With a little help from their friends, 168 spotted salamanders made it safely across Herrontown Road over a few “big nights” – shorthand for migration nights.
That was the report delivered to the Princeton Council by Princeton High School students Carina He and Bhavya Yaddanapudi, who are members of the all-volunteer Salamander Crossing Brigade.
For a few hours on selected nights between late February and early April, the volunteers picked up the salamanders on one side of Herrontown Road and put them down on the other side.
The salamanders migrate between the Herrontown Woods Preserve and the former Lanwin Development Corp. tract, which both have frontage on Herrontown Road, to reach vernal pools – seasonal bodies of water – where they go to breed.
The salamander crossings typically occur on the first rainy nights, when the temperature is above 40 degrees Fahrenheit and the ground has thawed and the vernal pools are free of ice.
Closing Herrontown Road is crucial to the salamanders’ survival, the students said.
In a side by side comparison of this year’s migration, 64 vehicles drove on Herrontown Road when it was open, Bhavya said. The result was 49 salamanders were saved by the volunteers, but 40 were killed by cars.
When access to Herrontown Road was limited, eight vehicles drove on it and the volunteers helped 119 salamanders cross the road, she said. And none of the salamanders were killed by passing motorists.
This is in contrast to last year’s salamander migration, when about 40% of amphibians – or 109 animals – were killed in spite of manned crossings by volunteers, according to the Friends of Herrontown Woods. The nonprofit group first organized the Salamander Crossing Brigade three years ago.
“If we continue to lose 40 percent of salamanders each year, this species – which is currently threatened – could possibly go extinct,” Bhavya told the Princeton Council.
Salamanders are considered to be keystone species because of their roles in regulating food webs, nutrient recycling and ecosystem resilience. They prey on insects and worms, but they are also food for predatory snakes and raccoons.
Carina used the analogy of a keystone in a building to salamanders’ role as a keystone species.
A keystone in a building holds up the entire structure, she said. If a keystone is removed, the entire building collapses. The same can be said of salamanders, who are a keystone in the ecosystem.
“When you take that keystone out, it will collapse the whole building, which will apply to the ecosystem and the roles that salamanders play in it,” she said.
Bhavya said most people have never heard of salamanders, and they do not know there is a way to save them. Princeton residents are lucky to have the amphibians literally living in their back yards, she said.
Princeton Councilwoman Mia Sacks said she hopes that next year it might be possible to form a partnership with the town to help figure out what is necessary for the maximum protection of the salamanders.
“We recently worked very hard to save the Lanwin property,” she said. “By saving the Lanwin property, we have made it possible for the salamanders to continue to come back.”
