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NISAW Webinar: American Bullfrog Management to Support Conservation and Recovery of Native Species in the West
February 24 @ 1:00 pm - 2:00 pmFree
American bullfrogs (Lithobates catesbeianus) are not native to western North America and threaten dozens of Species of Greatest Conservation Need and many federally Threatened or Endangered species. Control or eradication of American bullfrogs may seem impossible. However, a handful of success stories demonstrate that control is possible and benefits native frogs.
Yosemite National Park in California, known for breathtaking waterfalls and meadows, houses a unique assemblage of aquatic species. Bullfrogs introduced in the 1950s contributed to their decline, including native frog extirpations. Park biologists removed bullfrogs in Yosemite Valley from 2005-2019, achieving eradication and allowing the subsequent establishment of a California red-legged frog (Rana draytonii; federally Threatened) population there. The park is completing bullfrog removals at 2 more park sites (with red-legged frog re-introductions starting in 2023), collaborating with partners to eliminate bullfrogs outside Yosemite, and monitoring annually to prevent bullfrog re-establishment.
In Arizona, the federally threatened Chiricahua leopard frog (Lithobates chiricahuensis) declined by as much as 80% at the time of listing in 2002, primarily due to predation by bullfrogs, disease, and habitat degradation. Bullfrog control and other actions in the Recovery Plan have resulted in a three-fold increase in occupied sites, functioning metapopulations, and control of bullfrogs in key areas. Ongoing work includes continued bullfrog removal, maintenance of “buffer zones” designed to limit recolonization, and research on amphibian disease dynamics in the wake of bullfrogs. In northwestern Arizona, conservation partners recently released the relict leopard frog (L. onca; SGCN in Arizona, Utah, and Nevada) into a Mojave Desert spring that was occupied by bullfrogs until a long-term, multi-agency project successfully removed the last bullfrog in 2019.
The U.S. Fish and Wildlife Service is working with partners to build on these stories, communicating invasive bullfrog impacts, highlighting opportunities for control, and providing support for expanded American bullfrog control efforts to conserve and recover at-risk and listed species in the West.