Amphibian species have been facing a steep decline for decades, in large part because of a fungus, climate change, and environment disruption. As many as one-third of the world’s 6,300 amphibian species are threatened with extinction, and researchers fear their loss could wreak havoc on our ecosystem and food webs. Here are landmark studies that have defined the problems and—we hope—will help humans to figure out how to save their froggy friends.