Jodi Rowley and AM CEO and Executive Director Kim McKay continue their conversation about discovering new species, the audio DNA of frog calls and their place in global biodiversity.

"We are in the midst of a globally amphibian decline, a huge extinction crisis. They are a huge part of the ecosystem, so when we lose them, we actually lose a huge part of the ecosystem function and it doesn't seem to recover ... Other animals don't seem to step up into the same kind of rolls that amphibians had. So our ecosystems are irreversibly changed it seems."

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Kim McKay: Hello, welcome to AMplifiy, the Australian Museum's regular podcast. I'm Kim McKay, the director and CEO of the Australian Museum. And in this podcast series we look at what the Australian Museum Research Institute scientists are up to, as well as other members of our team, and take you behind the scenes.

Today I welcome again Dr Jodi Rowley, who is a herpetologist with the Australian Museum. Welcome Jodi.

Jodi Rowley: Thank you.

Kim McKay: Now Jodi, we know you are the frog expert, aren't you, at the Australian Museum, and in fact really up and down the east coast of Australia I think.

Jodi Rowley: I'm getting there.

Kim McKay: You're getting there. Now, you studied frogs originally, you did your PhD up in Queensland.

Jodi Rowley: I did. So when I finished my honours here at the University of New South Wales I went to see where in Australia I could do a PhD in frogs, and where else but the wet tropics, so I moved up there and it also gave me good training for later on. And I radio-tracked frogs, so stick tiny little radio transmitters with a little waist belt around frog waists and radio-track them in the forest for about two weeks at a time, finding them once a day and once a night, and that was some great experience at being in a forest for a long time, going through vines and boulders and putting my hand on a wasps nest and all sorts of things, and getting to know a bunch of frogs really well by stalking them for 16 days at a time.

Kim McKay: So you've got to be a bit rugged to want to track frogs.

Jodi Rowley: I don't appear that way when I'm in cities, so when it rains at lunchtime I don't go outside because…unless I'm looking for frogs, I don't see a point in getting wet. So I can be a bit city, but when I'm in the field I'm in the field and I will eat the lolly when it falls on the floor of the car and eat the baked beans out of the can, just cold. And look for frogs.

Kim McKay: And look for frogs. And of course frog diversity is under threat, isn't it.

Jodi Rowley: It is. So we are in…I guess I wouldn't say middle but we are definitely in the midst of a global amphibian decline, a huge extinction crisis, and amphibians all around the world are experiencing declines, particularly in eastern Australia where already three species of frogs are extinct already. And we have some that are on the brink, so we want to definitely stop that.

Kim McKay: So why does it matter, why do frogs that matter in our ecosystem?

Jodi Rowley: They are actually a really disproportionate effect on ecosystem functioning. Amphibians, although you don't often necessarily see them around, in many ecosystems they can be more abundant, more biomass than mammals or birds. Even in places like deserts, and you'll realise this when it rains, the biomass, so if you put all the amphibians in a desert in a pile and then birds and mammals in another pile, often amphibians will be the biggest pile. They are a huge part of the ecosystem. In North America they are driving nutrient cycling. So when we lose them, and we have experienced this in some places like Central America, we actually lose a huge part of the ecosystem function, and it doesn't seem to recover, so other animals don't seem to step up into the same kind of roles that amphibians had, so our ecosystems are irreversibly changed it seems.

Kim McKay: Well, I can't imagine going camping somewhere in Australia without hearing those beautiful frog calls at night, I mean, it's just part of, I think, being in Australia when you go out into the bush and listening to those frogs. And of course sometimes you can hear three or four or ten different calls at the one time. Who's calling?

Jodi Rowley: It's only the boys. So, often people think maybe it's the boys and girl frogs calling, but it's male frogs wanting to attract the female is to breed. So different frog species have different breeding seasons, different times when they will be calling. Some call in summer, some call in winter, some all year, some only one or two nights a year so you have to be super lucky…

Kim McKay: Or they have to be super lucky!

Jodi Rowley: Exactly. They call those ones explosive breeders.

Kim McKay: One or two nights a year, good luck to them.

Jodi Rowley: Well, they do well those nights, there are usually huge numbers of them. But it's really strange because you can go to a pond, you can see hundreds of one species of frog, you can go two nights later, nothing. So they've done their business and they've gone away. So they are the kind of frogs that are the hardest to find actually because you really do have to be Johnny-on-the-spot.

Kim McKay: I know frog species are under threat in Australia, as you've just described, but they are under threat right across the globe, and you have particularly focused a lot of your research here in Australian Museum on Southeast Asia, mostly in Vietnam. Can you tell us about your work there?

Jodi Rowley: So when I was finishing my PhD it was highlighted that amphibians were in so much trouble and that Southeast Asia was this black hole of knowledge. And so I decided there were enough biologists working in Australia and that I should move to Cambodia at the time and try and figure out what's going on there, try and get some information so that we can make informed conservation decisions. So the horrible reality is that we can't save all the forests that are there now, and there's not a lot there now, and we can't save all the species. So we need to get enough information that we can make informed decisions and prioritise our conservation.

Kim McKay: Is that because urbanisation is encroaching on those forests or are they being cut down or burned? What is the primary reason in Cambodia for example?

Jodi Rowley: Well, I guess largely it's just people, there's a lot of people living in those areas now and they all need to live. There's agriculture, there's logging, and there's just little slash and burns. So the average family that's living very simply but that needs to grow their crops and there's the forest, and also to get enough money for their family to eat they will cut down those trees, and so it's a really hard situation. And actually a lot of the forests that are actually in protected areas that are national parks or nature reserves, they actually experience the same amount of habitat loss as non-protected areas. So it's a real worry. Even if a frog is in a national park, it does not mean it is safe.

Of course the other threat over there is harvesting. Frogs and other amphibians are eaten for food, collected for traditional medicine, and they are also collected for the international pet trade, so illegally collected from the wild and exported overseas, and people will pay hundreds of dollars sometimes for a really beautiful tree frog or a salamander. But these things can be in really small areas and not that many of them, so it's quite a big threat.

Kim McKay: So you said eating frogs. We know that they often appear on French restaurant menus, and of course the French have had a big influence in Southeast Asia in terms of their cooking. Have you eaten many frogs Jodi?

Jodi Rowley: Well, I moved to Cambodia as a vegetarian, but working in the forest with the local people I think I broke down pretty quickly. So I have tried frog, I have indeed.

Kim McKay: And does it tastes like chicken?

Jodi Rowley: It does taste like chicken. Slightly fishy chicken but chicken nonetheless, and you can understand why people eat it because it's free. They can go into the rice paddies, they can go into the forest and they can collect free meat. And chicken is expensive. So it does make sense. And a certain amount of frog collecting can be sustainable but it's just when it gets too much that the frogs can't keep up.

Kim McKay: You've had I guess your most success in scientific terms in terms of identifying new species of frogs in Vietnam. I think you've discovered 16 new species, is that correct?

Jodi Rowley: Yes, that's the current tally, but there's another five coming right up.

Kim McKay: Wow, well you are a prolific frog discoverer. And one of those frogs is called Helen's flying frog. Could you tell us little bit about that? In fact you've brought in a few examples in jars of Helen's flying frog today, and I must say he does look pink and a bit crinkly but you said it is really bright green when you find them in the field.

Jodi Rowley: Yes, so in life they are one of the most beautiful frogs, they are about the size of the palm of your hand, so a very large frog, apple green, and with enormous hands and feet with big toe pads and webbing that goes all the way to the tips, and they are the best example that I know of of a flying frog. They are adapted for gliding out of trees, so using their hands and feet like parachutes and gliding out of trees into ponds below.

Kim McKay: How far can they glide for?

Jodi Rowley: They can probably glide for about 30 metres or so, and they actually have some manoeuvrability, so they have compared it to 30% of the ability of…I think it was some kind of hawk or something like that. So by moving their hands and feet they can decide exactly where they land. And this guy I first saw in 2009. It took me a couple of years to figure out that it was a new species, despite being enormous and green, because there is a frog that looks quite similar. But when I was convinced by looking at the other species of frog, looking at the DNA, we actually realised how much trouble this guy was in and it's now listed as endangered because it's so close to big cities, it's very close to Ho Chi Minh City, and it's surrounded by agriculture and only known for a few patches a forest.

Kim McKay: Why Helen's flying frog? That's an odd name for a Vietnamese frog, isn't it?

Jodi Rowley: It is indeed. Around the time that we discovered this frog, my mum was diagnosed with ovarian cancer, and I knew, as silly as it sounds, having a frog named after my mum would make her happy, and even if I sounded like a wuss to everyone else I decided, it didn't matter, the most important thing…so I asked my Vietnamese colleagues how they would feel if we called this frog Helen's flying frog, and in Latin the name is Rhacophorus helenae, and that sounds quite regal as well. And they thought it was perfectly fine, and so we did decide to call it Helen's flying frog after my mum. And she is obsessed with it. She has it on the back of her iPhone, she has a tote bag with Helen's flying frog on it, it's her desktop picture, her screensaver. So as much as people might say, 'A frog named after you? Frogs are all slimy.' No, my mum loves it.

Kim McKay: I think that's just wonderful and, you know, sometimes we think of scientists as being very clinical, so I think it's a nice juxtaposition that you are very engaged with this species but that you respected your mother and have honoured her in that particular way. I know you work with students a lot in the field, in Vietnam and Cambodia, that you've been doing a lot of capacity building there. And I know you get out there and literally climb up…in fact I know you've climbed up the Ho Chi Minh trail. Can you tell us about that expedition?

Jodi Rowley: The Ho Chi Minh trail in particular was in north-eastern Cambodia in a place called Virachey National Park, and this is an area that is under great threat from hydroelectric dams, illegal logging, and it was also a really tough place to get to. We had to walk for about four days carrying everything we had on our back the first time we went there, all the way into a kind of grassland where we could camp. And it's pretty tough conditions. I actually went back several years later, and we went by helicopter and that was a little bit easier.

Kim McKay: Isn't there a lot of unexploded ordnance on the trail?

Jodi Rowley: Yes, so the world 'trail' is probably…it must have been a road back in the day, but now you're on your hands and knees crawling, there's trees that are over the path, there's unexploded ordnances along the side, there's bomb craters everywhere. And one of the bad things…one of the…probably the least thing…is that bombing creates…bamboo is the first thing that comes back, so bamboo is thick and difficult to get through, it's really not a trail anymore, it was insane. And then sometimes you'd be in the middle of the forest and you'd find a bunch of bricks…and you like how on earth…I would throw my iPod away if I had it because we are carrying all our stuff on our back and it was tough. But I can't imagine what it was like back in the day.

Kim McKay: So it must be quite tough being out there in the field surrounded by this thick dense bushland, very humid conditions, very wet and muddy, and here you are looking for frogs.

Jodi Rowley: Yes, you get good at having antifungal powders and stuff because that's the one thing, people…I always laugh when they have these ads on television for rainforest scent, like deodorants or room spray. Uh-uh, that is not what rainforest smells like, rainforest smells like fungi and rotting wood, and I know the smell of fungus when it starts growing on my skin. So we definitely have to…because I work in the monsoon season, the frogs are out most when it's pouring with rain, and most other biologists even wouldn't be caught dead in the forest, me and my colleagues are out there looking for frogs in the pouring rain, sleeping in hammocks and going out at night with lights on our heads in the pouring rain looking for frogs. But it's fun.

Kim McKay: It sounds like enormous fun. I know, I've seen some photographs and film footage of you out there and I think you're a very tough woman. But you've bought another type of frog in to show us today, and it's a very little frog. What colour is this normally?

Jodi Rowley: Well, in preservative the frogs are a bit of a pale yellow, but in real life they are a transparent green. This frog is also known as the frogs that sings like a bird. And that's one of its amazing characters because instead of repeating the same call over and over again like most frogs, they sing like birds, they've got what's known as a hyperextended vocal repertoire. So it's a mixture of whistles and clicks, and no two calls are the same. So it's an amazing call to hear in the forest. But there's another couple of cool things. One is that the frog has green blood and turquoise bones, and you can actually see them through their skin in real life.

Kim McKay: You're kidding me, green blood?

Jodi Rowley: Green blood…

Kim McKay: And turquoise bones?

Jodi Rowley: Yes, they're pretty special. And the last is that they actually lay their eggs on the tips of leaves which then drop into the pools below, so they are a really awesome frog. They are about 2 centimetres, and this species was discovered by one of my colleagues, Vinh, in Vietnam, he was doing his PhD in Pu Hoat Forest and he took photos of them and sent them to me and I instantly knew this is a new species, and the following year we went back together and we found it and described it. So it's Quang's tree frog.

Kim McKay: Quang's tree frog…

Jodi Rowley: The frogs that sings like a bird.

Kim McKay: Isn't that great. I think what you're really describing is that you've been able to identify with this work that audio DNA exists.

Jodi Rowley: Yes, so often you can't tell frogs apart, so you need things like DNA and frog calls which can be described as audio DNA, so it's not until you look at all the evidence that you realise that actually something is a new species sometimes. Sometimes you find a frog and it's pink and yellow with spikes on it and it's really obvious that it's a new species because there's nothing like it, but more often you need to get the calls and the DNA involved.

Kim McKay: Well, Jodi Rowley, thank you for joining us today for AMplify, the Australian Museum's podcast, and taking us on this exceptional journey through Vietnam and Cambodia on your frog expeditions. We're all dying to come with you.

Jodi Rowley: For the fungus!

Kim McKay: For the fungus particularly. Thanks so much Jodi, and good luck with your work.

Jodi Rowley: Thank you.