During last week’s warm spell,
Emilie Holland saw and heard something she seldom detects this early in the year
– the first movement of frogs and salamanders from their woodland wintering
grounds to their springtime breeding pools. She observed wood frogs, spring
peepers, spotted salamanders and even a rare marbled salamander near her house
not far from the Great Swamp Wildlife Management Area in South Kingstown.
“We often get pretty early activity
here,” said Holland, an environmental scientist for the Rhode Island Department
of Transportation and a board member of the Rhode Island Natural
History
Survey. “For whatever reason, the micro-climate is good for them. The problem
is that my hotspot is along a road, and the frogs and salamanders are often
crossing it,” which puts them at risk.
Marbled salamander by Emilie Holland |
During the same warm days last week,
other observers reported hearing spring peepers in North Kingstown and
Cumberland and seeing a red-backed salamander in Middletown.
According to amphibian expert Lou
Perrotti, director of conservation at Roger Williams Park Zoo, frogs and
salamanders don’t typically migrate to their breeding ponds until mid-March in
most areas of the state. During the cold winter of 2015, when many ponds were
still frozen until April, amphibian migration was delayed by almost a month.
But it’s not unusual for rain showers during an especially warm period in late February
to trigger an early migration.
“When that happens, the migration
period tends to get extended,” Perrotti said. “A snowstorm or cold snap shuts
things down for a while, and then it picks back up again. You don’t have the
usual massive explosion of breeding activity all at once. It trickles along
instead.”
What happens to the frogs in the
ponds when the cold returns and the ponds freeze over again? Not much. Perrotti
said the animals are adapted to survive such conditions for short periods of
time. In fact, University of Rhode Island herpetologist Peter Paton said he
commonly sees wood frogs and spotted salamanders swimming beneath the ice of
local ponds in late winter. And wood frogs are uniquely adapted to freeze solid
and thaw out later with no negative consequences.
The bigger concern – as Holland
expressed – is that many frogs and salamanders must cross roads to reach their
breeding ponds, and untold thousands of them get run over by vehicles each year
in Rhode Island in the process.
“It’s a huge problem, one of the
biggest threats to amphibians and reptiles in the area,” Perrotti said. “I’ve
seen nights where there were hundreds of smashed wood frogs at just one site.
Toads get hammered, too, because they typically have huge breeding explosions
over a period of two or three nights. And gray tree frogs, too, which are
pretty clumsy on the ground.”
Amphibian movement to and from their
breeding ponds will likely continue through April – some species, like green
frogs, migrate later than others – but it typically happens at night when it is
raining. So Perrotti and Holland recommend driving carefully at night along
back roads in wetland areas during rain showers.
“It’s hard to avoid every frog in
the road, especially if you catch it on a good night for migration when they’re
everywhere,” Perrotti said.
One strategy that Perrotti said has
been employed in western Massachusetts to avoid the problem of amphibian
roadkill is the installation of what he calls “salamander tunnels” beneath roadways
in areas where large numbers of frogs and salamanders migrate across roads.
Barriers along the roadside funnel the animals toward the tunnel, which avoids
much of the mortality.
The idea has been discussed in Rhode
Island, but the cost is high and finding funding in municipal budgets is an
impediment. Signage encouraging drivers to slow down at certain locations is
another strategy that officials in the state have considered, though few have
been installed to date.
Holland notes that homeowners with sump
pumps should regularly check the system for amphibians that wander in and
cannot escape.
“I’m constantly fishing salamanders
and frogs out of mine,” she said. “People should monitor the sump in their basement and maybe they can keep a local
breeding population healthy by not letting the adults die in a pitfall trap
that they didn't even know they had.”
Those interested in learning more
about local amphibians and participating in a related citizen science project
should consider signing up for Frogwatch, a national program administered
locally by Roger Williams Park Zoo. Volunteers attend a training program to
learn the breeding calls of the various frog species that reside in Rhode
Island, then visit a designated pond in the evening once a week from March
through August to document breeding activity.
The next training session is
Saturday, March 3 at 1:30 p.m. and Sunday, March 4 at 1 p.m. Perrotti said that
families with children over 10 are encouraged to sign up together.
“Kids are especially good at it
because they’re inspired by the program and they’re good at remembering the
calls,” he said.
This article first appeared on EcoRI.org on March 1, 2018.
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