Witnessing extinction in real time
I started my amphibian research a little like Thoreau, living alone in a cabin in the woods and recording the seasonal variation in the natural world. I lived in a shack without plumbing or electricity, an hour away from the closest house, in a cloud forest on the top of a mountain that straddled the border between Costa Rica and Panama. I scrambled along mountain streams chasing seasonal reproductive data on treefrogs. The species I studied, Isthmohyla calypsa, remains one of the most spectacular frogs I have ever seen; adults were a brilliant, iridescent green with a bright white throat pouch, and their skin was as textured as the spikey moss they lived on, apparently camouflaging them from predators [1]. I was living a field biologist’s dream and expected to spend my career studying tropical montane amphibians in one of the most beautiful and least studied regions in the world. I couldn’t know that my study site in this remote cloud forest would give me a front row seat to one of the most distressing ecological mysteries of our time. As a graduate student, I had heard the ominous reports describing the mysterious disappearances of amphibian populations around the world. At the time, scientists were debating whether this was a real phenomenon, what might cause it, and whether these events were connected. The large number of species affected was especially worrisome; of the suspected threats, none typically caused extirpation or extinction of multiple species while leaving the habitat intact. It was more than a search for a needle in a haystack—we were still debating the existence of the haystack. I was just a graduate student, and while I wasn’t actively looking for the needle, I would step right on it. That was triggered with my intent to capture the early breeding season of an interesting toad (Incilius fastidiosus). These toads would emerge from underground to lay rosary-like strands of eggs amidst torrential downpours that turned the pastures into swampy meadows. I returned to my cloud forest site weeks earlier than usual, at the beginning of the rainy season in 1993, to continue some preliminary work from the previous year. But the toads never came out. I knew that a related species—the golden toad (Incilius periglenes)—had recently disappeared from its entire range just a few hundred miles north of me. But I was soon focused on other, more immediate concerns as I realized that it wasn’t just the toads that were gone, my mossy green treefrogs and the other stream frogs were also missing. I blamed the weather, my technique, the bright light of my headlamp—I was grasping at straws and I knew it, but I couldn’t really believe that this might be another “enigmatic decline.” Maybe it would have been different if I had found hundreds of dead frogs, but they had disappeared when I wasn’t looking. When I returned in 1996, the streams were dead silent—no frogs were calling, species were missing, overall abundance was down by 90%, and even the gelatinous egg masses were