West Marin BioDiversity

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Biodiversity, a combination of bio (life) and diversity, generally refers to the variety and variability of life on Earth.  Biodiversity typically measures variation at the genetic, the species, and the ecosystem level.

No feature of Earth is more complex, dynamic, and varied than the layer of living organisms that occupy its surfaces and its seas, and no feature is experiencing more dramatic change at the hands of humans. 

This layer of living organisms—the biosphere—through the collective metabolic activities of its innumerable plants, animals, and microbes physically and chemically unites the atmosphere, geosphere, and hydrosphere into one environmental system within which millions of species, including humans, have thrived.

Breathable air, potable water, fertile soils, productive lands, bountiful seas, climate and other ecosystem services are manifestations of the workings of life. It follows that large-scale human influences over this biota have tremendous impacts on human well-being. It also follows that the nature of these impacts, good or bad, is within the power of humans to influence.

Located just an hour from San Francisco, our mission-based work focuses on environmental issues facing the coastal communities of West Marin, the largest rural region of Marin County, California. The area generally extends from Dillion Beach to the north, south to Muir Beach, and west of Nicasio and the San Geronimo Valley, out to the Pacific Ocean. The area includes several unincorporated coastal communities (BolinasDillion BeachInvernessMarshallMuir BeachOlemaPoint Reyes StationStinson Beach, and Tomales), and is home to approximately 16,000 people, or about 6.5% of the population of Marin County, and receives over 2+ million visitors a year in search of respite, relaxation, and recreation. 

Our work is focused on bringing people, science and policy together, to solve some of these threats and champion innovative solutions. For over forty years we’ve worked on various projects to protect vital ecosystems, defend critical legislation, enforce accountability of leaders and legislators and rally our community to become stewards of their backyard. 

National DEsignations

Discover some of the national designations and reasons why West Marin is a unique part of the world where biodiversity thrives. 

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California Floristic Province

Marin County is located within the California Floristic Province, one of 25 internationally recognized botanical hotspots with the most concentrated biological diversity and most severe threat of loss according to Conservation International.

In West Marin, we work with agencies and partners who manage a wide range of parks, open space and agricultural lands where much of our unique biodiversity can be found. The biggest threats to botanical hotspots are development, non-native or invasive species, and climate change. Learn more 


Pacific Flyway

The Pacific Flyway is a major north-south route of travel for migratory birds across the Americas, from Alaska to Patagonia providing a range of habitats birds depend on. Every year, migratory birds travel some or all of this distance in spring and fall, following food sources, to their breeding and wintering grounds.

Migratory birds cross boundaries of habitat, state and country and are thus excellent indicators of the health of our environment across large distances.

Each year at least a billion birds migrate along the Pacific Flyway, but these birds are only a fraction of those that used the flyway a century ago. Habitat loss, water shortages, diminishing food sources, and climate change all threaten the birds of the Pacific Flyway.

Parks & Sanctuaries

A number of agencies protect large tracts of land in West Marin covering close to 188,000 acres, which provide a mild climate, and number of plant communities that provide habitat and food for a wide range of biodiversity to thrive in. 

California State Parks - Tomales State Park
California State Parks - Marconi Conference Center State Historic Park
Cordell Bank National Marine Sanctuary
Greater Farallones National Marine Sanctuary
Marin County Parks
Marin Municipal Water District
National Park Service Point Reyes National Seashore


West Marin BioDiversity

West Marin's biodiversity is most characterized by Point Reyes National Seashore's resources, as it covers over half of the region. Discover that makes this area unique below. 


Wildlife abounds in West Marin! Use the links below to discover life in and around the region.
Point Reyes National Seashore is as varied as the landscape itself, and ranges from large marine mammals such as the blue whale to the relatively small, endangered Myrtle's silverspot butterfly. 

  • 490+ North American bird species 
    Point Reyes National Seashore easily claims the prize for the greatest avian diversity in any U.S. national park with 490 species, or 54% of all North American bird species recorded within the park. The species total here, in fact, is larger than the species total in each of forty of the United States. Some of the factors responsible for attracting this amazing diversity are Point Reyes' proximity to the Pacific Flyway along the Pacific Ocean, its diverse habitats, and the shape of the peninsula which acts as a geographic magnet. Point Reyes has at least two special species of concern at the park including the threatened Western snowy plover and the Northern spotted owl.  
  • 80+ species of land and marine mammals
    From the blue whale, the largest mammal on the planet, to the short-tailed weasel, wildlife is very prevalent in the area. You would be hard pressed to not see a deer, coyote, fox, raccoon, skunk, rabbit, but the mountain beaver, American badger or ringtail may be more elusive. 
  • 85+ species of fresh and saltwater fish  
    From the endangered coho salmon and threatened steelhead trout, to more common leopard shark, rockfish and halibut, or the more elusive Great white shark, these species are rarely seen, but contribute to the ecosystem.  
  • 29+ species of reptiles and amphibians
    The 14 species of reptiles found at Point Reyes National Seashore are found in a wide variety of habitats. Turtles utilize habitats such as freshwater ponds, streams, drainage ditches, marshes, stock ponds and the open ocean. Lizards occur in almost every habitat except the dampest innermost forest and the tidal salt marsh. Snakes prefer warm and dry environments, therefore the humid environment at Point Reyes limits the population sizes of several species.
  • And thousands of aquatic and terrestrial invertebrate species including sea anemones, starfishbutterflies, insects and more

Additional Resources

San Francisco's Bay Area National Parks Science & Learning's website and viewing their picture galleries


Point Reyes National Seashore is home to a broad spectrum of aquatic and terrestrial environments which support a diversity of plant life including 900 species of vascular plants (15% of California plants); 61 endemic plants (found nowhere else on the planet), and 51 rare, threatened, or endangered species. These plants do not exist in isolation, but rather as part of plant communities such as forests, grasslands, coastal scrub, intertidal zones and marshes, coastal dunes and wetlands.

Check out a snapshot of each of the plant communities found at Point Reyes National Seashore using the resources below, or learn more about specific plants using the plant lists provided by the park:  

Defining Habitats Newspaper

Defining Habitats Curriculum Guide

Point Reyes National Seashore Checklist

Algae and Marine Plants of Point Reyes National Seashore 

Cone-Bearing Plants of Point Reyes National Seashore

Fern and Fern Allies of Point Reyes National Seashore 

Flowering Plants of Point Reyes National Seashore

Macrofungi of Point Reyes National Seashore

Nonnative Plants of Point Reyes National Seashore

Threatened, Rare, and Endangered Plants of Point Reyes National Seashore

Additional Resources

CalFlora, a reference tool to look up plant descriptions by physical characteristics, location or by common or latin name; or to add your own observations. 

Marin Chapter of California Native Plant Society for several comprehensive plant lists searchable by various locations in Marin County.

EAC Biodiveristy Partners


EAC Biodiversity Programs