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Vernal Pools

(click on photos to enlarge)

Photos taken at Planter's lower field vernal pool


Anyone interested in wetlands should read David Carroll's Swampwalker's Journal.   He's a local author and teacher and has spent a lifetime walking New Hampshire wetlands studying turtles.   Planter's lower field catches the Warner River spring overflow and creates the vernal pool where they lay their eggs every year.  In 2003, the egg masses dried up due to an unusually dry spring and low snowmelt.  This year (2004), we had a good rainy spell, so they have a better chance, despite a low snowmelt, of surviving.  Filling the flooplain (below) allows for development on the other side of the river.

floodplain_2b.jpg (40131 bytes)

1.  Mole Salamanders

Source: Vernalpool.org

(written by Mark Erelli)

The mole salamanders belong to the family Ambystomatidae, and are represented in the New England region by four main species: the spotted salamander (Ambystoma maculatum), the blue-spotted salamander (A. laterale), the Jefferson salamander (A. jeffersonianum), and the marbled salamander (A. opacum). Herpetologists have long debated about the taxonomic status of blue-spotted and jefferson salamanders. Both are now recognized as their own species, although it is thought that they evolved into two species when populations of a common ancestral species were separated by glaciers during the last Ice Age. After the glaciers melted, the two species came into contact again and interbred, producing hybrids with three or four sets of chromosomes ("triploid" or "tetraploid", as opposed to organisms with two pairs of chromosomes referred to as "diploid"). These hybrids are difficult to tell apart from jefferson and blue spotted salamanders, without performing genetic analyses. Blue spotted salamanders are generally blue-black and sprinkled with small blue spots, while Jefferson salamanders tend to be more brown with fewer blue or gray spots on the body. In contrast, both the yellow spotted and marbled salamanders are easy to identify. Spotted salamanders are distinguished by two dorsal rows of big yellow spots. Marbled salamanders have bands of white, grey, or silver on their backs.

Mole salamanders get their name from their subterranean habits (they are commonly found in underground tunnels and burrows produced by small mammals), and their ability to burrow under rocks, logs, moss, and other vegetative debris. It is here they spend their days foraging for a variety of invertebrates, ranging from earthworms to snails to both larval and adult insects. Most of the year, these stout-bodied animals are quite secretive and are unlikely to be seen unless you are actively searching for them. Fortunately for the naturalist who seeks to observe the habits of these secretive and fascinating creatures, there are certain times during the year when it is possible to observe these animals in high numbers.

In early spring, when the snow is melting, the ground is thawing out, and nighttime temperatures edge above freezing, mole salamanders make their migrations on rainy nights to ephemeral and permanent woodland pools where they congregate in large numbers to breed (note: marbled salamanders are the only species of mole salamander in our area which migrate to breeding pools in autumn). These migrations occur primarily on rainy nights, and individuals may migrate to woodland pools from as far as 120 m away, and tend to return to the ponds where they were born. These pools are usually dry for a portion of the year, thus insuring the lack of fish which prey upon salamander eggs and larvae, and fill up with spring rains, snow melt, and rises in the water table (hence the term "vernal" pool). Anyone who has not witnessed such a migration will most certainly be amazed by the scale of the phenomenon, which may involve hundreds of salamanders. Once in the ponds, the males will leave their spermatophores on the pond floor, where they will be picked up by the female and used to fertilize her eggs. Eggs are laid in masses which range from the size of golf balls to that of tennis balls, depending upon the species.

Salamander eggs are surrounded by a matrix of jelly, which distinguishes them from frog egg masses in which single eggs are merely clustered together. These eggs will hatch in four to seven weeks, and larvae will feed on small invertebrates in the pond until they metamorphose and move onto land in the autumn.

Spring migrations of mole salamanders are a fascinating and awe-inspiring event, for both children and adults alike. These migrations, however, can put salamanders in danger. During migration, salamanders may have to cross roads which have been made through wetlands or forests and can be run over by unsuspecting motorists. In addition, the small, ephemeral pools in which they breed might be regarded as "insignificant puddles" and filled in by developers or homeowners. You can help mole salamanders by being alert for migrations across roads when driving on rainy nights in early spring. Massachusetts also has a certification program run by the Natural Heritage and Endangered Species Program, which alerts the state to the existence of a vernal pool and provides information which may be used by the state to prevent irresponsible development in and around ponds which mole salamanders use for breeding.


Degraaf, R. M., and D. D. Rudis. 1986. New England wildlife: habitat, natural history, and distribution. General Technical Report NE-108, Northeastern Forest Experiment Station. 491 pp.

Hunter, M. J., J. Albright, and J. Arbuckle (editors). 1992. The amphibians and reptiles of Maine. Maine Agricultural Experiment Station Bulletin 838. 188 pp.

Kenney, L. P. 1995. Wicked big puddles: a guide to the study and certification of vernal pool. Vernal Pool Association. 58 pp. plus appendices.

Pfingsten, R. A., and F. L. Downs (editors). 1989. Salamanders of Ohio. Ohio Biological Survey Bulletin New Series Vol. 7 No. 2. 315 pp.

Tyning, T. F. 1990. Amphibians and reptiles. Little, Brown, and Company, Boston. 400 pp.

2.  NHESP Guidesline for Vernal Pool Certification. Massachusetts Natural Heritage

vernal pool list
Guidelines for evidence of vernal pool habitat

The Massachusetts Natural Heritage and Endangered Species Program has
issued guidelines for vernal pool certification. The following are five
sets of conditions which would indicate that a water body or depression is
a vernal pool. Methods A and B identify a vernal pool by the "obligate
species", those which require the fish-free yet temporary waters of a
vernal pool for their life cycle. Methods C, D, and E identify a vernal
pool by demonstrating that it has no fish yet does have "facultative
species", those organisms which require a few months of water for their
life cycle.
Wet pool - - obligate species
A. Existence of
a confined basin depression and
evidence of breeding in standing water by any of the following
amphibian species (these species breed only in vernal pools):
a. Wood Frog (Rana sylvatica)
b. Spotted Salalmander (Ambystoma maculatum)
c. Blue-spotted Salamander (Ambystoma laterale)
d. Jefferson Salamander (Ambystoma jeffersonianum)
e. Silvery Salamander (Ambystoma "platineum")
f. Tremblay's Salamander (Ambystoma "tremblayi")
g. Marbled Salamander (Ambystoma opacum)

B. Existence of
a confined basin depression and
the presence of fairy shrimp (Anostraca) or their eggs therein. These
species spend their entire life cycles in vernal pool habitat.

Wet pool - - facultative species
C. Existence of
a confined basin depression which
contains standing water that dries up during the year (or which for
other reasons is free of adult fish populations) and
the presence of two or more of the following in standing water (these
species are not found in water that persists for less than two
continuous months in the spring and/or summer):
a. Breeding spring peepers (Hyla crucifer)
b. Breeding gray treefrogs (Hyla versicolor)
c. Breeding green frogs (Rana clamitans)
d. Breeding American toads (Bufo americanus)
e. Breeding Fowler's toads (Bufo woodhousii fowleri)
f. Breeding four-toed salamanders (Hemidactylium scutatum)
g. Adult red-spotted newts (Notophthalum viridescens)
h. Spotted turtles (Clemmys guttata)
i. Painted turtles (Chrysemys picta)
j. Snapping turtles (Chelydra serpentina)
k. Water scorpions (Nepidae)
l. Predaceous diving beetle larvae (Dytiscidae)
m. Whirligig beetle larvae (Gyrinidae)
n. Dobsonfly larvae (Corydalidae)
o. Caddisfly larvae (Trichoptera)
p. Dragonfly larvae (Odonata, Anisoptera)
q. Damselfly larvae (Odonata, Zygoptera)
r. Leeches (Hirudinea)

Dry pool - - facultative species
D. Existence of
a confined basin depression which
lacks standing water or which contains standing water the dries up
during the year (or is otherwise free of adult fish populations) and
the presence of one or more of the following (a,b,or c) (these species
are found only in areas that contain water for at least two continuous
months in the spring and/or summer):
a. Cases of caddisfly larvae (Trichoptera)
b. Adults, juveniles or shells of either of the following:
Freshwater clams (Pisidiidae)
Amphibious air-breathing snails (Basommatophora)
c. At least six of the following wetland plant species:
Duckweeds (Lemna spp., Spirodela spp., Wolffia spp.)
Fountain moss (Fontinalis spp.)
False mermaid weeds (Proserpinaca palustris and P. pectinata)
Bur-reeds (Sparganium androcladum and S. chlorocarpum)
Buttonbush (Cephalanthus occidentalis)
Pondweeds (Potamogeton spp.)
Bladderworts (Utricularia clandestina, U. gibba and U. subulata)
Water-milfoils (Myriophyllum humile and M. tenellum)
Water plantain (Alisma plantago-aquatica)
Yellow water-crowfoot (Ranunculus flabellaris)
Featherfoil (Hottonia inflata)
Water-starworts (Callitriche spp.)
False pimpernels (Lindernia anagallidea and L. dubia)
Lance-leaved violet (Viola lanceolata)
St. John's-worts (Hypericum adpressum, H. boreale, H. canadense, and
H. mutilum)
Smartweeds (Polygonum amphibium, P. hydropiper, P. hydropiperoides, P.
pensylvanicum and P. punctatum)
A rush (Juncus pelocarpus)
Sedges (Rhynchospora capitellata and R. fusca)
Grasses ( Agrostis scabra, Glyceria acutiflora, G. canadensis, G.
fernaldii, G. pallida, Muhlenbergia uniflora, Panicum dichotomiflorum,
P. meridionale, P. philadelphicum, P. rigidulum, P. tuckermanii, P.

Wet /dry pool - - combination of obligate/facultative species
E. Existence of all of the following:
1. Documented presence of water in a confined basin depression for at
least two continuous months in the spring and/or summer; and
2. Confirmation that the vernal pool area becomes completely dry during a
portion of the year (or other documentation proving the absence of adult
fish populations); and
3. Presence of any amphibians and/or reptiles in standing water within the
confined basin depression.

Breeding evidence. The presence of any of the following will be
considered an acceptable proof that a vernal pool is utilized for
breeding purposes by one or more specific amphibian species:

1. Breeding adults
Frog or toad - - breeding chorus and/or mated pairs
Mole salamanders - - courting individuals and/or spermatophores
2. Two or more egg masses of any of the amphibian species
3. Frog or toad tadpoles or mole salamander larvae
4. Transforming juveniles
Frog or toad - - tail stubs evident
Mole salamanders - - gill remnants evident
Confined basin depression. A confined basin depression is low area which
collects water. It must not have a permanent above ground outlet.