Interviewer: By then the Canberra University College had just set up its Faculty of Science and you were offered a lectureship.

Yes, but by the time I took up that position – which was a year later, for a number of reasons – the College had been forcibly amalgamated with the Australian National University, much to the indignation of people at the ANU. I started a research project on marsupials and started getting PhD students. (They were assigned to an official supervisor in the Institute of Advanced Studies, though, because the Faculty was not allowed to have PhD students. That, of course, rankled a lot.)

So began the two projects on marsupial biology during my time there, both arising from projects of my students. First, Roger Smith – whom Geoff Sharman had sent to me from Adelaide – wanted to study reproductive biology in marsupials but didn’t really know what topic to take. When we asked John Calaby, who had all the wisdom about what was possible, what marsupial in this area would make a good research project, he said, ‘Well, the commonest animal in the forests around here is the greater glider, and there’s nothing known about it at all. Why not do that?’

Roger and I went out and looked for greater gliders in the forests near Tidbinbilla, but when we saw them about 60 feet up in the tops of the gum trees we said, ‘How the heck are we going to study these animals?’ We nailed cage traps about 30 feet up – as high as we could get – but they didn’t come into the traps and we were beginning to think that this wasn’t going to be a very suitable study. Then we heard that forests were being knocked down at Bondo, near Tumut, and lots of animals were coming out of the trees so we should be able to get all we wanted.

We drove over to Tumut to collect some animals and bring them back to the lab, but as soon as we saw the site I realised we had a wonderful opportunity to study the impact of forest clearance on animals in the forest. This was a patch of about 5000 acres of eucalypt forest, still standing. On one side of it was pine plantation from earlier clearing operations, and on the other side was farm land that had been cleared before. About a thousand acres a year were going to be felled for the next five to six years, and the only place for the animals from the felled area was to go into the forest which would be felled the next year.

We immediately changed Roger’s project to follow the felling for the next three years. We had two people out there with hard hats on, and as the bulldozers pushed the trees over we’d rush out and catch the animals, tag and measure them and so on, and let them go. So we got two studies in one. One study was the biology of the animals at the time that they were disturbed, in what we assumed was their normal place in the forest, and that gave us information about the distribution of the animals in the eucalypt forest and their biology. Then, from what happened to them afterwards, we got a measure of the impact of clear-felling on the population.

That showed very clearly that, although the animals were not damaged by the felling itself because they could glide out of trees, virtually 80 per cent were never seen again. Even though 20 per cent were recovered during that felling period, when we went back into the next bit of forest a year later we never got more than about 5 per cent of the ones from the year before. This was the first study in Australia to show the devastating impact of forest clearance on wildlife. Because all the animals that we were handling were protected fauna, we had to get a permit from New South Wales. But, in fact, at the end of three years we were able to tell the fauna authorities that virtually everything dies in this situation.

And that applied not only to the glider but to other animals as well?

We didn’t really look at that. That is a pity, but at the time the gliders were the most abundant and we just concentrated on them.

A windfall for museum collections

After the first three years, when Roger Smith got his MSc and went off to Canada, I continued the study with other students. We started doing more manipulative things because we could show the fauna authorities that the animals were all going to die and so we could get permission to actually shoot animals before the forest was felled, in order to test our ideas about them. We wondered whether the reason why so few survived the clear-felling was that there was nowhere for them to go – the remaining forest was already occupied. So we started a number of experiments where we would shoot out the residents of the forest that was going to be felled in a future year, depleting it to see whether the displaced animals would be able to move in there. They didn’t, which means that they don’t move from their home territory. If their home territory goes, they die on the site. We now know from much later work on eucalypt forest that probably the fat reserves in these animals are so low that they are living on the edge, and if they do not get food for three or four nights they will die.

It was difficult to do anything rigorous in the forests. The forestry commission tolerated us but didn’t see us as being serious, and basically we had no rights at all. On a couple of occasions in the late 1960s, although the worth of having invested a whole year of preparation in selectively shooting out a forest depended on the forestry people telling us when they were going to fell, they didn’t do so. They would tell me after it had happened. Such a waste of time, to have a year’s work sabotaged because the forest was gone, shifted my main interest back to reproductive biology.

Disagreeable though it had been, however, to go through the forest shooting those beautiful animals, because I knew they were all going to die anyway I wrote to all the museums around Australia asking if they would like to take advantage of the chance to get really good series of animals from one locality. Most museums have one or two specimens, but when David Ride was director of the Western Australia Museum he had alerted me to the importance of having good series. Three museums took up the offer. The National Museum in Victoria sent up a team to collect 50 skins and skulls, all from one area in 1966, as did a team from South Australia, where Peter Crowcroft was the director. The West Australian Museum took 100 – from an adjacent area – asking us to send them in formalin. Also, quite a number of skulls went into the National Wildlife Collection in Canberra. And there they lay for 30 years.

The closing of a circle

Interestingly, David Lindenmayer, at the ANU's Centre for Resource and Environmental Studies, recently started a study of the survival of animals in relict patches of eucalypt forest buried in pine plantation. Quite serendipitously, without knowing where we had worked in the 1960s, about five years ago he chose the very same area for his study site and somebody recommended that he come out and see me. I was very interested to hear that he was finding gliders in those little patches, because I had assumed from our study that they would have died out forever. The density is about one animal per hectare, and if 20 hectares are left, theoretically the maximum population of 20 animals would hardly be viable.

I told David of the big series of animals taken from this area at the time when the forest was felled, and suggested that we could now do DNA analysis of the original population and the small populations in the present day relics to see whether they show genetic drift or founder effects, or whether they are animals coming in from 10 kilometres away – although our experience in the ’60s was that they couldn’t even move 2 kilometres across country which was not eucalypt forest. David is now the major leader of that big project and Andrea Taylor, from Monash, is the DNA expert. I am involved a little bit with David and we are about to look at a real test of population viability analysis. There is a lot of theoretical stuff on it, but hardly any actual tests.

Having that material from 30 years ago is strengthened tremendously by the ability now to do DNA analyses of it.

It is a vindication of museum collections, as had been argued by the Victorians and others. Dick Schodde, Director of the Australian National Wildlife Collection in CSIRO Wildlife and Ecology, argues that history is stored in the specimens. From skulls or skin apparently you can get quite good quality DNA. We have 400 specimens from that time – not counting the West Australian ones, which unfortunately we were asked to put into formalin. We can’t use them because, apparently, the formalin breaks up the DNA. But who knows, it may be possible in the future. The project is a wonderful closing of a circle, however, using the work which we did in the ’60s.

Focus questions

• If clear-felling has such a devastating effect on wildlife, why do you think the logging companies continue to use this method of timber retrieval?

• Many museums maintain collections of species of animals. Can you suggest ways in which these collections could be used?