Springtime pool party: Understanding vernal pools and why they are so important

Spotted salamander

The spotted salamander is one amphibian species that uses vernal pools each spring to breed. (Photo by: Brian Gratwicke, Panama Amphibian Rescue and Conservation Project)

A vernal pool is a temporary pool of water made up of rainfall or ice melt. Although dry or partially filled with water for most of the year, they fill up completely around springtime (the word “vernal” means occurring in the spring). They stay full for a couple of months until about the end of summer. What’s great about these natural pools is that they don’t have any fish living in them—making it a lot easier for young amphibians to grow and thrive!

These unique habitats, found all throughout New England, are very important for certain organisms to survive. Many have even learned to use these temporary wetlands to the point that they have evolved over time into what are called “obligate” vernal pool species, meaning that they need these pools for certain stages of their lives. Fairy shrimp use them to hatch eggs in early spring, and wood frogs go there to lay their eggs in early spring, too— just to name a few.

Vernal pools are especially important in Massachusetts because even species that are listed as rare in this state—like the marbled, blue-spotted, and Jefferson salamanders—rely heavily on these pools for breeding. These mole salamanders get their name because they are usually found burrowed underground, but in the springtime they go to water to start their courtship and breed. Males leave their spermatophores on the pond floor, and females pick them up and use them to fertilize their eggs. They can’t get all of this done in permanent ponds because fish would eat their eggs, so it is very important that these temporary habitats remain protected and abundant.

Lucky for mole salamanders and other amphibians, vernal pools are protected by law under the Massachusetts Wetlands Protection Act. If they meet the state’s definitions of “wetlands,” certified vernal pools cannot be altered or tampered with at all. And if a pool lies within a recognized wetland, it will receive the same protection as the wetland and will be protected as an important feature of wildlife habitat. It is important that vernal pools are acknowledged and certified—and the best part is that anyone can help!

If you live in Massachusetts and think you have spotted a vernal pool, contact the Massachusetts Natural Heritage and Endangered Species Program to see if it can be certified as a wildlife habitat. They have certification forms and information on rare species on their website. You can also contact them at 1 Rabbit Hill Road, Westboro, MA, 01581, or by calling 508-792-7270.

Angela Caputo-Papastamos, Zoo New England

Brrr…it’s cold outside! How do frogs and toads survive?

Wood frog (Lithobates sylvaticus)

Throughout the winter, wood frogs (tadpole shown here) stop breathing, their hearts stop beating, and ice crystals form within their hibernating bodies. (Photo by: Brian Gratwicke, Panama Amphibian Rescue and Conservation Project)

Last week, as I was taking in the beauty of the snow-covered New England landscape, I started thinking about amphibians. With more than a foot of fresh snow covering the ground, I began to wonder where all of the frogs and toads go in the winter. We received so much snow from this recent snowstorm that I had to shovel a small path so our Boston terrier could navigate the backyard. If he needed help getting through the snow, how was a small frog or toad going to navigate the cold, wintry earth?

Well, it turns out that frogs and toads, particularly in the Northeast and other colder climates, spend their winters quietly tucked away while they hibernate in the mud at the bottom of lakes, carefully concealed in logs and tucked under leaf litter. Some toads even bury themselves to hibernate. Others continue to swim all winter long. Green frog and bullfrog tadpoles hatch in the summer and then spend all winter living and swimming below the ice in the nearly freezing water.

But none of these species compare to the wood frog when it comes to cold weather adaptations. This hearty frog is one of the more cold-adapted species with a natural habitat range extending farther north than any other amphibian species. In fact, the wood frog is the only frog found north of the Arctic Circle. These frogs hibernate during the winter in terrestrial or forested wetlands in very shallow earth. What’s most amazing is that the wood frog is so adapted to cold temperatures that its tissue can actually freeze and thaw.

Throughout the winter, wood frogs stop breathing, their hearts stop beating, and ice crystals form within their hibernating bodies, according to the Minnesota Department of Natural Resources. A special antifreeze they produce keeps liquids from freezing inside their cells and killing them. When spring arrives and the temperature rises, the frogs “thaw” and they emerge from hibernation.

The strategic advantage to this adaptation for the wood frog is that they are the first frogs out in the early spring, while other frogs are still hibernating deeper below. They are the first ones heard singing (the noise sounds like a chorus of “quacks”) and they begin breeding once they emerge. By late April, thousands of tiny black wood frog tadpoles can be found in vernal pools. Tadpoles develop quickly in order to metamorphose to froglets before the vernal pool waters dry up by late summer.

So, the next time you see a snowy landscape, take a moment to think about frogs and toads and their amazing cold weather adaptations. It’s incredible to think that just beneath the smooth sheet of glistening ice covering a pond that small tadpoles could be swimming through the freezing waters, or that a small toad or frog could be snugly nestled within a hollowed log deep in a winter slumber.

– Brooke Wardrop, Zoo New England

Vote to help the rescue project win $25,000

Heska Corporation has selected a proposal from Dr. Eric Baitchman, Zoo New England Director of Veterinary Services, as a finalist for the $25,000 prize in the 2010 Inspiration in Action contest. If Baitchman wins, the money will go to the rescue project. (Photo credit: Zoo New England)

Helping to save amphibians from imminent extinction in Panama is just a click away. Heska Corporation selected a proposal from Dr. Eric Baitchman, Zoo New England Director of Veterinary Services, as a finalist for the $25,000 prize in the 2010 Inspiration in Action contest and online voting is underway.

If selected, the money will support the veterinary efforts of the Panama Amphibian Rescue and Conservation (PARC) Project. Voting is open to the public and the polls are open until 11:59 p.m. MST on Dec. 15, 2010. Visit www.heska.com/action to vote. Heska Corporation, a leading provider of veterinary diagnostic and specialty products, has a core focus on the companion animal market where it strives to provide high-value products and unparalleled customer support to veterinarians.

The mission of the PARC Project, of which Zoo New England is a partner, is to rescue amphibian species that are in extreme danger of extinction throughout Panama. This is a collaborative international project and the efforts and expertise are focused on establishing assurance colonies and developing methodologies to reduce the impact of the deadly amphibian chytrid fungus, Batrachochytrium dendrobatidis, so that one day captive amphibians may be reintroduced to the wild.

As the lead veterinarian for this project, Dr. Baitchman is tasked with developing effective treatment protocols against the chytrid fungus, developing a preventative health and nutrition program for the long-term care of these animals, and training on-site biologists, zookeeper staff, volunteers, and other veterinarians in the principles of amphibian medicine and treatment. Urgent funding is needed for expensive medications used in treatment of chytrid, diagnostic testing, outfitting a laboratory space for diagnostic and treatment work, and travel expenses for veterinarians to Panama.

“This project serves as an example to other amphibian conservation initiatives around the world, particularly in its integrated approach to combine veterinary and conservation sciences,” said Baitchman.  “The benefits gained from the veterinary experience and knowledge obtained in working with this project will affect not only wild amphibian species, but will also enhance the profession’s ability to care for captive amphibians in practice, research, and educational collections.”

Inspiration in Action

Voting is open to the public and the polls are open until 11:59 p.m. MST on Dec. 15, 2010.

In the case of the global amphibian crisis, amphibian chytrid disease threatens the entire amphibian class, and in fact some species are disappearing rapidly and have not been seen in the wild in some time. The rate at which species are being lost in this single vertebrate class has not been seen on this planet since the extinction of the dinosaurs 65 million years ago.

The PARC Project currently includes two captive assurance colony sites in Panama, at the El Valle Amphibian Conservation Center, in El Valle de Anton, Panama, and at the Summit Zoo, in the Panama Canal Zone near Panama City, Panama. Experts from ZNE, Africam Safari, Panama’s Autoridad Nacional del Ambiente, Cheyenne Mountain Zoo, Defenders of Wildlife, El Valle Amphibian Conservation Center, Houston Zoo, Smithsonian’s National Zoological Park, Smithsonian Tropical Research Institute and Summit Municipal Park have pooled their energy and resources to form the PARC Project to protect a number of species from complete loss.

Currently at the El Valle site, there are more than 900 animals from 12 different families, represented by 61 different species, including a national symbol of Panama, the Panamanian golden frog, Atelopus zeteki. At the Panama Canal Zone site, there are approximately 180 animals from two different families and eight different species.

Media only: Contact Brianne Barrett, 617-375-9700

Giving a Frog a Bath (and Other Treatments)

So, just how do you give a frog a bath? And, why would you need to? When the biologists in Panama bring the frogs in from the wild to either the El Valle Amphibian Conservation Center or to Summit Municipal Park, one of the first things the frogs experience is a bath. Push those thoughts of tiny loofahs and soap bars right out of your head! No need for that here—rather, what these amphibians need is itraconazole, an antifungal medication.

Dr. Eric Baitchman

Dr. Eric Baitchman of Zoo New England gives one of the rescue project's frogs a bath in antifungal medication to ensure it doesn't spread chytrid to the rest of the captive population. (Photo courtesy of Zoo New England)

All frogs brought in from the wild go through a 10-day treatment protocol even before all of the amphibian chytrid results come back. The risks of missing a positive case and introducing chytrid to the entire captive population are too great to wait for results before beginning treatment. For 10 minutes each day, the frogs are bathed in the antifungal medication. Animals that are actively showing signs of illness also receive intensive supportive care to help them survive the course of treatment. The amphibian chytrid attacks the skin cells of amphibians, which can be quickly lethal for an animal that relies on its skin for the majority of respiratory function, hydration and electrolyte balance. Veterinary care for afflicted animals includes continuous fluid therapy to maintain hydration and replace electrolytes, as well as antibiotic treatment to protect against other infections that may take hold after the loss of the skin’s protective barrier.

Ten days after the bath cycle, the frogs are again tested for chytrid. If they test negative, they are cleared to go into the collection at EVACC and Summit Municipal Park after their mandatory 30-day quarantine period ends.

Chytrid is not the only health concern for the captive population. Lungworms, which commonly affect wild and captive frogs, are also a big concern and one that the veterinarians and staff caring for the captive collection at EVACC and Summit are working hard to treat. While frogs can normally live with lungworms in the wild, extra care is taken with captive frogs because of the potential longevity of the parasite’s lifecycle. While lungworms do not have any relation to the chytrid fungus, they can still make the frogs quite ill, which is why it is important to treat them.

Lungworm larvae

Lungworms (larvae shown here) aren't related to the chytrid fungus, but they can still make the frogs sick. The frogs are treated and their tanks cleaned thoroughly. (Photo by Eric Baitchman, Zoo New England)

As one would expect, lungworms live in the frog’s lungs. Because the larvae are passed through the feces, it is important to regularly clean the frogs’ tanks so the animals do not get re-infected. All of the tanks are designed so they can be washed thoroughly and substrate in the tanks is routinely removed.

The parasite is also another physiological stress on the animal, which the veterinarians and staff strive to minimize as much as possible. While in quarantine, each frog is treated for lungworms through an oral medication that is administered once and then followed up two weeks later.

While frogs can typically test negative for lungworms, this does not mean they are not infected— it could just mean that they are not passing larvae. If treated and monitored, the veterinarians and staff are able to keep this parasite under control. It’s yet another challenge, but one that can be managed through diligent and attentive care.

 –Brooke Wardrop, Zoo New England