San Francisco's biodiversity resides in iconic park lands like the Presidio, Twin Peaks, Glen Canyon, Lake Merced and Golden Gate Park. These park lands harbor a remarkable diversity of ecological communities of native habitats, plants and animals, including hundreds of species of resident and migratory birds. The wetlands, prairies, dunes, oak woodlands and other wildlife habitats of our geographic area are part of the California Floristic Province, identified by Conservation International and the Nature Conservancy as a global biodiversity hotspot. Our local bioregion is recognized by the United Nations as the Golden Gate Biosphere Reserve, which underscores the severe urban pressures on our local biodiversity.
Watch this short video of the natural treasures of Yerba Buena Island.
Our City's Wild Past
When the Yelamu Ohlone lived in the area we now call San Francisco, the northern peninsula looked very different than it does today. The Ohlone thrived in the San Francisco Bay Area for thousands of years, living remarkably ecologically sustainably without using intensive agriculture as we know it. The Ohlone interacted with the land substantially through hunting, gathering, fire management and other cultural practices, and the ancient natural landscape retained its incomparable biodiversity among a striking variety of habitat and ecological communities, including dunes, coastal scrub, wetlands, ponds and lakes, creeks and estuaries, oak woodlands and riparian forests. The natural habitats that are described in this section are what remain of that ancient environment.
What is Biodiversity and what is an Ecosystem?
Biodiversity, short for “biological diversity,” is the variety of interconnected species (flora, fauna, fungi, and bacteria) that have co-evolved into local ecological communities, ecosystems and processes of a particular place on Earth, plus, in cities, species imported from other places that contribute positively to vibrant and thriving dynamics of the remaining indigenous ecology of that city or town.
Coined in 1930, the word "ecosystem" means all the physical and biological components of an environment. It includes the biodiversity along with all the non-living physical components that interact with organisms, such as air, soil, water and sunlight. Ecosystem services are fundamental life support services upon which human civilization depends. Ecosystems provide our sustenance, including our food, water and medicine; supply us with wood, paper and minerals; regulate our climate; and provide cultural services, such as recreation.
Rare and Endangered Species
Located in a biodiversity hotspot known as the California Floristic Province, our city harbors dozens of rare and endangered plants and animals - birds, amphibians and insects - including over ten federally-listed endangered species! The Mission Blue Butterfly, California Red-Legged Frog and Western Snowy Plover are all endangered species that call San Francisco home. Our globally rare butterflies and plants are literaly found only in the San Francisco bioregion, and nowhere else on Earth.
Download a PDF list of the over 20 species of globally rare plants of San Francisco.
Impacts and Threats
Despite our rich ecological legacy, our Franciscan bioregion is under severe pressure from our urban civilization. Invasive plants, insensitive land uses, institutional neglect, and lack of awareness and marginalization continue to erode the city’s biodiversity. Climate change is an emerging threat to the city's natural heritage. Combined with invasive species, climate change can cause accelerated stress on our natural ecosystems. In response to these pressures, many people and organizations work hard every week to steward our local natural landscape. Please visit the San Francisco Weed Management Area website for more information about invasive plant management.
San Francisco was developed in a unique natural landscape, no less special than anywhere else on Earth. San Francisco, like other cities around the planet, has its own special ecological legacy, which deserves respect and protection just like the rainforests of Brazil or British Columbia. Around the world, people and policymakers have begun to acknowledge the importance of urban biodiversity. The United Nations, ICLEI-Local Governments for Sustainability, the Convention on Biological Diversity, and the International Union for the Conservation of Nature (IUCN) all have policies and programs that recognize the important of biodiversity in cities. New York City, Chicago, Los Angeles, Portland, Madison, Austin and Kansas City are examples of cities that have made conservation of their biodiversity a priority.