#173 - Should we protect feral animals?

[Music] Australians have been trying to exterminate or control animal species for so long most of us seldom question the logic behind it. After colonization we started killing native species because they made holes in farms, ate chickens and eggs and threatened sheep. So we killed Dingoes, quals, hawks and tazzy tigers just to name a few. Then rabbits got out of a hand and there weren't many Dingoes around to kill them so we did it. Now Dingoes are vulnerable and we call kangaroos, cats, rabbits and other species at a cost of hundreds of billions of dollars. Our media is awash with justifications for this form of environmental control but is exterminating animals actually achieving our goals. What are those goals? And what is the cost to our environment? Should we consider the suffering involved? And what would change if we just stopped? Today I'm speaking with Dr. Aiman Worcester, a postdoctoral research associate at the University of Technology Sydney who says killing both introduced and native wildlife isn't working and should stop. I didn't realise that Australia has water buffalo. Yes, yeah, yeah, it's crazy. Yeah, we've got a really diverse range of megafauna that came over with mostly British colonialists. Right. Okay, so it's been a long time. Yeah, and Australia has something like six or seven species of deer as well and about half of them are critically endangered in the native range. So it's acting like a refuge for some endangered species. It's like the rabbit as well and living around Sydney they're endangered in the native range. Really? Is it vulnerable one of the two? Where is that the native? The Iberian Peninsula. Right. Yeah, amazing. So they're thriving here and they're endangered there. Exactly, yeah, it's a really interesting contrast where you know they're pests and vermin over here but in the native range they're trying to save them. Incredible. Is that a recognised strategy of conservation? No, not really. So these species that occur outside of the native range are generally excluded from biodiversity counts or from assessments of their population by things like the IUC and Red List that generally excluded. So we don't see these animals represented in counts of their abundance or diversity or populations generally. Is that something you'd like to see changed? I think it's important to recognise that animals across that exist where they exist. I think it's important to know that if there's you know critically endangered deer species here that it's important to know that there's a large population Australia that's thriving it. I think it re-contextualises how we think about both those populations. The one in Australia might become more important. The one wherever else is equally important but we know that there's a safeguard population as well if this one continues to decline. So compassionate conservation. Can you explain what that is? Yeah, so compassionate conservation is the idea that some of the conservation practices that people undertake are inherently unethical. So there's things like large-scale killing that we don't support and that recent as conservation instead of being about populations, recent as individuals that matter. And we try to do no harm in preserving individuals and also preserving the collectives as well. And what sort of methods can you use as alternatives to killing? In Australia we have a lot of small mammals and other populations species that are declining. And we actually see that preventing things like land clearing and large-scale agriculture helps prevent those declines and then reinstating things like apex predators to control smaller predators which then promotes the prey species that are declining. It really seems to help. So when we stop and limit large-scale disturbances it seems to reverse that sort of stuff instead of promoting killing which seems to exacerbate the problem. So can you give an example of where that's happened in Australia or elsewhere? Yeah, yeah. In the middle of Australia we've seen a mass small mammal extinction and decline and that's really driven by a lot of habitat fragmentation and decline. And then in areas where we're trying to limit small-mammal decline what we tend to do is poison predators. We put out 1080 across these massive landscapes and that kills foxes and sometimes cats as well as they scavenge and eat the poison. So some work by Aaron Wollock in 2010 showed that when you stop killing these predators the dingoes come back and they limit the amount of foxes and cats in the area and that helps promote small-mammal populations. So it was the cessation of that poison that really brought back those populations. Right, okay. Would there ever be situations where you have to make an ethical choice? Which species do we save? The native one or the introduced predator? Yeah, so that's a question that's posed quite regularly and I mean it's impossibly challenging right because you have to be the same one species or another. And those sorts of situations only really happen at least as far as I'm aware on like those offshore islands with massive sea birds with like introduced rats that eat the eggs. That's the really common situation that we get and I don't know the answer. I don't know what you do in those situations. You have to make a judgment call and it just has to be the one that people are most okay with and it's an impossible situation. So do we either save the birds or you save the rats and that's a judgment call that wildlife managers make and face with that situation, I don't know what I do. I don't know. It's like the trolley problem. Do you know the trolley problem? Exactly the trolley problem. Yeah. If you're unfamiliar the trolley problem is a thought experiment which poses ethical questions such as if a train were going to run over five people would you flip a switch to divert it to a track where it would only kill one person. Of course once you've answered other variables are introduced to make the question even more ethically curly. So compassionate conservation is it against killing in all circumstances or just when it's avoidable? So it's a diverse school of thoughts there's people on either end of the spectrum. Some people think within compassionate conservation that in those situations you would kill the rats but others think that killing is completely off the table. I tend to sit somewhere in the middle. I'm not really not really sure what you do in those situations but other people would say that you either kill the rats or you let nature run its course and hope that the birds evolve and respond in response to the predation threat and then they hopefully don't go extinct but some people are against killing in all capacities and others aren't. Yeah and so it's not really a one size fits all kind of thing. It's people have diverse views within the group. Yeah you had some studies on introduced mega fauna into Australia. Our mega fauna went extinct what the lights lies to see. Right and those papers were saying that some of these introduced horses and donkeys could kind of recreate some aspects of the landscape from back then. What's desirable about that? Yeah these large herbivores they do really diverse and important things like biotebate soil and move seeds around and control fuel loads for fires to prevent massive mass scale wildfire and when those animals went extinct we lost that ecological function so we have large gaps in the things that happen in Australian landscapes that large herbivores tend to do and by those animals being reintroduced it's made the world more functionally rich and diverse which is generally considered a good thing to have a more diverse group of functions in in Australia or elsewhere as well. Are there always benefits though? I mean surely sometimes I could imagine that there aren't any obvious benefits in having introduced species is that that the case or I mean it's a benefit is like a funny way to put it because I think we we put these value judgments on nature about whether it's good or bad but nature just is so whether we have more of why or more of z it doesn't seem to it's not good or bad I think it just is. So having inherent benefits I mean it's a good thing to have more biotebate soil it means that more plants grow and you have seed dispersal across these large landscapes so but I mean it's also other things that they do as well like trample water holes or they you know there's the whole cosyoscope rumbi thing that's very controversial as well so I think there's diverse schools of thought on the role of large herbivores but there's there's no denying that those impacts that could be perceived as good by some people and bad by others but it's they just are what they are yeah. I guess at the heart of compassionate conservation it's about doing and correct me if I'm wrong as little harm as possible to living things is that right yeah and trying to I guess like limit human interference yeah not necessarily interference but limit human harm yeah right okay and then what are the values of the conventional approach how do they differ? Well I think that conservationists I mean they're inherently compassionate people as well they're trying to save the world right that's the whole reason people become conservationists or get involved in conservation but I just think that some of the methods that we choose to use whether it be the government or otherwise they don't consider the role of individuals the pain and suffering that they cause for individuals and sometimes the methods like we use like large scale predator control are really ineffective and actually waste to the taxpayer money so predator controls are really good one where it's really ineffective it doesn't do the things that we we want to do but we keep doing it because I guess we're trying to put the toothpaste back in the tube yeah exactly it's this idea that we want to turn Australia back into what it was pre pre colonization and that's just a it's just a goal that a lot of people are starting to realize and we talk about it just seems unattainable there's no getting rid of foxes and cats and other large herbivores and other introduced species across Australia it's just a kind of pie in the sky goal and we'll just never it doesn't seem like we'll ever be able to get there it's a magical day in the future that people wish for but there's no clear path to get there so we think that instead we should just be looking at the world the way it is and then we can figure out how everyone can live together in these spaces instead of trying to exclude others and kill them in ways that is ineffective and doesn't achieve the goals that we're actually trying to achieve yeah I guess you can look at an ecosystem in terms of states of stability and states of change right and we have obviously introduced a lot of instability and that's creating a lot of change in the ecosystem and I guess it seems to me by committing to continually eradicate certain animals that we see as pests we're kind of committing to that being the new stability in a way that we're sort of playing that role in the ecosystem I'm not sure that human predation is actually doing what we think it does it's not really stabilizing populations what we do is when we kill these animals on mass scales we just cause harm we don't actually reduce their populations that kind of control doesn't actually do what we wanted to do and I suppose what compassionate conservation says as a counterpoint to that is that we should be learning about nature and trying to figure out what it is now and then trying to create states of being within these ecosystems that promote stability across these systems and prevent extinction in turn as well so the classic Australians example is promoting tingoes stopping poisoning them protecting them and allowing them to regulate the system I think one of the important things that we don't discuss is that nature is and always has been dynamic species of always moved around I mean we've accelerated that with colonization and people moving across the world it's introduced more species and spread species out more than ever but the role that humans play is kind of a different matter because we think where these predators but we see that human predation has very different effects to natural predators or to non-human predators and we don't mimicly effects that apex predators have we inspire fear but on the same ways that apex predators do the very different effects at least that's what research says at the moment. Animals have a different fear response in regards to humans what does that mean? Yeah so humans inspire fear like predators do in prey as well but humans are inherently unpredictable so there's a different kind of avoidance that occurs when humans inspire fear there's this kind of like really mass scale avoidance whereas predator and prey there's a much finer scale avoidance so there's some evidence that prey learn to avoid predators and they avoid them on finer scales whereas when it's a human disturbance wildlife just leave they just kind of that's recent research coming out of the United States saying that even even small scale human disturbance just results in animals not being in the parts of national parks where humans are interesting and that's presumably a learned response or yeah I think it's it's to lethal end on lethal human disturbances yeah yeah well and so even just our being there can change an ecosystem yeah absolutely there's some really interesting research coming out as well it's showing that just human presence shifts animals to noctonality just makes them completely nocturnal stops them being present during the day this is complete like a spacey attempt for segregation between human activity and animal activity that's that's really not what you see between say apex predators and prey species incredible what sort of animals become nocturnal? really diverse kinds so there's a meta analysis by Caitlin Gainor from the University of British Columbia that shows it's animals like some bears and elephants and predators like cats and dingoes and mountain lions to massive paper with about a hundred or so species I think and that's just to protect themselves yeah just to get away from people yeah wow other other examples how else do species change the behavior to avoid humans? Yeah so Caitlin Austin who did a PhD with Daniel Rampe a couple of years ago was working on how human disturbance influences kangaroo behavior and what she found in her PhD thesis is that where kangaroos are disturbed by people where they're shot where they're persecuted that the joys won't come out of the pouch to play anymore so they almost stay exclusively within the pouch it's unclear why but it seems like a response to disturbance they just cessation of all play and they won't leave the pouch because it's too risky presumably so there's a real diverse way in which humans are shaping wildlife and preventing them from engaging in even just basic behaviors like play or foraging or being present in a territory that they normally would be so what about plants when we see an introduced plant thriving here perhaps even taking over killing other species how do we approach that and how do you think we should approach that? Yeah plants are a challenging one I'm no botanist and we don't really have a botanist on the team either we don't have a plant scientist but I think at least to me there's kind of two differences in the approaches if the resistance to killing to me comes from killing and pain and sentience and that sort of thing that hasn't been proven in plants then the other aspect is that idea that we should just let nature be how it is or we should change nature it's kind of this dichotomy choice we have to make about whether we these are these plants in Australia have similar or different effects versus where they are natively it's not really sure if that's the case or not and there's not much research on that either but introduce plants to play important roles as things like lantana which is you know one of the most I guess hated plants in Australia is a really important habitat refuge for things like skinks in Australia to prevent them being predated upon by animals like cats so these plants do have important roles here it's just understanding whether that's different or similar to their native range and I guess the value judgment can be a little different it's seeing as you're not exactly inflicting pain on plants it's a inherently different idea but it's whether you want to be in control or let that nature go I suppose so in regards to conservation what do you say to people when they say we should have an evidence first approach a science first approach to conservation and not let our feelings about sentience or animals get in the way of that yeah so I think that's a good point and I think that a lot of Australia's wildlife management is conducted by national parks the government is not evidence-based they're going against evidence by poisoning predators by by trying to remove them there's no evidence that that actually works or creates benefits and in regards to the feelings I don't think that but an objection to killing a sentient animals necessarily feelings I think it's an ethical obligation to be engaged and to make sure that we're not harming other animals around us I don't I don't think that's necessarily a feelings-based approach but an ethical obligation to try and reduce harm to the world which presumably is the end goal of everyone I suppose it's ultimately that's what conservation is trying to do absolutely it's a disagreement about how to get their I suppose yeah absolutely yep you sent me a paper about native species and their fear response to introduced animals yeah can you tell me a bit about that yeah absolutely so there's this idea that when you're an introduced predator you have inherently different effects when you're prey than you would a native predator so it's outlined in the prey naivety hypothesis which suggests that because prey species and a predator haven't shared a long period of evolution that prey won't recognize the predator as a threat so what we did is we took a lot of predation risk experiments where what they do is they expose small mammals to the the scent scat for urine of a predator and then the idea is that small mammals will respond in a particular way based on whether they're native or not so if they're a native predator you would predict that they would be more vigilant after you add the scent they would recognize that that's a threat and they would behave appropriately but what we found is there was no difference in the response of small mammals to predators based on whether they were native or introduced so it seems like prey are unable to recognize whether their predators are introduced or native it doesn't seem to matter to them what they recognize instead is things like body mass they're more scared of larger predators there's no relationship between whether a predator is native and how response of prey is yeah and that goes against conventional thought right yeah that goes against conventional thoughts so the prey naivety hypothesis is like a key mechanism to predator-driven decline in Australia so it's that that lack of a fear response is suggested to have caused decline across Australia ongoing as well is there ever a lack of a fear response because I saw the dodoes were mentioned in the paper and Darwin saying you could just walk up to this tuberverton club them right yeah is that an example of a lack of a fear response um I mean lack of fear responses do occur but we don't seem to see them in response to whether a predator is native or not sometimes there's there's there's a lot of complex mechanisms in predator prior ecology that we don't really yet understand sometimes there's a lack of fear and we generally see that in predators that are avoiding each other quite heavily sometimes there'll be really heavy space to your temporal avoidance where they're never active at the same place in the same time but there won't be a fear response when they're at those places that they share with that predator and that's just a mechanism that's been observed there's no explicit study as to why that occurs as of yet you know so what would you like to see changed in the way that uh Australia deals with introduced species yeah the main thing for me I think is the cessation of 1080 poisoning I think that that's an ineffective use of taxpayer money I think it doesn't achieve the goals that it sets out to do it doesn't save small animal species it actually puts some greater danger of predation by eliminating dingoes and I would like to see a shift towards science that is trying to identify conditions where uh native and non-native species can go exist because that seems like a more ethical and a more realistic goal for uh Australia moving forward as a biodiversion. Thank you Dr. Aiman Worcester for speaking with me think sustainability is made possible with the support of 2SER radio the University of Technology Sydney and is heard around Australia on the community radio network we are in Sydney on Gadigal land of the Euro nation whose sovereignty was never seeded you can listen to think sustainability wherever you get your podcasts I'm Lawrence Bull thanks for listening