Are Those Ducks Quacking?
Walking through the woods this time of year you may be fooled by the sounds of what seems to be ducks coming from large puddles in the woods. These puddles are vernal pools and the quacking ducks are actually wood frogs. In the Northeast, the pools fill with water in the fall and winter or with the meltwater and rain of the spring. These temporary wetlands lack outlets and most will completely dry up during the summer. The quacking sounds come from one of the three obligate species found in vernal pools. Wood frogs, fairy shrimp and mole salamanders are called obligate species because they must use vernal pools for part of their life cycle. These species reproduce in the vernal pools; the lack of fish (fish eat wood frogs, fairy shrimp & mole salamanders) make vernal pools a necessary part of these obligates’ life cycle. If you come upon a vernal pool, spend a few minutes peering into the shallow water and you may be lucky enough to find another of the vernal pools inhabitant’s the mole salamanders. The salamanders reproduce in the pools, the eggs develop in the pools, by the time the pools dry up the young salamanders emerge to live the rest of their lives as terrestrial animals. The third obligate are fairy shrimp, a small crustacean that spends its entire life in vernal pools. They live only a few weeks and then over winter as eggs waiting till next spring.
Not too long ago, these wetlands were threatened by development. They are especially vulnerable because much of the year they appear to be dry woods. Human development has a negative impact on vernal pools. This impact can come from road building, trail construction and the building of houses or out buildings. Destruction of vernal pools is especially significant because many amphibians return to the same pools where they were hatched. If one pool is lost, the pool’s returning amphibians may be lost as well. Enjoy your spring walks and keep an eye out for vernal pools!