Amphibians Blog

This summer, the San Francisco Bay Area Network’s coho and steelhead monitoring team started a two-year project to inventory aquatic species in streams across Point Reyes National Seashore and Golden Gate National Recreation Area using environmental DNA. Environmental DNA, or eDNA, is genetic material shed by organisms in the water column. By collecting particulate samples from the water, we hope to learn if species of interest are utilizing certain streams.

It’s tough for a park to conserve wildlife habitat and support sensitive species when no one is quite sure what creatures live there. Nor is it easy to learn what lives where when so many species' superpowers include avoiding human observation. Early on, such challenges weighed on biologists working at Rancho Corral de Tierra, which became part of Golden Gate in 2011. But now, answers are on the horizon. In August 2023, we launched the San Mateo Wildlife Inventory project.

Have you ever seen the elusive California giant salamander? This California endemic amphibian is one of the largest terrestrial salamanders anywhere, reaching 6-12 inches. Beyond their size, they are also identified by their blotchy brown coloring, with white to yellow underside. Although not federally listed, the California giant salamander is considered a special status species in need of conservation. A new inventory aims to help guide future efforts.

One way biologists monitor California red-legged frog populations is by counting their egg masses. Red-legged frog egg masses—grapefruit-sized and laid near the water’s surface— are much easier to count than the frogs themselves. During the 2023 breeding season (December 2022-March 2023), we found 348 egg masses across 37 sites in Marin San Mateo Counties.

One Tam partners are making a difference for foothill yellow-legged frogs in Marin, and are seeking the community’s help during their especially vulnerable breeding season. A new StoryMap is now available to help visitors protect them while enjoying parks in Marin. Using long-term monitoring data from One Tam partners, the story details why this indicator species is special, what One Tam partners are doing to support them, and how visitors can help.

Golden Gate National Recreation Area biologists have been monitoring federally threatened California red-legged frogs in the park for 20 years. This year, biologists were able to complete their surveys prior to local shelter-in-place orders to slow the spread of COVID-19. Their findings were heartening! They counted a new record of over 600 egg masses in the park.

Every winter, scientists count California red-legged frogs egg masses in ponds and streams at Muir Beach and at other sites in the Golden Gate National Recreation Area. 2016 and 2017 have seen the highest egg mass numbers at Muir Beach since monitoring began at this site in 2002.