From our Education Director, Rachel
The last few days have been anything but the warm, sunny days that make me think “spring is here!” It has been cold. Rainy. Dark. Dreary. I’m ready for spring! Exploring the new growth and life in the forest during the first warm weeks of spring is one of my favorite things to do. Part of that exploration is the careful observation of vernal pools.
Vernal pools are shallow depressions that fill with water for at least two consecutive months out of the year and do not contain fish. This makes vernal pools the perfect place for amphibians to breed and lay their eggs. Most amphibian species start out their lives in water as gilled larvae and later evolve into air-breathing adults. Consider the life cycle of a tree frog. The adults find a vernal pool to where they mate and lay their eggs. The eggs hatch, tadpoles emerge and grow in the vernal pool where they use their gills for their early life. The pool provides a home for the developing frogs. Eventually, the pool will dry up, but that is no problem because the tadpoles have gone through metamorphosis and transformed into their adult forms, complete with lungs.
What makes the vernal pool a better place to raise young than a pond or brook? Why not lay eggs there? Amphibians lay eggs in a vernal pool because of what is NOT there…fish! Fish are a threat to amphibians in their egg and larval forms. Many amphibians have adapted for the loss of eggs to predation by laying more eggs. The American bullfrog , for example, will lay up to 20,000 eggs in a single season! Other amphibians lay their eggs in vernal pools to avoid fish predation on their young. Some amphibian species are adapted to exclusively breed in vernal pools. In New Jersey, there are two frog species and five salamander species that require vernal pools for breeding.
Vernal pools are essential for breeding amphibians in New Jersey, but they do not have the protections of wetlands or other water bodies in the state. This is a scary thought because some of those obligate vernal pool breeders are listed as endangered species in the Garden State. Thankfully organizations like the Conserve Wildlife Foundation of NJ run programs to protect these species during their movement to and from vernal pools. Even with these organizational efforts, it is important for citizens like us to take our own steps toward protecting these animals. These steps include being careful about any water pollution that may come from our actions, such as washing a car or adding fertilizer to our lawns. The most important step we can take for these species is to leave them alone. If you see eggs (they look like balls of clear jelly), leave them be. If you see a frog or a salamander, do not interact with it but simply enjoy watching it. Besides the stress it might cause the animal to be held by humans, interactions with amphibians can be detrimental to their health. Amphibian skin is quite porous and any chemicals—even salt from our sweat—can negatively impact the animal.
This spring, while you are hiking about in New Jersey, keep an eye out for vernal pools! You might get lucky and spot some amphibians or their eggs or larvae in the water.
Source:
Tesauro, J. (n.d.). New Jersey's Vernal Pools. Retrieved from https://www.state.nj.us/dep/fgw/vpoolart.htm#list