Vernal Pool Ecology

Vernal pools, or seasonal pools, are a unique type of wetland habitat. They are typically small, shallow, ephemeral water bodies, and unlike a pond or a lake, they have no permanent inlet or outlet. They are filled each spring by rain and snow melt, then dry up for a period of time during the summer. These qualities of vernal pools distinguish them from other wetlands, and they support several species of animals that require these temporary wetland habitats for survival.

This site provides information on many aspects of vernal pool ecology, conservation, and management. Explore the website to find:

  • Information on vernal pool animals and identification
  • Best management practices for landowners with vernal pools
  • Educational presentation on vernal pool identification and conservation
  • How to register a vernal pool
  • State and federal laws that protect vernal pools

Register a Pool

Registering an unvegetated vernal pool can be done easily from the pool edge without entering the water. Photo Credit: Betsy Leppo

Vernal pools form in a variety of ways. The position of a vernal pool on the landscape can suggest its origin.

Vernal Pool Database

Vernal pools are considered hydrologically 'isolated' wetlands because they are not permanently connected to other water bodies. They receive most of their waters from rain and snow melt surface runoff.- -

Vernal Pool Ecology

Vernal pool in early spring. Credit: Betsy Leppo

Vernal pools tend to have an impermeable layer that results in ponded water.

Vernal Pool Animals

Marbled salamander (Ambystoma opacum)  Credit: Jack Ray

Vernal pools can host a wide variety of plants and predictable groupings of plants called communities.


Frequent mowing up to the edge of this marshy vernal pool (on the right) removes protective vegetation and woody debris where vernal pool animals can find food and shelter when they leave the pool. Credit: Betsy Leppo

All vernal pools dry up periodically. Some pools dry out every year, some others only during dry summers.


Semi-permanent and permanent ponds that infrequently or never dry up can support animals such as bull frogs whose tadpoles take at least two years to develop.  Bull frogs are voracious predators that alter the predator-prey balance in a vernal pool environment.  Credit: Jack Ray

Examples of woodland pools photographed by PNHP staff.

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