Tuesday, March 3, 2015
How Many Salamanders?
Ecologist Raymond Semlitsch and his doctoral student Katie O’Donnell are researching part of the Mark Twain National Forest in Missouri for salamanders. They crawl along the ground, raking the leaf litter with their hands, looking under rocks and logs, and when they find salamanders, they lift them gently from the dirt to be weighed and measured.
They are building a model of salamander populations and using the data from the sites they studied, they can estimate salamander populations in other parts of the woods.
How many salamanders are in the woods? The answer, according to the model, is between 1.88 and 2.65 billion salamanders. That’s within a district of the Mark Twain National Forest about 2,800 square kilometers in area, and those numbers 2-4 times higher than estimates made by other scientists in the 1970s.
Those earlier researchers, studying salamanders in the woods of New Hampshire, didn’t account for amphibians hiding underground. And more recent studies of other salamander species have found up to 10 times more salamanders than the 1970s research.
What about here in New Jersey?
NJDEP, Division of Fish and Wildlife’s Endangered and Nongame Species Program and the Conserve Wildlife Foundation of NJ have enhanced a complex of 12 vernal pools in Cape May County to create habitat for state-endangered eastern tiger salamanders and other vernal pool breeding amphibians. The interconnecting pools allowed eastern tiger salamanders to return to vernal pools to breed in early winter.
In mid-December, eastern tiger salamander egg masses can be found in the pools and egg masses collected from other sites have also been introduced into these pools as supplements.
Every year, volunteers on a wooded road in northwestern New Jersey spend some early spring nights looking for frogs and salamanders to count.
They wait for the amphibians to cross the road on their way from the wooded uplands where they winter to the marshy lowlands and vernal pools where they will do their spring mating
Wood frogs and blue-spotted salamanders are more common amphibians in northern New Jersey and not endangered.
The NJ’s Endangered and Nongame Species Program and Conserve Wildlife, along withe the NJ Audubon Society are partners on the Amphibian Crossing Survey Project. Relying again on volunteers to help monitor sites in Warren and Morris County, they identify additional crossings throughout the northern region of the state. (Due to limited resources, they are currently focusing efforts on northern New Jersey.)
It is estimated that one third of the world’s amphibians are threatened with extinction, according to the International Union for the Conservation of Nature (IUCN).
A Surfeit of Salamanders
NJ Online Field Guide for Reptiles and Amphibians