Last week I took a walk through Amagansett’s Stony Hill forest to visit a small vernal pond that is a breeding habitat for one of our unusual salamander species called the marbled salamander. Unlike most of our native amphibians that journey to their vernal pond breeding grounds in the spring and early summer, such as the wood frog, gray treefrog, spring peeper, Fowler’s toad, and spotted and tiger salamanders, the marbled salamander mates and lays eggs at these sites in autumn.What makes this species even more unusual is that the vernal ponds are often dry when the breeding season commences in early fall. Courtship, the external exchange of the tiny spermatophore packet, and egg laying all take place under the leaf litter in a damp but waterless section of the vernal pond.
After creating a small, oval “nest” (averaging 3” long by 2” wide and 1” deep) in the soil, the female lays 50-200 eggs. Unlike other mole salamanders and frogs whose eggs are connected by a jelly-like substance, the marbled’s eggs are laid singly and are unattached to one another. They are spherical in shape and measure one tenth of an inch in diameter.
Females will coil their 3.5- to 4.5-inch-long bodies around the eggs to protect them from potential predators (e.g. shrews and beetles), insulate them and keep them moist. She leaves, once autumn rains refill the pond to a point where the eggs are inundated. The embryos develop to an advanced stage within the egg, and hatching takes place within days of inundation.
This strategy gives the marbled salamander larvae a jump on other amphibians that may use the pond for a breeding site. They grow slowly during the winter, including periods when the pond is covered with ice, but by spring are large enough to feed on the newly hatched larvae of other amphibian species.
I did not find any adult marbled salamanders or nests containing eggs during my visit last week, but the deepest portion of the vernal pond had enough water to support clouds of daphnia, a.k.a. water fleas, an important source of food for salamander larvae. I also noticed quite a few mosquito larvae wriggling about to reposition their tube-like breathing structures at the water’s surface.
On the return walk through a section of the forest dominated by American beech trees, one of my favorite trees, I flushed a woodcock from the forest floor. It flew a very short distance before settling down on the fresh carpet of colorful leaves again, where it was very well camouflaged. Beech is not uncommon on Long Island, but it doesn’t form extensive forests here. Beech stands or groves within our oak-hickory forests are a welcome addition to our forest flora.
Beech trees are characterized by a very smooth, light gray colored bark that, unlike most of our native trees, retains its unwrinkled, smooth skin well into old age. A close look at the saplings around the larger specimens in a grove often reveals that the young shoots are growing directly from the shallow surface roots of the elder tree, making them clones.
Beeches often form uniform stands in the forest where no other species of plants—trees, shrubs or ground cover—are found. This makes for easy hiking and cross country skiing even where no trails or paths are found. I once assumed that this feature of beech groves was the result of allelopathic chemicals secreted by the beech’s roots system that acted as germination and growth inhibitors and suppressed the development of other forest plants.
Apparently this is not an example of allelopathy, but the impact of an aggressive, well developed, shallow root system that out-competes other species for nutrients and water, and a leaf arrangement that casts deep shade over the forest floor during the growing season. Whatever the cause, the result is beautiful.