Ep 3: w/ Geoff Williams | Australian Platypus Conservancy | Talking platypus and reintroducing to urban South Australia

On this episode we’ll be talking everything about platypuses and the in-and-outs of reintroducing them to metropolitan Adelaide with world-renowned platypus expert Geoff Williams from the Australian Platypus Conservancy. 

Welcome to another episode of the Green Adelaide Podcast. We are metro SA’s first environmental industry podcast.

 We’re your insider scoop on all things cool, green, and wild in metropolitan South Australia.

This podcast is for those who want or have a career in SA’s environmental industry. 

 We feature the experts, including the leaders and ecologists to the planners and marketers to chat the people, projects, and news of SA that you, our enviro-listeners, must know about.

 I’m your host Melissa Martin and I’m the Communications Manager at Green Adelaide who loves red-tailed black cockatoos.

Learn about Adelaide's environment: greenadelaide.sa.gov.au

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Transcript

Geoff Williams:

I was working at the zoos for example, I had to become a general manager as well as a biologist. That brought in a lot of useful skills in terms of knowing how to manage budgets and how to get sponsors and how to work with the media and all those sorts of things. That's just as important in a way as actually, your environmental skills. So, I would say to people, "Never turn down an opportunity to take on something that's a bit out of the mainstream and certainly never dismiss an opportunity to move to different areas."

Melissa Martin:

Welcome to another episode of the Green Adelaide podcast. We are Metro SA's first environmental industry podcast. We're your insider scoop on all things cool, green, and wild in metropolitan South Australia. This podcast is for those who want or have a career in SA's environment industry. We feature the experts, including the leaders and ecologists, to the planners and marketers to chat the people, projects, and news of South Australia that you, our environ listeners, must know about.

I'm your host Melissa Martin, and I'm the communications manager at Green Adelaide who has a love of red-tailed black cockatoos. Before we jump in, remember to subscribe to our podcast for new episode alerts. This is our third episode, and for this episode, we'll be talking everything about platypuses, it's not platypie, it's platypuses, and the ins and outs of reintroducing them to metropolitan Adelaide. Green Adelaide recently announced a scoping study that validated the possibility of reintroducing platypus to the River Torrens because it's in pretty good health.

This episode, we'll be diving deep into the details of reintroducing platypus to an urban area with platypus expert Geoff Williams who works and actually established the Australian Platypus Conservancy. The conservancy works across Australia and is a nonprofit environmental organization set up in '94 to conserve the platypus and its freshwater habitats. Welcome, Geoff. Can you tell us about how you started your career in the environment sector?

Geoff Williams:

Look, I studied biology back in England and was basically an ecologist. Therefore, what's always interested me, I guess, more than anything else is field work. I've spent a lot of my time being an administrative biologist in one sense, but what I really enjoy is field work and getting out there and getting your hands on animals, as it were, in terms of them being able to use that hands-on research to really find out about what the conservation needs are and then channeling those findings into actual action. That's what has always fascinated me about the whole business of getting involved in environmental management.

Melissa Martin:

What I've found talking to different people in the environment sector and what's very obvious now is the degree of people needing to move for their job when you're working in the sector. As you're saying now, you've moved to different places around Australia and of course from the UK to Australia. I get the common sentiment that you've got to be open to moving for certain roles in the environment sector.

Geoff Williams:

Yeah, look, very much so. I know I would really say to people who are considering a career that in a way, the more you move, the better. One of the things that I think is really important if you're going to work in the environment is to get a range of skills, and I was fairly lucky in that I was exposed not just to biology, but when I was working at the zoos for example, I had to become a general manager as well as a biologist. That brought in a lot of useful skills in terms of knowing how to manage budgets and how to get sponsors and how to work with the media and all those sorts of things. That's just as important in a way actually, your environmental skills.

So, I would say to people, "Never turn down an opportunity to take on something that's a bit out of the mainstream and certainly never dismiss an opportunity to move to different areas." For example, even if you take platypus, there's quite a lot of significant differences between the habitats that they use in different parts of the country and even the way they react. Tasmanian platypus actually seem quite different in the way they behave to platypus on the mainland. So, consequently, your opportunities to expose yourself to those sorts of things is a good one, and I think people should always be happy to give that a try.

Melissa Martin:

Good advice. You went from Wollongong university, then Taronga Zoo, and then what was the name of the last one?

Geoff Williams:

Healesville.

Melissa Martin:

Healesville?

Geoff Williams:

Healesville Sanctuary.

Melissa Martin:

Yep. After your time at Healesville, then you were one of the creators or establishers of the Australian Platypus Conservancy from then?

Geoff Williams:

We built up a fairly good team at Healesville who was specializing in Platypus. It was good to be able to take most of that team into the Platypus Conservancy and to really branch out and start looking at a wider range of things. At Healesville, obviously a lot of the work we were doing was linked to the captive management, but once the conservancy was established, our focus was really looking at how platypus were doing in the wild, and particularly to see how platypus were doing where they were living on the edge.

What I mean by that is in many places, platypus were doing fine. If conditions were good, you have platypus in good numbers. But obviously, there were many places where habitat quality had declined and platypus numbers had gone down or had even disappeared completely. So, we wanted to find where that point was where platypus dropped out. The way we did that in the initial instance was to look at the Yarra River, it flows into Melbourne, because we knew in the top of the catchment, it's quite good habitat and numbers were good.

But when you get to the center of Melbourne, then obviously you don't tend to find platypus at Flinders Street. Consequently, we knew there was a point there where platypus were living on the edge. So, we did a lot of survey work to find that point and then having found that point, we could then concentrate on the habitat qualities that made it good or bad for platypus and so on. That was a real step forward. That was something that had never been done before, and it was the first thing to also establish that platypus are very good habitat indicators. In the other words, the better quality the conditions are, the more platypus and vice versa.

Therefore, although you will occasionally get platypus in fairly crummy conditions and you can't even get them in really, heavily urbanized environments, you won't get them in the same numbers per kilometer as you will in high quality habitats. That's the real key to understanding platypus populations. You've got to look at the overall catchment, make a decision about the overall quality of it, and therefore can it support platypus. This is going to be one of the key issues about, can we get a platypus population reestablished in the Torrens?

Melissa Martin:

What do you wish you would've known before you started your career?

Geoff Williams:

Well, I guess, a couple of things really. One of them is I would've liked to have known how good I was doing at nocturnal field work. If you take on platypus, you spend a lot of sleepless nights and I'm not naturally a night owl. So, having done 500 or so sleepless nights chasing platypus, perhaps you would've reconsidered that decision.

The other thing though is probably recognizing what you enjoy doing most in the field of environmental work. I'll be honest and say, while I think I'm a pretty good manager and things like that, what I actually do is I'm a very physical hands-on person. If you are that, then make certain that you get involved in environmental work that is going to give you a lot of field work or a lot of practical, hands-on skills.

On the other hand, if you are the sort of person who likes being analytical and likes working on computer modeling and things like that, fine. But try and find those out. I think I learned it the hard way in some respects in that I spent a lot of time behind an office desk when I would've been happier out in the field. That's what's been great about the Platypus Conservancy.

Melissa Martin:

Great. I'm not sure if you listen to our other podcasts, but one of the things we do to get to know our special guests differently is a bit of a rapid fire round. It's to take you out of, I guess, the topics that we're going to talk about and just fire at you random questions and you just say the first thing that comes to mind. I'm going to give you 10 questions and they're pretty much this or that or your favorite things as the answer. We'll kick it off. To start off, what has been your favorite age so far?

Geoff Williams:

I think the fifties. When I was in my fifties, I was doing a lot of field work and also having the most maximum impact of using my experience and knowledge to good effect and probably also was at my most confident in my ability to do a whole range of things. So, I think that having that maturity is good.

Melissa Martin:

What is your go-to lazy dinner?

Geoff Williams:

I'm hopeless. I'll be honest and say, I love fish and chips. I'm quite happy.

Melissa Martin:

[inaudible].

Geoff Williams:

Yep.

Melissa Martin:

What is your favorite thing to do in the summertime?

Geoff Williams:

Basically go for walks in the bush. Look, I enjoy just being in a natural environment and getting out and seeing the country.

Melissa Martin:

How often do you floss?

Geoff Williams:

Not as much as I should. My dentist is always telling me I should do it more.

Melissa Martin:

What's one of your nicknames?

Geoff Williams:

Well, I shouldn't tell people this, but-

Melissa Martin:

[inaudible].

Geoff Williams:

I always used to be called Il Capo or Il Mafioso at one stage. I don't know-

Melissa Martin:

Tell us the context.

Geoff Williams:

When I was in management issues and so, I guess, I was considered a fairly hard-assed person to work for in terms of getting things done. I demand fairly high standards to get results, and I think there was a few bodies buried in the backyard who complained about that I think.

Melissa Martin:

On that same thing, if you had to change your first name, what would you change it to?

Geoff Williams:

That's a good one. Ridiculously, I would actually choose William, but you can't really have William Williams because it's-

Melissa Martin:

[inaudible].

Geoff Williams:

I actually like Bill as a name and that's so consequently...

Melissa Martin:

Bill Williams.

Geoff Williams:

Well, it doesn't work as William.

Melissa Martin:

What's your favorite movie of all time?

Geoff Williams:

Of all time? It probably makes me sound ancient, but I actually think Gone With The Wind is the most classic movie of moviedom, if you know what I mean, because it would seem dated now but of its time, I think it was a superb example of how films should and were made in the old days.

Melissa Martin:

What dish do you cook best?

Geoff Williams:

The spaghetti bolognese is about the only thing I can cook.

Melissa Martin:

Do you have a hidden talent?

Geoff Williams:

I'm very good at digging holes in the ground. We live in the old mining district in Central Victoria and it's really rock hard and if you want to plant trees, you've got to be really good at digging holes.

Melissa Martin:

Can you describe your fashion style in one word?

Geoff Williams:

Op shop.

Melissa Martin:

Nice. That is our rapid fire round. Thank you.

For our next topic, we're going to dive into all about platypus and just all the fun facts that everyone must know about them. Our listeners might not know, but the platypus was once native in the River Torrens and there are records of platypus living there in the early 1800s. Now, they're a missing vital part of the ecosystem and platypuses have been considered extinct on mainland South Australia since the 1970s. There are platypus on KI though.

Today, platypuses are listed as threatened species in Australia and are endangered in South Australia. Geoff, can you help demystify the platypus for our listeners because many probably haven't seen them in the wild before? Probably not in South Australia either. We all know they have a bill like a duck, a tail like a beaver. They lay eggs. They have otter-like fur and they have webbed feet. But have researchers been able to narrow down to really understand where these species actually evolved from? What are their roots?

Geoff Williams:

Well, they're definitely one of the key examples of reptiles evolving into mammals. It's still even unclear about how long ago, but perhaps 140, 120 million years ago, some reptiles started developing mammalian traits and that happened over many different examples in different ways. It's believed the platypus and the echidnas can be traced back to one of the first versions of that because they are egg-laying. In other words, as reptiles were evolved, they've maintained this egg-laying thing.

Obviously, other attempts of reptiles to evolve into mammals resulted in marsupials and eutherians like us who have placentas and so on. So, they trace their ancestry back a long way. Now, we don't know too much about that journey because the fossil record is very patchy. So, we can't say exactly what the lineage is, but clearly, that egg-laying mammalian, unusual type of mammal suggests that it was one of the earliest goals at this process.

Melissa Martin:

Is there only one type of platypus? The echidnas, there's different subspecies of that. Like in South Australia, there's the KI one compared to the mainland one. Is there different subspecies? I guess, another difference that comes to mind is Tasmania, they're bigger there. The size of the platypuses is bigger. I guess, is there subspecies?

Geoff Williams:

At this point in time, no, there are no recognized subspecies of platypus. I mean, there has been a strong case made for Tasmanian ones to be a subspecies, based on the fact that Tasmanian ones are bigger and tend to have some sort of behavioral differences of perhaps being a lot more terrestrial, where they come out on land much more and seem much more diurnal, but I think that's just a behavioral issue and not an evolutionary issue.

The size thing in itself is not, again, diagnostic of a subspecies. Basically, the size varies as you go northwards. Platypus, they become smaller, so the Queensland ones are very small compared to Tasmania, but that's very similar to the situation with koalas. It's really just a reflection that it's mainly a reaction to climatic conditions. In other words, you need big animals to do better in cold conditions and vice versa.

At this stage, there's been quite a lot of genetic analysis now over the last 10, 20 years and there is nothing really that supports the idea of subspecies. There are some, I think, three distinctive groupings genetically, but they have not yet satisfied the criteria for being a separate species. So, no, at this stage they're all considered one. It's possible. There's still a lot more work to be done on this. I always think Queensland ones look very different to the rest of the country, but that hasn't yet been finalized.

Melissa Martin:

Because they're semi-aquatics, so they're in the water and they're on land, are they the same speed in both or are they fast swimmers, slow on land, or I guess, how fast are they?

Geoff Williams:

Well, it's always a bit difficult saying how fast is an animal because it depends what it's doing at the time. But basically, what's been found with the platypus is its probably optimum speed in the water is about one and a half kilometers an hour. But if they want to, they can go much faster than that. Over short distances, they can do the equivalent of an aquatic sprint. I remember one occasion when we were radio tracking a platypus that really decided it was going to go off and travel upstream to find a feeding place, we couldn't keep up with it. Over for an hour, it was motoring along at probably four or five kilometers an hour. So, they can go faster if necessary.

It's the similar thing on land. They don't come out and walk around on land very much, although the ones in Tassie tend to a bit more. If they want to move fast, they can scuttle quite quickly. They're a bit unusual in that, again, one of the things that traces back to their reptilian ancestors is that they have a shoulder structure that's the same as a lizard and therefore their arms stick out at right angles as opposed to most mammals. They have their legs underneath them. So, they're not very good at walking. They shuffle more than walk. But having said that, they can really put on a bit of speed if they have to. It's never been properly measured, but they're by no means slouchy when it comes to mobility.

Melissa Martin:

When they're on land, is there a reason that they are not hanging out in the water? Is it to find different food source or something else?

Geoff Williams:

On the mainland, it's mainly a case of you get platypus on land almost totally related to the time when juveniles disperse. There comes a point when young platypus get basically kicked out of house and home. It's like when we get sick and tired of our teenagers and say, "Right, off you go to uni or whatever." Something. I mean, the adults don't want competition from the young ones. They have to go off and find territories of their own. They travel quite long distances sometimes, and part of that is that they sometimes go on land trying to find either their way over to a different catchment or just because they get disorientated and whatever. So, that's the main reason you'll find platypus on land. They don't search for food on land because their bill doesn't work. So, consequently, it's nearly all to do with dispersal movement.

Now, the exception to that, in Tassie, they will come out on land much more and we think this probably reflects the fact that... This is basically suggested platypus on the mainland probably used to do this much more as well, but have been under pressure now for a long time from things like foxes. So, consequently, there has been selection for platypus that don't come out and walk around on land very much. On Tassie, they do come out on land for a whole suite of reasons that don't seem to exist with the mainland ones and they will wander quite a long distance away from the waters. They take shortcuts around bends and things like this. That's the main reason they're terrestrial.

Melissa Martin:

A two-part question, are platypus found in all the states and territories around Australia?

Geoff Williams:

No, platypus are only found on the eastern side basically. Their strongholds are really the states of Tasmania, Victoria, New South Wales, ACT, and Queensland. In South Australia, as we know, they're found on Kangaroo Island. The only other place they are sometimes found is there is a little bit of the [inaudible] that for some obscure reason, about three kilometers of it in South Australia. So, you will get platypus that are crossing the border down there. Of course, in the Murray, they used to occur in the Murray system quite far down.

Now, we are occasionally getting reports of them starting to be seen on the South Australian side of the Murray border. So, that's again where you sometimes get them. The only other place we know there might be platypus is obviously, there were platypus introduced in Warrawong Sanctuary in the Adelaide Hills back in the '80s and it's believed that some of those perhaps escaped from the sanctuary and have established themselves around Warrawong. Now, that's something which needs a lot more research to actually confirm that.

Melissa Martin:

The other part of that question was through your experience working across the country with platypus, what are the best places to see them? I guess, they're renowned to being hard to spot, especially during the day, and people wait around and they get like, "Oh, where are they? It's so hard to spot them." Where would you suggest is one of the best spots to see them?

Geoff Williams:

All right, well, let me deal first with the fact about, are platypus hard to spot? There is a bit of a myth about this. Look, I mean, there is firstly the myth that platypus are nocturnal, so you don't see them during the day, and that we now know is not true. I mean, all of the studies that have been done suggest that platypus can be out 24 hours a day. They are predominantly nocturnal, but certainly, there are times of the year when they'll be out much more during the day and you can potentially see them at any time. So, it's always worth having a look.

The second thing is there's this myth that platypus are shy and sensitive and you can't see them because they'll disappear the minute you look at them. Again, it's not true. If you're prepared to be patient and quiet and still, you have a very good chance of spotting them. Once you know what you're looking for, they're not hard at all. In terms of places where you can see platypus easily, well, Tasmania is undoubtedly the best place. Most of the rivers in Tasmania, apart from one or two exceptions, have got pretty good platypus populations. So, there are places in Tassie where you can go. I've been in places where in five minutes, you can see five or six platypus. I mean, it's not hard. Even in the Hobart Rivulet, which is a tiny river that flows in the center of Hobart, you can see platypus there quite easily. So, Tassie is definitely the place.

Melissa Martin:

Do we have an understanding of the population of platypus, like numbers-wise, in Australia overall, seeing as they are an endangered species?

Geoff Williams:

No, look, really, there's been various attempts to estimate the number of platypus and the best estimate University of New South Wales has come up was something between 30,000 and 300,000. That's a fairly wide spectrum. It's very hard to say. It's not even really a relevant question. The question with platypus is always, how is a population doing within a particular catchment or river system? Because basically, while platypus can cross land, they do it with great difficulty. So, consequently, each platypus population is really got to be looked at in the context of its local catchment. You therefore need to look at the number of platypus that will be supported by the quality of habitat in that catchment.

By that, I mean there will be great variation. If you've got good quality habitat, you might have as many as five, six platypus per kilometer. When you go downstream and start to get into poor quality habitat and you get to very highly disturbed habitats, you may only have one or two platypus per kilometer and then zero. So, you've got to weigh that up and make an assessment. That's why when we look at the Torrens River, that's going to be one of the key issues is you need to do that sum of saying, "What's the total number of kilometers in the Torrens that can support platypus, and how many per kilometer based on the habitat quality can we ideally get in there? Does that then add up to a number that is going to be a viable population in the long run?"

Melissa Martin:

Can platypus glow in the dark?

Geoff Williams:

Look, this is a bit of a beat up in a away. They did a study in an American museum, where they looked at a couple of things to start with like possums... Sorry, opossums, American possums, that they found glowed in the dark when you [inaudible] I think. They had a platypus in their collection and they did it with platypus and found that glowed in the dark as well. But the reality is almost everything glows in the dark if you shine the right lights on it, and that includes people. If you ever go to certain type of nightclubs or discos, you'll notice that a lot of people, their teeth start to gleam.

Melissa Martin:

All right, now, we will dive a bit more into platypus in an urban area and more talking about Adelaide's urban area. So, the River Torrens. Geoff, with your work with Green Adelaide and our plan ahead around platypus, what are your thoughts on them living a good life in an urban setting compared to a conservation area or a national park?

Geoff Williams:

Look, I guess, it comes down to the fact that as long as their basic requirements are being met in terms of particularly their food. There are plenty of examples of platypus living in urban environments. In Melbourne, for example, they occur within 10 kilometers of the city center. So, they're well within the main, suburban area of metropolitan Melbourne. That is true of many other fairly big-ish regional towns throughout Australia. There is nothing fundamentally about living in an urban area that platypus can't adapt to. They are a quite adaptable species. They're not shy and sensitive. They're actually quite tough little animals really.

As long as there is enough food there and as long as there is enough of the other things they need, they would be fine. I mean, basically, an urban platypus is probably just at home in an urban area as a rural platypus is at home in a natural environment. They are not by themselves. They become adaptive. They are a flexible species. They're quite smart little animals and there is nothing fundamentally about an urban environment that really scares them. They adapt to the lights, they adapt to the noise. We've had platypus living right next to noisy highways and things like that. Fine, that's them. It's like say, humans. There are humans who live well in cities and there are humans who live well in the country and it's exactly the same thing.

Melissa Martin:

It's actually a really good point. Obviously, people do think that platypus like to hide and be hidden and be really shy. So, that's a good point that they can adapt and they're not shy as a creature that we keep assuming they are.

Geoff Williams:

Yeah, look, this is a real myth. Platypus are quite inquisitive animals. When I first started studying platypus, a lot of, for example, anglers used to tell me, "Oh, I was standing in a river and a platypus come over and swam up to me and swam around my legs and checked me out." I used to think, "Oh, another fisherman's tale." But it's true. I've seen it happen. I've been out, for example, sometimes, you're standing in the creek and the next thing you know, you've got a platypus right next to you. So, no, they are not shy and sensitive.

Melissa Martin:

We know in South Australia, platypus do exist on KI and there's lots of feral cats there. In the southeast of the country as well, there's foxes there and there's platypus too. How have you seen platypus manage predators like cats and foxes? You mentioned that maybe they don't spend as much time on land if they know lots of foxes are around. Have you seen them manage it and do you think it's a big concern in metropolitan Adelaide?

Geoff Williams:

Look, I think the problem is foxes, more than anything else. Cats and domestic dogs to a certain extent will occasionally take platypus, but I don't think it happens enough to be of any significance. But foxes certainly can take a proportion of the population and make dents in it, and it's particularly true they take juvenile platypus. Juvenile platypus, when they first come out, are very naive animals. They are not particularly good at swimming. They're not particularly good at knowing when to avoid danger. They paddle around in the shallows and that's exactly where foxes can get down and take them.

We know numerous examples where foxes have wiped out a lot of juveniles in a particular season. So, it is an issue and even in urban areas, foxes can tend to be a big problem. Foxes are much more found in urban areas than they're in rural areas in some instances. So, consequently, it is something that can be a problem. There's less evidence they have an impact on adult platypus. If you can get your adult populations established, you can overcome that threat. But it is nevertheless a significant one and you can't close your eyes to that fact.

Melissa Martin:

Because, I guess, foxes are all around metropolitan areas across Australia, how have you seen other states manage that?

Geoff Williams:

You can't. There are all sorts of theories about how you can control fox populations and so on, and being honest, none of them have been successful so far and we're a long way from eradicating foxes. So, I think the reality is that we need to try to make our environments difficult for foxes. In other words, I think what we should be trying to work towards is ensuring our native species have got enough refuge habitat, where they can hide from foxes, so that it becomes less of an issue. If we look at platypus for example, one of the obvious things that we recommend to management agencies is where you've got shallow areas, you make certain you have dense vegetation buffers. Plant along the banks at that point. In other words, you just make it more difficult for foxes to get down to the water level because I don't think they have the capacity to easily catch platypus in deep water. But in shallow water, that's where they can easily pick off.

Melissa Martin:

Now, we're going to go over to water rats, rakali. There is lots of rakali in the Torrens and other rivers across metropolitan Adelaide, and as you know, they always get confused with platypus. People think they've seen a platypus, but really, it's just a native water otter or water rat, whatever you want to call them. They're really super cute creature and, I guess, we don't want to jeopardize their population if we were to reintroduce platypus to the River Torrens. With their strong population today, and I guess this happens in other states as well when they've reintroduced platypus to an area, how have you seen that balancing act happen between rakali and platypus living together? Have you seen any significant changes [inaudible]?

Geoff Williams:

Well, the two species have occurred in many places together. They're not incompatible. Having said that, there is a degree of competition between them. They both will feed on aquatic invertebrates, but the difference is that the platypus feeds almost exclusively on aquatic bugs, whereas the rakali has got the capacity to eat a lot of other things as well. Small fish for example, platypus can manage small fish, but they're not good at it. They don't have teeth. So, they really have to gum fish to death. But rakali are very good at catching fish and catch quite big fish. They will also eat a wide range of other things as well. The other big difference between them is that rakali can come out on land and forage quite successfully.

In very simple terms, rakali have done very well in urban environments because they've got this extra capacity to go scavenging and picking up scraps of food all over the place. That's why in the old days in Adelaide, they were particularly found, for example, roundabout the abattoir areas because there was lots of food scraps getting in the water and on the land they could take advantage of. The picture therefore that we have from the studies we've done, if you've got fairly pristine habitats, platypus will tend to predominate. If you've got a fairly mixed habitat quality, then the two species tend to occur at ore or less equal numbers. When you get down into the more urbanized environment, then the rakali tends to dominate because it's got much more capacity to take advantage of other food sources.

That's the general picture. If we take the Torrens, look, one of the factors that's got to be faced up to is, will the presence of a strong rakali population make it difficult for platypus to get established? That is one of the key issues because the two species, there's not a lot of aggression between them, but rakali will definitely defend their resources perhaps a lot more effectively than the platypus will. Rakali are armed with fairly big teeth, whereas the platypus isn't. Therefore, it's believed in most encounters, the rakali will chase the platypus out of its territory. When we're doing platypus surveys where the two species occur together, for example, when we examine the tail of the platypus, you'll often find lots of little nicks out of the back of the tail.

We interpret this as basically what's happening is the rakali is giving them little bites. It's biting their tail, saying, "Get out. We don't like you because you're eating our food. Go away." They put this constant pressure on them to move on. So, we think this is what happens. Interestingly though, the platypus can stand up for itself. In the only very well-documented instance of violence between the two species, what happened was a fight took place over eight minutes and to cut a very long story short, at the end of eight minutes, it was the platypus that swam off with a dead rakali in its back feet.

Melissa Martin:

[inaudible].

Geoff Williams:

Basically, what had happened is the platypus had grabbed the water rat by its back feet, held it underwater for long enough to drown it. So, the platypus is not quite as defenseless as we would think. But having said all that, I think you can't get around the fact that when you've got a very high density rakali population in the urban areas, it may be very difficult for platypus to insert themselves naturally in that. In the reintroductions that have been done to date, that hasn't really been an issue. In the bigger reintroduction project we did in Cardinia Creek near Melbourne, rakali were not a big issue there at all. It didn't arise, but the Torrens will be a much different story.

Melissa Martin:

I guess, just to finish off with a last question, and it is maybe building on what you've already said, is... Because platypus, we know they eat 50% of their body weight daily in water bugs and the rakali and the platypus would be, I guess, not fighting but trying to get enough food for each other and we talked about how they had their own strengths if they were to fight each other, they had their own strengths to protect their resources and protect their population, what do you think would be the key tactics from your experience to manage that introduction of platypus to an already existing rakali populated area?

Geoff Williams:

Two things are going to be important. In addition to doing more study of the habitat quality of the Torrens, there is I think going to have to be more work put into the actual distribution of the rakali population. Now, what we know about rakali population is what I said earlier, they tend to be higher in numbers in disturbed habitats and somewhat lesser in good quality habitats. So, we will predict for the Torrens that the upper catchment is where there will be less rakali and the upper catchment also tends to be where the best quality is anyway.

I think the pattern of the reintroduction, based upon what we've done with other platypus reintroductions, is that you would start in the upper catchment and try to build up the platypus numbers there and then allow natural dispersal to take place. In other words, once there are enough juveniles being produced by the platypus in the upper catchment, the juveniles will naturally have to disperse into lower catchment. At that point in time, it will be an issue of, can they cope with going down into an area where they may be hassled a bit by the rakali? That is something which, I guess, is just one of the hard facts of life.

That occurs in a lot of places now and either the platypus are going to make it there or they're not. If they don't make it there, one would have to hope that there is enough good quality habitat in the upper Torrens for the population to be supported. So, I think at the risk of sounding a bit negative, the reintroduction of the platypus to the Torrens has got a lot of good prospects. I don't know you will ever get to the point where you'll be able to walk from the festival center or whatever it's called in the middle of Adelaide and go and see a platypus there. There is always going to be just the same as there is in Melbourne. There are plenty of platypus in the upper catchment, but you won't necessarily see them at Flinders Street Station. You'll have to put up with seeing rakali instead, which is not a bad alternative.

Melissa Martin:

Just to finish off, from your career in the environment sector around Australia, what are your clear takeaways that you would give people up and coming in their career into the sector?

Geoff Williams:

Look, never knock back any opportunity to get experience in any aspect of environmental management. A lot of universities these days don't necessarily provide enough hands-on experience of handling animals. So, I would strongly suggest to people that they try to find opportunities to volunteer with wildlife in its widest range of things, because I think the ability to work with animals in the wild is perhaps being lost and I still think in the long run that is something which we've got to encourage people to do. So, get out there and try and find where researchers are working in your area and see what you can do to join them in volunteer things.

The second thing is don't lose sight of the fact that getting involved with community groups is also really important, because definitely, the trend for the future will be that more and more environmental work will be done more and more by citizens, scientists, and by environmental community groups. Therefore, I think there is a bit of a tendency for these to be filled by older members of the population. There's nothing wrong with that, but I think more young people should be getting involved if they are looking for a career in the environment. They need to get involved, firstly because it's good hands-on experience, but it's also good experience of how to work with community groups, which will be a key aspect of any work you do in the environment these days. So, I think the key message I would say to people is don't be put off by joining groups that might be outside your normal age group. [inaudible] those as well, even if it's old buggers like me.

Melissa Martin:

Cool, great. That brings us to an end. Thank you so much, Geoff, for your time today. I feel like I've learned a lot about platypus and I hope our listeners have too. Thanks for your time.

Geoff Williams:

Pleasure, and we look forward to seeing how the Torrens project progresses, and we certainly hope there'll be a day when we'll have platypus in South Australia in good numbers again.

Melissa Martin:

That brings us to an end of episode three of the Green Adelaide podcast. Thank you to our special guest, Geoff Williams, or maybe Bill Williams, if he got his wish. He's from the Australian Platypus Conservancy, an organization that he established back in '94 to help protect and look after Australia's platypus population. I feel like I've learned a lot about platypuses and his journey to become one of the leading experts in the country.

This podcast is your insider scoop on all things cool, green, and wild in metropolitan South Australia. I'm your host, Melissa Martin. Remember, subscribe to our podcast for new episode alerts and I'll catch you for our next episode in late September. Bye.