Vernal pools a breeding ground

Vernal pools are unique, temporary bodies of water that provide critical breeding habitats for some amphibians, such as wood frogs and spotted salamanders, and invertebrates, such as fairy shrimp. These pools provide a safer breeding ground for these species than permanent waters because there are no fish to eat the eggs or larvae. They provide water, food, cover and the absence of some predators. Vernal pools exist in all parts of the state but are most common in flatter regions of central and southeastern New Hampshire. They can be smaller than one-tenth of an acre or larger than two acres. Some vernal pools flood in the spring with water from melting snow and rain and are dry by the end of the summer. Some fill with rain in the autumn, hold water all winter and spring, and then dry out again by late summer.

In early spring, adult salamanders leave their woodlands and find their way back to the vernal pools in which they were born. After breeding, the adult salamanders leave the pool and return to the forest, which is usually within 600 yards of the pool. The tadpole-like larvae gradually transform into young adults after two or three months (usually between July and September) and then leave the pool for the next phase of their lives in the forest. Likewise, wood frogs, with their chorus of ducklike quacks, also come back to the vernal pools and their breeding home. Fairy shrimp never leave the vernal pools. Their eggs survive the mud of dried pools and hatch early the next spring when the pool is full of water.

Care must be taken when visiting vernal pools not to disturb the site or harm the wildlife. The biggest threat to vernal pools is development. Placing land in conservation easements helps to preserve these critical habitats. Our Bedford Land Trust owns two properties and holds conservation easements on nine properties in Bedford. Perhaps on your next hike in Bedford, on your own land or elsewhere, you can be on the lookout for vernal pools. If you are interested in locating, identifying and documenting vernal pools and species in this habitat, you can find extensive information on the Internet.