Our online forums with special guest speakers explore the complex world of invasive species in Australia.

All Things Harmless, Useful, and Ornamental

Look around your garden or neighbourhood right now. What do you see? Can you pick the native species from the non-native?

What about in the trees and sky? Do sparrows, starlings and Indian mynas outnumber the pardalotes, parrots and rosellas?

Our new online Q&A Sessions: Aliens Among Us, are aimed at exploring the complex and chaotic world of invasive species in Australia. How did they get here? Are they harming our native ecosystems, plants and wildlife? And what’s being done to repair the damage they have caused up.

Our fourth session with State of the Environment Report 2021 co-author Barry Hunter

Australia’s State of the Environment Report 2021, finally released earlier this year, makes for grim reading. But how central are invasive species to Australia’s extinction crisis? What can we take from the record level of Indigenous authorship in this edition of the report? What do cut flowers have to do with the state of Australia’s environment?

Our fourth Aliens Among Us session welcomes Barry Hunter, one of the co-authors of Australia’s latest State of the Environment Report. Alongside Barry is author and biologist Tim Low, Invasive Species Council Indigenous Ambassador Richard Swain, and Invasive Species Council CEO Andrew Cox as host.

Additional Q&A

Our panel was kind enough to write some quick answers to some of the questions asked during the session that we didn’t have time to get to. 

  • The flow of people and goods into Australia has become such a torrent that quarantine, usually called biosecurity these days, has become very difficult to do properly The Inspector-General of Biosecurity keeps issuing critical (and sometimes scathing) reports saying the department is operating poorly and lacks an adequate budget. See:  – Tim
  • The technology does not currently exist to allow NZ to achieve that goal. The Australian Government would need to see better methods of controlling cats than currently exist. – Tim
  • It is my view that Indian mynas are a classic case of the horse that has bolted, meaning they have become unstoppable. Traps can be used to limit breeding, but not to stop breeding altogether because they sometimes choose high dead trees. The proper response to the Indian myna is to say lets not let more introduced birds spread in Australia. That means a strong response when a few foreign birds appear, eg. the Canada geese culled in NSW some years ago, and house crows arriving in Fremantle on ships. – Tim
  • I don’t know, but it is interesting to read Sharwood’s book The Brumby Wars. He says the NSW Government knew it should not have banned the shooting of horses but the public pressure was so relentless it submitted to that. Ray Hadley on 2GB is currently telling listeners that a recent cull of horses in Kosciuscko National Park was immoral and that he will be talking about it at the next election if he doesn’t get answers. Governments want to get re-elected so they may understand scientific advice but not heed it for that reason. The Invasive Species Council does its best to argue for sensible policy. – Tim
  • Books you could obtain from a library include my Feral Future and A Plague of Rats and Rubbervines. – Tim
  • Insufficient awareness is a big concern to us. A recent survey found 18% of Australians think horses and foxes are native. There are academics in Australian universities who want the native-introduced dualism to be forgotten about. I am criticising their thinking in my next book. – Tim
  • No. Bridal creeper is very well-established over a large area. Efforts to eradicate weeds have only succeeded where the weed was very limited in occurrence. In other words, action has to be taken very early on the invasion curve. Biocontrol agents can be a good way to reduce weed success and two agents – a leafhopper and rust fungus – are helping curb bridal creeper. The Invasive Species Council puts pressure on governments to limit the possibilities of more garden plants becoming weeds. – Tim
  • They are considered a pest by the grazing industry because they can reach very high numbers and they eat pasture wanted for cattle and sheep. They are considered a problem in some national parks and nature reserves in temperate Australia where, with no dingoes as predators, they achieve such high numbers they threaten survival of some ground orchids and other rare plants. As a native animal, they are not a species that the Invasive Species Council has anything to do with. – Tim
  • Varroa mites are an interesting issue because they will reduce feral bees if they establish, and feral bees nest in tree hollows wanted by mammals and birds, and take nectar and pollen wanted by native pollinators. In other words, varroa mites could benefit native bees and other wildlife by reducing honeybee numbers. The control measures may work, but attempts to eradicate varroa mites elsewhere in the world haven’t worked. – Tim
  • Not necessarily. Some Australian plants taken from one part of the country and grown in another become weedy and undesirable, for example sweet pittosporum and Cootamundra wattle. Most local governments in Australia produce lists of undesirable weedy garden plants (foreign and Australian) to guide gardeners and these should be consulted. Many foreign plants, for example roses, pansies, snapdragons, do not spread from gardens so they are safe to grow. – Tim
  • It partly reflects our visual biases and also our orientation as a land-dwelling mammal. Invasive fish are difficult to detect and also difficult to eradicate. If a new weed appears at the side of the road it may be noticed very quickly, but if someone dumps aquarium fish in a stream they might not noticed for several years, by which time it is not feasible to remove them. The Siamese fighting fish established near Darwin are an example of that. Brown trout can be counted as one of our worst invasive species, having caused the near-extinction of some native fish, but the fishing lobby is so powerful they mostly get their way on trout. Aquatic weeds are a high priority for governments because they tend to be visible and have very serious impacts including clogging water supply dams and irrigation channels. Kakadu National Park is very serious about limiting semi-aquatic hymenachne and para grass. – Tim

Our third session with ecologist and author John Read

Our third Aliens Among Us session welcomed John Read, ecologist and author of Among the Pigeons; Why our cats belong indoors. John is considered by some to be Australia’s leading expert on the impacts of feral and roaming cats, and this is a special opportunity to see the world of cats through his eyes. 

Alongside John was our expert panel consisting of former Tasmanian Senator Christine Milne, author Tim Low and Invasive Species Council CEO Andrew Cox. 

Additional Q&A

Our panel was kind enough to write some quick answers to the many questions that were asked during this session. It was fantastic to see so much interest in what is such a tricky issue to talk about!

  • The Invasive Species Council would favour using iNaturalist as the best smartphone app for recording sightings since all data is publicy available and is imported into the Atlas of Living Australia. Feral Scan has a specific app for feral cats – FeralCatScan – and in addition to records of sightings, also allows the recording of cat damage or attacks and control activities.  – Andrew
  • Cats already now cover over 99% of the Australian continent, numbering between 5.9 – 10.1 million cats depending on rainfall conditions. There is evidence cats have contributed to the extinctions of 27 native animals in Australia since colonisation. Recent expert assessments of extinction risks have found that 25 species are at 20% or higher risk of extinction within 20 years due largely or substantially to cats. Many more mammals at extreme risk from cats are now safe from extinction because they have been translocated to islands or fenced reserves.  – Andrew
  • Good question. Often it is better to target invasive prey first and the invasive predators. Rabbits increased on Macquarie island after cat eradication, before the rabbits too were eradicated.  – John
  • Legislate that cats are registered and contained exactly like dogs, same encouragement, same fees and same fines. But even though several proactive councils have introduced such bylaws they are very difficult to monitor or enforce. Therefore councils should look to trial ADIMA Safepet Bluetooth tracking technology developed by Thylation to help reunite wandering pets with owners and allow councils to enforce ‘cat free zones’.  – John
  • Lobby councils about the health risks to humans of free-ranging cats and the welfare risks to the cats themselves – introduce them to the Safe Cat program run by Zoos etc.  – John
  • Typically the remit of Local Government although State and Federal Government could potentially enforce cat-free zones in high value parks etc and hence indirectly encourage/enforce cat containment.  – John
  • es, any animal (including sheep, mice, humans, bandicoots and even seals etc) can become infected, but the Toxoplasmosis life cycle (production of oocysts) requires a Feline host, so Toxo will rapidly diminish without free-ranging cats.  – John

  • Feral cat numbers are primarily driven by kitten survivorship which is primarily driven by food availability. Where mice or rats (native or exotic) or rabbits are abundant, feral cat numbers can increase dramatically, likewise dumps and other resource-rich locations often support high densities of feral/stray cats. Effective strategies to control cats include reducing food availability and absolutely banning feeding of any stray cats. Technologies include traps (some monitored remotely), Felixers and specialised cat baits (Eradicat/Curiosity), each with their own advantages and limitations.  – John
  • Introduce them to safe cat literature that shows indoor cats are safer and make healthier, longer-lived pets.  – John
  • The Invasive Species Council is currently launching a national cat campaign to advocate for feral cats to be controlled and pet cats contained at all times. We will look at how to support existing education efforts and to ensure that there are also clear rules (increasing over time) so there are consequences for those that choose to ignore the impacts. The NSW Government has recently announced $2.5 million for RSPCA NSW to deliver a Keeping Cats Safe at Home project. There is also a Safe Cat Safe Wildlife project in Victoria run by Zoos Victoria and RSPCA Victoria.  – Andrew
  • The ‘average’ Australian domestic cat kills approximately 186 animals a year, although only 28 (on average) of these victims are visible to their owners. Not sure on the data on dogs but dogs are largely restricted to yards whereas most cats are not.  – John
  • Outdoor cat enclosures are a fantastic way of ensuring cats can get some fresh air while not endangering native wildlife providing all cats are fully contained at all times.  – Andrew
  • Several scientific studies referenced in Among The Pigeons.  –  John
  • Unlike dingoes that require surface water, at least in summer, feral cats derive all the moisture they need from their prey. They are awesomely adapted to deserts.  – John
  • Absolutely, and this is an important consideration. Macropod-proof fencing should allow small mammals to walk through or climb over. In addition, you call install one way gates.  – John
  • Dingoes are better at reducing the numbers and hinting ability of foxes than cats, although in some (open) environments they do limit cats to some extent. In areas with many trees, caves or warrens, cats are pretty good at evading dingoes.  – John
  • There is a need to provide more cost-effective and low-tech traps for cat control. In some circumstances, soft-jawed foothold traps can be used in Victoria with ministerial approval.  – Andrew

Our second session with author Leslie Anthony

For our first Aliens Among Us of 2022, we welcome Leslie Anthony – author of the book that we named this series after!

Join Leslie, former Tasmanian Senator Christine Milne, author Tim Low and Invasive Species Council CEO Andrew Cox as they explore the complex and chaotic world of invasive species.

Based in Whistler, Leslie is a writer, editor, biologist and occasional filmmaker. His former life as an editor for a number of acclaimed mountain and ski publications has left his name printed into the masthead of a swathe of magazines.

His zoology PhD from the University of Toronto and postdoctoral fellowship at McGill University’s Redpath Museum have left him well-equipped as he has turned his attention towards writing about travel, adventure and science.

Aside from being the inspiration (with permission!) for the name of this seminar series, his book ‘The Aliens Among Us: How Invasive Species are Transforming the Planet—and Ourselves’ is a thoughtful, accessible look at the rapidly growing issue of invasive plants, animals, and microbes around the globe. He draws on science, travel, history and humor to understand the ecological, social, and economic aspects to the burgeoning problem of invasive species.

Our first Q&A with author Pete Minard

Our first session stars Australian author Pete Minard, who wrote All Things Harmless, Useful and Ornamental.

Pete grew up in regional Australia surrounded by a landscape infested with rabbits, sparrows and hares. His fascination with how Australia’s landscape and ecology has changed through the introduction of non-native plants and animals reveals an intriguing history shaped and formed by the men behind early acclimatisation societies.

In his book he tells the story of this movement, arguing that far from attempting to re-create London or Paris, settlers sought to combine plants and animals to correct earlier environmental damage and to populate forests, farms, and streams to make them healthier and more productive.

By focusing particularly on the Australian colony of Victoria, Minard reveals a global network of would-be acclimatisers, from Britain and France to Russia and the United States.

Although the movement was short-lived, the long reach of nineteenth-century acclimatisation societies continues to be felt today, from choked waterways to the uncontrollable expansion of European pests in former colonies, including Australia.

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