Vernal Pools

What Am I Looking At?

You are looking at an area that could be a baby nursery for a wood frog in the spring.This is a vernal pool in a forest. Vernal pools are the only kind of wetland in Maine that are defined by what breeds in them instead of by what type of plants grow in them, like swamps and marshes.

What is a Vernal Pool?

Vernal pools are naturally occurring, temporary or semi-permanent pools in shallow depressions of forested landscapes that typically fill in the spring and dry during the summer. There are no permanent inlets or outlets and no permanent fish.

Why are Vernal Pools important?

  • They are a primary breeding place for wood frogs, blue spotted and spotted salamanders, and fairy shrimp.
  • They are an important habitat for many of Maine’s rare, threatened or endangered species of turtles, snakes, and dragonflies.
  • The above species are food for higher predators such as snakes, turtles, birds and mammals.
  • They consume a large amount of the forest insects and other invertebrates — we like those salamander larvae eating our mosquito larvae!
  • They play an important role with releasing and distributing aquatic nutrients into the forest system.
These are the common species that use vernal pools as their breeding ground in the spring. Clockwise from top left: spotted salamander, blue spotted salamander, fairy shrimp, wood frog

Did You Know?

The wood frog freezes during the winter months and then thaws out in the spring to keep on croaking!

Finding these salamander eggs in a depression filled with water would verify that indeed it is a vernal pool.

Raccoon Tracks
Courtesy Maine Department of Inland Fisheries & Wildlife

What's Next?

See if you can find any of the animals above, or depressions in the forest floor that might be a “baby nursery” for our vernal pool dwellers.