Vernal Pools

Spring is the season to investigate vernal pools. These small bodies of water are very important to amphibians that lay their eggs in water, spend part of their lives with gills, and finally develop into frogs, toads, and salamanders. Most vernal pools dry up later in the summer, although in a wet year they may retain some water until snows and spring rains again fill them. Most important for the amphibians that use them, however, they lack a connection to a stream or river, so that fish cannot reach them to eat the eggs and tadpoles.

Vernal pools are protected in Massachusetts, but the amphibians that use them also need undisturbed woodland or meadows so they can survive on land as adults. If you find a vernal pool, look in it in March, after a night when there has been a warm rain, and you will probably see some egg masses. These look like black dots surrounded by clear or whitish jelly, and are stuck together in a floating mass that may be attached to a branch or other growth in the water.

Later, when the eggs have hatched, you will see tadpoles. If the pond has bullfrogs, their tadpoles may eat those of smaller amphibians such as wood frogs. Some tadpoles change into land-dwelling frogs or salamanders quickly, while bullfrogs may take two years to change.

Vernal pools serve as home to numerous other life forms, such as fairy shrimp, dragon fly and damsel fly larvae, and various diving beetles. Some in woodland may have leafy bottoms, such as the large one on the LPS Winthrop Dahl Preserve. Others that get more sunlight and different nutrients may have sphagnum moss and grasses growing in them, such as the one on the orange trail in the LPS Woodward Forest. There is also a vernal pool in the Henrich Woods where a research site has been established for work on a Master's Degree project on salamanders.
The Land Preservation Society has numerous vernal pools on its properties and there are many others in Norton. These are gradually being registered with the State to protect them and the fragile species that need them for part of their life cycle.
As of Fall 2008, the Town of Norton has 100 certified vernal pools. Eleven of these are on LPS land. Look for LPS vernal pools in Woodward Forest, on Red Mill Road, on Carpenter Road, on Union Road, on the Copperworks property, on the Dahl land, in the Henrich Woods, in the Johnson Woods, on the Foster Refuge and the Reinhard Pasture land.


Frances Shirley 2005
update by Linda Kollett 2008

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