Vernal Pools
Called “vernal pools” because they fill with snow melt and rain water in the spring and most drying up during the summer. They are bodies of water with no inlet or outlet and depend on the surrounding watershed to provide clean water for breeding and larval development of salamanders, fairy shrimp, and Wood Frogs. Survival of larvae and hatchlings is a race against time, as hatchlings must leave within a few months for upland forest, before many small pools dry up by early summer. All three are “indicator species”, meaning their presence signifies a healthy area environment that supports a diverse plant, amphibian, animal, fish, bird, as well as we humans.
Wood Frog
Wood Frogs are terrestrial except during the early spring when they migrate to vernal pools, forming breeding congregations.
Wood Frog egg mass with hatching tadpoles.
Spotted Salamander
Spotted Salamander coming out of its winter retreat at the pond opposite the Log Cabin. This individual is about to migrate to the pond where it will join hundreds of other individuals in the annual spring breeding congregation. Then, on another rainy night, it will migrate back to the surrounding forest where it will spend the summer and winter in burrows beneath the leaf litter.”
Spotted Salamander egg masses in a vernal pool on East Mountain. Each mass is surrounded by a layer of jelly, which can be either clear or opaque and white. The eggs are laid in the early spring and hatch into gilled, aquatic larvae, which must transform into terrestrial juveniles before the pond dries up.
Jefferson’s-Blue Spotted Salamander
A female salamander of the Jefferson’s-Blue Spotted Salamander complex migrates to the pond across from the Log Cabin. This the animal is probably a hybrid with three sets of chromosomes, two from a Jefferson’s Salamander and one from a Blue-spotted Salamander male. Jefferson/Blue-spotted hybrids are nearly always females that reproduce asexually.
Marbled Salamander
Marbled Salamander, photographed during the autumn breeding migration at a pond near the Notch on the Holyoke Range. The pond was dry at the time but flooded later in the fall, allowing the Marbled Salamander eggs to hatch.
Pictures and descriptions courtesy of a friend of the Mt. Tom Range.
Fairy Shrimp
Fairy shrimp are fairly widespread in southern New England, They are most often seen in early spring, shortly after ice-out in vernal pools located in relatively undisturbed forest to roadside pools across the Mt. Tom Range. More text to come. Input much appreciated.
Image courtesy of a friend of the Mt. Tom Range.
The numbered illustration below highlights the Spotted Salamander’s ( Ambystoma maculatum ) breeding cycle. It takes place on a warm rainy late March or early April night on the Mt. Tom Range. For more detail about their breeding cycle refer to other website descriptions. Sample sites to come.
1) Males and females spend winters underground and migrate to vernal ponds during the first warm rainy nights in the spring.
2) Once entering the pool the males gather for what might be in a collective display, a unique characteristic, possibly in anticipation of arriving females..
3) Males deposit spermatophores leaf litter on the pool bottom. Females often gather multiple samples in their cloaca to fertilize eggs internally, later laying those eggs around the pool floor. Each female lays her eggs in a mass surrounded by a jelly envelope and attaches it to vegetation or sticks and twigs. Spotted Salamander egg mass differs from those of Wood Frogs in having a jelly layer that surrounds the entire mass of eggs, each of which is also enclosed in an individual jelly envelope.
4) A symbiotic relationship exists between the spotted salamander and a single cell green algae known as Oophila amblystomatis. Alga produces oxygen as a byproduct of photosynthesis, which uses carbon dioxide as a carbon source to produce glucose. Alga might also acquire nutrients such as nitrogen from the larva’s metabolic waste products. Alga gives older egg masses a greenish tint and the algal cells occur in the larva’s tissues as well as the egg jelly.
5) Since amphibian eggs don’t have shells, their larvae don’t “hatch.” The egg develops into an aquatic larva that emerges from the jelly envelope. Water temperature affects the time salamander larvae hatch from their eggs. It is in one to two months before entering the pool to develop legs and grow to adequate size.
6) Terrestrial “juveniles” that have undergone metamorphosis, i.e. lost their gills, developed eyelids, and undergone other changes. Maturing over a three to four year period, the Yellow Spotted Salamanders generally return to their place of birth to breed.
Representative illustration courtesy of a friend of the Mt. Tom Range. Description from various informed sources. Corrections and additions appreciated.