They appear like mirages in the dark of winter, burst into full-throated glory in Spring and fade away with the summer sun. Vernal ponds remind me of Brigadoon, the Scottish village in the classic musical that comes to life for one day every hundred years. The first time I came upon a gleaming pond in a field that had been dry just weeks before, I was as stunned as if a bag-pipe-playing Highlander had suddenly materialized.
“Where did all this water come from?” I asked. “A spring? A nearby stream?”
Neither, said our tracking guru Jim Sullivan, author of the forthcoming Dirt Time: Finding Meaning in Nature, who explained that shallow depressions in the land collect rain from winter storms. Clay-like “hardpan” under the top soil seals so thoroughly that water accumulates rather than drains. In wet winters like this year’s, ponds emerge as early as January.
Named for Spring (vernum in Latin), the transient pools pass through three seasons in their brief lifespans. During the Aquatic phase, low-lying areas flood. In Flowering, life surges in and around the pools. During the long spell called Drought or Desiccation, water evaporates, and the exposed earth dries and cracks. Once-vibrant nurseries turn into what Sullivan calls lifeless “infernal pools.”
Unlike brooks that babble and rivers that run, vernal ponds, with no inlets or outlets, are almost surreally still. Their glass-smooth surfaces mirror the sky, with clouds skidding across by day and galaxies shimmering by night. But in their stillness and silence, life stirs—often in forms that exist nowhere else on the planet.
Some 200 plants grow in California’s vernal ponds—most native annuals with survival strategies that evolved over tens of thousands of years. When inundated, some absorb oxygen through long, hollow stems; some, directly from water; some, from floating leaves that absorb enough air for the entire plant.
The fleeting ponds, as a poet put it, “midwife Spring into summer.” Wildflowers, including sun-bright Goldfields, white Meadowfoam and blue-tipped Downingia, carpet the shores in vibrant hues. Their urgent mission: Attract pollinators and produce abundant seed to lie dormant underground, patiently awaiting next winter’s wet kisses.
No fish swim in ponds destined to die. Safe from finned predators, fresh-water amphibians and invertebrates—including rare frogs and salamanders—mate, lay eggs and move on. Some crustaceans have evolved in perfect harmony with the ephemeral waters. Tiny ostrocods or seed shrimp, for instance, hatch from eggs that survived the harsh dry season. As detritivores, they eat almost anything organic and grow quickly, reproducing and leaving behind the next generation of desiccation-defying eggs.
Ostrocods and other pond inhabitants provide food for millions of migrating birds and waterfowl on the Pacific Flyway. Terrestrial wildlife—racoons, deer, rabbits, weasels, fox, coyotes—also converge at the local watering holes. As the final dregs of moisture evaporate, these visitors leave trails cemented in the hardened earth.
Vernal ponds, which shelter many species from extinction, face the same danger. More than 90 percent of California’s ephemeral pools have vanished— overrun by agriculture, grazing and development. Some communities have tried to construct artificial seasonal ponds, with limited success. Their slopes may be too steep, analysts speculate, their depths too great, their rims too wide or narrow.
Perhaps man-made engineering simply cannot compare with nature’s genius. Its vanishing wonders open themselves to the heavens, drink the rain, glow with sunshine and starlight, offer respite to the hungry and weary, leave seeds for tomorrow — and then fade away, like Brigadoon, into the mists of memory.
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If you’re local or happen to be in the area, you’re invited! Wherever you are, you can find out more about the epic story of a determined coalition of ordinary-citizens-turned-activists who took on a corporate Goliath–and won. Watch “The Battle of Bodega Head” webinar on the Stewards of the Coast and Redwoods YouTube channel.
