YOSEMITE TOAD REINTRODUCTION: SURVIVAL, BEHAVIOR, AND PREDATION AT ‘TOAD ISLAND’ IN YOSEMITE NATIONAL PARK

Tiffany A May; National Park Service/San Francisco State University; aurora6853@gmail.com; Rob Grasso, Ninette Dainele, Rochell Stiles, Vance Vredenburg

Once abundant, Yosemite toads (Anaxyrus canorus) now occupy less than 50 percent of their historical range. Climate change impacts, such as low snowfall, higher temperatures, and fires have altered toad phenology and spatial/temporal connectivity among seasonal habitats. At ‘Toad Island’ Yosemite toads had not been observed since the 2013 Rim Fire, though there was previously a healthy population. To aid species’ recovery and develop reintroduction methodology, the park embarked on a pilot project to re-establish Yosemite toads at Toad Island. In 2022, we collected tadpoles from 3 robust populations and the San Francisco Zoo successfully headstarted a reintroduction cohort. In June of 2024, we released 118 adults to Toad Island. To understand dispersal, micro-habitat use, and survivability, we fitted 30 toads with radio-transmitters and tracked their movements from June-September; we performed visual surveys weekly to monitor un-tagged toads. Here we present initial findings, including movement, morphometric, and predation data, as well as ‘lessons learned’ from the 2024 pilot.

Natural History of Amphibians   Student Paper