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Spring is a Backyard Vernal Pool

spotted salamanderGuest Post by Mark Southerland.

This year, spring really sprung to life in my backyard when an unexpected visitor arrived—the spotted salamander. Eight years ago I added a 1 square meter pond to my 1/3 acre lot just 1 km from the Columbia Mall. As I had hoped, the pond was frequented off-and-on for 6 years by green and pickerel frogs. They made themselves know by plopping into the water when I walked past to deposit my week’s compost in the backyard bin.

vernal poolLast year was special, however, because I discovered wood frog eggs in the pond. My small pond made out of a simple plastic shell had become a vernal pool—a depression that generally holds water only part of the year so that no fish are present to eat the frog eggs. Wood frogs—Rana sylvatica—only breed in such “seasonal pools” and are therefore an indicator species.  Wood frogs also have raccoon-like masks and can freeze solid during the winter—look it up.

spotted salamander eggsAll this was prelude to the bigger surprise of Easter Weekend this year. I was both exhilarated and saddened to discover a dead adult spotted salamander—Ambystoma maculatum—on a stone next to the pond. The salamander had a bite mark, likely from a raccoon or opossum that quickly spat out this distasteful salamander. The bright yellow spots on this black salamander are a warning, sometimes unheeded, to such predators. Buoyed by the knowledge that spotted salamanders existed in my backyard (they spend 95% of their lives underground), I went to look for salamander eggs in the pond.  I quickly found 4 masses with dozens of eggs clumped together in a gelatinous matrix. Next I decided to check under one of the stones framing the pond before putting my weight on it. Although I should have been prepared, I really wasn’t ready to see a beautiful adult spotted salamander under the stone—likely the female that had just laid the eggs.

mark Southerland, salamander and poolOther than being the highlight of the spring—and the most successful Easter egg hunt ever—what does having a vernal pool in your backyard mean? It means that even small patches of natural habitat left intact can support a wondrous ecosystem with players known to very few. While these salamanders needed only a 1 square meter pond to breed, their continued existence near the center of Columbia is a result of local regulations and conscientious development that preserved mature forest that they  require in the midst of suburbia.

For more information on vernal (seasonal) pools in the Mid-Atlantic read this 2005 document from EPA:

Take-a-way: Our backyards are great places to restore the badly damaged ecosystems of suburbia. Time to convert some or all of our lawns to more native habitat.

Mark Southerland has a doctorate in biology and lives and works in central Maryland. He can be reached at


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