Tunnel to Marin Headlands Closed
The tunnel on Bunker Road from Alexander Avenue in Sausalito towards the Marin Headlands is closed for construction. Please follow the detour signs to Conzelman Road (just above the north end of the Golden Gate Bridge) to go up over the hill. More »
Muir Beach (but not nearby Muir Woods) parking lot closed June-November 2013
Muir Beach parking lot will be closed from June-November 2013 due to construction. Restrooms or nearby parking will not be available at Muir Beach during this period. Pacific Way is closed except to residents. Check back for updates or call (415)561-3054 More »
CAUTION: Post Storm Damage to Coastal Trail
The Presidio Coastal Trail segment just north of the Pacific Overlook and adjacent to Lincoln Blvd remains CLOSED indefinitely. We have posted signage to alert bicyclists and hikers and with information for safe trail alternatives. More »
Wetlands, Marshes and Swamps
Estuaries provide transition from ocean to land. Freshwater streams meet saltwater tides creating one of the most fertile habitats on earth. Fast growing marsh vegetation provide habitat for decomposers, and the food system is based on detritus (decomposed plant materials) rather than live plants. Estuaries also act as a doorway for ocean fish who spawn in freshwater streams such as Coho salmon and steelhead trout. For other fish and crabs, estuaries are the perfect place to spawn, leaving the juveniles in the protection of the vegetation and abundant food supply to grow up until they are ready to enter the open ocean. Estuaries also provide important stopovers for migrating ducks and shorebirds as they fly thousands of miles up and down the Pacific Flyway.
The life of marshes is determined by the tides that wash in and out twice daily. They are either submerged by salty water or left high and dry as the tides recede. Marsh organisms are distributed at different tidal levels, depending on their ability to withstand the stress of tidal inundation. Eelgrass beds grow in channel bottoms and deep basins, supporting sponges, tunicates, and moss animals. Most of these animals are filter feeders or graze on microscopic algae that grow on the leaves of the eel grass. In the mudflats (shallow areas where little vegetation grows), are worms, clams, and snails. Most of these animals are detritivores, filtering organic particles from the water like crabs and shrimp. Raccoons and fox also regularly come down to water’s edge looking for a snack.
The threatened Point Reyes bird's beak ranges along the central California coast, but due to widescale development of marshlands, numbers have quickly dropped. This small annual was introduced to the recreated salt marsh at Crissy Field in 2001.
The endangered California sea blite, although once abundant from Morro Bay up the central California coast, has been extirpated from San Francisco Bay. This small succulent shrub was also introduced to the recreated salt marsh at Crissy Field in 2001. It has since done poorly and reintroduction status is being considered.
Did You Know?
Graywacke sandstone is a common rock at Golden Gate and was deposited on the deep sea floor by underwater landslides called turbidites.