Amphibians need vernal pools

Vernal pools are important for development of amphibians in our area since these seasonal wetlands do not hold fish, the main predators of amphibian eggs and tadpoles.

A dry period this spring had its effect on vernal pool habitats for amphibians. A vernal pool is a temporary pool or wetland that exists in wetter months and dries out during dry periods. Several weeks of dry weather this spring saw many vernal pools dry up at a time when tadpoles were developing.

Several species of frogs and toads in our area deposit eggs at different times, from late winter to early summer, in ponds and vernal pools. Wood frogs, spring peepers, American toads and spotted salamanders are among the early spring breeders. Leopard frogs breed later in the spring, and bullfrogs and green frogs in the summer.

Vernal pools are important for development of amphibians in our area since these seasonal wetlands do not hold fish, the main predators of amphibian eggs and tadpoles.

The early spring dry spell caught some developing amphibian populations at a stage when they could not survive. Tadpoles need several weeks to develop before they can survive out of water, usually when they lose their tails, yet they still take in moisture through their skin. The variation in breeding times between species and individuals helps ensure species survival in vernal pools.

Year-round ponds, though higher in fish predation for eggs and larvae, provide permanent amphibian habitats that balance the risk of vernal ponds drying up at critical stages of development.

Vernal ponds also provide habitat for plant and tree species that are tolerant of wet areas. High bush blueberry, red maples and sycamores are woodland species often associated with vernal wet areas. Caddis flies, dragonflies and other insects may develop in vernal pools. While predator species, including garter snakes, turtles and foxes, can frequent vernal pools looking for amphibian meals.

Article by FCFCDB

Nature Notes for 5/20/2012