Bullard Memorial Farm Association
The Bullard Farm's Vernal Pool
Vernal pools are small temporary ponds, with no inlet or outlet. They hold water for only part of the year and contain no fish. They are essential for a healthy ecosystem because certain amphibians must live in a vernal pool for some part of their lives. These species include wood frogs, spadefoot toads, spotted salamanders, and fairy shrimp. Other animals may use vernal pools but can live in other habitats as well.
To get to the vernal pool at the Bullard Farm, cross the road by the house, and take the trail to the circle. Go left until a trail comes in from the right. On the left side of the trail, in that area, is the pond.
The following can be found in the Bullard Farm's vernal pool:
Wood Frogs The wood frog is a small (about 2") frog of moist woodlands which has a range of most of northern
Green Frogs The green frog is found mostly in the eastern United States. Along with bullfrog, they are never far from the water, except during hibernation. In fact, they spend the majority of their time on the shores of lakes and ponds and the banks of rivers waiting for prey to cross their path. When approached, green frogs will typically leap into the safety of the water while letting out a loud cry. Hence, the old nickname 'the screaming frog'. Green frog are commonly confused with bullfrogs during all stages of their life. As small tadpoles, the two species are difficult to impossible to separate, but older tadpoles can be distinguished on close inspection. As adults, green frogs can be readily identified from bullfrogs by the dorsal-lateral ridge, whereas bullfrogs lack this ridge. In Massachusetts, green frogs are widespread and common. They occupy a wide variety of habitats and appear to be less affected by development and degraded habitats than other amphibian species. In fact, some studies suggest that green frog populations have actually increased over the years and thus may benefit from manmade habitat alterations.
Fingernail Clams Fingernail clams are also referred to as "pill clams" or "pea clams". As the name implies, they are the size of a fingernail. They live at the bottom of ponds and brooks. Fingernail clams are self-fertilizing, the young developing inside the water tubes of the adult. Mussels have a very elaborate and intriguing process; the larvae, called glochidia, develop inside the adult female and are released into the water where they eventually attach onto a host fish. Then they parasitize the fish for about two weeks until they drop off and develop on the stream bottom into an adult. They are primarily filter feeders. They filter organic debris and plankton out of the water, and are preyed upon by numerous fish and mammals.
Caddisflies Caddisflies are considered underwater architects because many species use silk for building throughout their larval life. Many species of caddisfly larvae enter a stage of inactivity called the pupa stage for weeks or months after they mature, but prior to emergence. Their emergence is then triggered by cooling water temperatures in the fall, effectively synchronizing the adult activity to make mate-finding easier. Caddisflies pupate in a cocoon spun from silk. Caddisflies which build the portable cases attach their case to some underwater object, seal the front and back apertures against predation though still allowing water flow, and pupate within it. Once fully developed, most pupal caddisflies cut through their cases with a special pair of mandibles, swim up to the water surface, cast off skin and the now-obsolete gills and mandibles, and emerge as fully formed adults. In a minority of species, the pupae swim to shore and crawl out to emerge. Many of them are able to fly immediately after breaking from their pupal skin. The adult stage of caddisflies, in most cases, is very shortlived, usually only 1-2 weeks, but can sometimes last for 2 months. Most adults are non-feeding and are equipped mainly to mate. Once mated, the female caddisfly will often lay eggs (enclosed in a gelatinous mass) by attaching them above or below the water surface. Eggs hatch in as little as three weeks.
Dragonflies Female dragonflies lay eggs in or near water, often on floating or emergent plants. When laying eggs, some species will submerge themselves completely in order to lay their eggs on a good surface. The eggs then hatch into nymphs. Most of a dragonfly's life is spent in the naiad (that is, nymph) form, beneath the water's surface, using extendable jaws to catch other invertebrates, or even vertebrates such as tadpoles and fish. They breathe through gills.Some nymphs even hunt on land. The larval stage of large dragonflies may last as long as five years. When the larva is ready to metamorphose into an adult, it climbs up a reed or other emergent plant. Exposure to air causes the larva to begin breathing. The skin splits at a weak spot behind the head and the adult dragonfly crawls out of its old larval skin, pumps up its wings, and flies off to feed on midges and flies. In flight the adult dragonfly can propel itself in six directions; upward, downward, forward, back, and side to side. The adult stage of larger species of dragonfly can last as long as five or six months.
Damselflies Damselflies are similar to dragonflies , but the adults can be differentiated by the fact that the wings of most damselflies are held along, and parallel to, the body when at rest. Furthermore, the hindwing of the damselfly is essentially similar to the forewing, while the hindwing of the dragonfly broadens near the base. Damselflies are also usually smaller, weaker fliers than dragonflies, and their eyes are separated. Damselflies undergo incomplete metamorphosis, with an aquatic nymph stage. The female lays eggs in water, sometimes in underwater vegetation, or high in trees in bromeliads and other water-filled cavities. Nymphs are carnivorous, feeding on daphnia, mosquito larvae, and various other small aquatic organisms. The gills of damselfly nymphs are large and external, resembling three fins at the end of the abdomen. After moulting several times, the winged adult emerges and eats flies, mosquitoes, and other small insects.