Vernal Pools

What are Vernal Pools? By Elliott Bartels, 2011

Vernal pools are temporary pools of water that are typically created and formed after the snow begins to melt in early spring.  They are commonly found in forests and near the edge of fields.  Vernal pools, unlike ponds,  are devoid of fish, which allows insects and amphibians to safely lay eggs and raise their young.  Vernal pools are home to many animals in PA including: many specie of frog, toad, salamander and newt, Eastern Box Turtle, Eastern Garter Snake, Northern Water Snake, Wood Turtle, Spotted Turtle, and many different macro-invertebrate. 

Why are Vernal Pools Important?
Vernal pools lack fish, which allows many amphibians the chance to breed and lay their eggs before the water dries up in the summer.  Many of these specie of amphibians do not lay their eggs in any other body of water; they rely on the protection of vernal pools to raise the next generation of their specie.   Some of the rarest amphibians and reptiles in PA can only be found near vernal pools or in areas where vernal pools are common.

About Vernal Pools

Every year in the early spring, after the first great snowmelt, late in a cool, dark evening, hundreds of thousands of salamanders and frogs emerge from hibernation and begin their great migration to nearby vernal pools.  The air fills with the sounds of thousands of frogs croaking, looking to attract a mate.  This phenomenon can be witnessed throughout the eastern United States and has been occurring since prehistoric amphibians emerged from the water. 

Vernal pools are defined as seasonal wetland pools that fill with water from spring snowmelt and precipitation.  They often remain filled until late summer.  The pools dry up during the late summer and autumn months and remain dry until the next snowmelt.  During the time the pools are filled, hundreds of thousands of different animal specie, especially amphibian, inhabit the pools and make use of their abundance of resources.  Frogs, toads, and salamanders rely on the existence of vernal pools because they mate, lay their eggs, and raise their offspring in them.  After mating, amphibians return to the surrounding fields and forests and remain there until the following spring when they migrate to repeat the mating process.  However, this amazing natural process in recent years has been greatly impacted by human expansion.  Suburban development destroys vernal pool habitats in multiple ways.  Segmentation of habitat, construction, drainage of the pools, and pollution are examples of negative human impact on the environment.

This small frog is a Spring Peeper.  They are very common in the vernal pools and their high pitched calls can be heard from very far away
These are spotted salamanders.  These salamanders leave their burrows during rain showers in late March to migrate to the nearest vernal pool to mate and lay eggs. 
Pictures Copyright Elliott Bartels 2011