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.
