Are There (Vernal) Pools in Your Back Yard?
By Mary Pierce
Spring is here, with its special sights and sounds.
On a rainy night when the temperature is above 40 degrees you can not only
hear the chorus of frogs but see northern New England's wonderful
amphibians. Keep your eyes peeled for frogs and salamanders coming out of
the woods, crossing your yard, the road, or whatever obstacle might be in their
way. These critters are making their annual migration from winter habitat to
breeding habitat – they are headed for vernal pools.
Vernal pools (vernal comes from the Latin word for spring) are generally small
depressions in the woods that fill with water during spring and fall, and
frequently dry up in the summer. These woodland pools don’t have fish living
in them, and don’t have an inlet or outlet that would allow fish to get to them.
That’s why they make great nurseries—no fish to eat the eggs, tadpoles, and
In fact, in northern New England, vernal pools provide the primary breeding
habitat for wood frogs, spotted, blue-spotted, and four-toed salamanders, and
fairy shrimp. They also provide critical habitat for some endangered species
such as the Blanding’s turtle and the ringed boghaunter dragonfly.
Vernal pools are valuable to many other animals as well. All of those hundreds
of eggs that the frogs and salamanders lay are meals for hungry skunks,
weasels, and other larger animals including bears. Other animals such as deer
and moose visit the pools in early spring for fresh leaves because vernal pools
tend to green up earlier than the rest of the woods.
The surviving eggs hatch within a few weeks, and tadpoles and larvae emerge.
Once the young frogs and salamanders leave the pool, they are still hunted by
skunks and weasels and lots of others looking for food.
The frogs and salamanders that survive make their way to either a forested
swamp or some dry part of the woods to spend the summer. Wood frogs have
been shown to migrate up to 1000 feet from the pond they were born in to find
summer habitat – that’s a long way for an animal that small!
Next spring, this new generation of frogs and salamanders will make their way
back to the same vernal pool in which they were born, to start the process all
over again. It is important to protect not only the vernal pool itself, but also the
land around the pools, since many organisms spend most of their lives in the
Effective September 1, 2007, a new law enacted by the Maine Legislature is
helping to protect the vernal pools and surrounding areas to make sure this
continuing cycle of life can take place.
To learn more about vernal pools go to MaineDEP.com and click on the
Keyword “vernal pools” for more information.
This column was submitted by Mary Pierce, formerly an Environmental Specialist with
the Maine Department of Environmental Protection’s (DEP) Bureau of Land and Water
Quality. In Our Back Yard is a weekly column of the DEP. E-mail your environmental
questions to infoDEP@maine.gov or send them to In Our Back Yard, Maine DEP, 17
State House Station, Augusta, ME 04333.