The overall objective of our research is to identify the interactive effects of multiple stressors on amphibian populations in California. To accomplish this objective, we will employ a combination of intensive field monitoring, cutting-edge statistical approaches, multifactorial mesocosm experiments, and site-specific models to explore management scenarios. In our research, we focus on two threatened amphibian species that occur widely on DoD lands: the California red-legged frog (CRLF = Rana draytonii) and the California tiger salamander (CTS = Ambystoma californiense), which we will refer to as our ‘target species’. However, we will also collect data on the entire amphibian communities as well as other DoD-relevant species in the freshwater systems at our field sites, and the insights and methods generated here have broad applicability to aquatic taxa across DoD installations.

Specifically, we will address the following questions:

- What are the most important ecological and climatic variables influencing the occurrence and abundance of each of our target amphibian species?

- How do extreme weather events, including fluctuations in hydroperiod resulting from drought and flooding events, alter the occurrence and abundance of each of our target amphibian species?

- What are the individual and interactive effects of variation in hydroperiod, temperature, infectious disease, and invasive species on our target species?

- What realistic management actions have the potential to improve the occurrence and abundance of populations of our target species in response to an increasingly variable future?