If you were a frog or salamander, where would you lay your eggs? In a pond filled with fish that feast on eggs and larvae, or a pond without fish?
If amphibians had the ability to choose, undoubtedly they would pick fish-free ponds where the odds of their offspring surviving are better.
It seems as though they’ve made the choice. Several species of frogs and salamanders breed exclusively in fishless ponds - known as vernal pools, intermittent ponds, ephemeral ponds or temporary ponds.
This state we’re in has an estimated 3,000 to 5,000 vernal pools that get their water from snowmelt, rain and rising groundwater. Spring is the season when they’re usually full – hence, the name vernal, meaning “of, in, or appropriate to spring.” By mid-summer, most of these seasonal pools dry up.
Vernal pools can be natural or manmade, large or small, with ponded water for at least two consecutive months between March and September. Because they’re dry for most of the year, fish can’t survive.
Seven New Jersey amphibians are entirely reliant on vernal pools. They include state-endangered Eastern tiger salamanders and blue-spotted salamanders; marbled and Jefferson salamanders, both species of special concern; and spotted salamanders, wood frogs and Eastern spadefoot toads.
Another 16 New Jersey amphibians breed in vernal pools but are more flexible and can sometimes reproduce in pools with fish. These species include state-endangered Southern gray treefrogs; Pine Barrens treefrogs and long-tailed salamanders, both state-threatened species ; carpenter frogs and Fowler’s toads, both species of special concern; and Northern gray treefrogs, Northern spring peepers, bullfrogs, and four-toed salamanders.
Vernal pools are also important for wading birds, turtles, snakes and mammals, as well as rare plants and invertebrates like fairy shrimp and dragonflies. Turtles found in New Jersey’s vernal pools include wood turtles, a state-threatened species; and spotted turtles, a species of special concern.
Most vernal pools are not protected by wetlands regulations and face many challenges, including pollution, filling for development projects outside of the regulated Pinelands and Highlands regions, and damage from off-road vehicles.
On public lands for the last few decades, irresponsible riders have ripped through vernal pools during both wet and dry seasons - leaving deep tire tracks, crushing rare animals and destroying plants.
When vernal pools are turned into mud pits, our rare species can’t reproduce. These creatures are hard-wired to follow the same path each year to breed and lay eggs, so they’re out of luck when vernal pools are destroyed.
Recently, the New Jersey Department of Environmental Protection launched a pilot project to protect vernal pools in the Pine Barrens, many areas of which are being ravaged by illegal off-road vehicles. With the help of volunteers, the Department of Environmental Protection built wooden barriers around four pools in Wharton State Forest in an attempt to prevent illegal vehicle access.
"Now that these barriers are in place at pilot locations, Park Service personnel and State Park Police will monitor these areas,” said Mark Texel, State Park Service director. “Our goal is to expand to other sensitive areas."
Hopefully the pilot project in Wharton State Forest will be the start of stronger protection for vernal pools throughout the state. Consistent enforcement of environmental and motor vehicle laws will also be needed, as well as stronger regulations about sensitive areas that are off-limits to motorized vehicles.
Spring is a perfect time to sit quietly by an undisturbed vernal pool in the deep woods and witness ancient rituals. As dusk approaches on an early spring evening, listen for male frogs courting females and look for salamanders heading toward their breeding ponds from their hibernation sites in the forest.
If spring rains are dependable, the pool will stay wet just long enough for the eggs to hatch into larvae, grow and metamorphose into adults, and finally leave the temporary pools for the dense forest.
To learn more about vernal pools, go to the state Division of Fish & Game webpage at http://www.state.nj.us/dep/fgw/ensp/vernalpool.htm.
And for more information about preserving New Jersey’s land and natural resources, visit the New Jersey Conservation Foundation website at www.njconservation.org or contact me at firstname.lastname@example.org.
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