On rainy spring evenings, have you ever encountered large numbers of salamanders and frogs crossing the road? Do you ever wonder where they came from and where they are going? New Jersey’s forests are home to a group of amphibians that breed in small, temporary wetlands called vernal pools. Within northern New Jersey, this group includes wood frogs, spotted salamanders, and Jefferson salamanders.
These salamanders are elusive, often concealed under foliage, moss, or in burrows created by small creatures. They belong to the Ambystomatidae family, earning the nickname “mole salamander” due to their subterranean tendencies. Feeding primarily at night on various invertebrates like earthworms and insects, they, along with wood frogs, play crucial roles in forest ecosystems as vital links in the food chain and are indicators of ecosystem health. Emerging from winter hibernation during rainy nights in late winter and early spring, they embark on journeys to vernal pools for mating and egg-laying, marking the onset of the amphibian migration.
Complete the lyrics: Nothing else matters in the whole wide world when you’re in love with a…
If you said Jersey Girl, then you’d be correct! Coincidentally, that’s also where volunteers and supporters alike gathered last month to show their love for amphibians. Jersey Girl Brewing in Mount Olive, that is.
Two years ago, we partnered with Jersey Girl to host a trivia event to raise awareness for our Amphibian Crossing Project, an initiative that seeks to reduce mortality among populations of frogs and salamanders whose migratory pathways are bisected by roadways. We chose the location based on its proximity to our largest crossing site, Waterloo Road, in the hopes that many of our hardworking volunteers could attend. We had a great turnout and a lot of fun. Following several requests, we decided to bring it back this year for round two.
Participants, including former CWF intern, Nicole Bergen (who helped write and host our first trivia event) pause during answer deliberation to smile for the camera.
Lots of familiar faces were in the crowd at Jersey Girl, including CWF’s Founder, Linda Tesauro, trustees Steve Neumann, Rick Weiman, and Amy Greene, former amphibian crossing leads MacKenzie Hall and Allegra Mitchell, former CWF intern, Morgan Mark, and many new and seasoned volunteers, like Barb and Rick McKee, without whom, this project could not succeed.
This post is the second in our “super salamander (and frog)” series in which we’re exploring some of the unique adaptations exhibited by local amphibians that would seem more appropriate within the confines of a comic book than out and about in our Garden State landscape. Today’s focal species is the spotted salamander (Ambystoma maculatum), our benevolent Poison Ivy. Full disclosure, this topic has nothing to do with plant, though salamanders themselves are not sensitive to the compounds that make humans itchy and have been known to use “leaves of three” as sources of shelter.
For those of you who may be unfamiliar with the DC Comic Universe, Poison Ivy is a villain who often opposes Batman (and occasionally Superman) during her crusade to protect plants and rid the world of environmental destruction. Though her goals may seem in line with ours here at CWF, her methodology differs dramatically and she is often defined as an eco-terrorist. A former botanist, Poison Ivy, AKA Pamela Isley, was poisoned by her professor. Though she survived the experience, the toxins drove her insane and transformed her into a human-plant hybrid. And that is where our connection lies…
If you’ve ever seen an egg mass deposited by a spotted salamander, you may have noticed that the casing often appears green. This is caused by an association with a very particular kind of green algae called Oophilia amblystomatis. The connection between salamanders and algae has been recognized for > 130 years. For most of that time, it was thought that the algae just occurred within the egg. This is a sensible mutualism- it is auspicious to both species involved. Spotted salamander eggs develop in vernal pools. These temporary wetlands may have relatively low concentrations of dissolved oxygen, so the introduction of algae, which can create oxygen through photosynthesis, into eggs can certainly benefit growing larvae. Under experimental conditions where salamander eggs containing algae were cut off from sunlight, growth and development was delayed and resulting individuals were smaller than those exposed to natural circumstances. On the other side, larvae produce CO2 and nitrogenous wastes, which can be used to the advantage of the algae. Studies have shown that Oophilia are most successful in water that has been exposed to spotted salamander eggs, even if they are not within the eggs themselves. Case closed, right?
Developing spotted salamander larva with Oophilia algae. (C) R. Hangarter
Wrong. In 2011, a team of researchers at Dalhousie University in Halifax, Nova Scotia, discovered that the relationship between these two organisms is, literally, skin deep… The algae don’t just infiltrate the salamander’s egg masses. They are also found within the salamander’s tissue cells. This type of connection is called an endosymbiosis- one cell living inside another cell. Coral reefs and their associated algae are the poster children for this phenomenon, but it is not uncommon among invertebrates. Vertebrates, however, tend to have much more active immune systems that are programed to recognize a cell growing within another cell as a health threat. We can be grateful for that, as dangerous pathogens (e.g., malaria), can spread this way. In the case of salamanders and algae, the above-mentioned team discovered that the amphibians were actively suppressing their immune systems to allow for the success of the algae, which indicates that they must continue to benefit from this association. The algae show signs of stress when encapsulated within the body of salamanders; sunlight becomes harder to access, so rather than creating energy through photosynthesis, they switch to the process of fermentation.
The endosymbiotic mutualism between spotted salamanders and green algae is totally unique among vertebrates. No other amphibians, reptiles, mammals, birds, or bony fish are known to support a similar relationship. Research on the mechanisms and the meanings of this “partnership” are ongoing, but scientists are hopeful that the discovery could yield novel techniques for medical advancement.
While spotted salamanders are certainly not hybridizing with their algal associates, in a way, they walk the animal-plant boundary as they incorporate both types of cells within one compact package, therefore making them the amphibious analogs of DC’s Poison Ivy.
Spotted salamander crossed during the 2022 migration.
Our final installment will shift the focus to frogs and, in particular, one that doesn’t mind the late winter chill…
Rainy nights with evening temperatures edging into the mid-40s or above. Seems easy to plan for rescue nights, doesn’t it? Certainly not this year!
CWF’s Amphibian Crossing Project targets the earliest breeders in northern New Jersey, including wood frogs, spotted salamanders, and Jefferson salamanders. These vernal pool obligates must find their way from forested winter habitat to ephemeral wetlands each spring in order to successfully reproduce. Snowmelt and warm, moist air signal individuals to resume activity after a long winter’s brumation (hibernation for ectothermic “cold-blooded” animals) underground. As soon as they emerge, they head to the pools which, in our increasingly fragmented world, often means entering into a real-world game of Frogger. The stakes are incredibly high and many do not make it out alive.
Spotted Salamander (Ambystoma maculatum)
To combat this problem, our team of devoted volunteers has been braving the elements for the last 20 years, ferrying slow moving amphibians across busy roadways during the earliest wave of the annual migration. Their efforts not only increase survivorship and breeding potential, but also raises awareness and contributes valuable data to justify the construction of long-term solutions. This season, 103 participants were involved in the project, working across three CWF managed roads in Byram, Liberty, and Hampton Twps. and one site in Hardwick Twp. organized by Blaine Rothauser, a senior ecologist for GZA GeoEnvironmental and Dennis Briede, stewardship manager at the Land Conservancy of New Jersey. All together, we assisted with the movement of 2,456 amphibians of 9 species, 26% of which represented species of concern.
Wildlife Biologist Ethan Gilardi poses with a Wood Frog before helping the frog safely across a busy roadway.Amphibian Crossing Project manager Christine Healy shows off a Wood Frog rescued from the busy roadway.
Without a doubt, these numbers are impressive, however, I can’t help but reflect on this season with agitation. Late February and March featured dramatic temperature swings, characterized by sunny days in the 70s followed by cold snaps with snow and ice. Freezing conditions can damage amphibian egg masses and fluctuating weather may punctuate and elongate the migration, making movement difficult to predict. Lightning storms and heavy wind kept us off the roads during a few of the seasons peak nights, though based on the results of morning mortality surveys, the same cannot be said for drivers…
While amphibian rescue events do localized communities a lot of good, seasons like this one really highlight the need to remove a dependence on humans from the survival equation, especially as global climate change continues to cause deviations from “normal”. We’re anticipating the first frog/salamander-specific wildlife passage in NJ to break ground at our Byram Twp. site in the summer of 2023, after years of planning by the Endangered and Nongame Species program and many partners.
We can’t wait to see the impact this project has on the population of amphibians reliant on New Jersey’s largest vernal pool and how it inspires similar projects in the future.
A volunteers handles a spotted salamander. Photo by Mackenzie Hall
The Conserve Wildlife Foundation has been partnering with NJ’s Endangered and Nongame Species Program (ENSP) since 2002 for the annual Amphibian Crossing Project. On warm, rainy nights in the early Spring, we work with a fleet of incredible volunteers to hustle amphibians across the road at three key rescue sites. Still groggy from their winter hibernation, roads can be incredibly dangerous for the slow moving frogs and salamanders trying to reach their breeding grounds.
Over the course of this project, we’ve crossed an estimate 14,000 individuals at the Byram Township site alone!
Commenting on last Thursday’s crossing, the first of 2021, Amphibian Crossing Project Coordinator Christine Healy had the following to say:
“We were a little unsure of what to expect, since the temperature was a little on the cold side, but we crossed 1,215 amphibians at Byram Twp., 1,132 at Stillwater, and 963 at Liberty Twp.
I’d call that a success! Really proud of all the volunteers who made it happen.
Conditions look like they could be good toward the end of this week for round two!”
Bruce A. Scruton of The New Jersey Herald recently spoke with Christine to discuss the Amphibian Croosing Project and its storied history.
You can read the profile over on NJHerald.com to learn more about what it takes to help hundreds of our amphibian friends hop and meander across dangerous roadways.
The spotted salamander is one of the key amphibian species which crosses roads on their journey to reproduce every Spring, prompting road closures and volunteer crossing efforts like the Amphibian Crossing Project.
Wild New Jersey Revisited is a monthly series of excerpts from Conserve Wildlife Foundation executive director David Wheeler’s 2011 book Wild New Jersey: Nature Adventures in the Garden State. Today we focus on a springtime migration…of miniature proportions – and one that could be occurring again tonight!
Excerpt from Chapter 22
Wild Nights in Suburbia
It’s not often that I find myself praying for rain on the way out the door. No, when I’m about to spend three-plus hours standing outside on a chilly Sunday evening in March, I usually prefer to stay dry. I’m kind of picky that way.
So if it seems odd that I let out a quick cheer when a few raindrops appear on my windshield as I navigate treacherous backroads in Warren County – well, there’s good reason. Without the rain, there are no salamanders crossing the road. And without salamanders or frogs, the scientists and a truckload of committed volunteers have no reason to be out here in the chilly twilight.
I arrive at the site, and my windshield is dry again. I fear that those lone raindrops were just a big tease. It could be a long night. Somewhere in the distance, a great horned owl hoots. Near the road, a lone spring peeper calls without end like a soapbox preacher. Perhaps he is divining the future for his fellow amphibians, and for us.
After all, this is their migration. We are just here as bouncers, keeping cars and trucks from crashing their party. Tonight, rain is the only question mark. The temperature is in the ideal range, mid- to upper forties. As planned, the night grew dark when the sun went down. (Whew – that’s a relief!) So that’s two out of three needs for the crossing to begin.
All we need is rain. One volunteer checks the Doppler radar weather forecast on his phone every few minutes.
“There’s a system over Lehigh Valley now, but it’s moving our way pretty quickly.”
Another volunteer reminisces about the good old days.
“2002 – that was the best year. We got a torrential downpour.”
A wood frog, held by an Amphibian Crossing volunteer. Photo by Mackenzie Hall.
Salamander Crossing
The volunteers take their places. For the next few hours, each person will walk a roughly 50-foot stretch along the dotted yellow traffic line in the middle of the road. Volunteers will tally any amphibians that pass through by number and species. The salamanders and frogs cross the road to get from their upland wintering areas to the vernal ponds on the other side, where they can safely lay their eggs. These vernal ponds, or temporary pools, dry up for part of the year. That means no fish are present to eat the amphibian eggs and tadpoles.
“We focus not only on salamanders, but on amphibians as a whole, because they are ecological indicators,” says Kris Schantz of New Jersey Fish and Wildlife, who started the migration night surveys in 2002 and has run them every year since. “They play an important role in helping us understand the ecosystem health, water availability, and water quality. If there are problems with the water, we will see it in them first.”
Schantz, along with MacKenzie Hall from the Conserve Wildlife Foundation of New Jersey and Mike Anderson from New Jersey Audubon, works with municipalities to coordinate these rural road closings for two or three nights each year. Yet Schantz is also calling for a permanent solution: culverts underground. Such systems are in place in Massachusetts and Europe, but have not yet been tried in New Jersey, which has more roads per square mile than anywhere else in the country. Culverts would do wonders here.
The first three-hour shift is ending without a single crossing. I say my goodbyes and begin walking back to the car. And then – “Spring peeper!”
“Salamander!”
A volunteer shines his beam on the spotted salamander, a good six inches of stunning dark blue dotted with bright yellow spots. A few feet away, the spring peeper – a tiny tree frog no bigger than my thumb, with a beautiful darkened X pattern across its olive-colored back – slowly makes its way across the road. It feels great to see these brave individuals, who appear to be testing the conditions for the rest of their groups – perhaps they are the amphibian equivalents of “guinea pigs.”
Oasis in the Forest
While state surveys are manned only by trained volunteers, there’s another opportunity for anyone to experience a salamander migration first-hand. Each March and April in East Brunswick, the town closes down a half mile of Beekman Road to drivers for a handful of rainy nights. Scores of local residents gather to observe the migration, watching spotted salamanders, spring peepers, red efts, and red-backed salamanders.
This unique public event started in the early 2000s when environmental scientist David Moskowitz found his first dead salamander on the road. He told then-Mayor William Neary about it, and the mayor was surprisingly receptive to closing the road. Each year since, the rural road has shut down for up to nine nights, depending on the quality of each mass movement.
The crossing attracts large numbers of participants, largely because it seems like such a different world in the middle of suburban East Brunswick. During my visit to the crossing, the frog calls echo so loudly that I might as well have entered a tropical rainforest.
“On many nights, we actually have a parking problem, so many families want to come out,” says Moskowitz. “Our message is that the perfect analogy of the vernal pool is the oasis in the forest. If you lose a vernal pool, you lose all of those species that go into a vernal pool.”
Ten Years Gone
In the decade since Wild New Jersey was published, the amphibian crossings in northwestern New Jersey have continued each year, though with some scaling back in 2020-21 due to Covid safety restrictions. Christine Healy of Conserve Wildlife Foundation manages the 2021 crossing project, and MacKenzie Hall still provides major oversight – albeit now as a New Jersey Division of Fish and Wildlife scientist.
David Moskowitz continues to manage the East Brunswick amphibian crossing, attracting hundreds of people each spring to safely enjoy the wonders of seeing these unique creatures, including introducing many people to the first close-up looks at a salamander or spring peeper. Visit the environmental commission’s project webpage for a detailed overview and regularly posted updates of conditions and likelihood of the road closing during this time of year.
– David Wheeler, March 2021
*Special Note, March 18, 2021*
Tonight’s forecast calls for relatively ideal conditions, so be sure to check out the East Brunswick salamander crossing updates for the likelihood of a road closure and the chance to visit the amphibian migration tonight!
Stay tuned for April’s installment of “Wild New Jersey Revisited” – a trip to the “Bayshore Bayou” in search of bald eagles!
Read the previous installments of Wild New Jersey Revisited:
Wildlife habitats all over the country have been broken into ever smaller pieces by human development, making it challenging for animals to safely find food, mates or a place to make a nest or den. This is especially true in New Jersey, which has more people per square mile than any other state by far.
The PBS EcoSense for Living episode ”Wildlife Crossings” has captured the challenges habitat fragmentation poses to wildlife, along with the amazing work that scientists, engineers, and wildlife managers are doing to help. Projects supporting New Jersey Division of Fish and Wildlife’s Connecting Habitat Across New Jersey (CHANJ) initiative, including CWF’s Amphibian Crossing Project, are featured beginning at 14:10.
On warm, rainy spring evenings salamanders, frogs and toads venture out for the most eventful nights of their year. They have but one goal – to make it to a vernal pool to breed. But between them and the pool is a road, filled with cars barreling along, completely oblivious to their big plans.
A single vehicle can crush dozens of these slow-moving animals as they try to make it across the road. From the driver’s seat they may look like mere twigs, leaves, or raindrops bouncing off the road. With high mortality rates year after year, it doesn’t take long for a population to nose-dive.
The Amphibian Crossing Program helps hundreds of salamanders, frogs and toads make that hazardous journey so they can have their big night. We are also assisting NJDFW in preparing for a wildlife crossing structure system consisting of under-road tunnels and guide fencing to help amphibians at our busiest migration site.
Successful “critter crossings” at this priority site could pave the way for many other projects, allowing salamanders, frogs, and toads (as well as snakes, turtles, and other small animals) to safely and independently cross between their upland habitats and breeding pools each spring. To see how the Amphibian Crossing Project fits in with other statewide projects supporting wildlife habitat connectivity see Connecting Habitat Across New Jersey (CHANJ).
Want to help? Volunteers for the Amphibian Crossing Project must complete a training session. If you are interested in being a part of next year’s project, please contact allegra.mitchell@conservewildlifenj.org.
About the author: Annabel is a sophomore at Indian Hills High School in Oakland, New Jersey. When not helping amphibians cross the road she enjoys photography, the beach and badminton. Thank you for volunteering and sharing your experience Annabel!
Please note: the Amphibian Crossing Project activity described here occurred before restrictions for COVID-19 were in place. At this time CWF is only performing essential wildlife monitoring and conservation duties while practicing social distancing and following all state and CDC guidelines.
In early March, my dad Rick got an email from wildlife biologist Allegra Mitchell of the Conserve Wildlife Foundation of NJ (CWF) saying tonight was the night. My dad came home from work excited, got the flashlights and rain coats out, and called my Aunt June and cousin Sarah asking if they wanted to go with us. We had all signed up to be CWF amphibian crossing volunteers.
On a Tuesday morning, Conserve Wildlife Foundation of New Jersey biologist Allegra Mitchell and I, GIS Intern Taylor Forster, went to the New Jersey State Museum in Trenton. We were looking at a newly identified species recently found in one of the largest metropolitan areas – New York! I learned that this species was discovered because of its unique “call.” A “call” is the sound a male frog makes to attract a female frog, and each frog species’ call is unique. It seems that this species remained undiscovered for so long because of its similar appearance to other, closely-related leopard frog species. The cryptic nature of this new species meant that the only noticeable distinction between it and other leopard frogs was the sound it makes.
After looking at this newly discovered frog, now known as the mid-Atlantic coast leopard frog, a few defining characteristics came to light that set it apart from the other leopard frogs. These characteristics make it easier to identify other mid-Atlantic coast leopard frogs that have been preserved and categorized as other species for museum collections. With this information in mind, Ms. Mitchell and I were at the New Jersey State Museum to investigate when and where this frog had been found throughout the state before anyone realized its significance.Continue reading “The Atlantic Coast Leopard Frog – Uncovering the past”
Waterloo Village in Byram Township, Sussex County is more than a tourist attraction and local gem, it is also home to the largest cross-road amphibian migration in New Jersey. Each spring, frogs, toads, and salamanders stir from their hibernation to make their way to their breeding sites. Some of these sites, like the one at Waterloo, are vernal pools – small, temporary bodies of water that appear in early spring as snow melts and rain and groundwater gathers, and disappear throughout the summer as they evaporate. The ephemeral nature of these pools can’t support fish, which would prey on amphibian eggs and larvae. Vernal pools therefore provide some protection for amphibian offspring, with many species such as wood frogs and spotted and Jefferson salamanders – both of which are listed as New Jersey species of Special Concern – relying exclusively on these vernal pools for breeding.
The greatest challenge for amphibians breeding at Waterloo Historic Village is crossing Waterloo Road. Living in the most densely population state takes a toll on many species of wildlife in the form of habitat loss, degradation, and fragmentation. Each year, many amphibians become victim to vehicular collision as they move from their hibernation sites across Waterloo Road to the vernal pool in which they reproduce. Amphibians may be disproportionately affected by vehicle-caused road mortalities compared to other wildlife because of their tendency to migrate en masse to breeding sites. These annual road mortalities can have devastating effects on amphibian population sizes, especially for the local at-risk salamander populations. In fact, as little as about 10% annual risk of road mortality in spotted salamanders can lead to the local extinction of an entire population.
Wood Frog eggs. Photo courtesy of MacKenzie Hall.
To address this problem, the Conserve Wildlife Foundation of New Jersey (CWF) and the New Jersey Endangered and Nongame Species Program (ENSP) organized amphibian rescue efforts. Since 2002, dedicated volunteers have assisted frogs, toads, and salamanders across Waterloo Road during the busiest migration nights. This aid has proven effective in reducing amphibian road mortalities, but it is not a permanent solution to the problem. Efforts are underway to construct under-road tunnels to help guide amphibians safely across Waterloo Road. These tunnels will provide safe passage for these critters throughout the breeding season, including on their migration back into the woods where they will hibernate. Since this return migration is more sporadic and less weather-dependent than migration to the vernal pool, it is much harder to protect amphibians as they make their way back to the forest.
This year, CWF scientists have begun the initial phases of research to understand current amphibian population sizes and the impact of vehicle traffic on these animals at Waterloo. Scientists and volunteers have been out 7 days a week since amphibian migrations began in late February to tally daily roadkill on Waterloo Road. This study will be used to evaluate changes to frog, toad, and salamander populations as the under-road amphibian tunnels are installed. CWF scientists have also conducted egg mass counts in the vernal pool at Waterloo Village to estimate the current population sizes of the different amphibian species in the area. Having this knowledge will allow CWF to improve on future projects to minimize road-related human-wildlife conflicts.
Spotted Salamander egg mass. Photo courtesy of MacKenzie Hall.
Along with improving conditions for amphibians in this location, CWF’s work at Waterloo Village will serve as an example of New Jersey statewide initiatives to reconnect wildlife habitat as a part of the Connecting Habitat Across New Jersey (CHANJ) program. The goal of CHANJ is to make our state landscapes more permeable to wildlife movement so that all of New Jersey’s residents – human and wildlife – will have the space they need to thrive.
In an effort to bring people and wildlife together in a positive way at Waterloo Village, CWF scientists are leading educational walks for the public and local schools. Through hands-on interaction, local residents can learn about and appreciate the remarkable wildlife right in their own back yards and what they can do to support conservation efforts.
All New Jerseyans can help wildlife this season by planting native plants for their gardens, building bat boxes where bats can roost, and, of course, by keeping an eye out on the roads, especially on warm, rainy nights when amphibians might be migrating.
