An in-depth look at the amphibian crisis with Dr. Jennifer Pramuk, curator of herpetology at the Bronx Zoo. Second in a 2-Part Series.
Frogs around the world are in crisis, which has prompted a worldwide conservation initiative called The Amphibian Ark. The Bronx Zoo has taken responsibility for the nearly extinct Kihansi spray toad, protecting and breeding the species until it is safe to release them again into the wild. Below, an interview with Dr. Jennifer Pramuk, the curator of herpetology at the Bronx Zoo.
E Magazine: What work do you do with the Kihansi spray toads?
Dr. Pramuk: I liaison with our vets and keeper staff to ensure the best care for our toads (as well as the many other animals in our collection). We have a great staff of people who take care of them every day including feedings, censuses of the animals, etc. I attended a workshop in Tanzania a year ago with two WCS staff as well as folks from the Toledo Zoo. The workshop was intended to determine the timeline for return of the spray toads to their native Tanzania. We would like to see this happen as soon as is reasonably possible.
E Magazine: How did the Bronx Zoo get involved with the Amphibian Ark Project?
Dr. Pramuk: The Bronx Zoo, like all zoos, can be involved with the Amphibian Ark simply by becoming an amphibian champion and taking on at least one species to save from extinction. There is plenty of work to do and many species (at least 500) that need our help.
E Magazine: What are the efforts currently underway at the Bronx Zoo in conjunction with the Year of the Frog?
Dr. Pramuk: We have had special events for both Leap Day, which was an international effort to raise awareness for amphibian decline, and our Living in Green (Saint Patrick's Day weekend) that highlights green animals and focused again on amphibians. Events included keeper chats, crafts, coloring pages and other goodies. We also are opening a temporary amphibian exhibit in our historical Zoo Center building this week. In the long term, we are in the feasibility stage of planning an amphibian propagation center on the Bronx Zoo grounds to aid in our conservation projects. Right now, we have capacity for one species, the Kihansi spray toad, but hope to increase our capacity to hold at least six more species to save from extinction until a time comes when they can be reintroduced into the wild.
E Magazine: How many Kihansi Spray Toads are currently at the facility?
Dr. Pramuk: We have approximately 280, although the number fluctuates constantly. Sometimes we get a baby boom (these toads give live birth [meaning, directly giving birth to toads, not tadpoles] unlike most other frogs) and other weeks, we lose a number to old age or sickness. It is like managing a tiny city of toads that encounters the same problems that people do. Toledo Zoo also has around the same number of toads.
E Magazine: How has the population changed since they were brought in?
Dr. Pramuk: Originally, when the Bronx Zoo received the toads 8 years ago, there were 499 that came into captivity, but this number dropped significantly early on in the project because this species was never kept in captivity before. The husbandry needed fine-tuning. Essentially, it is like a detective story. If something is not right when keeping a new species in captivity, you have to do a lot of work to figure out which variable is the one needing change. In this case, the proper lighting and water source needed to be worked out. They are very sensitive to phosphate levels in NYC water, so we needed to find the right filter for the job. These toads also are diurnal (active during the day) so we needed to find the right kind of lighting (little halogen bulbs that put out a lot of the right wavelength of light). Food also is an issue: when you are an inch long, you can't eat a cricket, so we had to produce our own food including fruit flies and springtails (teeny tiny mite-like insects) that the toads relish. [Melissa Mohring, a Bronx Zoo Wild Animal Keeper in the Herpetology Department, says that these toads are "smaller than anything we've ever had to feed before."]
E Magazine: Did the caretakers have to treat the chytrid fungus?
Dr. Pramuk: Chytrid fungus did not come in with the toads as far as we know. However, about a year ago, we had an outbreak of the disease in one tank. We treated the animals, but all of them in that one tank perished despite our best efforts to treat them. This is disconcerting at best and does keep me awake some nights. Thankfully, through good hygiene efforts, including wearing lab coats, and sterile gloves that are changed between toad enclosures, the other toads did not come down with the disease.
Amphibian chytrid fungus is an emergent disease that is wiping out amphibians in many areas of the world including Australia, Africa, parts of Asia, and the Americas. It has been called the worst vertebrate disease ever recorded in terms of its virulence and ability to wipe out entire populations in a very short period of time. This is heady stuff, indeed, but gives you an idea of what we are dealing with in our captive breeding efforts.
E Magazine: How have you determined how best to manage these animals?
Dr. Pramuk: Through lots of trial and error. A new species in need of conservation doesn't come with a care manual—you have to write it yourself after many years and long hours of fine tuning and applying what you know from other closely related "surrogate" species.
E Magazine: What have been some of the difficulties you (and the zoo) have faced in breeding and sustaining these toads?
Dr. Pramuk: Some of the difficulties involve dealing with a 110-year old building that was never designed for housing sensitive amphibians. We are addressing this problem with our planned facility that will be built in the next year.
E Magazine: How is their original habitat recreated?
Dr. Pramuk: We use tall, glass terraria and have mist systems installed in the tanks. The misters deliver a fine mist of purified water that mimics their native habitat, which was adjacent to a powerful waterfall. We have plants and mosses in the tanks as well that help to reconstruct their native habitat.
E Magazine: How long do you think the toads should remain in a captive-breeding program?
Dr. Pramuk: No one knows the answer to this question. Before they are released to their native gorge, we have to work with pathologists and veterinary staffs to "clean" the toads of potential pathogens prior to considering a release of a subset animal. We also are working on capacity building within Tanzania. Scientists there are being trained on husbandry of the toads. The plan is for them to build (with our help) a captive propagation facility in Tanzania where the toads will be bred there prior to release. You have to have dedicated teams of local people working on a project like this one for it to be successful in the long run.
E Magazine: What significant roles can amphibians play?
Dr. Pramuk: Kihansi spray toads and many other amphibians do provide cures for disease. Some of these include poison dart frogs, from which painkillers 200X stronger than morphine and heart rhythm regulating medications have been developed. The Chinese have used toad toxins for centuries as cures for ailments such as impotence. Other roles they play are as e
ffective biological control (they consume millions of tons of insects, such as disease carrying mosquitoes, every year); food for other animals such as humans; cultural significance (they are considered symbols of fertility and new life to many cultures of the world). They also have been used as model laboratory organisms for the past two centuries. Without them, we would not know nearly as much as we do about the physiology of our own species.
E Magazine: How have threats to amphibians changed since you began studying herpetology?
Dr. Pramuk: Threats have only increased, unfortunately. When I was in high school in the mid to late 1980s, scientists were already reporting tremendous losses of amphibians in Central America and Australia. The golden toad in Costa Rica was one of the first documented and visible casualties of the amphibian chytrid fungus. Since then, we have lost more than 120 species of amphibians and are losing more with every passing year. We think that without significant action, we could lose up to one half of the 6,000 known species. In the 1980s, amphibian chytrid fungus hadn't been described yet, but it was already having a negative effect on populations in these areas of the world. Now we know the cause of these declines, but are not much closer to solving the problem in wild populations. We can cure it in captivity, however, and this is one of the primary reasons we are turning to captive breeding as an immediate measure to ameliorate the problem.
E Magazine: How can the average person try to solve or combat these problems?
Dr. Pramuk: The average person should do whatever they can to help amphibians, because these measures will also help save our own species. Amphibians have been called the canaries in the coalmine, essentially ecological indicator species that tell us humans what is going on out there. The news is not good, but it is not too late to slow or even stop our effects on frogs, salamanders, and the rest of the environment. There are many small things we all can do to help save amphibians from extinction. These things include using less fossil fuels, recycling, using fewer (or no) toxic chemicals in your home, not purchasing wild caught animals, etc. We've all heard these things before, but we need to act, and we must act NOW!
E Magazine: Is there anything else you would like to say to readers?
Dr. Pramuk: Come visit your local zoo, aquarium, or botanical garden to see what they are doing for amphibian kind. Volunteer to clean up a local wetland. Get involved in your local bio survey such as Bioblitz, a 24-hour survey of local wildlife, and take your kids with you. Through these activities you can learn more about the amphibian crisis and what you can do in your own backyard to help.
MARA SCHECHTER is an editorial intern at E.