How Many Salamanders?

Eastern Tiger Salamander (endangered in NJ)

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).

SOURCES:
A Surfeit of Salamanders
NJ Online Field Guide for Reptiles and Amphibians

Why Did the Amphibian Cross the Road?

Eastern Tiger Salamander (endangered in NJ)

Not only can you ask "Why Did the Amphibian Cross the Road?" but why would it try to cross a Jersey road?

In the article "Death by Rubber" on ScienceLine, they look at global amphibian declines and the scientists and volunteers who are trying to preserve backyard biodiversity.

That article looks at some volunteers on a wooded road in northwestern New Jersey, last March who were 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.

Their night wasn't very successful and it's interesting that even experts are unsure what exactly triggers the spring migration. It might be rising ground temperatures, dropping barometric pressure and even the sound of the raindrops since the amphibians need the rain to stay moist and will need the vernal pools when they cross the road. In that case, they were hoping to see at least wood frogs and blue-spotted salamanders (pdf) which are more common amphibians in northern New Jersey and not endangered.

The NJDEP, Division of Fish and Wildlife’s Endangered and Nongame Species Program, the Conserve Wildlife Foundation of NJ, and the NJ Audubon Society are partners on the Amphibian Crossing Survey Project(pdf). They use volunteers to help us monitor sites in Warren and Morris County and to identify additional crossings throughout the northern region of the state. Due to limited resources, they are currently focusing efforts on northern New Jersey.

Seven years ago, volunteers had reported over 400 amphibians crossing the road in one night. Of course, crossing an NJ road has got to be a bit more hazardous than some other places and traffic has only increased in those 7 years.

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).

One habitat in Morris County, has probably lost its local population of blue-spotted salamanders which are an endangered species in the state, probably because of road kill during these crossings.

But roads also cause problems because of car exhaust, road salt & chemicals that leach into neighboring waterways and damage amphibian eggs and tadpoles and the simple fact that roads break large amphibian breeding groups into small, fragmented populations.

And NJ is not immune to other factors besides loss of suitable habitat. Even in safe areas, droughts and drier conditions have made these vernal pools disappear, perhaps due to climate change.


NJ Online Field Guide for Reptiles and Amphibians