The Toads of Mount St. Helens

Today being the 30^th anniversary of the eruption of Mount St. Helens, I wanted to describe a visit I made to the mountain several years ago. I was out in the field with Charlie Crisafulli, a researcher for the U.S. Forest Service. We were heading to small lake about eight miles north of the crater when Charlie told me “Be careful where you step as we approach the lake.”

At first I didn’t understand why he warned me; the terrain was level and we were walking on a four foot wide path. As we got closer, though, the ground began to move. Dark, half-inch-long toadlets hopped everywhere. Scores crossed the path. More moved along the sides and others disappeared into the dense green understory. At the lake, we found thousands in pulsating piles collected along the water’s edge.

When I looked closely, I saw that many of the little hoppers had yet to loose their tails. Charlie, who had been studying the mountain since the eruption, explained to me that they were recently metamorphosed boreal toads and that they soon would head up into the hillsides that surround the lake and continue one of the most amazing stories at the volcano.

During Charlie’s first ten years on the mountain, he had noticed large numbers of boreal toads. This surprised him because the toads, warty, four to five-inch long, brownish green hoppers, had been on the decline throughout the west. (They are listed as “endangered” in Colorado and New Mexico and designated as a protected non-game species in Wyoming.) Trying to determine why the toads thrived at the volcano, he surveyed every lake in the national monument in the early 1990s and found that four lakes had far and away the areas of highest toad density.

In an ongoing study of the one lake where we had tiptoed through the toads, Charlie discovered why so many toads now lived at the volcano. Each June, he and his crew hike out to the partially frozen lake, where hundreds of toads and a handful of northwest salamanders hop and crawl across the snow. The researchers then wade into the water, push aside rafts of ice, and wait. Males arrive first. After the females arrive, pairs mate quietly (the male lacks the typical toad mating call), and produce teeming masses of eggs, up to 12,000 per female. Eggs hatch 7 to 10 days later. The toads we saw had recently crawled out of the water and were preparing to disperse into the mountains surrounding the lake.

“We think that this is what happened in 1980. During the eruption, the frogs were hibernating underground and emerged a month or so later and continued their normal life cycle,” said Charlie. In the long term, the toads benefited because the eruption blasted down all of the trees around the lake, making the water warmer thus increasing food resources during the summer and allowing tadpoles to mature more quickly. The blast also removed most of the toads’ predators, so more toadlets and adults survived.

Thirty years later, the toads are still thriving at Mount St. Helens. In doing so, they have contributed to a new understanding of ecological recovery. In landscapes where geologic and ecologic change is the rule and not the exception, disturbance plays an important role in the life of the ecosystem. Fires, volcanic eruptions, and floods regularly reshape broad swaths of the American West. Sometimes, entire ecosystems are devastated. But every time a cataclysm happens, the plants and animals recover.

It’s a lesson, perhaps, in patience: What we see today as a natural disaster may not be a disaster at all, just a natural clock resetting, a cycle starting over again. Lessons come in all shapes, sometimes even little green ones.