What is a Vernal Cache?
Physical description of a vernal pool
A vernal pool is a contained basin depression lacking a permanent above ground outlet. In the Northeast, it fills with water with the rising water table of fall and winter or with the melt-water and runoff of winter and spring snow and rain. Many vernal pools in the Northeast are covered with ice in the winter months. They contain water for a few months in the spring and early summer. By late summer, a vernal pool is generally (but not always) dry. Below are views of the same pool at three different times of the year
Biological description of a vernal pool
A vernal pool, because of its periodic drying, does not support breeding populations of fish. Many organisms have evolved to use a temporary wetland which will dry but where they are not eaten by fish. These organisms are the "obligate" vernal pool species, so called because they must use a vernal pool for various parts of their life cycle. If the obligate species are using a body of water, then that water is a vernal pool. In New England, the easily recognizable obligate species are the fairy shrimp, the mole salamanders and the wood frog. Fairy shrimp are small (about 1 inch) crustaceans which spend their entire lives ( a few weeks) in a vernal pool. Eggs hatch in late winter/early spring and adults may be observed in pools in the spring. Females eventually drop an egg case which remains on the pool bottom after the pool dries. The eggs pass through a cycle of drying and freezing, and then hatch another year when water returns. The presence of fairy shrimp indicates that a water body is a vernal pool. Wood frogs are an amphibian species of upland forests. They venture to vernal pools in early spring, lay their eggs, and return to the moist woodland for the remainder of the year. The tadpoles develop in the pool and eventually follow the adults to adjacent uplands. The presence of evidence of breeding by wood frogs (chorusing or mating adults, egg masses or tadpoles) indicates that a pool is a vernal pool. The mole salamanders are also upland organisms. They spend most of their lives in burrows on the forest floor. Annually, on certain rainy nights, they migrate to ancestral vernal pools to mate and lay their eggs. They soon return to the upland. The eggs develop in the pool and, by the time the pool dries, the young emerge to begin their life as a terrestrial animal. Evidence that mole salamanders breed in an area, make that water body a vernal pool. Breeding evidence would be a breeding congress, spermatophores, egg masses or larvae.
The vernal pools surrounding Mt. Agamenticus are one of the few remaining locations essential to the survival of Blandings turtles in Maine.
Special Thanks to the Vernal Pool at www.vernalpool.org for the description of vernal pools and it’s inhabitants.
The Mount Agamenticus Conservation Region contains over 10,000 acres of land and is one of the largest remaining unfragmented forests in coastal New England. The region is known for its abundance of vernal pools, rich biodiversity, and unique trail system and is also home to many of Maine’s rare plants and animals.
State, local and non-profit landowners are working together to protect this land and to balance wildlife and water quality along with sustainable recreation. These landowners make up the Mount Agamenticus Steering Committee and include: the Towns of York and South Berwick, The York Water District, Maine Dept. of Inland Fisheries and Wildlife, Great Works Regional Land Trust, York Land Trust, and The Nature Conservancy.
As you enjoy the land around Mount Agamenticus please follow the guidelines for use (posted in the summit kiosk) and treat the land and wildlife with respect. Remember that this area contains fragile habitat and is unlike any place else on earth. Its conservation depends on you!
The Mount Agamenticus Conservation Coordinator may be contacted at 186 York Street, York, ME or (207) 361-1102