Spring Peepers: Sounds as Environmental Health Indicators

 

Looking for frogs in a vernal pool

    Spring is the season to hear the "spring peepers," the frogs and toads and in some places, salamanders, singing their mating sounds and vibrating the waters in the wetland vernal pools that appear in the spring with the snow melt and rain, and disappear in the dry summer weather. As it happens, an article by Margaret Renkl that appeared four days ago in the New York Times called attention these spring peepers. They're able to mate and their offspring to mature in these pools because of the absence of fish--indeed, these ephemeral wetlands are not fed by springs or streams and cannot support the fish that would prey on them.

     The amount of wetland habitat for these amphibians has, of course, been shrinking in the face of land clearing and development; and although river and stream environments enjoy some environmental protection in the US, wetland vernal pools do not. As a result, the amphibian population has been declining, most recently at the rate of 4% per year. That may not seem like much in one year, but over the years it does add up. In her article, Renkl notes that amphibians are recognized as "indicator species": "the health of an ecosystem's amphibian population is one way to measure the health of the ecosystem itself," Renkl writes. But how does one measure the health of the ecosystem's amphibian population? She doesn't say, but one implication is clear: by sound. That is, the louder and more raucous the peepers, the larger the population and the healthier the ecosystem.

    Sound, in other words, is a key to evaluating environmental health in the natural world.