Saving the Sandwort: Reviving One of California’s Rarest Plants

In late October, Golden Gate National Recreation Area ecologists planted 45 endangered marsh sandworts in the lower Rodeo Valley wetland restoration area near Fort Cronkhite.

NPS

November 2020 - Near Fort Cronkhite, a watershed that once contained a barren parking lot now hosts a more robust population of one of the rarest plants in California - marsh sandwort (Arenaria paludicola). In late October, park ecologists planted 45 endangered marsh sandworts in the Lower Rodeo Valley area of Golden Gate National Recreation Area. These plants were introduced to supplement a population planted in 2011 as part of the Rodeo Valley wetland restoration.

Historically marsh sandwort grew along the coast from California to Washington, but alteration and destruction of its habitat reduced the population to just one known locality. Today, there are only 12 wild individuals left in the world. To bring the marsh sandwort back from the brink of extinction, scientists have been propagating the plants at the University of California, Santa Cruz. They then transplanted the sandworts to sites with similar conditions to the extant populations in San Luis Obispo. The sandwort population in the Marin Headlands is helping scientists understand this rare plant while increasing local biodiversity and improving native habitats.

Historically, marsh sandwort grew along the coast from California to Washington. But alteration and destruction of its habitat has reduced the wild population to just 12 individuals. The plants now growing in Rodeo Valley were propagated and donated by the University of California, Santa Cruz.

© Michael Chassé / Photo 48646388 / 2019-07 / iNaturalist.org / CC BY-NC-ND

The marsh sandwort’s new home near Rodeo Beach has its own history of ecological revival. The US Army drastically altered the landscape throughout its tenancy, building hundreds of structures, roads, and other infrastructure. These changes reshaped the area's hydrology, how water moves and interacts with the land. Once-thriving wetlands were reduced to a fraction of their original size. In 2013, Golden Gate ramped up restoration just north of Rodeo Beach, reclaiming three acres of vital native wetland from the parking lot that had been built over it.

In addition to planting native plants like marsh sandwort, restoration efforts included removing invasive plants and re-grading the former parking lot to restore natural hydrology. Ongoing efforts in the area include removal of invasive cape ivy, and invasive plant early detection and monitoring.

For more information

• California Department of Fish & Wildlife: Marsh Sandwort
• Golden Gate National Recreation Area Restoration and Management: Learn about restoration priorities and other park restoration efforts.
• Contact Golden Gate Biologist Michael Chassé

By Science Communication Intern Laurel Teague, San Francisco Bay Area Inventory & Monitoring Network

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