In the spring, natural pools form and, as if by magic, fill with life. Then, just as suddenly, they disappear. Despite their evanescent status, they are crucial to the life cycle of frogs and other tiny critters.
There is no border, no beach or shoreline in an ephemeral wetland. You’ll know when you’re in it because you begin to sink. The cool water presses the waders against your feet, your calves, and then your thighs.
As the name implies, such a place is a now-you-see-it-now-you-don’t phenomenon. It’s little more than a poorly drained depression in the land, and the spring rain pours in as winter recedes. Life awakens from dormant forms buried in the ground: fairy shrimp, daphnia, copepods. When summer heat arrives, slowly, pools like this wither and dry.
In fact, it’s likely that a visitor would mistake the ephemeral pond outside the Wehr Nature Center for a muddy puddle.
On a cool day in mid-March, spring has not yet mounted its verdant, vibrant push. Yet this dark pool is building momentum, waking spores and larvae and gathering eggs. A clamor of frog calls rises. “They sound like cackling old men in the woods,” Julia Robson says, identifying them as wood frogs before asking, “Ready for some fun?” Clad in thigh-length waders and a quilted dark Milwaukee County Parks sweatshirt, Robson picks her way through the underbrush to the sodden edge.
These pools serve as essential incubators for the tiny critters that call them home. In Wisconsin, they are as crucial to some amphibians and their wetland companions as coral reefs are to fish in the sea – a place to spawn, a place to get big enough to brave the wider world. Their importance to the ecosystem explains why a growing crew of scientists, both professionals and citizens, takes to the marshy landscape each spring to catalog and protect what lurks within.
Robson’s title is assistant natural areas coordinator, but her metier is clearly mud. “It’s like every year I have to learn to walk again,” she laughs as her feet feel along the bottom, invisible under the turbid slosh of mud and dead leaves. She’s learned the hard way that it can get suddenly, surprisingly deep: “You’re not a wetland monitor until you fill your waders.”