The recent series of rain events that has occurred over the past several weeks has elevated the level of streams and rivers, reduced the threat of wildfires, and brought trail conditions back to a more typical spring muddy state.
This wet period has also helped greatly in rejuvenating vernal pools that are critical breeding areas and nurseries for many forest dwelling amphibians and has created the damp soil conditions essential to these wet-skinned animals. Among these moisture loving vertebrates that commonly occurs in stands of mature forests throughout the Adirondacks is a sizeable dark colored creature known as the spotted salamander.
Averaging between 6 and 7 inches in length, the spotted salamander is one of the longest terrestrial amphibians that exist in the Park. The bright yellow circular spots that form an irregular row on each side of its back gives this creature its name and makes it easy to recognize on those rare occasions when one is spotted.
Like most salamanders, the individuals of this species strongly prefer to confine their activities to the area just under the layer of dead leaf litter. It is in this carpet of decaying matter that this bug predator searches for worms, beetles, grubs, spiders, millipedes, centipedes, slugs and other similar invertebrates that it can grab hold of with its tongue.
Because adult amphibians have such poorly developed lungs, they often depend on the ability of their smooth, moist skin to absorb additional amounts of this gas into their system. A loss of moisture from its skin reduces the ability of this organ to diffuse this elemental compound into its blood stream. As a result, terrestrial amphibians naturally avoid places that dry their skin and limit their respiratory capabilities. Moist soil conditions are also far more attractive to the wealth of invertebrates on which the spotted salamander depends for food.
It is in the early to mid spring in the Adirondacks that the spotted salamander exits the safety of its subterranean winter retreat, however, it does not immediately rush to the closest breeding pool, as do several other amphibians. The spotted salamander ordinarily waits until the night air is completely saturated with water, such as during a period of showers or when a heavy mist is falling. Also, because this creature functions best when the surrounding temperature is close to 50 degrees, a cold rainfall that is mixed with snow is generally shunned.
Once a thermally favorably wet period develops at night, all of the salamanders within a general area make their way toward the closest pool of water that is suitable for breeding. This sensitivity to a specific temperature range is believed to synchronize the migration to their breeding sites. As is the case with the wood frog, the mating period for the spotted salamander lasts for only about a week. After this period, the adults exit the pool and journey back to the area in which they will reside for the remainder of the summer season.
Depending on the temperature of the water, their eggs hatch in about 3 weeks and it takes another 2 to 3 months before the larvae develop their primitive lungs allowing them to emerge onto land. Should these pools dry up during a prolonged period without any precipitation, the young still confine to these pools may all perish. Last year, with the abundance of the rain, these seasonal pools remained intact through the summer and were successful in allowing many young salamanders to form.
While a seasonal pool of water may not always insure the success of these immature amphibians, such places are strongly preferred over more permanent bodies of water because of the presence of predatory organisms in larger aquatic setting. Fish, frogs, turtles, ducklings and an array of large aquatic bugs are all known to gobble up any tadpole-like organisms that they happen to detect nearby. Since seasonal pools of water lack most of these larger creatures, they allow for a much higher rate of successful development of the eggs and immature amphibians compared to any permanent body of water.
The exceptionally dry period that our region experienced earlier this spring created stress on our spotted salamander population, however, recent rainy periods have made up for the lack of water earlier this spring. Continued bouts of wet weather should allow these nighttime phantom of our mature hardwood forests to function properly, and maintain the pools of water that contain the immature salamanders, along with the zillions of mosquito larvae that will soon be hatching into hungry adults.
United States Department of Transportation photo courtesy Wikipedia.