Lessons Learned in the First Three Years of a Long-Term Invasive American Bullfrog (Lithobates catesbeianus) Removal Effort at Conboy Lake National Wildlife Refuge
Presenters: Trevor Sheffels and Robyn Reeder King, U.S. Fish and Wildlife Service, Conboy Lake National Wildlife Refuge
Conboy Lake National Wildlife Refuge has completed the first three field seasons of a long-term effort to eradicate the invasive American bullfrog (Lithobates catesbeianus) from the Glenwood Valley in Washington State. The local bullfrog population is a primary stressor for the federally threatened Oregon spotted frog (Rana pretiosa) population through direct and indirect competition. We use multiple techniques to remove all bullfrog life stages with special emphasis on late metamorphs, juveniles, and adults. The data collection system is built around an integrated two-pronged approach: spatially referenced field data and morphometric measurements in the lab. This system is designed to help us optimize bullfrog capture efforts, with results being used to inform detailed field crew planning efforts both within and between field seasons.
About the speakers
Trevor Sheffels, Ph.D., has worked for the U.S. Fish and Wildlife Service in the National Wildlife Refuge System since 2013 and has been Refuge Manager at Conboy Lake National Wildlife Refuge since 2016. He has been involved in aquatic invasive species invasive species
An invasive species is any plant or animal that has spread or been introduced into a new area where they are, or could, cause harm to the environment, economy, or human, animal, or plant health. Their unwelcome presence can destroy ecosystems and cost millions of dollars.
Learn more about invasive species work in the Pacific Northwest since his graduate programs at Portland State University where he studied the invasive nutria (Myocastor coypus). Although he does not have an amphibian research background, Trevor has thoroughly enjoyed the opportunity and challenge to learn on the job about amphibian population management (both imperiled native frogs and invasive frogs) through his work at the Refuge.
Robyn Reeder King is the Biological Technician for the U.S. Fish and Wildlife Service at Conboy Lake National Wildlife Refuge. She has been the lead for the bullfrog eradication project since its beginning in 2020. Robyn started working at Conboy in 2019 as an AmeriCorps and fell in love with its unique ecosystem and diversity. Robyn received her bachelor’s degree from the University of California, Berkeley where she majored in integrative biology. While much of her field experiences post-college were seasonal and focused on one species, Robyn’s focus now is place-based: she aims to understand the inner workings and relationships of the flora and fauna at Conboy Lake NWR.
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Contact Matt Grabau (matthew_grabau@fws.gov) if you have questions!
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