San Bruno Mountain is a unique island of biodiversity in the heart of the Bay Area. This ecological treasure is home to several endangered species, dozens of rare plants, year round springs and creeks, ancient native oak groves, and 5,000-year-old Native American village sites. San Bruno Mountain is also the last viable remnant of the Franciscan bioregion that once covered San Francisco and is listed by renowned Harvard biologist E. O. Wilson as one of the world's 18 biodiversity hotspots in need of immediate preservation.

The goal of our stewardship program is to foster diverse communities of people dedicated to caring for and experiencing the remarkable life of San Bruno Mountain. We craft meaningful restoration activities that encourage the survival of the mountain's endangered butterflies, protect its unique communities of native plants, and connect people to each other and the mountain.

Featured below are some areas that benefit from our dedicated stewardship efforts:

Buckeye and owl canyons

The grassy ridges of Buckeye and Owl Canyon sparkle with wildflowers and provide some of the mountain's best habitat for the endangered Callippe Silverspot and Mission Blue butterflies. Saved by a Mountain Watch grassroots effort and a California State bond measure in 1989, the land is owned by the California Department of Fish and Wildlife. Stewardship efforts maintain the grasslands in good condition by removing invasive vegetation and planting natives that nourish and shelter the butterflies.

The daly city dunes

The Daly City Dunes, on the western end of San Bruno Mountain, are the last remnant of an ancient dune system that formed 80,000 to 125,000 years ago during the Pleistocene era, when high sea levels made the present day San Francisco an island, separate from the rest of the peninsula.

These sand dunes provide refuge for rare flora, including the endangered San Francisco lessingia (Lessingia germanorum).  San Bruno Mountain Watch launched the "Dune Defenders" program in May of 2016, to grow public awareness of this fascinating landscape and recover open dune habitat from the stifling weight of invasive vegetation like ice plant (Carpobrotus edulis).

The headwaters of colma creek on San Bruno Mountain


Like many urban creeks and rivers, much of Colma Creek has been locked into fenced concrete canals or buried underground as it flows through Colma and South San Francisco towards the bay. 

Yet on San Bruno Mountain, the creek has been spared the fate of city-life. The headwaters of Colma Creek abound with the shimmer of willows, wax myrtles, and the ruby glow of creek dogwood. Rushes, sedges, and birdsong gush from wetland meadows along the "Bog Trail."

San Bruno Mountain Watch continues to restore this rich riparian area in the mountain's "saddle."




Sweeping grasslands cover significant portions of the mountain's south side and provide important habitat for the endangered Mission Blue and Callippe Silverspot butterflies. The South San Francisco Weed Warriors bolster the blooming prairies by limiting the spread of invasive plants.



Tucked behind a parking lot in Guadalupe Valley's Crocker Industrial Park is an urban stream and wetland that has been lovingly restored by volunteers. The valley, the mountain's largest, was once a mix of grassland and wetland, drained by multiple tributaries that fed into a salt marsh mingling with the San Francisco Bay. A joint project with the City of Brisbane, this gem is also a Pacific chorus frog habitat, ringing with delightful "ribbits!"  Guadalupe Valley Stewards meet on Tuesday mornings to plant native vegetation, remove invasive plants, and prevent trash from washing into the bay. Watch our award-winning video about this wetland below.