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.
Photos from the
project.
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