Exploring Vernal Pools in NYC Parks and How They Help Amphibians Thrive

Picture this — it’s a beautiful spring day as you walk through the woods of your favorite park: the sun is warm on your face, birds are singing in the branches around you, and you notice a small pond in a low-lying area between the trees. Was that there last summer? You don’t remember it. You may have stumbled upon a vernal pool!

vernal pool with plants at Van Cortlandt Park

What is a vernal pool?

A vernal pool is a temporary body of water that often appears in the spring (“vernal” means relating to spring) and dries up by mid to late summer. These ephemeral wetlands source their water from precipitation (rain and snowmelt) and stormwater runoff, but they are more than just puddles. Not only are vernal pools evidence of New York City's geologic history, but they are also valuable ecosystems that play an important role in the life cycles of some of our most vulnerable wildlife today.

Why do vernal pools form?

In the New York City area, vernal pools are in low-lying areas in our landscape that were left behind by glaciers more than 10,000 years ago. Back then, as the glaciers retreated, large chunks of ice broke off from the main sheet and continued to melt in place, leaving behind depressions (low-lying areas) in the ground and creating what’s known as knob and kettle topography. You can recognize this kind of landscape by the presence of irregularly-shaped hills (“knobs”) near depressions (“kettles”). Today, these depressions can fill with water seasonally as snow and ice melt and rain falls in the spring, creating vernal pools!

Vernal pools can be found in some parks in New York City, particularly in woodland areas in Queens and Staten Island.

* Click on the image to the right to take a closer at a vernal pool at Bucks Hollow in Staten Island's Greenbelt.

Benefits of Vernal Pools

Vernal pools provide critical breeding habitat for amphibians, such as frogs, toads, salamanders, and newts, who spend some of their lives in water and some on land. These animals depend on the water in our vernal pools for the early stages of their life cycles — some amphibians lay eggs underwater and their babies continue to live completely in the water before transforming into adults. The temporary nature of vernal pools is perfect for this purpose because fish that could potentially prey on amphibian eggs in other water bodies, such as lakes and ponds, cannot survive in vernal pools that regularly dry up.

Meet our vernal pools’ greatest amphibi-fans!

Come springtime, our vernal pool areas are often filled with amphibians that hang out by the pool to breed and find a mate. Take a look at some of the amphibians you might discover nearby a vernal pool:

* Click on images below to zoom in

Spotted salamander

You’ll definitely know when you spot this salamander — it has spots! Spotted salamanders have two rows of yellow or orange spots covering them from head to tail. These animals spend most of the year underground but surface to breed in vernal pools each spring.

Wood frog

About the size of your palm, with distinctive dark markings across the eyes, wood frogs travel to vernal pools and fill the air with a chorus of quack-like mating calls.

Spring peeper

It might be a challenge to see the thumbnail-sized peepers, but you can listen for the namesake high-pitched peep mating call around vernal pools in early spring.

Threats to Vernal Pools and the Impact of Climate Change

Despite the value of these ecosystems, they are not protected by the legal regulations that safeguard larger, more permanent wetlands. As such, vernal pools are vulnerable to destruction from development.

Climate change is also a threat, as rising temperatures and altered precipitation patterns can affect the timing and depth of water that collects in the pools. For example, an unusually warm winter day can inspire amphibians to emerge early from the vernal pools, only to be caught in a dangerous cold snap, and different rain patterns can change when vernal pools form, how deep they are, and when they dry up, impacting the survival of young amphibians.

How NYC Parks Cares for Vernal Pools

With the help of local partners, NYC Parks monitors the condition of vernal pools in our parks across the city. By doing so, we can better identify high-priority or vulnerable vernal pools and inform best practices for nearby land management and development.

For pools near forest restoration work, our natural resources staff work to manage any problematic plant species that are nearby and could affect the health of the pool.

Explore a Vernal Pool in High Rock Park With Our Urban Park Rangers

How You Can Help Vernal Pools Thrive

Step Lightly! — Use caution while walking around these rare and delicate ecosystems. Foot traffic around the edges of the pools can cause soil compaction and disturbance, harming the wildlife within. Try to keep a buffer of a few feet between you and the pool’s edge.
Show Your Parks Some Love — Be sure to take any trash out of the park with you. Vernal pools are small enough already, let’s keep them free of trash! Leaf litter is the only litter we want to see in our vernal pools!