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Environment and Communications References Committee
14/10/2020
Impact of feral deer, pigs and goats in Australia

BOWMAN, Professor David, Private capacity

JOHNSON, Professor Christopher, Private capacity

Evidence was taken via teleconference—

Committee met at 9:17

CHAIR ( Senator Whish-Wilson ): I declare open this hearing of the Senate Environment and Communications References Committee's inquiry into the impact of feral deer, goats and pigs in Australia. I begin by acknowledging the traditional owners of the land on which we meet and I pay our respects to their elders past and present. On behalf of the committee I welcome you all here today. Today the committee will be conducting its hearing in person and via videoconference. This is a public hearing and a Hansard transcript of the proceedings is being made. The hearing is also be broadcast on the Australian Parliament House website.

Before the committee starts taking evidence I remind all witnesses that in giving evidence to the committee they are protected by parliamentary privilege. It is unlawful for anyone to threaten or disadvantage a witness on account of evidence given to a committee, and such action may be treated by the Senate as a contempt. It also a contempt to give false or misleading evidence to a committee. The committee generally prefers evidence to be given in public, but under the Senate's resolutions witnesses have the right to request to be heard in private session. If a witness objects to answering a question, the witness should state the ground upon which the objection is taken, and the committee will determine whether it will insist on an answer having regard to the ground which is claimed. If the committee determines to insist on an answer, the witness may request that the answer may be given in camera. Such a request may of course also be made at any other time.

I now welcome Professor Johnson and Professor Bowman. I understand that information on parliamentary privilege and the protection of witnesses has been provided to you. Would you like to make a short opening statement?

Prof. Bowman : Thank you. I'm a research professor at the University of Tasmania and I have experience in feral animal management. I've probably been thinking about feral animals for my whole career. There’s my experience and my theory. My background is that I worked for the Northern Territory government for the first 14 years of my career. I naturally had to work with feral animal management practitioners. Then I moved to the university sector and I directed an Australian Research Council centre, which basically involved supervising students and staff working on feral management, working with stakeholders and, most importantly, establishing relationships with Aboriginal people—

CHAIR: Sorry to interrupt. You're not coming across very clearly.

Prof. Bowman : To recap my career: Northern Territory government, university sector, experience in the Northern Territory with pigs, buffalo, banteng, now working on deer in Tasmania. The theory that I think is important to explain is my understanding of feral animals in ecosystems and food webs.

CHAIR: Sorry to interrupt again. I might have to get you to start from the beginning.

Prof. Bowman : I want to very briefly introduce my career, my experience and my theory. In the first 14 years of my career I worked in the Northern Territory government as a wildlife management officer. I worked with other wildlife managers who were involved in feral animal control. So I have a deep acquaintance with feral animal control issues. I have published in the Northern Territory on pigs and on buffalo and banteng, which are feral bovines. I would argue that I have some grounding in this area. I now work on deer issues in Tasmania.

But this is where my theoretical perspective is different from that of a mainstream feral-animal manager: I have theory, and the theory starts with thinking about the extinct marsupial megafauna. We have in Australia a lot of empty niches that were ready to be filled by large animals which were introduced following colonisation. The interaction of these large animals with the environment is particularly important, particularly with bushfires. There is a reasonable hypothesis that one of the reasons deer populations on the mainland are irrupting is because of the interaction between bushfires and the deer populations and the changing habitat quality and habitat availability. With my experience in the Northern Territory, I worked with Aboriginal people on country and I understood how they incorporated feral animals into their cosmology, into their economy and into their subsistence life. So, again, I've been able to understand how different cultures in Australia have been able to respond to novel large organisms. The bottom line, and what I'm arguing, is that we need to understand these feral animals. They're not ever going to be eliminated from Australia. They are part of the Australian fauna. They need to be integrated in food webs. It needs to be understood that they're going to respond to bushfires. We need to understand that human beings are a top predator and that they play a vital role in regulating feral animal populations. When I say 'human beings are a top predator', it's a fancy way of saying that humans need to hunt these things to control their populations. If they don't hunt them, the populations will irrupt, and they will cause environmental harms, as has occurred in the Northern Territory.

I don't know whether that's a heterodox or an orthodox view, based on what your committee has heard, but it's unambiguous in any mind that we have to understand these animals as part of a food web. They're part of the Australian fauna. The Australian Aboriginal cultures have been able to incorporate them into their economies through hunting. What we need to do is to figure out smart ways of not wasting a resource but exploiting a resource to get the co-benefits from controlling these animals, which potentially, as the brucellosis and tuberculosis campaign shows, are major reservoirs of dangerous livestock diseases. We need to regulate these animals. They can do environmental harm to sensitive habitats like World Heritage areas, but they are also a resource in terms of meat and recreational hunting. We need to wrap our minds around that. I would say that the barriers to feral-animal control are as much cultural as they are biological. Thank you.

CHAIR: Thank you, Professor Bowman. Professor Johnson, before you go on, I might, with the committee's indulgence—because we're running 10 minutes behind time due to technology—extend this slot for 10 minutes. We'll then go into our morning break a little bit later, if that flows through. Thank you.

Prof. Johnson : I'll just talk for a couple of minutes about the deer population and its impacts in Tasmania. Very briefly, though, goats and feral pigs—there are very few populations of feral goats in Tasmania mainly, I think, because the state government has been proactive in eliminating populations that do establish. There's really only one feral pig population. It's on Flinders Island. It does not get much attention, but it's a concern, because it's in a Ramsar listed wetland. I think that's something we should be thinking more about.

As for deer, we have one species of deer in Tasmania—fallow deer. It occupies about one-third of the state. It has been present for a long time and is quite well established. The population has the potential to increase. We've done modelling that suggests that fallow deer could occupy practically all of Tasmania. It is likely that they could become abundant right across the north of the state and be of a higher density there, but they could also easily occupy most of the World Heritage area, the Tasmanian Wilderness World Heritage Area. A recent census tells us that the current deer population is about 54,000. It is a large number, but I'd suggest that it could get much bigger. If we allow for geographic spread and an increase in density, half a million deer or more in Tasmania is not implausible over the next few decades. It's worth noting that that census of the deer population returned an estimate of 30,000 for the size of the population of grey kangaroos in Tasmania. That's telling us that the fallow deer is now the ecologically predominant large wild herbivore in Tasmanian ecosystems.

The deer have a rather different foraging behaviour to kangaroos. They tend to browse more and they eat woody vegetation. Their impacts, or at least the ones we understand at present—and this is still not well studied—primarily affect the regeneration of woody plant species in forests and woodlands. It's quite possible in the future that we will find that Tasmanian deer are blocking the regeneration of some of the woodland cover in grassy woodlands in the Midlands. They could also have large impacts on very sensitive plant communities in the World Heritage area. It's quite likely that they influence the way in which vegetation is able to recover following fire. We could get the replacement of some sensitive vegetation communities, particularly in the World Heritage area, as a result of deer preventing their re-establishment following catastrophic wildfire.

To me, the priorities for the management of the deer population of Tasmania are to prevent their further spread. They're already well established, and there's no desire or likelihood that they could be eradicated where they're present—and they provide benefits, so we certainly acknowledge that. But potentially there will be much larger impacts in the future if the population is allowed to continue to increase. The modelling that we're doing suggests that the natural rate of geographic spread of deer in Tasmania is quite low. That makes it feasible on biological demographic grounds that we could contain the further spread of the population. That could be done by reacting quickly to incursions of deer in new areas and also by doing concentrated hunting along the range boundaries, where that hunting aims to remove a large proportion of the population rather than manage it sustainably, as is the default policy elsewhere where deer are present.

One of the factors that's accelerating the expansion of deer in Tasmania is human influence on their movement—the escape of deer from deer farms and probably illegal translocations from time to time. At the moment those escapes aren't managed. The policy settings don't allow for a rapid response and eradication of those satellite deer populations, and that's contributing to their spread. I would like to see more attention given to the concept of the containment of the deer population so that we can avert potentially much larger impacts in the future. I will stop there. Thank you.

CHAIR: Thank you, Professor Johnson. I might ask a few questions before I go to Senator Urquhart for some questions. I understand that you wrote a joint article back in January 2016 on feral deer in Tasmania. That also included Ted Lefroy. In that article you warned that, under current government policy, the deer population could reach a million by mid-century. Are you still sticking with that? Just then you mentioned half a million as a possibility. Is your modelling suggesting any changes to that original estimate?

Prof. Johnson : I think it's still plausible. We're currently doing more sophisticated modelling that is trying to better understand the way in which the deer population spreads. We haven't yet got to the point of testing that number. But, as I said, I think it's plausible. The only thing I'd say about that number is that it's a bit easy to be distracted by single figures. We could have half a million deer or a million, or a million and a half. The most important thing is that it's almost certain that we will have a great many more deer in the future unless we act to avert that. The population of deer is currently increasing by at least five per cent per year, based on the most recent census data, and the state government's monitoring program is showing rates of increase at least as large as that.

CHAIR: We hope to have DPIPWE present at the committee today so we can put some detailed questions to them about their latest census. I understand there's been quite a bit of criticism around that census. A number of stakeholders have pointed out what they see as weaknesses in how that population estimate was collected. Do you have any comments about the census? Have you viewed the methodology? Are you comfortable with the way that was tallied, shall we say?

Prof. Johnson : Yes, I have. The problem of doing a census on populations of wild animals is really difficult. In my view, this census was well conducted. It dealt with the major difficulties of getting accurate census estimates. If anything, I'd suggest it's an underestimate. The reason I say that is that, because of flying conditions, they missed some areas of the Central Highlands, where other evidence suggests there are abundant deer. It would not be unreasonable to add a few thousand to that figure and still be within the bounds of plausibility. The figure itself is quite reasonable.

CHAIR: I have two other questions and one is a very big question. It's to Professor Johnson or Professor Bowman. You acknowledged in your statements there are some benefits to having deer, but, theoretically and technically, do you think eradication of feral deer is possible, given their current numbers, if that were the policy aim? Do you think it's a possibility?

Prof. Johnson : In my view, in Tasmania, it's extremely unlikely to be successful. It would certainly not get community support, for the reason that deer provide cultural and some economic benefit. What is possible is the eradication of isolated populations outside the current consolidated geographic range of deer, which is largely between Hobart and Launceston, in the Midlands. There are outlying populations on Bruny Island, on the north-west, and to the south of Hobart. Under those conditions, I think eradication would be feasible. Part of the reason I say that is that deer have been successfully eradicated in other places, particularly in New Zealand, and there's a long history of good practice in New Zealand, taking advantage of the knowledge and skills of hunters but giving them incentives to hunt populations down to very low numbers so that eradication becomes feasible.

CHAIR: Thank you. Do you have anything to add, Professor Bowman?

Prof. Bowman : I have another panoptic observation, and that is that we've got to be very careful with feral animal impacts, seeing it as a binary, as a black-and-white issue. It's not. The trick with this is understanding the impacts and how they scale to density. That's where we can lead to sustainable management of these large animals—which will be through hunting, in my opinion—by setting target population densities that will enable environments to function ecologically. For instance, there have been resident deer in the Midlands of Tasmania for over 100 years. They have affected the environment but not catastrophically. If we allow very high densities to develop, it will have extremely negative impacts on the remnant native vegetation, but also the agricultural enterprises. Frankly, there will be a high-speed cultural collision—there will literally be collisions with vehicles—if we allow the populations to irrupt. This is really the point that we need to understand about management of feral animals, because we don't have large predatory animals, other than human beings: all of these large animals are on the cusp of irrupting. We're seeing irruptions now of deer on the mainland. We've seen pig irruptions in certain areas with, say, irrigation. We saw a buffalo irruption. Our role as land managers is to cap the irruptions. One thing I have learnt from Aboriginal people, who obviously have a deep understanding of their country, is they're very happy to have buffalo on their country. They know they're dangerous, but they're a fantastic resource. They just don't want high densities of them. That's where, culturally, we need to get to an understanding. It's not about a black-and-white issue; it's about setting realistic targets.

CHAIR: Senator Urquhart, would you like to ask some questions?

Senator URQUHART: I would. Thank you very much. Professor Johnson, you mentioned in your opening statement the prevalence of goats and pigs here in Tasmania. You mentioned that the government has been active in relation to the eradication of feral pigs. Why do you think that's been concentrated on pigs as opposed to goats? Is it not fair to say that they haven't been as active?

Prof. Johnson : I meant to say that the local eradications of goats have been quite effective. As far as I know, there have never been significant feral pig populations on the main island of Tasmania. The only problem is on Flinders Island. Why that's been successful I don't know. I guess it just relates to the history of the introduction of deer as compared with goats and pigs. Deer were introduced from the very beginning as an important cultural resource for hunting. Their populations were managed from the very beginning to maintain them as a sustainable resource for recreational hunting. Goats and pigs were only ever escapees of domestic stock. They were never highly regarded as a resource for hunters, so it was much more straightforward to make the decision to remove them.

Senator URQUHART: One of the things that I'm interested in through this inquiry is the impact on the environment that these feral animals are having. You can drive down the Midlands now, particularly if you go up over the central lake area, and you can spot deer in the paddock in the daylight, effectively. Can you describe what sort of impact they're having on the environment of Tasmania? What are the primary concerns in relation to the growth of the deer population? Obviously that is going to have an effect on the environment. Can you talk me through some of those concerns?

Prof. Johnson : The main concern is over-browsing. That's illustrated by the fact that attempts to restore native woody vegetation cover in the Midlands now face as their main problem over-browsing by deer. Deer will browse seedlings of eucalypts, and antlered males thrash their antlers on saplings and damage them. That causes mortality rates that have been measured in Greening Australia restoration projects of 50 to 80 per cent of trees dying. That means that organisations like that need to expend a lot of effort and money putting up tree guards to protect individual plants. It's very, very difficult to establish a native vegetation community when you have to protect each individual plant from deer. In the Midlands now it's noticeable that there's very little natural regeneration of tree cover. The only situation in which eucalypt seedlings can survive is when they grow up through the middle of dense thickets of prickly vegetation, like some of the spiny hakeas and lomandra clumps, and even just piles of woody debris. They provide physical protection from browsing and that allows tress to establish. But in the open grassy understorey there's effectively no regeneration of canopy trees. It means that that mixed grassy woodland, which has high conservation value, is threatened by over-browsing by deer. I

I would point out that the deer census that produced that figure of 54,000 may have surprised people, because it's quite a large number. But if you translate it to a density, it's still only 2.7 deer per square kilometre. The density of fallow deer has been measured at upwards of 50 per square kilometre in other sites in Australia where they've reached their carrying capacity. It's not unrealistic to expect that the abundance of deer in that habitat could still increase by a factor of 10. In that case, the signs that we're seeing now of deer reshaping the structure of vegetation and blocking recovery of woodlands will become much more significant.

Senator URQUHART: So in your view is there such a thing as a sustainable deer population in Tasmania? What would that look like and how can we better control the population?

Prof. Johnson : Yes, I certainly think there's a sustainable deer population. I agree with David Bowman's comments that we really have to think in terms of density. At some point we have to decide what density of deer we think provides a balance of benefit and cost. I suspect it's a density that's probably a bit lower than the density we currently have. We should seek to contain the population so that we don't have to deal with impacts on vegetation that might be even more sensitive to deer browsing than the places where they currently occur. The biggest worry is about the effect that deer could have on vegetation on the World Heritage area, especially in the uplands.

Recreational hunting, it would seem, is having quite a significant impact on the rate of growth of the deer population at present. Some analysis based on the recent census suggests that the deer population would be growing twice as fast in the absence of recreational hunting. That suggests that we wouldn't need to do that much more hunting in order to contain the population density and population expansion. Probably it would mean incentivising hunters to concentrate their efforts on populations that are targeted for reduction, and push density down and hold it down. As I mentioned, there's a lot of experience on how this can be done in New Zealand. It can be quite effective. Hunting is a useful tool for management of deer populations. I do see that as being the key to doing it sustainably. I think by definition that could be sustainable if we understood the ecological density that we wanted. If we're using hunters to help achieve that density, the hunters are getting the benefit from that also.

Senator URQUHART: We certainly know from the census, but we also know from anecdotal evidence, that the concentration is more around the Midlands area of Tasmania. Therefore, when you talk about 2.7 deer per square kilometre, it's actually much more concentrated in those areas where we have a lot of grazing and we have a lot of farmers who have quite large farms and rely on grass and other growth for their livelihoods. I've seen pictures of deer in paddocks along the Midlands where they're so thick they look like cattle. Recreational hunting is not going to solve that problem, is it?

Prof. Johnson : The density estimate of 2.7 applies to the core range of deer, which was censused in that recent exercise. It's all essentially good deer habitat. We would expect that habitat to allow deer to live at quite high density. Comparison with deer populations elsewhere suggests that they've got a long way to go yet. They can still increase in abundance. The average density across that same region could be much higher than the average density we currently have. And you're right that deer concentrate in large numbers and they have large impacts where that occurs. But the current hunting practice doesn't solve that problem and it hasn't prevented increase. Deer have still been increasing. We would have to change the way that hunting is done. To me, one of the keys to that is to give landholders more freedom and more capacity to manage deer on their properties. That applies to private landholders, but it applies very strongly as well to managers of conservation land, like the Tasmanian Land Conservancy. As I understand it, currently they need to go through the same bureaucratic process to get permission to remove deer from their properties as is set up for the recreational hunting exercise. It strikes me as being a bit restrictive. It's a system that's not designed to contain or reduce density. What we need to think about is using hunting to manage density, but to change the policy that currently governs the way that hunting is carried out.

Senator URQUHART: Professor Bowman, did you have anything to add to the comments that Professor Johnson has made?

Prof. Bowman : I really want to reinforce that the deer are filling a browsing niche. They're exploring the environment. And the environment is changing because of climate change and bushfires. They haven't got into some of the vegetation on the west coast. That experiment is underway. We must understand that what we've observed up to this point in time isn't necessarily how it will play out. There are some surprises embedded in here. What I suspect has happened on the mainland is that large areas that have been affected by bushfire and warming—milder winters—are driving the deer populations to irrupt. That's my hypothesis. I suspect that there's going to be an irruption of deer in response to environmental changes above and beyond the demographic drivers that we've been talking about. In other words, we can't assume that what we know is how it's going to be into the future and just rely on the projections of the models; we also have to equip ourselves to think about surprises. We've got the opportunity to do some novel interventions to at least box in this animal, to stop that experiment occurring, because there's an outside chance that we may get a nasty surprise. If they get onto the west coast, we will be in a very different place, because even surveying the wretched creatures would be difficult because of the canopy cover and the terrain. It's more remote. We may be sitting back in the future regretting that we didn't act now in a strong interventionist way.

As I said, the barriers are cultural. We have to wrap our minds around hunters on conservation lands. We have to wrap our minds around using a resource in a new way, and changing some legislation. In my view, the status quo view, or just tinkering with the current legislation, is not going to cut it. We're sitting on a biological powder keg. These animals want to expand their range. They want to reproduce as fast they can. We're basically in a food web with them, and either we're going to be a top predator and put them in their place, or they're going to try to get the upper hand on us. That's my opinion.

Senator URQUHART: Finally, you both talked about policy and legislation. Could you paint me a picture of where you see that the legislation needs to be changed and what it needs to look like in order to be able to provide the control that we need.

Prof. Johnson : I would say that there should be a clear policy intention to prevent the spread of deer, which could be done by exterminating incursions, and to manage the density of deer where they occur. At the moment, there seems to be a gap, in that the state government is reluctant or prevented from intervening to manage deer populations. Likewise, private landholders are often restricted in their ability to manage deer populations, and it is largely left to recreational hunting to provide the management. But, as I was saying earlier, the structure of the governance of recreational hunting is not directed towards removing populations or controlling density; its primary goal is to provide a sustained supply of high-quality animals for hunters, where quality relates to size and particularly the availability of males with large racks of antlers. We probably need to think much more carefully about the goals of containment and the management of density, and to allow more freedom to increase hunting where it's needed to achieve those goals.

Senator URQUHART: You said that the state government were stopped from intervening. Could you elaborate on that a little bit. I would have thought that the state government were the ones that provide the legislation. Therefore, why are they stopped from intervening? Is it because of the legislation as it is? They have the capacity to change it.

Prof. Johnson : I'd say that they're reluctant to intervene. I have to say that I'm not an expert on legislation. Deer are protected wildlife. They're classified as being partly protected wildlife. That entails a permitting process before any deer can be removed. Someone has to apply for permits for a set number of deer. Typically they have to specify the class of deer—antlered, non-antlered and so on—and the numbers have to be determined. There's a capacity for applying for permits to remove deer to protect crops. But, still, the fundamental default position is that deer are protected, and, therefore, special permission has to be sought to remove them. That means that the goal to eliminate a population is inconsistent with the current, I suppose, stated objective of the legislation.

CHAIR: I've got a few follow-ups, or a few things to clarify, from Senator Urquhart's questions. Obviously, the target densities are going to vary around the state. Do you believe that the Commonwealth has a role to make sure that we have no feral deer in our World Heritage areas? Do you think that the target should be zero? I asked you about eradication more broadly before, but do you think eradication is possible in World Heritage areas?

Prof. Johnson : In my view, that should be the goal, and I think it is possible. The main reason is that the deer have already made incursions into the World Heritage area on the eastern side—but the numbers are still quite small and the extent of those is quite small. On the mainland, , for example, there's quite a lot of work being done to control deer populations by shooting them from helicopters. That can be quite effective. It should be effective in large parts of the World Heritage area. Again, I'm not familiar enough with the governance of the World Heritage area to say whether this is something on which the Commonwealth or the state government could take the lead, but someone should. It should be a very high priority to prevent deer from occupying the World Heritage area.

As I mentioned earlier, even quite simple models of the potential distribution of deer have them occupying most of the World Heritage area and all the way across to the west coast. It's hard to predict exactly what they would do to the World Heritage area if they got into it, but it would almost certainly be significant damage.

CHAIR: I understand that the threatened species council, the Bob Brown Foundation and others have for many years been lobbying the government to implement a deer management strategy that keeps the World Heritage area and other high conservation areas free of feral deer. Are you aware of any work that's underway at a state level to look specifically at how to manage and eradicate deer in those World Heritage areas? Are you involved in any of that yourself?

Prof. Johnson : Not at this point. Some of the research that I'm involved in at the moment is in collaboration with the state government. Ultimately that is aiming to produce some guidelines or to at least put bounds on what is reasonably possible for management and to determine, if we're going to kick them out of the World Heritage area, where to concentrate control efforts to make that most effective. At the moment, I'm not aware of any development of policy in relation to that, except that I heard that, following the deer census, there is an intention to review the management plans for deer in Tasmania—and I would hope that preventing incursions into the World Heritage area would be a prime objective of that.

CHAIR: Excellent. Thank you. Professor Bowman, you mentioned that if the deer get to the west coast we're in trouble. I think that's roughly what you said. I was having a look at the Tasmanian [inaudible] submission. They have an attachment, figure 4, which is the estimated fallow deer range in Tasmania. They do have deer in the broader Tarkine area as farm escapees and translocations in low densities and isolated pockets. Are you familiar with any other work that's been done in the Tarkine area of Tasmania?

Prof. Bowman : No, I'm not. One of the things that I'm trying to reiterate is, with habitat suitability modelling and these projections that Professor Johnson's been talking about, they're based on the assumption the world works the way we know it works, and the world is changing because of climate change and, I reiterate, bushfires. What I'm particularly concerned about is there have been large fires in the Tarkine, in the eastern edge of the World Heritage Area, and that may really change the relationship of habitat and deer, because the deer will be able to find a new food resource—it'll be more open—and be able to expand very rapidly. So what I think we need to be equipping ourselves with is an expectation of surprises and the capacity of these animals to irrupt.

Another point I want to make is when there are satellite populations the biggest misunderstanding in feral management control is you don't have to do anything when you've a low population. In any case, trying to eliminate low populations is very, very expensive. Getting those last few animals is very expensive. But, do you want to know something? That's actually the best investment you can make, because, if you try to get on top of a feral animal population which is irrupting, then you have to spend a huge amount of effort to drive it down to a low population. By that time, you've exhausted the goodwill of the people who are funding you and you leave a little residual population to just explode again. You're left with a saw-tooth trajectory of control and irruptions. What we need to be doing in western Tasmania is seizing the opportunity, I believe, to make the very expensive but very important investment to stop these things spreading now while we've got the chance.

That leads to the question, Senator Urquhart, about policy. We have a game management framework. Really, we need to refresh this to understand it's a large animal management question and, as Senator Whish-Wilson has said, that's going to be region-specific and ultimately devolved to, in the best case scenario, individual landowners who can actually develop plans. They might want to encourage a certain level of deer. Some landowners might want to be trying to eliminate them. Obviously it's got to be integrated at a regional level, but we've got to be more trusting and more devolving down responsibility of the animal control, because the government, whichever government, isn't going to do it, and even if they have a program it's going to be a flash in the pan. These programs have to be relentlessly continuous, because as soon as you turn your back on a feral animal its populations will grow. That's the nature of biology. So you have to be in for the long haul and develop cultures and sustainability, and that's why we need to completely re-imagine in Tasmania deer, goats, pigs, buffaloes—all feral animals in Australia need to be reimagined, as I said in my opening remarks—as an inherent part of the food web. We, as predatory animals, as hunters, controllers and fire lighters, are also in that food web, and we need to work out a way of managing these animals for the maximum co-benefit, which is biodiversity and economic benefit and protecting primary industries.

CHAIR: Thank you, Professor Bowman. Senator Fawcett, did you have any questions?

Senator FAWCETT: I have one very quick question for Professor Bowman. You've mentioned all these feral animals as being part of a food web and suggest that we seek ways to maximise the benefit. I'm wondering if that applies to feral pigs, particularly where they are diseased and aren't necessarily of much use for human consumption or many other uses, and whether you'd support some of the more modern baiting systems, such as sodium nitrate with the Hog-Gone system, in an attempt to control numbers effectively or, where possible, eliminate them?

Prof. Bowman : That's a really fantastic question, thank you. The poisoning question comes exactly into the point of the food web. The danger of poisoning, apart from the fact that you do gulp at the humanity of it, is that you are putting poison into food webs, so other creatures will consume this material. And we need to be careful about: Is there going to be collateral damage for native and non-native predatory animals? Could we further disturb food webs? That's where I'm much more a pro-hunting feral-control person, whether it's using marksmen and helicopters to try to clean out an area or finding really creative ways to incentivise recreational hunters to do important work. I'm certain, if we can have some trust and creativity, we could actually put to work a lot of people who enjoy hunting to do really useful environmental work, but obviously there needs to be training and regulation. We can't have a Wild West scenario of people tearing around on private properties or national parks firing away at whatever they feel like. So I would be concerned about poisoning because of the collateral damage, but it would need research. I'm not saying I'm opposed to it; I would just be concerned about it because of the non-target impacts.

Senator FAWCETT: Professor Bowman, that's specifically why I asked about sodium nitrate, because pigs have a particular vulnerability to that. They don't have the protective enzymes that other creatures do, which is why it's very effective and quite a humane method of eliminating pigs. Anyway, if you have further comments on that, I'd be pleased if you'd take it on notice. I can see the chair is edgy because of time, so I will mute myself.

CHAIR: Thank you, Senator Fawcett, I appreciate your cooperation in that respect. Thank you to the two professors from Tasmania. We appreciate all the work you do and your evidence this morning.