Amphibians worldwide are declining at unprecedented rates. An invasive fungus is one culprit that is doing damage in the Rocky Mountains. Though once common in Colorado, the state-endangered boreal toad has disappeared from many high-elevation wetlands coincident with the arrival of the fungus. My research identifies the factors that make some boreal toad populations more susceptible to disease than others, and also investigates how to detect the fungus where amphibians no longer exist. My work helps managers at Rocky Mountain National Park and beyond make smart decisions as they try to restore imperiled amphibian populations.