Todd McLeish: Be careful -- salamanders, frogs on the march
A spotted salamander.
Via ecoRI News (ecori.org)
During last month’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, R.I.
“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 hot spot is along a road, and the frogs and salamanders are often crossing it.”
During the same warm days last month, 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 during those journeys.
“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, such as green frogs, migrate later than others — but it typically happens at night when it’s raining. 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 noted that homeowners with sump pumps should regularly check the system for amphibians that wander in and can’t 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.
Rhode Island resident and author Todd McLeish runs a wildlife blog.
Todd McLeish: The wildlife effects of defoliation by caterpillars
Hills deforested by caterpillars.
The massive defoliation of trees in southern New England by winter moth and gypsy moth caterpillars this spring and summer has totally changed the look of the regional landscape. And while scientists say it’s unlikely that many trees will die as a result of one year of defoliation, it raises the question of how it will affect other species of wildlife.
University of Rhode Island ornithologist Peter Paton noted that several varieties of songbirds are likely benefiting from the huge number of caterpillars swarming the area. Black-billed and yellow-billed cuckoos, two species that are known to eat large numbers of caterpillars, including the prickly gypsy moth caterpillars that many other birds avoid, are likely to thrive this year. He said birdwatchers in the region have noticed an unusually large number of very active cuckoos since the birds arrived from their wintering grounds in South America in May. As a result, these birds will probably have a very successful nesting season.
“Last week I was watching some robins 40 feet up in a tree foraging, which is a pretty unusual place to find them eating,” Paton said. “So I’m guessing they were probably feasting on caterpillars, too.”
Paton also observed blue jays and hairy woodpeckers tearing apart some of the abundant caterpillar cocoons, another unusual behavior brought about by the caterpillar infestation.
“And if the defoliation ends up killing trees,” he said, “that could eventually have a positive impact on woodpeckers,” which consume insects that live in dead trees and which drill nesting cavities in dead trees.
As for other possible impacts on wildlife, he speculated that the absence of leaves on many trees will enable sunshine to filter down to the forest floor and other areas that are typically shady, which may provide additional sunny areas for turtles and snakes to nest and sun themselves.
On the other hand, fewer shady areas may make it more difficult for wood frogs and salamanders living in the forest to remain cool and moist, according to David Gregg, executive director of the Rhode Island Natural History Survey.
“Ferns and other forest floor plants are also more likely to have a negative experience of this phenomenon than a positive one,” he said.
Natural History Survey botanist Hope Leeson said there will be both winners and losers on the forest floor, depending on the needs of the species living there. “If there is an understory of trees and shrubs, they’ll be happy to have the sun.”
Leeson noted greenbrier as one plant that will thrive with the additional sunlight penetrating to the forest floor, and it will provide benefits to other species that may be at risk.
“At the moment, any small mammal living in the forest doesn’t have any cover,” she said. “Deer have eaten all the tree seedlings and shrub seedlings, so there isn’t anything for the mice and chipmunks to hide under. Once the canopy was removed by the caterpillars, it made it easy for the hawks and owls to see the small mammals pretty well.”
The increased growth of greenbrier, she said, will provide the small mammals with new places to hide.
Both Leeson and Gregg also noted that some unwanted invasive species may also thrive this year, thanks to the defoliation. Amur cork trees, for instance, an Asian species, have invaded forests throughout the Mid-Atlantic states and are now found in small numbers in coastal forests of Rhode Island as well. They grow very slowly in the shade, with some 25-year-old trees no more than 8 feet tall with trunks only an inch or two in diameter.
“They just wait it out in a shady situation,” Leeson said. “They just eek out an existence and wait for the moment when there’s light, and that’s when they put on a lot of growth.”
This year could be the year they will shoot skyward.
According to Rick Enser, retired biologist for the Rhode Island Department of Environmental Management, if the region experiences another gypsy moth infestation next year, tree mortality will likely increase, which could create gaps in the forest for new species to move into.
“Unfortunately, invasives are highly adept at dispersal, although small infestations within forest openings should theoretically be reduced or eliminated as the canopy returns,” he said.
Enser noted winged euonymus, also known as burning bush, as one invasive species that can spread quickly to new areas and survive when the forest canopy returns. It’s a shrub that has become a primary concern at URI’s W. Alton Jones Campus in West Greenwich.
Since it has been more than 30 years since Rhode Island has experienced such a severe defoliation, many of the environmental effects are uncertain and unstudied, leaving some scientists with more questions than answers.
“I was wondering about the nutrient balance,” Gregg said. “Normally oak leaves breakdown in a certain way at a certain time, but this year they've been consumed by caterpillars and turned into manure and sprinkled all over the forest floor. So is that good for the plants? What’s the nutrient analysis of gypsy moth poop?”
Author and EcoRI News contributorTodd McLeish runs a blog about wildlife. Hit this link to read it.