pathway, stretching away in undulating folds far to the south and east.”

-Article titled "Twenty years ago," 1866 in Sacramento Daily Union

Tule elk and dwarf coast live oak in Golden Gate Park in 1899. Photo courtesy of Greg Gaar.
Lobos Creek in 1896. Illustration courtesy of the San Francisco Chronicle.


Riparian habitats are made up of lush, water-loving plants that live along springs, creeks, and streams. Historic San Francisco had a number of springs and creeks that collected water and hosted verdant vegetation and diverse communities of wildlife in an otherwise dry, harsh landscape. Lobos Creek, for instance, which drains Mountain Lake on the west side of the Presidio, was shaded by a riparian canopy of coast live oaks (Quercus agrifolia), willow (Salix spp.), Pacific wax myrtle (Myrica californica), and other species.

Early 1900s, about Adams’ (1902-1984) youth: “With a resolute whisper, Lobos Creek flowed past our home on its mile-long journey to the ocean. It was bordered, at times covered, with watercress and alive with minnows, tadpoles, and a variety of larvae. Water bugs skimmed the open surfaces and dragonflies darted above the stream bed. In spring, flowers were rampant and fragrant. In heavy fog the creek was eerie, rippling out of nowhere and vanishing into nothingness. I explored every foot, tunneling through the thick brush and following the last small canyons in the clay strata before I met the Pacific.”

-Ansel Adams, ca. 1983 in Ansel Adams: An Autobiography


Freshwater wetlands are habitats that are either seasonally or perennially flooded or have saturated soils. While water is essential for life, poorly drained, inundated soils present a trade-off: they are often low in oxygen, making it difficult for the roots of plants to breathe. As a result, wetlands often host very specialized plant communities that can tolerate these oxygen-deprived soils and constant inundation. San Francisco’s historic landscape once contained a diversity of freshwater wetlands, including emergent marshes, wet meadows, dune ponds, bogs, and willow groves.

“In 1850 the head of the family went far into the wilderness and built on Harrison and Sixth streets, on a little dry knoll in the middle of a swamp, a residence where he lived for a number of years and which became, in 1856, the famous Russ Gardens. A narrow causeway was built from Folsom street to the gardens, and woe to the unlucky rider who deviated from the narrow road; both horse and rider were likely to be engulfed.”

-Zoeth Skinner Eldredge, 1912 in The Beginnings of San Francisco

Lake Merced in 1881. Illustration courtesy of the Bancroft Library, University of California, Berkeley.

“How many of this generation know that Spring Valley once lay between Mason and Taylor, Clay and Washington streets, and gave its name to the company, that now supplies San Francisco with water? A great springy, boggy hollow, sixty feet deep, was Spring Valley, and from the springs there coming to the surface it was supposed that an adequate water supply could be obtained for the City. So a company was formed, but it got nothing but a name from the valley. The water supply was a delusion and a snare, so runs tradition, and later J. B. Haggin filled in the valley, and the City crept over it, as over many another unmarked and long-forgotten grave.”

-Article titled “The valleys of San Francisco,” 1896 in the San Francisco Call

Illustration courtesy of Ryan Jones.


Grasslands, supporting a diversity of grasses and wildflowers, occupied hillslopes, tablelands, and rocky ridgelines in many parts of San Francisco. Serpentine grasslands formed a distinct vegetation community comprised of plants specially adapted to tolerate serpentine soils. Serpentine soils possess an unusual soil chemistry: they are low in potassium and calcium, which are necessary nutrients for plant growth, and contain high levels of elements that are toxic to plants, such as magnesium, chromium, and nickel. These serpentine soils are found in patches in and around the Presidio, so a suite of plants have evolved to tolerate the unique combination of these harsh serpentine soils and San Francisco’s cool-summer Mediterranean climate. Today, serpentine grasslands can still be found in the Presidio near Inspiration Point.

“March 28… While on our way [SB: to white cliff at Fort Point from Mountain Lake] we went up a small-sized knoll and at once came onto a very handsome, green, flowery tableland with a great many field violets, of which there are a great many hereabouts and which I had not seen anywhere until today in any of the country I have been traveling through.”

-Father Pedro Font, 1776 in With Anza to California, 1775–1776: The Journal of Pedro Font, O.F.M.

What other habitats have you seen around the Bay Area that may have once been found in San Francisco?