American Bullfrogs as Invasive Species: A Review of the Introduction, Subsequent Problems, Management Options, and Future Directions
Nathan P. Snow and Gary Witmer
USDA APHIS Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado
ABSTRACT: Native to the eastern United States, American bullfrogs have been introduced throughout the western U.S. and to several other countries and islands around the world. Bullfrogs are well adapted for many of the permanent water sources that occur within the U.S., and once introduced, they typically become dominant. Because of their large size and voracious appetite, bullfrogs outcompete and prey upon many indigenous species. They are hypothesized to be cause significant negative impacts, which may contribute to the endangerment and extinction of some sensitive species. There are few, if any, effective and efficient control methods to manage invasive bullfrogs. Current methods such as hand or net capture, shooting, and gigging can be labor intensive and often fail to reduce bullfrog numbers. Draining wetland habitats and broadcasting toxicants have severe negative effects on non-target species. New management options, such as locally-sprayed toxicants and multiple-capture traps, could be useful for reducing populations of invasive bullfrogs. However, researchers should make certain that non-target species are not affected by these management techniques.
