Vernal Pool Construction and Management
Temporary or ephemeral pools are important breeding sites for
frogs and salamanders and are also used by other wildlife such as
reptiles, migrating shorebirds and waterfowl and many types of
insects. These pools are important because they provide breeding
habitat free of predators such as fish and bullfrogs. These predators
will eat the eggs and young of amphibians. Since the time of settlement
there has been a marked decrease in temporary wetlands and
they have been replaced by permanent ponds.
While most of Tennessee's amphibians are spring breeders, there
are a few salamanders which breed in the fall. Some of the common
species which use these areas are western chorus frogs, spring
peepers, southern leopard frogs and tiger salamanders.
To select a site for your pool, you should look for natural low spots
or dips in the landscape that may hold water for short periods of time,
particularly during the spring. These sites can occur almost anywhere,
on flood plains, uplands, forests, fields, or pastures. These areas may
already have wetland plants such as smartweed and sedges. If the site
holds water for 2 or 3 months, there is a good chance it is already
being used and shouldn't be disturbed. Areas on flood plains are
especially attractive since they will fill up during floods.
A small pool can be constructed in less than a day using a small
bulldozer or a tractor and blade. A depth of one to two feet is ideal
and the pool should have sloping sides. Pools can be of almost any
size or shape depending on the site. Trees around the site should be
left in place.
Once the pool is constructed, there is usually no need to introduce
aquatic plants or animals. The soil in a seasonally wet area will
frequently have a seed bank of wetland plants and animals are good
at finding wetlands on their own. If plants are introduced, care
should be taken not to use aggressive species such as cattails or
If done correctly, your pool will dry up during the hottest part of
the summer and fill up again in the fall or spring, just in time for the
next breeding season.