Lathrop’s Quiet Vernal Pools

by Barbara Walvoord

First Printed in Lathrop Lamp Post, Nov.  18-24, 2017

Last spring, our vernal pools were jumping with visible life.  Mating wood frogs quacked in a loud chorus.   On rainy nights, salamanders paraded en masse to the pools from their woodland borrows and rockpiles. New-hatched fairy shrimp darted about in the water. Later, tadpoles and baby salamanders popped out feet and developed lungs. Predators circled–turtles, snakes, owls.

All that springtime life and movement is a race against time, because, at least every few years, vernal pools, by definition, dry up in summer, creating an environment free of the fish that would otherwise eat the eggs of vernal pool creatures.  Fish-free is good, BUT–the creatures have to adapt to the summertime drying and wintertime freezing of the pool.  Fairy shrimp lay eggs that stay in the pool, surviving both drying and freezing to hatch in spring.  Wood frogs and salamanders leave the pool for the surrounding woods.  Walkers in the woods this summer could spot little wood frogs hopping away.  By now, the frogs are hunkering down in leaf litter.  In winter, their hibernating bodies, half frozen but protected by special chemicals, will retain the memory of their natal pool, and come spring they, along with the salamanders, will begin their sex-crazed race back to the very pool they were born in, and again make the waters jump with visible life.

Our vernal pools are filled with fall rains now, and they look quiet, in the afternoon sun, their still waters mirroring the trees. But the life they support lies at the bottom of the pool, or under rocks and fallen leaves in the nearby forests, where still, half-frozen creatures hold in memory the jumping pool, the life to come.

On the east campus, you can walk to the beautiful vernal pool pictured here by going from the blue shed down the wide woods path and then across the meadow to the far left corner, and into the woods a few yards.  North campus residents can find a number of vernal pools in the Fitzgerald Lake area adjacent to the north campus (Trail maps for east and north, including Fitzgerald Lake, are on the Land Conservation Committee website:  The Fitzgerald Lake vernal pool locations are described at,  p. 22).

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