Each year at the end of Reptile and Amphibian Day, Bryan Stuart feels exhausted, but optimistic. The curator of herpetology at the North Carolina Museum of Natural Sciences puts substantial effort into planning the day, the second largest annual museum event behind Bug Fest, and closes it out thrilled at the number of people he meets who are fascinated by amphibians and reptiles.
In frogs alone, this year’s theme, there’s a lot to find fascinating.
“There’s such tremendous diversity to them,” he says. “There are frogs that spend most of their lives living underground ... there are frogs that glide, that essentially have controlled flight, and a huge amount of diversity in between.” From an evolutionary standpoint, they can adapt to a wide range of niches and habitats: the green pond frog – the kind that inspired Kermit, Stuart says – represents a tiny sliver of that variety. There are 7,000 or so recognized species, representing 90 percent of the world’s amphibians.
Yet frogs are especially sensitive to disease, pollution and habitat loss, often reacting to problems in the environment sooner than non-amphibians. We spoke with Stuart about frogs – and their cousins, salamanders – ahead of Saturday’s Reptile and Amphibian Day.
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Q: Could you talk about your Frogs of the World lecture?
A: Frogs just have a tremendous diversity of their adaptations, morphological variation, and modes of reproduction. If there’s some bizarre way of reproducing, there’s very likely to be a frog out there doing something close to it. One of my very favorite frogs is this really bizarre frog called the gastric brooding frog, this species that was discovered and described to science in the late 1970s in Queensland, Australia.
Scientists only got a few years to actually know the species. What was learned during that very short period was that the female frogs take their stomachs, their proper stomachs that are normally used for digestion, and they shut off their gastric secretions and turn that into a nursery for their tadpoles. Basically the young frogs developed in her stomach and when they become miniature froglets, she vomited them out.
And then that species was gone, and hasn’t been seen in the wild since. I think that summarizes the global plight of frogs: there are a lot of species out there, lots of species continue to be discovered to science, lots of species continue to go extinct right before our eyes, and each one of these little frogs has a remarkable story behind it.
Q: Are frogs threatened both by loss of habitat and susceptibility to pollution?
A: Definitely. There seem to be three major drivers of frog extinction. The primary loss would be habitat destruction, another would be pollutants in the environment. Frogs, like all amphibians, have water-permeable skin, and that means they are very sensitive to chemicals that are in their environment. In some ways, they sort of serve as a canary in a coal mine for us – when the amphibians are disappearing, it’s a warning that something is going on around us.
The third primary cause for global amphibian population declines and extinctions is thought to be disease. There are a number of diseases that are considered emerging infectious diseases. In any case, there is a virus called ranavirus. There is something called an amphibian chytrid fungus, and we now know of two species. It’s a fungus, it grows in the skin of amphibians, and it causes morbidity or can even lead to death. It seems to be spreading all around the world through commerce of amphibians, namely animals being moved around alive for the medical trade, for the pet trade, and probably through some other vectors we don’t really understand.
Q: Is that related to your talk on fungus and North Carolina salamanders?
A: In 2013, there was a second species of amphibian chytrid fungus that was discovered to science. It’s only been a couple of years we’ve even known about the existence of this thing, but it was first associated with a big die-off of salamanders in Europe. It seems like it may have co-evolved with Asian newts, and they developed a resistance to it. What’s unfortunate is that Asian newts are highly targeted as pets around the world and there is a very large commerce in large Asian newts – for example, what are called fire belly newts that you see in pet shops. That fungus has not yet been detected in the wild in the United States, but it has been detected in some captive animals, including here in North Carolina.
We are a global biodiversity hot spot for salamanders – we have 61 species, just tremendous diversity. Herpetologists come from all over the world to see salamanders in North Carolina, so it’s a real concern for people like myself that this pathogen could be introduced into wild populations in North Carolina. The museum has recently started a project ... to see if that pathogen is around and if anything needs to be done about it. The U.S. Fish and Wildlife Service just last month proposed a moratorium on moving live salamanders, they had a list of about 200 species, moving them into the United States and between states. That’s a pre-emptive effort to prevent the introduction and spread of this pathogen.
Q: What can people do?
A: Discouraging the purchasing of exotic amphibians as pets is definitely important, and going hand-in-hand with that is the problem of people releasing unwanted pets. The introduction and intentional moving of live amphibians seems to be a real problem. Amphibians, like so much of our biodiversity, suffer from general loss of habitat, severe habitat modification and so forth. Our number one priority, and not just for amphibians, is really protection of natural habitat.
Reptile and Amphibian Day
When: 9 a.m.-5 p.m. Saturday
Where: N.C. Museum of Natural History, 11 W. Jones St., Raleigh
Info: 919-707-9800 or naturalsciences.org