Amphibians are widely believed to be highly vulnerable to population declines, with nearly one third of all amphibian species at risk of global extinction. The first step in understanding and preventing amphibian declines is knowing where amphibians occur. The Lost Coast of northern California is a rugged and remote area, located in Humboldt and Mendocino counties, where little is known about regional amphibian diversity. We conducted a stream-dwelling amphibian survey during June-August, 2021 to characterize the diversity and distribution of amphibians of the Lost Coast. We conducted three visual encounter surveys and collected environmental DNA (eDNA) samples at 29 sites within the Sinkyone Wilderness State Park, King Range National Conservation Area and Lost Coast Headlands. We found 12 native amphibian species and 1 native turtle, and no nonnative amphibian or turtle species. We recorded 8-10 species during each round of visual encounter survey, and 6 species from eDNA samples. One species was only detected from eDNA samples. Our results demonstrate that even when targeting a limited suite of taxa, such as stream-dwelling amphibians, rapid assessments of biodiversity should include repeated surveys using a variety of methods.

Brian Hudgens is a Research Ecologist at the Institute for Wildlife Studies in Blue Lake, California, USA. He received his BA from Pomona College, and PhD from Duke University. His research combines field research and predictive modeling to address questions about connectivity and population viability for a wide range of taxa, including fritillaries, frogs, foxes, plovers and pronghorn.