Cooperative Agreement with a Partner of the Pacific Northwest Cooperative Ecosystem Studies Unit (CESU)

The US Geological Survey, Northern Rocky Mountain Science Center (NOROCK), is offering a funding opportunity to use a Before-After-Control-Impact (BACI) design to measure responses of aquatic species to eradication of invasive America Bullfrogs. Invasive bullfrogs threaten the persistence of many native herpetofauna in the western USA through predation and spread of emerging infectious diseases, especially in the Southwest. Under the 2016 Cooperative Recovery Initiative (CRI), the USFWS funded a large landscape-level effort to eradicate American bullfrogs from one of their last strongholds in south-central Arizona. In 2016, the USGS used environmental DNA (eDNA) methods to characterize aquatic communities in 21 bullfrog eradication sites and 17 control sites (8 with bullfrogs, 9 without), just prior to eradication efforts. These 2016 samples revealed sites with bullfrogs were very unlikely to host Chiricahua Leopard Frogs but were more likely to have amphibian chytrid fungus (Bd) and ranaviruses (RV), pathogens that are threats to the Chiricahua leopard frog. Have observed Chiricahua Leopard Frogs quickly re-colonizing sites where bullfrogs were eradicated, and these observations suggest the eradication actions were successful and produced the intended management response. This opportunity will allow for the analysis of environmental DNA filters collected in 2020-2021, from the same 39 sites that were originally sampled in 2016. The proposed analysis is needed to validate successful eradication of invasive bullfrogs and to measure responses by aquatic pathogens and several imperiled herpetofauna and pathogens.