Vernal Pools/Ponds                                    Bob Gregorski

April Showers Create Vernal Pools

In Connecticut the general public may not be aware that vernal pools/ponds are productive breeding areas for many species of creatures including: spotted, Jefferson’s and marbled salamanders, wood frogs, eastern spadefoot toads and fairy shrimp.
Vernal pools are small pockets/puddles of fresh water created by snowmelt, high water tables and/or rain. Typically the water settles in depressions in the forest floor that are separate from other wetlands. The vernal pool water needs to be contained for a period of time necessary for breeding to be productive.

According to the CT DEEP Wildlife Division the following four criteria must be met for a standing body of water to be classified vernal pool: it contains water for approximately two months during the growing season; it occurs within a confined depression or basin that lacks a permanent outlet stream; it lacks any fish population and it dries out most years, usually by late summer.

Most people have never observed fairy shrimp. These small crustaceans are one of the many invertebrates, which breed in vernal pools. Measuring 0.5-1.0 inches long, they look like tiny shrimp. Typically they swim just below the water surface on their backs with their legs pointed skyward. When the vernal pool water dries up adult shrimp deposit their eggs in the soil and under the litter at the bottom of the depression. Adult shrimp die off when the pools dry completely. The eggs remain dormant until the pool fills the following spring. And -- the life cycle continues.

The Wild life Division recommends the following to protect vernal pools. ”Do not clean up in and around vernal pools. Leave trees, bushes and understory vegetation, as well as brush, logs and dead trees alone. Leave a buffer of natural vegetation around the pool for as great a distance as possible back from the edge of the pool’s high-water mark. A buffer of at least 100 feet will help maintain water quality, but will do little to protect amphibians living around the pool. Vernal pool breeders require large areas of natural habitat around their pools in order to survive.

Do not fill in the pool, even when it is dry, by dumping leaves or other debris in it.
Avoid activities that alter the movement of surface water of the upland area that drains into the pool. Digging ditches and similar activities can change runoff into the pool, thereby altering its flooding cycle.

Do not dig into the bottom of the pool, even when it is dry, as this will disturb the non-permeable layer of soil that allows the pool to flood. For further information on vernal pools contact DEEP’s Inland Wetlands Division at 860-424-3019.