Dr Tracy Dawes-Gromadzki, ecologist

Ecologist

Dr Tracy Dawes-Gromadzki completed an honours degree in ecology at the Flinders University of South Australia. In 1999 she received a PhD for her research into the role of predation and nutrients in the distribution and structuring of terrestrial arthropod communities.

In 1999 she was awarded a postdoctoral fellowship at the Tropical Ecosystem Research Centre of the CSIRO Division of Sustainable Ecosystems. Her work there focused on the biology and ecology of termites - they are a poorly understood but vital part of the Australian tropical savannas. Part of her work was developing an effective termite sampling method.

She was promoted to Research Scientist in 2001. Using descriptive studies and manipulative field experiments, she investigates how terrestrial invertebrate communities function. Areas of particular interest to her are the relationship between macroinvertebrate diversity and various ecosystem processes, and the impact of human-made disturbances on this relationship and the potential use of termites as a tool to aid in the restoration of degraded landscapes.

Teachers' notes to accompany this transcript.
You can order the DVD from the Academy for $15 (including GST and postage)


Interviewed by David Salt in 2002.

Contents


Early life and childhood memories

Tracy, would you tell us about your early life?

I was born in Adelaide, South Australia, in 1972. I'm from a family of four, with a younger sister, Robyn, who is a nurse in Adelaide. My parents are now retired, but Mum was a high school teacher and Dad was a bricklayer. Our family has had a variety of pets over the years, but mainly dogs – some of which were strays that Dad kept finding at various job sites – as well as cats, fish, birds and, unfortunately at one stage, rats (courtesy of Robyn!).

Mum and Dad worked really hard to take my sister and I away on many different family trips during school holidays. These included camping in the Flinders Ranges and along the Murray River, trips to Mount Buller where we saw snow for the first time, a trip across the Nullarbor to the Great Australian Bight where we climbed down caves, and trips to Singapore and Africa. Most of my Dad's family reside in Zimbabwe and South Africa and the most different and exciting family holiday was when Mum and Dad took my sister and I over there to meet our cousins, aunties, uncles and grandparents for the first time. I was 12 and it was my first overseas trip. Even today I remember that trip so vividly – meeting the family but also seeing elephants, zebras, lions and hippos in the wild for the first time!

What are your memories of your school years?

Generally I enjoyed school, both intellectually and socially. I was, and still am to a certain extent, a perfectionist, and always wanted to succeed and do things to the best of my ability. Mum and Dad were always extremely supportive of me in anything that I did. Looking back I think they must have also been abnormally patient, as my perfectionist nature with respect to my schoolwork and sporting interests must have driven them crazy! In my final year at school I was school captain and captain of athletics and was awarded the Year 12 geography prize.

Back to top

First and foremost an ecologist

Tracy, you are a soil ecologist and you are often referred to as an expert on termites. How would you describe yourself?

First and foremost I would describe myself as an ecologist – I am interested in looking at the interactions between plants, animals and the environment, and how these systems work. But yes, my job description is a soil ecologist, and I have worked on termites and a variety of other invertebrates.

Termites are often known as white ants, but they’re not really ants at all, are they?

No. They are white and they do look very similar to an ant, and the big termite mounds that scatter the Northern Territory landscape tend to be called anthills. But although ants often nest in termite mounds, the actual termites are not related to ants at all. Their closest relative is the cockroach!

Termite contributions to tropical savannas

You are based in Darwin with CSIRO. How important are termites in the Northern Territory?

Termites are a really critical component of the ecosystem, particularly in tropical regions and definitely in the tropical savannas which cover about a quarter of the Australian continent. Tropical savannas are big landscapes where you’ve got trees with an understorey of grass, and in Australia they stretch from Townsville right across to Darwin and through to Broome in the Kimberleys.

In these systems, termites are very important in keeping the environment healthy. They play a crucial role in decomposing and cycling nutrients through the system, and they also burrow and tunnel and feed through the soil, helping to aerate it and so revitalise or recondition it. The termites are also a critical food source for a lot of our Top End fauna. Our environment would be very different if the termites weren’t there doing their thing.

How do termites fit into the food chain?

Towards the bottom of it. Termites are major decomposer insects – the major decomposer insects in the tropics. There are thousands of them in one square metre of soil. At the base of the food chain you have got all the plants, and by feeding on dead plant material the termites help recycle nutrients through the system. A lot of energy and nutrients are locked up in that plant material, waiting to be released, and when the termites feed on the plant material they themselves become little nutrient/food packages for the rest of the organisms in the environment: other insects, spiders and smaller lizards. As they feed on the termites, they attract larger and larger animals into the system.

Unlike most insects in the tropics, termites are available all year round. A lot of insects in the Northern Territory, for example, flourish at the end of the wet season and then die off, but the termites continue to be active throughout the dry season. So they are crucial as a reliable food source for other animals.

I have heard that the total biomass of termites in northern Australia is more than all the other grazers – cows, kangaroos and so on – put together.

That’s right. That’s where our savannas differ from African ones. In the tropical savannas of Africa, the main herbivores are the major grass feeders – the elephants, the giraffes, all those big animals that we imagine grazing the plains of Africa – whereas in the tropical savannas, termites are the major grass feeders. Their biomass can exceed that of the residing mammals and domestic livestock.

Back to top

Southern termites are important too

In southern Australia, termites are thought of mainly as a pest species. Do they play an important ecosystem role in the south?

The termites that you come across in southern Australia are often eating their way through someone’s home, so it is not surprising that they are regarded as pests. But termites do play an important role in southern Australia. They have their greatest impact in the tropical savannas of northern Australia, where their diversity is the greatest and their abundance is the highest – they outnumber all the other insects there – but even in southern Australia some species are really important in the natural environment, again for recycling nutrients and maintaining the health of the environment. In the south, however, termites make up a smaller proportion of the soil creatures, so earthworms and ants probably play a more important role.

How many different types of termite are there?

Across Australia we have around 350 different species or types of termites. Of those, only around 20 are actually pests, and only a handful are the ones that cause serious damage. Even the pest species, though, still play a really important role in the natural environment: recycling the nutrients, providing a food source for a lot of animals that burrow through the soil, and helping to keep our natural environments healthy.

Back to top

How do you catch termites?

What is the nature of your work with termites?

My present work focuses on how important termites, as well as other soil creatures such as earthworms and ants are in maintaining the actual health of our northern tropical environments by recycling nutrients, revitalising the soil, providing important food sources. All the animals running around in the soil play a really important role in keeping the soils healthy. And if the soils are healthy, that’s a good start for the environment to be in a healthy state.

How do you catch termites – with small tweezers?

We do! That’s one of the easiest, or least difficult, ways to collect termites. Unlike a lot of other insects, termites are very difficult to sample in the environment. For such creepy crawlies as ants, for example, we bury plastic jars in the soil with the lids off, and put the preservative agent in the bottom. The ants just run along the surface and drop into these vials – a really easy way of catching them. For grasshoppers we sweep nets like big butterfly nets through the grass, collecting spiders at the same time.

But termites are really difficult, because they live in a variety of habitats: in mounds, in dead wood, under the soil. So you need a variety of techniques to sample them in the environment. For example, we do open up mounds and I pick the termites out with the tweezers; I get an axe, break open any dead wood on the ground and pick them out with tweezers. And we use a range of baits, putting wooden stakes and even toilet rolls (which they love) on the ground for them to feed on.

An offer too good to refuse: attracting termites into degraded landscapes

I understand there is an exciting possibility of using termites to rehabilitate land. How might that work?

One aspect of my research at the moment is looking at whether we can use termites as a management tool, to kick-start the restoration process in degraded landscapes like disused mine sites, or very bare areas that have been so severely overgrazed that when the cattle are removed, the system can’t bounce back – even with sufficient rainfall and no grazing, the system is still in a degraded state. You have hard soils, there’s no grass, the trees are gone, the area is in quite an unhealthy state. So the idea is to try and introduce termites into that landscape to start increasing its health.

But because it’s really hard to physically go out and collect termites and dump them into a landscape, we have to attract them there by using their food resources. There is quite a range of feeding strategies amongst the termites. Most people think of them as wood feeders, but we also have termites that feed on grass, on litter or on soil, and the idea is that we put patches of attractive food resources down in the bare, degraded landscape. I am using straw to try and attract grass-feeding termites, and bits of wood to attract wood-feeding termites.

Termites that are attracted in to start feeding on all that dead plant material – the straw and the wood – help to recycle the energy and nutrients that are locked up in it: unless something comes along and breaks it down, those nutrients remain inaccessible to the rest of the system. And as the termites start burrowing and creating tunnels through the soil and setting up nests, that starts aerating the soil, a bit like earthworms in your garden at home breaking up the soil and reconditioning it. Then, because the nutrients are cycling through and the termites are creating lots of holes in the soil, water can get into the soil more easily, rather than running off the surface, and a much more attractive environment is created for plants to start growing. And if the plants start growing, that attracts other insects in. So we have a flowthrough effect, from the termites conditioning the environment and improving its health, up through the food chain. You get other insects moving in and then lizards come in, and birds and so forth.

Have you actually set up some test sites to work on this?

Yes. For a year now I have been setting up some really basic test sites, the first in Australia for this type of work. (A couple of preliminary studies have been done on the African savanna systems, which have a lot of similarities with the Australian ones.) And I’ve found already that termites are actually moving into the areas where the food resources have been put out, so it’s looking good.

Back to top

Vital steps toward a sustainable Australia

Would you say that ecosystems research is an important component in developing a sustainable Australia?

Yes, particularly in the north. In northern Australia we are lucky that many of our landscapes are quite pristine or at least in very good condition compared with southern Australia, so it is a golden opportunity for us to understand how these ecosystems work. Such an understanding is essential if we want to come up with management practices that can utilise that land in a sustainable way. In southern Australia it is obvious, from the level of degradation and the salinity that we see, that a lot of mistakes have been made. If we’d understood beforehand a bit more about how these ecosystems work, it might have helped us to improve and maintain the sustainability of these systems. In the north, where the land is in much better condition, we’ve still got that chance.

But the challenge for us is to tell people the significance of our research, when often people want instant results. We can’t come up with appropriate land management practices unless we know how the system works to start with.

In my case, I need to know how all the creatures in the soil are helping keep the environment healthy. We know in general that termites and ants and earthworms are important for a healthy environment, but we don’t know whether the termites help in one particular way, perhaps as a food source, the earthworms in another way, perhaps in keeping the soil healthy, and the ants in a different way again. They all may help in slightly different ways, but we don’t know yet. We need to understand the particular contributions of all those little creatures in the soil, and how they work together to keep the environment healthy, before we can go on to understand how cattle grazing or any other disturbances – fire, for example – may affect groups of termites or earthworms or ants and how the whole system is affected. And then, hopefully, we can come up with ways to keep those landscapes sustainable and to conserve the biodiversity – the diversity of insects, birds, spiders, animals in general, and plants – in that system.

Back to top

The more creepy crawlies in the soil, the better?

Do you think we value the biodiversity of the soil as much as we should?

Probably not. Slowly, I think, people have become more aware that we need healthy soils if we are going to have a healthy environment. Quite often the focus in an area has been just on water, say, or the vegetation, but it is becoming more recognised that we really need to focus on making sure the soils are healthy. Healthy soils become healthy by having lots of soil creepy crawlies in them that help cycle nutrients and water through the system. When we talk about a healthy environment, we really mean one where lots of nutrients are cycling through the system, and water is being captured by the environment and recycled through the system. If that environment is holding on to its nutrients and water, then it provides great conditions for animals and plants to live there.

Changing people’s perceptions is a very gradual process, particularly because it can be difficult to understand what is going on in soil ecology. It is underground, where you can’t see a lot of the processes that are happening. That certainly presents us with a challenge, but to have healthy environments you must have healthy soil, and achieving that begins with looking at the invertebrates in the soil and how they may contribute to its health.

So if someone wanted to make a big difference to Australia’s future, you would recommend a career in soil ecology?

I would! What is going on in the soil is vital.

Back to top

Following the academic trail into ecology

What got you into ecology, then? Have you been into insects since you were a little kid?

I have to admit I wasn’t one of those that ran round with a bug-catcher, I wasn’t totally interested in insects. Going through school I always hated writing long English essays but I tended to enjoy the science subjects and developed a general interest in science. I started a Bachelor of Science degree at Flinders University in 1990. I met my future husband, Adam, in orientation week!

I really enjoyed ecology topics at university, especially the ecosystem ecology – looking at how plants and animals interact in the environment, understanding the processes that are going on and what keeps the environment healthy, and then looking at factors that can lead to a decline in the health of the environment. So it wasn’t so much insects that I was interested in, but more the processes that were going on in the environment.

Adam did an honours degree in marine biology and during a year break between my honours and PhD we both worked as fisheries research assistants which was great fun. This involved looking at the by-catch from prawn trawlers, which we also got to go on!

Then it was just a natural progression. Through my PhD I was interested in looking again at how systems tick and what can lead to an environment becoming unhealthy. And it happened that I worked in the mid‑north of South Australia on an insect community, looking at the interactions between different insects, at predators on those insects and at how a variety of factors influence the interactions among the different groups of insects.

Adam and I were married in 1995 and moved to Darwin in 1999 at the end of my PhD so I could take up a post-doctoral position with CSIRO. Adam completed a Bachelor of Education while I was doing my PhD and had a job lined up at Darwin High School when we arrived.

What courses would you advise a student who wanted to become an ecologist to take?

Well, obviously courses vary from university to university, but I think things have changed a bit since I went through, in that there’s much more variety in the courses. I went through by doing a Bachelor of Science, which was quite general and so gave me a broad taste of the different areas of science – in my first year I did a bit of biology, a bit of chemistry and a bit of Earth science, which I really enjoyed – but still allowed me to specialise into those ecology topics as I went through my degree and then on to honours and a PhD. There is even more variety now than when I went through, ranging from a BSc to environmental management. I think the important thing is to look into all the options. There is nothing wrong with being a bit broad to start with, because only so much can be covered at school level and among the wider choices available at university you might come across something you hadn’t considered before.

Back to top

Collaboration and communication for rewarding research

What other skills outside of science are important to researchers today?

Communication is really important. People must to be able to communicate to each other about what they are researching and also its significance. Collaboration is a big one as well. In the past, I think, many people have been quite protective of the research they are doing, and probably a little bit unwilling to share ideas, but I think the nature of research and science in general is changing. More people realise that you need to partner up, to collaborate, to share ideas – a mutual, two‑way thing makes it much easier to achieve the goals that people are setting. So if I am working in an area similar to one that somebody else is working in, it is great to be able to bounce ideas off each other, to exchange ideas, and to work collaboratively on projects.

That’s one of the great things: I’m with CSIRO but also with the Tropical Savannas Cooperative Research Centre, which funds this new project to look at how important termites and other soil creatures are in maintaining the health of the environment, and then the impacts of disturbances. The Tropical Savannas CRC is really keen for collaborative research to take place, so even though I am with CSIRO I get to work with people from a range of research organisations, which is fantastic. Collaboration and being able to communicate to those people is very important.

What is the most rewarding aspect of your work?

It is hard to single out one aspect, but I do particularly enjoy working with a great group of people on such an important issue as trying to achieve sustainable development of the north. The work I do is looking at the creatures in the soil and assessing how important they are; someone else is looking at the trees; someone else is looking at the water and how it moves through the landscape. So each of us has a specialist area. But then you put it all together and it paints a bigger picture. That’s really rewarding, to be able to work with other people and to share ideas – knowing that it is for a good cause.

Back to top

An inspiring mentor

Have any role models or mentors been important to your development in science?

Fortunately, throughout my time at university and also through CSIRO and working with other people, I’ve been around really good people, many of them older and more experienced than myself. In general I have been surrounded by some very good scientists, who are always willing to share ideas, who let me bounce ideas off them and point me in the right direction.

A particular great influence early on was my supervisor through my honours and also my PhD, Professor Mike Bull, from Flinders University. He was always very open‑minded and very helpful. He was the one that really got me interested in ecology in the second and third years of my BSc, when he took a lot of the ecology topics: ecosystem ecology, community ecology. He sparked my interest in understanding the processes behind what’s going on, in looking at how different organisms interact in the environment – not so much focusing on a particular type of insect or a particular tree species, for example, but standing back and looking at the environment as a whole, at how it is working and what makes it tick. A lot of his lifetime’s work has been looking at lizards, but if people ask him, ‘Who cares about lizards? Who cares what’s going on? What’s the significance?’ he says that what matters is not so much the organism you’re working on but the processes you are trying to understand, and how things interact. That view sparked my interests, and led to my love for the theories behind what’s going on.

Back to top

Golden opportunities: work and play in the Top End

Darwin is seen as a frontier town. Is it a good place for an aspiring young ecologist?

It’s a great place for an ecologist to work and to start a career. For me the opportunity to go there after my PhD was a fantastic turning point. Because in northern Australia we have been lucky enough to avoid a lot of the environmental mistakes that have happened further south, we have a golden opportunity to learn from those mistakes and to make sure that before we get to a degraded stage we understand the system, so that we can go about trying to develop ways to make sure that we use the landscape in a sustainable way. In the north we have such a unique landscape, much of it still in relatively good condition, and such a unique flora and fauna, that it is a terrific place for an ecologist to work.

Can you pursue other interests, away from science, in the Top End?

Oh yes. I really enjoy outdoors, camping, a range of things – lots of travelling when I can, even just camping holidays or getting out and going for drives. Up in the Territory we’re very lucky, in that we get good weather most of the year round, and it’s nice to go for drives over to Kakadu, for example, or to Broome. And I enjoy reading and exercising and movies, and things like that.

Is science a place for women?

Do you think science is a place for women?

Absolutely. For a variety of reasons, science has traditionally been thought of as a male domain, I guess you could say. But over the last few years more and more women have been going into science, doing university honours and even PhDs. That is great, but I think the major problem at the moment is that we tend to get quite a big drop‑out between PhD and a postdoctoral fellowship or finding a job somewhere.

A lot of that drop‑out is probably family-related, because science traditionally has not been an easy discipline to get back into after being out of it for a while. You have to keep publishing your work, you have to be very active in keeping the research going. Nowadays, though, employers and other people are becoming aware of the difficulties for women who have decided to take a break to start a family but then want to get into science again, and ways are being found to facilitate that. It’s definitely going in the right direction.

Back to top

A beckoning path: understanding environmental processes

Do you think you will still be studying termites in 10 years’ time?

I don’t know. The work I am doing at the moment is extremely interesting and I am really enjoying it.

The first two years I had with CSIRO were more termite focused. We don’t know much about termites in Australia at all, apart from the pest side of things; we don’t know a lot about the good things they do in the environment. So my first couple of CSIRO years was mainly contributing to knowing a bit more about termites, including looking at how we go about sampling them effectively, because there hasn’t been much work even done on that.

Now I’m looking not just at termites but also at the role of other soil creatures – earthworms, ants, spiders, beetles. I am thinking of all these invertebrates as a whole, looking at how important they are to keeping the environment healthy and also at the effects of disturbances, particularly cattle grazing. That is a big concern in the north, because it may be that intense cattle grazing will disrupt a lot of the soil creatures. In areas where the cattle grazing is really heavy, the ants might drop out, or the earthworms, or the termites might disappear. That may then have an effect on the health of the environment, because if you don’t have many creatures in the soil, the soil health is going to decrease and there will be a flowthrough effect.

So, in future, it may be that I’m not working specifically on termites. But, hopefully, I will still be working in the area of trying to understand the impacts that humans have on the environment and trying to conserve the biodiversity in an environment while also allowing sustainable production to happen – trying to get that fine line between production from the environment, through cattle grazing or whatever, and conserving the animals that are there, making it all work in a sustainable way.

Back to top


© 2017 Australian Academy of Science

Top