tag:theconversation.com,2011:/fr/topics/invasive-species-1110/articlesInvasive species – The Conversation2024-02-26T15:44:21Ztag:theconversation.com,2011:article/2243962024-02-26T15:44:21Z2024-02-26T15:44:21ZCould tardigrades have colonized the Moon?<p>Just over five years ago, on 22 February 2019, an unmanned space probe was placed in orbit around the Moon. Named <a href="https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2019-009B"><em>Beresheet</em> and built by SpaceIL and Israel Aerospace Industries</a>, it was intended to be the first private spacecraft to perform a soft landing. Among the probe’s payload were tardigrades, renowed for their ability to survive in even the harshest climates.</p>
<p>The mission <a href="https://davidson.weizmann.ac.il/en/online/sciencepanorama/what-happened-beresheet">ran into trouble from the start</a>, with the failure of “star tracker” cameras intended to determine the spacecraft’s orientation and thus properly control its motors. Budgetary limitations had imposed a pared-down design, and while the command center was able to work around some problems, things got even trickier on 11 April, the day of the landing.</p>
<p>On the way to the Moon the spacecraft had been travelling at high speed, and it needed to be slowed way down to make a soft landing. Unfortunately during the braking manoeuvre a gyroscope failed, blocking the primary engine. <a href="https://spacenews.com/spaceil-says-chain-of-events-led-to-crash-of-lunar-lander/">At an altitude of 150 m, <em>Beresheet</em> was still moving at 3,000 km/h</a>, far too fast to be stopped in time. The impact was violent – the probe shattered and its remains were scattered over a distance of around a hundred metres. We know this because the site was photographed by NASA’s LRO (Lunar Reconnaissance Orbiter) satellite on 22 April.</p>
<p><a title="NASA/GSFC/Arizona State University/Wikimedia" href="https://commons.wikimedia.org/wiki/File :Beresheet_Crash_Site_Spotted_LRO_02.gif"><img width="512" alt="Beresheet crash site spotted by LRO 02" src="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6b/Beresheet_Crash_Site_Spotted_LRO_02.gif/512px-Beresheet_Crash_Site_Spotted_LRO_02.gif"></a></p>
<h2>Animals that can withstand (almost) anything</h2>
<p>So what happened to the <a href="https://www.livescience.com/57985-tardigrade-facts.html">tardigrades</a> that were travelling on the probe? Given their remarkable abilities to survive situations that would kill pretty much any other animal, could they have contaminated the Moon? Worse, might they be able to reproduce and colonize it?</p>
<p>Tardigrades are microscopic animals that measure less than a millimetre in length. All have neurons, a mouth opening at the end of a retractable proboscis, an intestine containing a microbiota and four pairs of non-articulated legs ending in claws, and most have two eyes. As small as they are, they share a common ancestor with arthropods such as insects and arachnids.</p>
<p>Most tardigrades live in aquatic environments, but they can be found in any environment, even urban ones. <a href="https://biophysique.mnhn.fr/fr/annuaire/emmanuelle-delagoutte-9017">Emmanuelle Delagoutte</a>, a researcher at the CNRS, collects them in the mosses and lichens of the Jardin des Plantes in Paris. To be active, feed on microalgae such as chlorella, and move, grow and reproduce, tardigrades need to be surrounded by a film of water. They reproduce sexually or asexually via parthenogenesis (from an unfertilised egg) or even hermaphroditism, when an individual (which possesses both male and female gametes) self-fertilises. Once the egg has hatched, the active life of a tardigrade lasts from 3 to 30 months. A total of <a href="https://link.springer.com/book/10.1007/978-3-319-95702-9">1,265 species have been described</a>, including two fossils.</p>
<h2>Otherworldly powers</h2>
<p>Tardigrades are famous for their resistance to conditions that exist neither on Earth nor on the Moon. They can shut down their metabolism by losing up to 95% of their body water. Some species synthesise a sugar, trehalose, that <a href="https://www.nature.com/articles/s42003-022-04015-2">acts as an antifreeze</a>, while others synthesise proteins that are thought to incorporate cellular constituents into an amorphous “glassy” network that offers resistance and protection to each cell.</p>
<p>During dehydration, the tardigrade’s body can shrink to half its normal size. The legs disappear, with only the claws still visible. This state, known as <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/cryptobiosis">cryptobiosis</a>, persists until conditions for active life become favourable again.</p>
<p>Depending on the species of tardigrade, individuals need more or less time to dehydrate and not all specimens of the same species manage to return to active life. Dehydrated adults survive for a few minutes at temperatures as low as -272°C or as high as 150°C, and over the long term at high doses of gamma rays of 1,000 or 4,400 Gray (Gy). By way of comparison, a dose of 10 Gy is fatal for humans, and 40-50,000 Gy sterilises all types of material. However, whatever the dose, radiation kills tardigrade eggs. What’s more, the protection afforded by cryptobiosis is not always clear-cut, as in the case of <em>Milnesium tardigradum</em>, where radiation affects both active and dehydrated animals in the same way.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/577940/original/file-20240226-18-qtnl5g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/577940/original/file-20240226-18-qtnl5g.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/577940/original/file-20240226-18-qtnl5g.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/577940/original/file-20240226-18-qtnl5g.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/577940/original/file-20240226-18-qtnl5g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/577940/original/file-20240226-18-qtnl5g.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/577940/original/file-20240226-18-qtnl5g.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The species <em>Milnesium tardigradum</em> in its active state.</span>
<span class="attribution"><a class="source" href="https://fr.wikipedia.org/wiki/Tardigrada#/media/Fichier:SEM_image_of_Milnesium_tardigradum_in_active_state_-_journal.pone.0045682.g001-2.png">E. Schokraie, U. Warnken, A. Hotz-Wagenblatt, M.A. Grohme, S. Hengherr, et al. (2012).</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Lunar life?</h2>
<p>So what happened to the tardigrades after they crashed on the Moon? Are any of them still viable, buried under the moon’s <a href="https://en.wikipedia.org/wiki/Lunarsoil">regolith</a>, the dust that varies in depth from a few metres to several dozen metres?</p>
<p>First of all, they have to have survived the impact. <a href="https://pubmed.ncbi.nlm.nih.gov/33978458/">Laboratory tests</a> have shown that frozen specimens of the <em>Hypsibius dujardini</em> species travelling at 3,000 km/h in a vacuum were fatally damaged when they smashed into sand. However, they survived impacts of 2,600 km/h or less – and their “hard landing” on the Moon, unwanted or not, was far slower.</p>
<p>The Moon’s surface is not protected from solar particles and cosmic rays, particularly gamma rays, but here too, the tardigrades would be able to resist. In fact, Robert Wimmer-Schweingruber, professor at the University of Kiel in Germany, and his team have shown that the <a href="https://www.science.org/doi/10.1126/sciadv.aaz1334">doses of gamma rays hitting the lunar surface were permanent but low</a> compared with the doses mentioned above – 10 years’ exposure to Lunar gamma rays would correspond to a total dose of around 1 Gy.</p>
<p>But then there’s the question of “life” on the Moon. The tardigrades would have to withstand a lack of water as well as temperatures ranging from -170 to -190°C during the lunar night and 100 to 120°C during the day. A lunar day or night lasts a long time, just under 15 Earth days. The probe itself wasn’t designed to withstand such extremes and even if it hadn’t crashed, it would have ceased all activity after just a few Earth days.</p>
<p>Unfortunately for the tardigrades, they can’t overcome the lack of liquid water, oxygen and microalgae – they would never be able to reactivate, much less reproduce. Their colonising the Moon is thus impossible. Still, inactive specimens are on lunar soil and their presence raises ethical questions, as <a href="https://www.prindleinstitute.org/2019/09/the-ethics-of-sending-life-to-the-moon-and-beyond/">Matthew Silk</a>, an ecologist at the University of Edinburgh, points out. Moreover, at a time when space exploration is taking off in all directions, contaminating other planets could mean that we would lose the opportunity to detect extraterrestrial life.</p>
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<p><em>The author thanks Emmanuelle Delagoutte and Cédric Hubas of the Muséum de Paris, and Robert Wimmer-Schweingruber of the University of Kiel, for their critical reading of the text and their advice.</em></p><img src="https://counter.theconversation.com/content/224396/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Laurent Palka ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Tardigrades are tiny animals known for their extraordinary survival skills, but are they tough enough to survive a space-probe crash and conditions on the Moon?Laurent Palka, Maître de conférences, Muséum national d’histoire naturelle (MNHN)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2233572024-02-26T03:17:26Z2024-02-26T03:17:26ZOur native animals are easy prey after a fire. Could artificial refuges save them?<figure><img src="https://images.theconversation.com/files/577816/original/file-20240226-24-d5noma.jpeg?ixlib=rb-1.1.0&rect=80%2C187%2C1816%2C1348&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A tawny-crowned honeyeater in an artificial refuge</span> <span class="attribution"><span class="source">Author provided</span></span></figcaption></figure><p>Australia is home to some of the most spectacular and enigmatic wildlife on Earth. Much of it, however, is being eaten by two incredibly damaging invasive predators: the feral cat and the red fox. </p>
<p>Each year in Australia, cats and foxes kill an estimated 697 million reptiles, 510 million birds, and 1.4 billion mammals, totalling a staggering <a href="https://doi.org/10.1111/ddi.13497">2.6 billion</a> animals. Since the predators were introduced more than 150 years ago, they have contributed to the extinction of more than 25 species – and are pushing <a href="https://researchers.cdu.edu.au/en/publications/degrees-of-population-level-susceptibility-of-australian-terrestr">many more to the brink</a>.</p>
<p>Research suggests cats and foxes can be <a href="https://link.springer.com/article/10.1186/s42408-023-00183-6">more active in areas</a> recently burnt by fire. This is a real concern, especially as climate change increases the <a href="https://www.nature.com/articles/s43247-020-00065-8">frequency and severity of fire</a> in south-eastern Australia.</p>
<p>We urgently need new ways to protect wildlife after fires. Our <a href="https://doi.org/10.1016/j.biocon.2024.110501">study</a> trialled one such tool: building artificial refuges across burnt landscapes. The results are promising, but researchers need to find out more.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/kkxYqW0-SZE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Video showing a buttonquail using an artificial refuge built by the researchers.</span></figcaption>
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<h2>Triple threat: cats, foxes and fire</h2>
<p>Many native animals are <a href="https://theconversation.com/surprisingly-few-animals-die-in-wildfires-and-that-means-we-can-help-more-in-the-aftermath-174392">well-adapted to fire</a>. But the changing frequency and intensity of fire is posing a <a href="https://doi.org/10.1111/conl.12905">considerable threat</a> to much of Australia’s wildlife.</p>
<p>Fire removes vegetation such as grass, leaf litter and shrubs. This leaves fewer places for native animals to shelter and hide, making it <a href="https://www.nature.com/articles/srep22559">easier</a> for cats and foxes to <a href="https://doi.org/10.1111/brv.12853">catch them</a>. </p>
<p>We conducted <a href="https://doi.org/10.1016/j.biocon.2024.110501">our experiment</a> in three Australian ecosystems: the forests of the Otway Ranges (Victoria), the sand dunes of the Simpson Desert (Queensland) and the woodlands of Kangaroo Island (South Australia). Each had recently been burnt by fire. </p>
<p>We built 76 refuges across these study areas. They were 90cm wide and up to 50m long – and backbreaking to install! They were made from wire mesh, mostly covered by shade cloth. Spacing in the mesh of 50mm allowed small animals to enter and exit from any point, while completely excluding cats, foxes and other larger animals. The shade cloth obstructed the vision of predators.</p>
<p>We then placed <a href="https://nesplandscapes.edu.au/wp-content/uploads/2015/10/5.2.4_a_guide_to_use_of_remote_cameras_for_wildlife_surveys_final_web.pdf">remote-sensing camera traps</a> both inside and away from each refuge, and monitored them for periods ranging from four months to four years.</p>
<p>The placement of the cameras meant we could compare the effect of the refuges with what occurred outside them.</p>
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<strong>
Read more:
<a href="https://theconversation.com/a-season-in-hell-bushfires-push-at-least-20-threatened-species-closer-to-extinction-129533">A season in hell: bushfires push at least 20 threatened species closer to extinction</a>
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<h2>What we found</h2>
<p>Across the three study areas, the artificial refuges were used by 56 species or species groups. This included the critically endangered Kangaroo Island dunnart, the threatened white-footed dunnart and the threatened southern emu-wren. </p>
<p>For around half the species, we detected more individuals inside the refuges than outside. As we predicted, the activity of small birds and reptiles, in particular, was much higher inside the refuges. </p>
<p>But surprisingly, reptile activity was also generally higher inside the refuges, particularly among skinks. We had not predicted that, because the shade cloth likely made conditions inside the refuges cooler than outside, and reptiles require warmth to regulate their body temperature.</p>
<p>Over time, the number of animals detected inside the refuges generally increased. This was also a surprise. We expected detections inside the refuges to decline through time as the vegetation recovered and the risk of being seen by predators fell.</p>
<p>But there were also a few complicating factors. For example, in the Otway Ranges and Simpson Desert, similar numbers of the mammals were detected inside and away from the refuges. This suggests the species didn’t consider the refuges as particularly safe places, which means the structures may not reduce the risk of these animals becoming prey.</p>
<p>So what’s the upshot of all this? Our findings suggest that establishing artificial refuges after fire may help some small vertebrates, especially small birds and skinks, avoid predators across a range of ecosystems. However, more research is required before this strategy is adopted as a widespread management tool.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/this-critically-endangered-marsupial-survived-a-bushfire-then-along-came-the-feral-cats-185133">This critically endangered marsupial survived a bushfire – then along came the feral cats</a>
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<h2>Important next steps</h2>
<p>Almost all evidence for an increase in cat and fox activity after fire comes from <a href="https://link.springer.com/article/10.1186/s42408-023-00183-6">Australia</a>, particularly the <a href="https://www.nature.com/articles/srep22559">tropical north</a>. But cats are an invasive species in more than <a href="https://www.gbif.org/species/2435035">120 countries and islands</a>.</p>
<p>That means there’s real potential for post-fire damage to wildlife to worsen globally, especially as <a href="https://www.nature.com/articles/s43017-020-0085-3">fire risk increases</a> with climate change. </p>
<p>Our results suggest artificial refuges may be a way to help animals survive after fire. But there are still important questions to answer, such as:</p>
<ul>
<li>can artificial refuges improve the overall abundance and survival of individuals and species?</li>
<li>if so, how many refuges would be required to achieve this?</li>
<li>in the presence of natural refuges – such as rocks, logs, burrows, and unburnt patches – are artificial refuges needed?</li>
<li>does their effectiveness vary between low-severity planned burns and high-severity bushfires?</li>
</ul>
<p>These questions must be answered. Conservation budgets are tight. After fires, funds must be directed towards actions that we know will work. That evidence is not yet there for artificial refuges.</p>
<p>Our team is busy trying to find out more. We urge other ecologists and conservationists to do so as well. We also encourage collaboration with designers and technologists to improve on our refuge design. For example, can such large refuges be made <a href="https://www.australianwildlife.org/biodegradable-flat-pack-homes-to-help-wildlife-survive-after-bushfires/">biodegradable and easier to deploy</a>?</p>
<p>Solving these problems is important. It’s almost impossible to rid the entire Australian continent of cats and foxes. So land managers need all the help they can get to stop these predators from decimating Australia’s incredible wildlife. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/ytZM3Tm_oQc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The impact of roaming pet cats on Australian wildlife.</span></figcaption>
</figure><img src="https://counter.theconversation.com/content/223357/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Darcy Watchorn receives funding from the Hermon Slade Foundation, Parks Victoria, the Conservation and Wildlife Research Trust, the Ecological Society of Australia, the Victorian Environmental Assessment Council, and the Geelong Naturalists Field Club. He is a member of the Ecological Society of Australia and the Society for Conservation Biology Oceania.</span></em></p><p class="fine-print"><em><span>Chris Dickman receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Don Driscoll receives funding from the ARC, Melbourne Water and Parks Victoria. He is affiliated with the Ecological Society of Australia and the Society for Conservation Biology.</span></em></p>We need every tool at our disposal to stop feral cats and foxes from decimating Australia’s incredible wildlife after fires. Artificial refuges show promise.Darcy Watchorn, PhD Candidate, Deakin UniversityChris Dickman, Professor Emeritus in Terrestrial Ecology, University of SydneyDon Driscoll, Professor in Terrestrial Ecology, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2226102024-02-14T23:50:02Z2024-02-14T23:50:02ZAustralia’s shot-hole borer beetle invasion has begun, but we don’t need to chop down every tree under attack<figure><img src="https://images.theconversation.com/files/574604/original/file-20240209-18-7stpt1.jpg?ixlib=rb-1.1.0&rect=46%2C0%2C6183%2C4147&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/shotgunlike-lesions-on-tree-bark-trunk-1754480912">jgeyser, Shutterstock</a></span></figcaption></figure><p>A <a href="https://www.agric.wa.gov.au/borer">new pest attacking Perth’s trees</a> threatens to <a href="https://www.outbreak.gov.au/current-outbreaks/polyphagous-shot-hole-borer">spread across Australia</a>, damaging crops and native forests as well as our urban forest. To control its spread, the Western Australian government is <a href="https://www.watoday.com.au/national/western-australia/absolutely-devastating-a-tiny-exotic-beetle-will-see-180-of-hyde-park-s-trees-cut-down-20240130-p5f16n.html">chopping down hundreds of established trees</a>. But these losses may be in vain. </p>
<p>Originally from southeast Asia, the polyphagous (meaning “many-eating”) shot-hole borer has <a href="https://doi.org/10.1079/cabicompendium.18360453">invaded several countries</a>. It attacks <a href="https://www.agric.wa.gov.au/sites/gateway/files/PSHB-WA-Host-List.pdf">more than 400 tree species</a>, including <a href="https://www.agric.wa.gov.au/sites/gateway/files/PSHB-Global-Host-List.pdf">crops</a> such as apple, avocado, macadamia and mango. <a href="https://doi.org/10.3389/ffgc.2021.654702">Trees grown for timber</a>, such as ash, elms and oaks are not safe either. And with every new country it invades, it threatens an increasingly large number of native trees.</p>
<p>Australia plans to <a href="https://www.watoday.com.au/national/western-australia/absolutely-devastating-a-tiny-exotic-beetle-will-see-180-of-hyde-park-s-trees-cut-down-20240130-p5f16n.html">eradicate this pest using one method: felling established trees</a>. But the borer has been eradicated only once – in <a href="https://doi.org/10.1007/s10530-022-02929-w">isolated tropical glasshouses in frosty Europe</a> – demonstrating the difficulty of eradication from larger agricultural and natural ecosystems.</p>
<p>To achieve this worthy but difficult goal, everyone will need to work together. We need a wide range of experts to fully evaluate all available control methods, and consider the most appropriate time frame for eradication. Understanding the impacts of both the pest and its management will ensure we get the best possible outcomes in both the short and long term.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1744269134043464069"}"></div></p>
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Read more:
<a href="https://theconversation.com/trees-in-south-africa-are-under-attack-why-its-proving-hard-to-manage-130804">Trees in South Africa are under attack. Why it's proving hard to manage</a>
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<h2>The nature of the beast(s)</h2>
<p>The borer probably arrived in Australia as a stowaway with <a href="https://www.abc.net.au/news/2024-01-30/shot-hole-borer-attacks-hyde-park-trees/103406280">untreated wood</a> and remained undetected until August 2021, when a <a href="https://www.wa.gov.au/government/announcements/fremantle-residents-asked-look-exotic-insect-borer">concerned resident of East Fremantle</a> noticed unusual holes in her backyard maple trees. Now <a href="https://www.abc.net.au/news/2024-01-30/shot-hole-borer-attacks-hyde-park-trees/103406280">more than 80 suburbs</a> in 25 councils are affected. Fortunately, the pest has not yet been detected outside the Perth metropolitan area.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of Perth and the Polyphagous shot-hole borer quarantine area" src="https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=848&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=848&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=848&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1066&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1066&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1066&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The pest borer quarantine area covers 25 local government areas in Perth.</span>
<span class="attribution"><a class="source" href="https://www.agric.wa.gov.au/borer">Department of Primary Industries and Regional Development</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>The borer attacks so many tree species because it has an accomplice, in the <a href="https://doi.org/10.1016/j.fgb.2013.04.004">form of a fungus</a>. The two live in a mutually dependent “symbiotic” relationship. </p>
<p>The borer creates a Swiss cheese-like matrix of tunnels through the wood. The fungus feeds on the wood lining the tunnels as it grows, and the borer eats the fungus. </p>
<p>The tunnels weaken the structure of the wood, but tree death occurs when the fungus invades and blocks the <a href="https://doi.org/10.1038/s41598-023-48809-8">flow of water and sap between roots and leaves</a>.</p>
<p>The borer’s small size likely limits its natural rate of spread, however we <a href="https://doi.org/10.1111/afe.12321">don’t know how far it can fly</a>. There is a risk of human-assisted spread over long distances as the borer can survive in <a href="https://doi.org/10.1093/ee/nvaa103">small pieces of wood for weeks</a>. To make matters worse, a single female borer can <a href="https://doi.org/10.1111/afe.12155">produce offspring without a mate</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Six development stages of the shot hole borer, arranged in a circle to show the life cycle, on a white background" src="https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=560&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=560&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=560&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=704&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=704&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=704&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The life cycle of the polyphagous shot-hole borer, also known as the Asian ambrosia beetle (<em>Euwallacea fornicatus</em>)</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/development-stages-asian-ambrosia-beetle-euwallacea-513402742">Protasov AN, Shutterstock</a></span>
</figcaption>
</figure>
<h2>Responding to the threat in Australia</h2>
<p>The threat to Australia can be estimated from the experience in other invaded locations. As in Perth, the invasion usually begins in cities, then spreads into the surrounding countryside, attacking horticulture and forests, including <a href="https://doi.org/10.1007/s12600-012-0223-7">avocado production in Israel</a> and <a href="https://doi.org/10.1094/PDIS-03-12-0276-PDN">California</a> and <a href="https://doi.org/10.1007/s13314-023-00524-z">stone fruit in South Africa</a>. This overseas experience has informed models of <a href="https://doi.org/10.1111/afe.12566">potential impacts for WA</a>.</p>
<p>But local effects are hard to predict. Figs and eucalypts not susceptible in <a href="https://doi.org/10.3389/ffgc.2021.654702">California and Israel</a>, yet <a href="https://www.agric.wa.gov.au/sites/gateway/files/PSHB-WA-Host-List.pdf">figs are preferred and some eucalypts are susceptible in WA</a>.</p>
<p>The <a href="https://www.outbreak.gov.au/current-outbreaks/polyphagous-shot-hole-borer">national biosecurity response led by WA</a> has allocated A$41 million to eradicate the borer. This funding was based on an assessment of what it should cost. But there is only a short window of opportunity to effectively deploy these resources to achieve eradication.</p>
<p>The response includes trapping and surveillance to determine the spread of the pest. More than <a href="https://www.wa.gov.au/government/media-statements/Cook-Labor-Government/Vital-biosecurity-response-to-stop-invasive-beetle-pest-20240130">1.5 million trees on more than 50,000 properties</a> have been inspected and some 3,000 traps laid. </p>
<p>These traps catch flying beetles, which fly just once in their lives, so there’s a low catch probability. This makes it hard to detect false negatives, when no beetles are trapped but there are beetles in the area. This can be improved with alternative <a href="https://doi.org/10.7717/peerj.3656">trap designs</a> and <a href="https://doi.org/10.1371/journal.pone.0179416">chemical lures</a>.</p>
<p>When infested trees are found in WA, the response is “<a href="https://www.agric.wa.gov.au/borer">removing infested trees to save healthy trees</a>”. This could mean hundreds of trees at popular public locations such as <a href="https://www.wa.gov.au/government/media-statements/Cook-Labor-Government/Vital-biosecurity-response-to-stop-invasive-beetle-pest-20240130">Perth Zoo, Lake Claremont, Kings Park and Hyde Park</a> will be felled and chipped.</p>
<p>Continuing with the one control method, felling trees, will leave us with fewer trees, particularly if the eradication campaign runs for many years. Reduction of the <a href="https://theconversation.com/does-higher-density-city-development-leave-urban-forests-out-on-a-limb-57106">urban tree canopy</a> <a href="https://theconversation.com/fewer-trees-leave-the-outer-suburbs-out-in-the-heat-33299">could be profound</a>, and <a href="https://www.abc.net.au/news/2023-02-18/perth-tree-canopy-conference/101980438">Perth already has the sparsest urban tree canopy in the nation</a>. </p>
<p>The flow-on consequences could mean even <a href="https://theconversation.com/trees-are-a-citys-air-conditioners-so-why-are-we-pulling-them-out-21890">higher urban temperatures</a> and poorer <a href="https://doi.org/10.3389/fevo.2021.603757">human</a> <a href="https://doi.org/10.1016/j.amepre.2012.09.066">health</a>. </p>
<p>Urban trees are also valued for their beauty, shade and habitat for animals. All these benefits can be assigned a <a href="https://doi.org/10.1016/j.ufug.2017.11.017">significant monetary value, which would be even higher</a> if intrinsic or cultural value could be included.</p>
<h2>Waging war on the shot-hole borer</h2>
<p>Although felling and chipping entire trees is necessary, there are <a href="https://ipm.ucanr.edu/PMG/PESTNOTES/pn74179.html">other effective control methods</a>. Alternatives may include removing and chipping <a href="https://doi.org/10.1007/s12600-017-0598-6">infested branches only</a>, which may be more <a href="http://doi.org/10.3389/finsc.2023.1279547">cost-effective than felling entire trees</a>, to <a href="https://doi.org/10.1016/j.cropro.2020.105136">injecting at-risk but uninfested trees</a>, and <a href="https://doi.org/10.1094/PDIS-10-17-1569-RE">slowing</a> <a href="https://doi.org/10.1093/jee/toy423">infestations in trees</a> or spraying <a href="https://doi.org/10.3390/biom13040656">repellents onto uninfested trees</a>. In California, traps were developed into an <a href="https://www.californiaavocadogrowers.com/sites/default/files/Trapping-Optimization-and-Development-of-attract-and-kill-strategy-for-the-Polyphagous-Shot-Hole-Borer-in-avocado.pdf">attract-and-kill strategy</a> to tackle the borer in avocado orchards.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Polyphagous shot-hole borer trap set by the OC Parks Department and the University of California, in Irvine Regional Park. The large, multi-tiered black trap with a white collection vessel at the bottom is hanging from a metal pole." src="https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=898&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=898&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=898&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1129&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1129&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1129&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The best trap for the borer, developed in California, is not being used in Perth.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/orange-california-24-feb-2017-polyphagous-1938882280">Steve Cukrov, Shutterstock</a></span>
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</figure>
<p>While a rapid response is crucial for eradication, we need to keep improving on this, using the most effective methods available. Relevant solutions from around the world suggest <a href="https://doi.org/10.1007/s10340-024-01744-7">broader community engagement</a>, beyond Perth, would be beneficial.</p>
<p>It is unclear what has been learned so far from efforts in WA. Is it still <a href="https://doi.org/10.1007/s10530-013-0529-5">feasible to eradicate the pest completely</a>? We need more experts to evaluate and advise on the response as it continues.</p>
<p>Making the right response choices will be crucial. Just consider other threatening invaders such as the <a href="https://www.outbreak.gov.au/current-outbreaks/red-imported-fire-ant">red imported</a> <a href="https://theconversation.com/how-to-know-if-were-winning-the-war-on-australias-fire-ant-invasion-and-what-to-do-if-we-arent-121367">fire ant</a>, the honey bee <a href="https://www.outbreak.gov.au/current-outbreaks/varroa-mite">varroa</a> <a href="https://theconversation.com/australia-has-officially-given-up-on-eradicating-the-varroa-mite-now-what-214002">mite</a>, and <a href="https://www.dcceew.gov.au/environment/invasive-species/diseases-fungi-and-parasites/myrtle-rust">myrtle</a> <a href="https://theconversation.com/myrtle-rust-is-devastating-australian-forests-a-new-high-tech-spray-holds-out-hope-for-native-trees-219411">rust</a>.</p>
<p>As the borer has only been detected in Perth, the window of opportunity is open now. Let’s make sure we have the best plan of attack so we can achieve eradication. </p>
<p>Australians pride themselves on working together to get things done. If we can bring everyone together to rapidly tackle this insect invasion, the whole nation will benefit.</p>
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<strong>
Read more:
<a href="https://theconversation.com/citizen-scientists-collect-more-nature-data-than-ever-showing-us-where-common-and-threatened-species-live-212372">Citizen scientists collect more nature data than ever, showing us where common and threatened species live</a>
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<img src="https://counter.theconversation.com/content/222610/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It’s a horror story unfolding in the west that could sweep across the country. Beware the shot-hole borer, an exotic pest that threatens our tree crops, plantations, urban forests and wild places.Theo Evans, Associate Professor, The University of Western AustraliaBruce Webber, Principal Research Scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2234612024-02-14T01:12:59Z2024-02-14T01:12:59ZA secret war between cane toads and parasitic lungworms is raging across Australia<p>When the first cane toads were brought from South America to Queensland in 1935, many of the parasites that troubled them were left behind. But deep inside the lungs of at least one of those pioneer toads lurked small nematode lungworms.</p>
<p>Almost a century later, the toads are evolving and spreading across the Australian continent. In <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2023.2403">new research</a> published in Proceedings of the Royal Society B, we show that the lungworms too are evolving: for reasons we do not yet understand, worms taken from the toad invasion front in Western Australia are better at infecting toads than their Queensland cousins.</p>
<h2>An eternal arms race</h2>
<p>Nematode lungworms are tiny threadlike creatures that live in the lining of a toad’s lung, suck its blood, and release their eggs through the host’s digestive tract. The larva that hatch in the toad’s droppings lie in wait for a new host to pass by, then penetrate through its skin and migrate through the amphibian’s body to find the lungs and settle into a comfortable life, and begin the cycle anew.</p>
<p>Parasites and their hosts are locked into an eternal arms race. Any characteristic that makes a parasite better at finding a new host, setting up an infection, and defeating the host’s attempts to destroy it, will be favoured by natural selection. </p>
<p>Over generations, parasites get better and better at infecting their hosts. But at the same time, any new trick that enables a host to detect, avoid or repel the parasites is favoured as well. </p>
<p>So it’s a case of parasites evolving to infect, and hosts evolving to defeat that new tactic. Mostly, parasites win because they have so many offspring and each generation is very short. As a result, they can evolve new tricks faster than the host can evolve to fight them. </p>
<h2>The march of the toads</h2>
<p>The co-evolution between hosts and parasites is most in sync among the ones in the same location, because they encounter each other most regularly. A parasite is usually better able to <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1461-0248.2007.01028.x">infect hosts from the local population</a> it encounters regularly than those from a distant population.</p>
<p>But when hosts invade new territory, it can play havoc with the evolutionary matching between local hosts and parasites. </p>
<p>Since cane toads were released into the fields around Cairns in 1935, the toxic amphibians have hopped some 2,500 kilometres westwards and are currently on the doorstep of Broome. And they have <a href="https://www.nature.com/articles/439803a">changed dramatically</a> along the way. </p>
<p>The Queensland toads are homebodies and spend their lives in a small area, often reusing the same shelter night after night. As a result, their populations can build up to high densities. </p>
<p>For a lungworm larva, having lots of toads in a small area, reusing and sharing shelter sites, makes it simple to find a new host. But at the invasion front (currently in Western Australia), <a href="https://www.publish.csiro.au/wr/WR08021">toads are highly mobile</a>, moving over a kilometre per night when conditions permit, and rarely spending two nights in the same place. </p>
<p>At the forefront of the invasion, toads are few and far between. A lungworm larva at the invasion front, waiting in the soil for a toad to pass by, will have <a href="https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/09-0530.1">few opportunities</a> to encounter and infect a new host. </p>
<h2>Lungworms from the invasion front</h2>
<p>When hosts are rare, we expect the parasite will evolve to get better at infecting the ones it does encounter, because it is unlikely to get a second chance.</p>
<p>To understand how this co-evolution is playing out between cane toads and their lungworms, we did some experiments pairing hosts and parasites from different locations in Australia. What would happen when toad and lungworm strains that had been separated by 90 years of invasion were reintroduced to each other?</p>
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<em>
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Read more:
<a href="https://theconversation.com/is-toadzilla-a-sign-of-enormous-cane-toads-to-come-its-possible-toads-grow-as-large-as-their-environment-allows-195929">Is 'Toadzilla' a sign of enormous cane toads to come? It's possible – toads grow as large as their environment allows</a>
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<p>To study this we collected toads from different locations, bred them in captivity and reared the offspring in the lab under common conditions. We then exposed them to 50 lungworm larvae from a different area of the range, waited four months for infections to develop, then killed the toads and counted how many adult worms had successfully established in their lungs.</p>
<p>As expected, worms from the invasion front were best at infecting toads, not just their local ones. Behind the invasion front, in intermediate and old populations we found that hosts were able to fight their local parasites better than those from distant populations. </p>
<p>While we saw dramatic differences in infection outcomes, we have yet to determine what biochemical mechanisms caused the differences and how changes in genetic variation of host and parasite populations might have shaped them. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/in-the-evolutionary-arms-race-between-cane-toads-and-lungworms-skin-secretions-play-a-surprising-role-163821">In the evolutionary arms race between cane toads and lungworms, skin secretions play a surprising role</a>
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<img src="https://counter.theconversation.com/content/223461/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lee A Rollins receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Rick Shine receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Greg Brown does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Cane toads are evolving as they spread across Australia. Parasitic lungworms are becoming more infectious to keep up.Greg Brown, Postdoctoral researcher, Macquarie UniversityLee A Rollins, Scientia Associate Professor, UNSW SydneyRick Shine, Professor in Evolutionary Biology, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2227592024-02-12T03:40:47Z2024-02-12T03:40:47ZThe good news: 25 Australian birds are now at less risk of extinction. The bad news: 29 are gone and 4 more might be<figure><img src="https://images.theconversation.com/files/574559/original/file-20240209-20-jdrrpv.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3982%2C2656&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/southern-cassowary-known-doublewattled-1845050383">mujiri/Shutterstock</a></span></figcaption></figure><p>What does it mean to save threatened species? How often do we achieve it? And how often do we fail? Our new research answers these questions for Australian birds.</p>
<p>One of the goals of conservation is to reduce the risk of a species becoming extinct. While this might be seen as a low bar for conservation managers, it is seldom achieved. A new set of <a href="https://doi.org/10.1080/01584197.2024.2304903">research papers</a> on the conservation of Australian birds looks at cases of success over the <a href="https://doi.org/10.1080/01584197.2023.2291140">past 30 years</a> and where we have failed over the <a href="https://doi.org/10.1080/01584197.2023.2240345">past 200</a>.</p>
<p>We found extinction risks had reduced for 25 bird species and subspecies in at least one of the decades between 1990 and 2020. <a href="https://doi.org/10.1080/01584197.2024.2304903">Nine of these</a> would have gone extinct if not for hard work and expertise to prevent it happening.</p>
<p>The most effective action has been eradicating invasive species from islands. This work benefited 13 birds. </p>
<p>Most Australians <a href="https://www.sciencedirect.com/science/article/abs/pii/S000632072100375X">approve of killing invasive species</a> to save threatened species. They have good reason: it works.</p>
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Read more:
<a href="https://theconversation.com/ridding-macquarie-island-of-pests-pays-off-as-seabirds-come-back-from-the-brink-but-recovery-has-just-begun-221992">Ridding Macquarie Island of pests pays off as seabirds come back from the brink – but recovery has just begun</a>
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<h2>What were the successes?</h2>
<p>Nine of these successes are <a href="https://theconversation.com/ridding-macquarie-island-of-pests-pays-off-as-seabirds-come-back-from-the-brink-but-recovery-has-just-begun-221992">seabirds nesting on Macquarie Island</a>. The <a href="https://www.theguardian.com/environment/2022/aug/10/rats-and-rabbits-invasive-species-macquarie-island-southern-ocean-aoe">program there</a> was so successful it had a significant positive impact on <a href="https://doi.org/10.1080/01584197.2023.2289999">Australia’s Red List Index for birds</a>, a way of measuring overall progress on threatened species status. </p>
<p>This success also changed the <a href="https://doi.org/10.1080/01584197.2023.2285821">average characteristics</a> of Australian threatened birds. Before the pest eradications on Macquarie Island, large seabirds dominated the profile of the threatened Australian birds. Now the average threatened bird is smaller and lives on land. </p>
<p>Further programs have the potential to have a similar impact. The likely huge benefits from <a href="https://lhirodenteradicationproject.org/">eradicating rodents</a> from Lord Howe Island, for example, are yet to show up in these figures.</p>
<p>Another four birds benefited simply from having their habitat protected. Protection of rainforest reduced extinction risk for the southern cassowary (<em><a href="https://ebird.org/species/soucas1">Casuarius casuarius</a></em>) and Albert’s lyrebird (<em><a href="https://ebird.org/species/alblyr1">Menura alberti</a></em>). One of the largest national parks in New South Wales <a href="https://npansw.org.au/2020/11/03/ambitious-expansion-of-national-parks-warmly-welcomed/">was acquired</a> for the Bulloo grey grasswren (<em><a href="http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=67065">Amytornis barbatus barbatus</a></em>). The Tasmanian wedge-tailed eagle (<a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=64435#:%7E:text=The%20Wedge%2Dtailed%20Eagle%20(Tasmanian)%20is%20a%20large%20bird,(Bell%20%26%20Mooney%201998).">Aquila audax fleayi</a>) also had more of its nesting habitat protected.</p>
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Read more:
<a href="https://theconversation.com/prince-albert-had-nothing-to-do-with-the-lyrebird-bearing-his-name-should-our-birds-be-named-after-people-217792">Prince Albert had nothing to do with the lyrebird bearing his name. Should our birds be named after people?</a>
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<p>For another species, simply enforcing the law reduced the threat. In south-western Australia, culling of Muir’s corella (<em><a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=25981">Cacatua pastinator pastinator</a></em>) for agriculture threatened it with extinction. Now, with better protection, there are <a href="https://www.dbca.wa.gov.au/management/muirs-corella-management-western-australia">thousands</a>.</p>
<p>Some threatened birds have benefited from intensive interventions by dedicated conservation agencies, non-government organisations and individuals. </p>
<p>Translocations of <a href="https://ebird.org/species/goupet1/">Gould’s petrels</a> to <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320705004416">new breeding islands</a> and of eastern bristlebirds (<em><a href="https://ebird.org/species/easbri1/">Dasyornis brachypterus</a></em>) to <a href="https://parksaustralia.gov.au/news/eastern-bristlebird-translocation-success/">heathlands</a> were exemplary. </p>
<p>Very few glossy black-cockatoos (<a href="https://www.dcceew.gov.au/environment/biodiversity/threatened/recovery-plans/south-australian-subspecies-glossy-black-cockatoo-calyptorhynchus-lathami-halmaturinus"><em>Calyptorhynchus lathami halmaturinus</em></a>) on Kangaroo Island were nesting successfully before their <a href="https://www.researchgate.net/publication/339831737_From_the_brink_of_extinction_successful_recovery_of_the_glossy_black-cockatoo_on_Kangaroo_Island">nests were protected</a> from predatory possums. </p>
<p>Rats twice <a href="https://www.researchgate.net/publication/320411348_Back_from_the_brink_-_again_the_decline_and_recovery_of_the_Norfolk_Island_green_parrot">almost wiped out</a> Norfolk Island green parrots <a href="https://ebird.org/species/noipar1/"><em>Cyanoramphus novaezelandiae cookii</em></a>. Their population has <a href="https://www.tandfonline.com/doi/full/10.1080/01584197.2023.2267606">increased ten-fold</a> since nests have been better protected.</p>
<p>These examples show our society can make changes that help to prevent extinctions. </p>
<figure class="align-center ">
<img alt="A glossy black-cockatoo eats seeds from a casuarina tree on Kangaroo Island" src="https://images.theconversation.com/files/574560/original/file-20240209-29-9fdvn2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574560/original/file-20240209-29-9fdvn2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574560/original/file-20240209-29-9fdvn2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574560/original/file-20240209-29-9fdvn2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574560/original/file-20240209-29-9fdvn2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574560/original/file-20240209-29-9fdvn2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574560/original/file-20240209-29-9fdvn2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Protecting glossy black-cockatoo nests from possums on Kangaroo Island has boosted the population.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/glossy-black-cockatoo-picks-casuarina-seed-2120254118">Paleokastritsa/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-identified-the-63-animals-most-likely-to-go-extinct-by-2041-we-cant-give-up-on-them-yet-182155">We identified the 63 animals most likely to go extinct by 2041. We can't give up on them yet</a>
</strong>
</em>
</p>
<hr>
<h2>There have also been setbacks</h2>
<p>Our stories contain salutary lessons too. The pathway to recovery can have reversals.</p>
<p>In the past decade, Gould’s petrel and the bristlebird have <a href="https://doi.org/10.1080/01584197.2023.2291140">suffered setbacks</a> due to new or escalating threats. A <a href="https://afo.birdlife.org.au/afo/index.php/afo/article/view/2304">new report</a> suggests Tasmanian wind farms are killing and injuring significant numbers of eagles – and many more windfarms are planned.</p>
<p>Our analysis of improvements in the conservation outlook for Australian birds was complemented with an assessment of <a href="https://doi.org/10.1080/01584197.2023.2240345">Australian bird extinctions</a>. Sadly, we found extinctions are continuing. </p>
<p>Even with the conservation effort of the past 30 years since Australia’s first endangered species legislation, three birds are gone forever. The Mount Lofty Ranges spotted quail-thrush (<em><a href="https://www.dcceew.gov.au/environment/biodiversity/threatened/conservation-advices/cinclosoma-punctatum-anachoreta">Cinclosoma punctatum anachoreta</a></em>), white-chested white-eye (<a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=25899"><em>Zosterops albogularis</em></a>) and southern star finch (<em><a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=26027">Neochmia ruficauda ruficauda</a></em>) were still surviving in the 1990s, but were extinct by 2010. </p>
<p>The number of extinct birds has risen steadily since Australia was colonised in 1788. There was an initial burst of extinctions on islands, particularly big birds that were good to eat and probably had small populations. More recent losses have tended to be small birds whose mainland habitat has been cleared or modified.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/scientists-re-counted-australias-extinct-species-and-the-result-is-devastating-127611">Scientists re-counted Australia's extinct species, and the result is devastating</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/574558/original/file-20240209-18-5jl1x3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A museum specimen of a white-breasted white-eye, now an extinct bird" src="https://images.theconversation.com/files/574558/original/file-20240209-18-5jl1x3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574558/original/file-20240209-18-5jl1x3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574558/original/file-20240209-18-5jl1x3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574558/original/file-20240209-18-5jl1x3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574558/original/file-20240209-18-5jl1x3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574558/original/file-20240209-18-5jl1x3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574558/original/file-20240209-18-5jl1x3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The white-breasted white-eye is now found only in museum collections, having gone extinct by 2010.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Naturalis_Biodiversity_Center_-_RMNH.AVES.133455_1_-_Zosterops_albogularis_Gould,_1837_-_Zosteropidae_-_bird_skin_specimen.jpeg">Naturalis Biodiversity Center/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>29 birds are gone, but we can halt the losses</h2>
<p>At present, 29 Australian birds are known to have become extinct. It’s a <a href="https://theconversation.com/scientists-re-counted-australias-extinct-species-and-the-result-is-devastating-127611">lower percentage than for mammals</a> but still far too high. </p>
<p>Grave fears are held for <a href="https://theconversation.com/we-identified-the-63-animals-most-likely-to-go-extinct-by-2041-we-cant-give-up-on-them-yet-182155">another four</a> – the Tiwi hooded robin (<em><a href="http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=67092">Melanodryas cucullata melvillensis</a></em>), buff-breasted button-quail (<em><a href="https://ebird.org/species/bubbut1?siteLanguage=en_AU">Turnix olivii</a></em>), Coxen’s fig-parrot (<em><a href="http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=59714">Cyclopsitta diophthalma coxeni</a></em>) and Cape Range rufous grasswren (<em><a href="https://bioone.org/journals/bulletin-of-the-british-ornithologists-club/volume-140/issue-2/bboc.v140i2.2020.a6/Two-new-but-threatened-subspecies-of-Rufous-Grasswren-Amytornis-whitei/10.25226/bboc.v140i2.2020.a6.full">Amytornis striatus parvus</a></em>). We don’t know whether they persist or not.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-the-buff-breasted-button-quail-still-alive-after-years-of-searching-this-century-old-bird-mystery-has-yet-to-be-solved-175647">Is the buff-breasted button-quail still alive? After years of searching, this century-old bird mystery has yet to be solved</a>
</strong>
</em>
</p>
<hr>
<p>For the 29 extinct birds, we can do nothing. The important lesson is that this number of losses need grow no more. We have the resources and skills to prevent extinction.</p>
<p>A recent <a href="https://www.abc.net.au/news/2024-01-31/bob-brown-judge-logging-suspension-tasmania-rare-swift-parrot/103411922">court order</a> halting forestry activity in swift parrot (<em><a href="https://ebird.org/species/swipar1/">Lathamus discolor</a></em>) habitat suggests at least some environmental laws are making a difference. </p>
<p>Other judgments expose legal shortcomings and show how much more needs to be done. The revisions of national environmental laws <a href="https://www.agriculture.gov.au/sites/default/files/documents/pathway-reforming-national-environmental-law.pdf">now being negotiated</a> provide an opportunity to fill loopholes through which threatened species might fall.</p>
<p>Extinctions are neither accidental nor deliberate. They are a failure of policy and people. </p>
<p>However, the examples of birds whose risk of extinction has declined show what can be achieved. While some of these improvements were mostly a matter of good luck, many were the result of hard work, advocacy, investment and well-judged interventions. And they give the world hope.</p><img src="https://counter.theconversation.com/content/222759/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Woinarski is affiliated with Charles Darwin University, the Australian Wildlife Conservancy and the Biodiversity Council.</span></em></p><p class="fine-print"><em><span>Sarah Legge receives funding from the Australian Research Council. She is a member of the Biodiversity Council; the Conservation and Science Committee for the Invasive Species Council; and the Threatened Species Committee for Birds Australia.</span></em></p><p class="fine-print"><em><span>Stephen Garnett receives funding from the Australian Research Council. He is affiliated with BirdLife Australia. </span></em></p>It’s hard work saving birds from extinction, but we have the evidence of successful interventions to show we can avoid further losses.John Woinarski, Professor of Conservation Biology, Charles Darwin UniversitySarah Legge, Professor of Wildlife Ecology, Australian National UniversityStephen Garnett, Professor of Conservation and Sustainable Livelihoods, Charles Darwin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2206532024-01-25T20:46:32Z2024-01-25T20:46:32ZThe botanical imperialism of weeds and crops: how alien plant species on the First Fleet changed Australia<figure><img src="https://images.theconversation.com/files/570269/original/file-20240119-22-lcj7rr.jpg?ixlib=rb-1.1.0&rect=34%2C22%2C7618%2C3774&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://collection.sl.nsw.gov.au/record/Ydma46R9/8pg0LrwplLmxJ">Dixson Library, State Library of New South Wales</a></span></figcaption></figure><p>Locally grown produce fills Australian shops, but almost all of these species were imported, as native as cane toads. Icons of Australian agriculture, like the Big Banana and Big Pineapple, proudly display the regions’ crops, but these are newcomers to the continent.</p>
<p>British ships carrying plants and seeds from around the world arrived in Botany Bay on <a href="https://firstfleetfellowship.org.au/ships/the-voyage/">January 20 1788</a>. This story is overshadowed by convict ships and Royal Navy vessels, but the cargo on board also had a lasting impact. Colonists, convicts and Indigenous Australians were all affected when new species transformed the landscape.</p>
<p>British colonists introduced plants as foreign as the people who carried them. Some of these plants, ranging from <a href="https://firstfleetfellowship.org.au/wp-content/uploads/2013/11/PLANTS-AND-SEEDS-FROM-RIO-DE-JANEIRO-pdf.pdf">bananas to wheat</a>, were food sources, promoting self-sufficiency. Others were attempts to expand the British Empire. Could the new territory be exploited as a tropical plantation? </p>
<h2>Botanical imperialism</h2>
<p>In the parliamentary debate over destinations for convict transportation, Sir Joseph Banks and James Matra, both members of James Cook’s 1770 expedition, spruiked the potential of the new colony as an extension of the empire. </p>
<p><a href="https://www.google.com.au/books/edition/Historical_Records_of_New_South_Wales_pa/ML4NAAAAYAAJ?hl=en&gbpv=1">Matra claimed</a> the colony was “fitted for production” of “sugar-cane, tea, coffee, silk, cotton, indigo and tobacco”. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=898&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=898&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=898&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1129&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1129&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1129&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sir Joseph Banks.</span>
<span class="attribution"><a class="source" href="https://victoriancollections.net.au/items/64a215525a416af5117dd67e">Victorian Collections</a></span>
</figcaption>
</figure>
<p><a href="https://australian.museum/learn/first-nations/unsettled/recognising-invasions/plans-for-a-colony/">Banks claimed</a> Botany Bay was an “advantageous” site, with fertile soil – and virtually no inhabitants. </p>
<p>Two plants carried by the First Fleet stand out as examples of botanical imperialism: prickly pear cactus (Opuntia) and sugarcane. Banks, as head of the Royal Society of London, selected these species as experiments to compete with European trade rivals. </p>
<p>His goal was to break a Spanish monopoly in producing fabric dye and to expand British cultivation of sugar outside the West Indies.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-captain-cook-to-the-first-fleet-how-botany-bay-was-chosen-over-africa-as-a-new-british-penal-colony-128002">From Captain Cook to the First Fleet: how Botany Bay was chosen over Africa as a new British penal colony</a>
</strong>
</em>
</p>
<hr>
<h2>The secret of the colour scarlet</h2>
<p>Prickly pear cactus was imported because it is the preferred food of the cochineal insect. Dried <a href="https://www.webexhibits.org/causesofcolor/7.html#google_vignette">cochineal</a> were crushed to make a vibrant, colourfast scarlet dye for textiles. Discovered in the New World by Spanish colonists, cochineal replaced kermes, another insect that had provided red dye since antiquity. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and White Photo" src="https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=805&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=805&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=805&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1012&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1012&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1012&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Man standing in an invasive prickly pear forest in Queensland, 1935.</span>
<span class="attribution"><a class="source" href="https://www.archivessearch.qld.gov.au/items/ITM1143347">Queensland State Archives</a></span>
</figcaption>
</figure>
<p>Cochineal dye was ten times stronger than kermes or vegetable dyes. From cardinals’ capes to British officers’ red coats, cochineal was a product for elite consumers signifying power, wealth and prestige.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and white photo, looks like a haystack" src="https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=945&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=945&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=945&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1187&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1187&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1187&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">2,200,000 eggs of cactus moth, collected to combat the invasive prickly pear in 1928.</span>
<span class="attribution"><a class="source" href="https://onesearch.slq.qld.gov.au/permalink/61SLQ_INST/1dejkfd/alma99183712416402061">State Library of Queensland</a></span>
</figcaption>
</figure>
<p>New Spain, based in Mexico, had a monopoly on cochineal. Banks wanted to break the stranglehold on the scarlet dye by establishing production in New South Wales. Plants infested with the precious insects were imported from Brazil in 1788. </p>
<p>The project soon failed when the cochineal died, but the cacti survived. Colonists used cacti as natural fences and drought-resistant animal fodder. Without insects to feed on them the plants spread, uncontrolled, to cover more than <a href="https://www.nma.gov.au/defining-moments/resources/prickly-pear-eradication">60 million acres</a> of eastern Australia by the 1920s. Poison, crushing and fire failed to stop the cactus.</p>
<p>In 1926, a moth species from Argentina was introduced to eradicate the plants, but Opuntia cacti remain an environmental hazard. Trade in the plants, classified as <a href="https://weeds.dpi.nsw.gov.au/WeedListPublics/CategoryResults?showImages=True&categoryId=1&pageTitle=Weeds%20of%20National%20Significance">weeds of national significance</a>, is banned in most states.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/exposing-australias-online-trade-in-pest-plants-weve-found-thousands-of-illegal-advertisements-212647">Exposing Australia's online trade in pest plants – we've found thousands of illegal advertisements</a>
</strong>
</em>
</p>
<hr>
<h2>The first sugar grown in Australia</h2>
<p>Sugarcane was imported from the Cape Colony, now South Africa. Before sugar was planted in Queensland, or even Port Macquarie, in the 19th century, sugar was grown in a small garden plot in Sydney and as an experimental crop on Norfolk Island in 1788.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration of a house on Sydney Harbour" src="https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=501&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=501&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=501&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=630&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=630&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=630&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sugarcane was first grown in garden plots in Sydney.</span>
<span class="attribution"><a class="source" href="https://archival.sl.nsw.gov.au/Details/archive/110316551">Mitchell Library, State Library of New South Wales</a></span>
</figcaption>
</figure>
<p>The Royal Navy targeted Norfolk Island as a source of flax and timber, but it also served as an agricultural laboratory, testing tropical crops like sugar and coffee for Banks.</p>
<p>Philip Gidley King, lieutenant-governor of Norfolk Island, reported in his correspondence with Banks in 1790 that his four canes had multiplied into more than 100 plants. Within a few years he sent <a href="https://transcripts.sl.nsw.gov.au/page/letter-received-banks-philip-gidley-king-8-may-1792-series-39004-no-0004">samples</a> of sugar, rum and molasses to Sydney. By 1798, the cane was declared “prolific” and Norfolk Island was in “a state of cultivation equal to the West Indies”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and white photo" src="https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">South Sea Islander workers standing in a sugarcane field in Queensland.</span>
<span class="attribution"><a class="source" href="https://onesearch.slq.qld.gov.au/permalink/61SLQ_INST/tqqf2h/alma99183799211402061">State Library of Queensland</a></span>
</figcaption>
</figure>
<p>This favourable comparison with the West Indies ignores the use of convict labour in producing sugar, and foreshadows the advent of “<a href="https://theconversation.com/from-the-caribbean-to-queensland-re-examining-australias-blackbirding-past-and-its-roots-in-the-global-slave-trade-158530">blackbirding</a>”, a euphemism for the abduction or coercion of Melanesian workers. Blackbirding was introduced in Queensland canefields in <a href="https://www.nma.gov.au/defining-moments/resources/islander-labourers">1863</a> as penal transportation ended and cheap convict labour became unavailable. </p>
<p>Once essential to the sugar industry, in 1901 Pacific Islanders in Australia were deemed undesirable, competing unfairly with white workers. As part of the White Australia Policy, many were deported under the <a href="https://humanrights.gov.au/our-work/race-discrimination/publications/australian-south-sea-islanders-century-race">Pacific Island Labourers Act 1901</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-the-caribbean-to-queensland-re-examining-australias-blackbirding-past-and-its-roots-in-the-global-slave-trade-158530">From the Caribbean to Queensland: re-examining Australia's 'blackbirding' past and its roots in the global slave trade</a>
</strong>
</em>
</p>
<hr>
<h2>The fruits of empire</h2>
<p>Reconsidering the impact of alien plant species on Australia gives us additional insight into the process of colonisation. </p>
<p>Transplanting species from around the world to create a new environment was a major endeavour in the 18th century, and a manifestation of imperial power and control. </p>
<p>Indigenous connections with Country were disrupted when foreign botanical landscapes displaced native species. The roots of these early imperial projects are deeply embedded in Australian culture and history, with an enduring legacy.</p><img src="https://counter.theconversation.com/content/220653/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Garritt C. Van Dyk does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It wasn’t just colonists and convicts who invaded Australia in 1788 – invasive plant species arrived too.Garritt C. Van Dyk, Lecturer in History, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2207192024-01-17T09:05:15Z2024-01-17T09:05:15ZWe are losing tetrapod species at a faster rate than we are rediscovering them<figure><img src="https://images.theconversation.com/files/569552/original/file-20240116-22672-a3vxe4.jpeg?ixlib=rb-1.1.0&rect=8%2C20%2C1908%2C1256&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Voeltzkow’s chameleon was rediscovered in Madagascar in 2018.</span> <span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/2583347">Martin Mandák/iNaturalist </a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Lost species are those that have not been observed in the wild for over ten years, despite searches to find them. Lost tetrapod species (four-limbed vertebrate animals including amphibians, birds, mammals and reptiles) are a global phenomenon – there are more than 800 of them, and they are broadly distributed worldwide.</p>
<p><a href="https://onlinelibrary.wiley.com/doi/10.1111/gcb.17107">Our research</a>, published today in the journal <em>Global Change Biology</em>, attempts to pin down why certain tetrapod species are rediscovered but others not. It also reveals that the number of lost tetrapod species is increasing decade-on-decade. This means that despite many searches, we are losing tetrapod species at a faster rate than we are rediscovering them. In particular, rates of rediscovery for lost amphibian, bird and mammal species have slowed in recent years, while rates of loss for reptile species have increased.</p>
<p>This is not good news. Species are often lost because their populations have shrunk to a very small size due to human threats like hunting and pollution. Consequently, many lost species are in danger of becoming extinct (in fact, some probably are extinct). However, it is difficult to protect lost species from extinction because we don’t know where they are.</p>
<h2>Rediscoveries lead to conservation action</h2>
<p>In 2018, researchers in Colombia successfully searched for the <a href="https://www.iucnredlist.org/species/22735460/181746724">Antioquia brush-finch</a> (<em>Atlapetes blancae</em>), a bird species unrecorded since 1971. This rediscovery led to <a href="https://www.rainforesttrust.org/urgent-projects/last-stand-for-the-antioquia-brush-finch/">the establishment of a reserve</a> to protect the remaining population of the brush-finch, which is tiny and threatened by habitat loss caused by agricultural expansion and climate change.</p>
<p>The <a href="https://www.smithsonianmag.com/smart-news/scientists-find-the-extinct-victorian-earless-dragon-not-seen-since-1969-180982440/">Victorian grassland earless dragon</a> (<em>Tympanocryptis pinguicolla</em>) was rediscovered in Australia last year. It hadn’t been recorded for 54 years, and was presumed to be extinct, due to the loss of its grassland habitat and predation by invasive alien species including feral cats. Its rediscovery resulted in <a href="https://minister.dcceew.gov.au/plibersek/media-releases/joint-media-release-reptile-thought-be-extinct-rediscovered-victoria">government funding</a> to trial new survey techniques to find further populations of the species, a breeding program, and the preparation of a species recovery plan.</p>
<p>Thus, rediscoveries are important: they provide evidence of the continued existence of highly threatened species, prompting funding for conservation action. The results or our study may help to prioritise searches for lost species. In the image below, we mapped their global distribution, identifying regions with many lost and few rediscovered species.</p>
<h2>What factors influence rediscovery?</h2>
<p>Sadly, many quests to find lost species are unsuccessful. In 1993, searches in Ghana and the Ivory Coast over seven years failed to rediscover a lost primate, <a href="https://www.science.org/content/article/where-have-you-gone-miss-waldrons-red-colobus">Miss Waldron’s red colobus</a> (<em>Piliocolobus waldronae</em>). The research team concluded that this noisy and conspicuous monkey, unrecorded since 1978, may well be extinct. Its demise has been caused by hunting and the destruction of its forest habitat. Further searches in 2005, 2006 and 2019 were also unsuccessful, although <a href="https://iucn.org/resources/publication/red-colobus-piliocolobus-conservation-action-plan-2021-2026">calls that were possibly by this species were heard in 2008</a>.</p>
<p>In 2010, searches for the Mesopotamia beaked toad (<em>Rhinella rostrata</em>), unrecorded in Colombia since 1914, were unsuccessful (<a href="https://news.mongabay.com/2010/11/pictures-mr-burns-frog-discovered-in-colombia-along-with-2-other-new-species/">but did lead to the discovery of three new amphibian species</a>). Last year’s search for the <a href="https://www.rewild.org/lost-species/sinu-parakeet">Sinú parakeet</a> (<em>Pyrrhura subandina</em>), unrecorded in Colombia since 1949, was also unsuccessful. Nevertheless, the project team did identify the presence of <a href="https://www.birdguides.com/articles/conservation/exciting-rediscoveries-boost-hopes-of-finding-sinu-parakeet/">ten other parrot species in the survey area and large tracts of suitable habitat</a>, giving hope for the continued existence of the Sinú parakeet.</p>
<p>So why is it that some species are rediscovered while others remain lost? Are there specific factors that influence rediscovery? We aimed to answer these questions in our study, in order to improve our ability to distinguish between the types of lost species we can rediscover, from those that we cannot, because they are extinct.</p>
<p>Our project team comprised members of the organisation <a href="https://www.rewild.org/lost-species">Re:wild</a>, which has been leading efforts to search for lost species since 2017, along with species experts from the <a href="https://www.iucn.org/our-union/commissions/species-survival-commission">International Union for Conservation of Nature (IUCN) Species Survival Commission</a> (SSC).</p>
<p>We compiled <a href="https://doi.org/10.5061/dryad.c866t1gdf">a database of 856 lost and 424 rediscovered tetrapod species</a> (amphibians, birds, mammals and reptiles). We then proposed three broad hypotheses about factors that might influence rediscovery: characteristics of (i) tetrapod species, and (ii) the environment influence rediscovery, and (iii) human activities influence rediscovery.</p>
<p>For example, body mass (a species characteristic) may positively influence rediscovery, as larger lost species should be easier to find. Lost species occupying dense forests (a characteristic of the environment) may not be rediscovered as searching for them is difficult. Lost species affected by threats associated with human activities (e.g., invasive alien species, which are being spread to new locations by global trade) may not be rediscovered, as they may be extinct.</p>
<p>Based on these hypotheses, we collected data on a series of variables associated with each lost and rediscovered species (for example, their body mass), which we then analysed for their influence on rediscovery.</p>
<h2>Hard to find + neglected = rediscovered</h2>
<p>On the upside, our results suggest that while many lost species are difficult to find, with some effort and the use of new techniques, they are likely to be rediscovered. These species include those that are very small (including many lost reptile species), those that live underground, those that are nocturnal, and those living in areas that are difficult to survey.</p>
<p>In fact, since the completion of our study, <a href="https://www.theguardian.com/environment/2023/nov/30/back-from-the-brink-de-wintons-golden-mole-feared-extinct-rediscovered-after-86-years-aoe">De Winton’s Golden Mole</a> (<em>Cryptochloris wintoni</em>) has been rediscovered in South Africa. This species hadn’t been recorded in the wild since 1937. It lives underground much of the time, so searches were conducted using techniques including environmental DNA and thermal imaging.</p>
<p>Our results also suggest some species are neglected by conservation scientists, particularly those that are not considered to be charismatic, such as reptiles, small species and rodents. Searches for these species may also be rewarded with success. Voeltzkow’s chameleon (<em>Furcifer voeltzkowi</em>), a small reptile species, was <a href="https://www.livescience.com/lost-chameleon-rediscovered-after-century.html">rediscovered in Madagascar in 2018</a>.</p>
<h2>Lost or extinct?</h2>
<p>Unfortunately, our results also suggest that some lost species are unlikely to be found no matter how hard we look, because they are extinct. For example, remaining lost mammal species are, on average, three times larger than rediscovered mammal species. Some of these large, charismatic, conspicuous species should have been rediscovered by now.</p>
<p>Furthermore, one third of remaining lost mammal species are endemic to islands, where tetrapod species are <a href="https://www.sciencedirect.com/science/article/pii/S2351989421003978">particularly vulnerable to extinction</a>. The Bramble Cay melomys (<em>Melomys rubicola</em>), which was once considered to be a lost species, has recently been <a href="https://www.dcceew.gov.au/environment/biodiversity/threatened/nominations/comment/bramble-cay-melomys-2018">declared extinct</a> by the Australian Government. It occupied a small island that has been extensively surveyed – if it still existed it should have been rediscovered by now.</p>
<p>Lost bird species have, on average, been missing for longer than those that have been rediscovered (28% have been missing for more than 100 years), and many have been searched for on several occasions – perhaps some of these species should also have been rediscovered by now.</p>
<p>Nevertheless, unexpected rediscoveries of long-lost species like the <a href="https://www.edgeofexistence.org/species/cebu-flowerpecker/">Cebu flowerpecker</a> (<em>Dicaeum quadricolor</em>) do occur, so we shouldn’t lose hope, and we should definitely keep searching. However, some searches are being carried out for long-lost species that are considered to be extinct, such as the <a href="https://www.sciencedirect.com/science/article/pii/S0048969723014948">thylacine</a> (<em>Thylacinus cynocephalus</em>). Perhaps the limited resources available for biodiversity conservation would be better used to search for lost species likely to still exist.</p>
<hr>
<p><em>The author’s former MSc student, Tim Lindken, contributed to writing this article.</em></p><img src="https://counter.theconversation.com/content/220719/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Evans received funding from The Alexander von Humboldt Foundation.</span></em></p>There are hundreds of lost tetrapod species across the globe and their number are increasing decade-on-decade. This study aims to find out why some are rediscovered, while others are not.Thomas Evans, Research scientist, Freie Universität Berlin, Université Paris-SaclayLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2048132024-01-07T19:03:59Z2024-01-07T19:03:59ZDogs are incredible – if unlikely – allies in conservation<figure><img src="https://images.theconversation.com/files/565576/original/file-20231213-15-j64ksb.jpg?ixlib=rb-1.1.0&rect=10%2C10%2C6699%2C4436&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source"> UniSC Detection Dogs for Conservation</span></span></figcaption></figure><p>Dogs have been working with people for centuries. Think hunting dogs, herding dogs, police dogs or search and rescue dogs. But have you heard of conservation dogs?</p>
<p>Conservation dogs fall mainly into two categories: guardian dogs and sniffer dogs (also called scent, detection or detector dogs).</p>
<p>Guardian dogs protect vulnerable species from predators, while sniffer dogs locate targets of interest using their powerful sense of smell.</p>
<p>In the past 15 years, dogs have begun to play a <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/2041-210X.13560">crucial role in conservation</a> around the world. So let’s take a closer look at them, with a focus on their work in Australia. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/koala-detecting-dogs-sniff-out-flaws-in-australias-threatened-species-protection-121118">Koala-detecting dogs sniff out flaws in Australia's threatened species protection</a>
</strong>
</em>
</p>
<hr>
<h2>The nose that knows</h2>
<p>Guardian dogs were made famous by the 2015 movie <a href="https://www.imdb.com/title/tt3401748/">Oddball</a>. The film is based on the true story of <a href="http://www.warrnamboolpenguins.com.au/maremma-dogs#:%7E:text=In%20a%20world%2Dfirst%2C%20Maremma,for%20the%20Middle%20Island%20Project.">Maremma dogs</a>, trained to protect little penguins from foxes on Middle Island near Warrnambool in southwest Victoria. The penguin population had dwindled to fewer than ten before the Maremma dogs got involved. The breed was chosen for its long association with guarding sheep in Europe. </p>
<p>But most conservation dogs are sniffer dogs, because there are so many uses for them. They can be trained to find animals or plants, or “indirect” signs animals have left behind such as poo or feathers. </p>
<p>Dogs can detect <em>anything</em> with an odour – and <em>everything</em> has an odour.
<a href="https://www.ecolsoc.org.au/?hottopic-entry=detection-dogs-provide-a-powerful-method-for-conservation-surveys">Sniffer dogs</a> are trained to detect a target scent and point it out to their human coworker (sometimes referred to as handler or <a href="https://roguedogs.org/iwanttobeabounder">bounder</a>).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565582/original/file-20231213-26-j686k1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a sniffer dog during training, dropping to the ground to show where she found the target odour in a jar" src="https://images.theconversation.com/files/565582/original/file-20231213-26-j686k1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565582/original/file-20231213-26-j686k1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565582/original/file-20231213-26-j686k1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565582/original/file-20231213-26-j686k1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565582/original/file-20231213-26-j686k1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565582/original/file-20231213-26-j686k1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565582/original/file-20231213-26-j686k1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">During training, sniffer dog Billie Jean drops to the ground when she finds her target odour.</span>
<span class="attribution"><span class="source">Russell Miller, UniSC Detection Dogs for Conservation</span></span>
</figcaption>
</figure>
<p>Sniffer dogs have been trained for various missions such as:</p>
<ul>
<li><p>finding rare and endangered species</p></li>
<li><p>detecting invasive animals during eradication or containment such as <a href="https://www.abc.net.au/news/2015-07-16/sniffer-dogs-help-fight-battle-against-fire-ants-in-queensland/6623876">fire ants</a> or <a href="https://abcnews.go.com/US/python-sniffing-dogs-floridas-newest-weapon-fighting-invasive/story?id=74776821">snakes</a> </p></li>
<li><p>locating <a href="https://www.abc.net.au/listen/programs/canberra-saturdaybreakfast/oakley-the-conservation-dog-helping-the-act/102722540">pest plants</a></p></li>
<li><p>supporting wildlife surveys by detecting scats (<a href="https://www.abc.net.au/news/2016-02-17/koala-poo-sniffing-dog-recruitment/7176218">poo</a>), urine, <a href="https://blog.csiro.au/sniffing-out-solutions-detection-dogs-are-helping-threatened-species/">vomit</a>, nests, carcasses and even <a href="https://molecularecologyblog.com/2019/08/19/interview-with-the-author-detecting-pathogens-in-koalas-dogs-versus-qpcr/">diseases</a>. </p></li>
</ul>
<p>They have worked in extreme conditions on land (including on <a href="https://www.abc.net.au/news/2020-06-11/wonder-dog-protects-island-from-rodents/12338438">sub-Antarctic islands</a>) and <a href="https://whalesanctuaryproject.org/dio-the-dog-goes-sniffing-for-whale-poop/">at sea</a>, and can even detect <a href="https://www.nationalgeographic.com/animals/article/sniffer-dogs-conservation-sea-turtles-florida">scent located underground</a>. Sniffer dogs have also trained to recognise <a href="https://www.jstor.org/stable/4496200">individual animals such as tigers</a> by scent.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566063/original/file-20231215-23-tvog7v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sniffer dog poses with an open copy of a french book about the incredible nose of the dog by Frank Rosell" src="https://images.theconversation.com/files/566063/original/file-20231215-23-tvog7v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566063/original/file-20231215-23-tvog7v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566063/original/file-20231215-23-tvog7v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566063/original/file-20231215-23-tvog7v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566063/original/file-20231215-23-tvog7v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566063/original/file-20231215-23-tvog7v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566063/original/file-20231215-23-tvog7v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sniffer dog Maya poses with a french copy of a book about the incredible nose of the dog by Frank Rosell.</span>
<span class="attribution"><span class="source">Romane Cristescu, UniSC Detection Dogs for Conservation</span></span>
</figcaption>
</figure>
<h2>The ultimate scent detection machine</h2>
<p>A dog’s nose is estimated to be <a href="https://press.uchicago.edu/ucp/books/book/chicago/S/bo27611471.html">100,000 to 100 million times</a> more sensitive than a human nose (depending on the dog breed). A much larger proportion (seven to 40 times larger) of the dog’s brain is dedicated to decoding scent. </p>
<p>That means dogs can detect very low scent concentrations – the equivalent of <a href="https://www.exploratorium.edu/blogs/spectrum/dogs-smell-time#:%7E:text=With%20up%20to%20300%20million,continuously%2C%20even%20as%20they%20exhale">a teaspoon of sugar in five million litres of water (or two Olympic-sized swimming pools)</a>. They can also differentiate between very similar odours. </p>
<p>Dogs analyse the air from each of their nostrils independently, detecting tiny variations in scent concentration. This gives them a directional sense of smell that can guide them left or right until they’ve honed in on the origin of the scent.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871809/">Thanks to very sophisticated nostrils</a>, dogs can avoid contaminating an odour with their own breath (exhaling air through the nostrils’ sides). They also can analyse odours continuously regardless of whether they are inhaling or exhaling. </p>
<p>Besides being the ultimate scent detection machine, dogs are great ambassadors for conservation – melting hearts all the way to <a href="https://ew.com/movies/2019/11/28/tom-hanks-twitter-nice-tweets/">Hollywood</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565570/original/file-20231213-27-awguev.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A still from a video on twitter featuring Hollywood actor Tom Hanks reading and responding to tweets including one about the koala detection dog Bear." src="https://images.theconversation.com/files/565570/original/file-20231213-27-awguev.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565570/original/file-20231213-27-awguev.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=361&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565570/original/file-20231213-27-awguev.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=361&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565570/original/file-20231213-27-awguev.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=361&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565570/original/file-20231213-27-awguev.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=453&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565570/original/file-20231213-27-awguev.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=453&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565570/original/file-20231213-27-awguev.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=453&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">While reading a tweet about our IFAW / UniSC koala detection dog Bear, Hollywood actor Tom Hanks said: ‘This is a Disney movie that must be made’, before suggesting a title: ‘The story of Bear: The Koala Detection Dog’. ‘I like bear!’</span>
<span class="attribution"><span class="source">X/Twitter</span></span>
</figcaption>
</figure>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1723910643353587775"}"></div></p>
<h2>Finding the right candidate for the job</h2>
<p>Some organisations rescue their dogs. They look for the toy-obsessed kind – those dogs that never stop playing.</p>
<p>In many cases these dogs were abandoned for that very reason. They require constant entertainment and become difficult to care for in a normal family setting, where people have to leave for work and devote time to activities other than entertaining their dog. </p>
<p>A sniffer dog gets to be with their handlers almost every day of the week. That work consists of long walks with lots of play. </p>
<p>Trainers use toys and play as a reward, so dogs learn to associate this reward with the target scent.</p>
<p>Learning through association – called <a href="https://open.lib.umn.edu/intropsyc/chapter/7-1-learning-by-association-classical-conditioning/">classical or pavlovian conditioning</a> – is very easy for dogs. It’s so easy that the scent-learning part of the job is usually the quickest. Training a dog to feel confident and be safe in the natural environment is more challenging. And if the dog had a troubled background before being rescued, rehabilitation is the most time-consuming and difficult component of the training. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565581/original/file-20231213-25-h9ef4v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Rear view of two sniffer dogs sitting with their handler in a grassy hilltop gazing into the distance" src="https://images.theconversation.com/files/565581/original/file-20231213-25-h9ef4v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565581/original/file-20231213-25-h9ef4v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565581/original/file-20231213-25-h9ef4v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565581/original/file-20231213-25-h9ef4v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565581/original/file-20231213-25-h9ef4v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565581/original/file-20231213-25-h9ef4v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565581/original/file-20231213-25-h9ef4v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sniffer dogs with their handler Russell Miller near Gympie region in Queensland, Australia.</span>
<span class="attribution"><span class="source">Katrin Hohwieler, UniSC Detection Dogs for Conservation</span></span>
</figcaption>
</figure>
<h2>What type of dog can become a sniffer dog?</h2>
<p>The most important aspect of the association learning process is having the right dog – one with obsessive behaviour. And <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/2041-210X.13560">any breed, sex and age of dog</a> can present this personality type.</p>
<p>Some breeds might tend to have higher proportions of obsessed and toy-focused dogs, but all breeds, including crossbreeds, have been successfully deployed as sniffer dogs.</p>
<p>Some breeds do have better sniffers – the bloodhound is the champion of olfactory performance – but depending on the target scent, most dogs’ noses are still extremely efficient and more than capable of the task.</p>
<p>Robust, agile and high-energy breeds are better suited to working outdoors. Medium-sized breeds are usually better able to crawl under and jump over obstacles, while also light enough to be easily carried by their human coworker as needed.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553803/original/file-20231015-23-54t3en.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A wildlife rescuer wearing fire protective gear carries detection dog Bear" src="https://images.theconversation.com/files/553803/original/file-20231015-23-54t3en.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553803/original/file-20231015-23-54t3en.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553803/original/file-20231015-23-54t3en.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553803/original/file-20231015-23-54t3en.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553803/original/file-20231015-23-54t3en.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553803/original/file-20231015-23-54t3en.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553803/original/file-20231015-23-54t3en.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">International Fund for Animal Welfare IFAW / UniSC koala detection dog ‘Bear’ was deployed during the Black Summer fires (2019-20) to find survivors. Pictured here with the author Romane Cristescu at Two Thumbs Wildlife Trust sanctuaries in Cooma, New South Wales.</span>
<span class="attribution"><span class="source">Kye McDonald, UniSC Detection Dogs for Conservation</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/scientists-find-burnt-starving-koalas-weeks-after-the-bushfires-133519">Scientists find burnt, starving koalas weeks after the bushfires</a>
</strong>
</em>
</p>
<hr>
<h2>Top jobs for conservation dogs</h2>
<p>Meet dogs working in conservation around the world:</p>
<ul>
<li><p><a href="https://whalesanctuaryproject.org/dio-the-dog-goes-sniffing-for-whale-poop/">detecting orca poo</a></p></li>
<li><p><a href="https://www.australiandoglover.com/2016/06/detector-dogs-saved-macquarie-island.html?m=0">making</a> and <a href="https://www.abc.net.au/news/2020-06-11/wonder-dog-protects-island-from-rodents/12338438">keeping</a> World Heritage-listed islands and Antarctica pristine </p></li>
<li><p><a href="https://theconversation.com/scientists-find-burnt-starving-koalas-weeks-after-the-bushfires-133519">wildlife search and rescue</a></p></li>
<li><p>working as <a href="https://www.warrnamboolpenguins.com.au/maremma-dogs">guardians</a></p></li>
<li><p><a href="https://www.abc.net.au/news/2015-07-16/sniffer-dogs-help-fight-battle-against-fire-ants-in-queensland/6623876">containing fire ants</a></p></li>
<li><p>leading weed eradication on <a href="https://www.abc.net.au/news/rural/2022-01-23/weed-sniffing-dogs-unleashed-n-tasmanian-central-highlands/100773942">land</a> or <a href="https://www.abc.net.au/listen/programs/canberra-saturdaybreakfast/oakley-the-conservation-dog-helping-the-act/102722540">water</a></p></li>
<li><p><a href="https://onlinelibrary.wiley.com/doi/full/10.1111/aec.13220">monitoring wind farms</a></p></li>
<li><p><a href="https://www.brisbanetimes.com.au/national/queensland/how-a-vomit-sniffing-dog-is-helping-save-endangered-owls-20190124-p50tg6.html">finding vomit</a> (rejected owl pellets, to be precise)</p></li>
<li><p><a href="https://www.abc.net.au/news/2016-02-13/sniffer-dogs-could-help-win-the-battle-against-extinction/7163098">supporting environmental assessments</a></p></li>
<li><p><a href="https://theconversation.com/meet-moss-the-detection-dog-helping-tassie-devils-find-love-142909">helping Tasmanian devils find mates</a></p></li>
<li><p><a href="https://molecularecologyblog.com/2019/08/19/interview-with-the-author-detecting-pathogens-in-koalas-dogs-versus-qpcr/">detecting diseases</a>.</p></li>
</ul>
<p>These are just a few of the dogs making a difference in our fight to protect biodiversity. But we have barely scratched the surface of their potential!</p><img src="https://counter.theconversation.com/content/204813/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Romane H Cristescu works for Detection Dogs for Conservation, at the University of the Sunshine Coast. She is receiving external funding through multiple government-funded, foundation association, not-for-profit group, and research council grants. She is a founding member and current executive of the Australasian Conservation Dogs Network.</span></em></p>Conservation dogs perform vital roles across Australia. Some are guardians protecting wildlife from predators while others put their powerful sense of smell to use as sniffer dogs or detection dogs.Romane H Cristescu, Researcher in Koala, Detection Dogs, Conservation Genetics and Ecology, University of the Sunshine CoastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2119042024-01-01T20:35:03Z2024-01-01T20:35:03ZCrocs love feral pigs and quolls have a taste for rabbit – but it doesn’t solve the invasive species problem<figure><img src="https://images.theconversation.com/files/563781/original/file-20231205-17-652gxf.jpg?ixlib=rb-1.1.0&rect=0%2C27%2C4624%2C3433&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Across the vast Australian continent, feral pigs, feral deer and European rabbits roam in their millions. By different names – wild boar, venison and lapin – these could all be served in a Michelin star restaurant. </p>
<p>Feral and invasive species are becoming popular meals for native wildlife too. For species like the saltwater crocodile and spotted-tailed quoll, the menu is expanding and changing due to the arrival of <a href="https://zenodo.org/records/10004329">invasive alien species</a> – one of the greatest threats to biodiversity globally. </p>
<p>The good news is, many invasive alien species make good tucker. Around the world, native wildlife are dining on increasing numbers of exotic prey. In the United States, endangered <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2022.0820">snail kites</a> — a wetland raptor — crunch through invasive apple snails, <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0024299">red-banded snakes</a> swallow North American bullfrogs in China, dingoes devour <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/aec.13214">feral sambar deer</a> and <a href="https://www.publish.csiro.au/rj/RJ22002">goats</a> in Australia, <a href="https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2010.1512">Sulawesian toads</a> gobble up introduced yellow crazy ants in Indonesia, and <a href="https://www.pnas.org/doi/10.1073/pnas.012422499">golden eagles</a> and <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2021.0676">saltwater crocodiles</a> both love eating feral pigs on opposite sides of the Pacific. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563784/original/file-20231205-27-m3dbjo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="feral pigs in mud" src="https://images.theconversation.com/files/563784/original/file-20231205-27-m3dbjo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563784/original/file-20231205-27-m3dbjo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563784/original/file-20231205-27-m3dbjo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563784/original/file-20231205-27-m3dbjo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563784/original/file-20231205-27-m3dbjo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563784/original/file-20231205-27-m3dbjo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563784/original/file-20231205-27-m3dbjo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Feral pigs are a very damaging invasive species in Australia.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Of crocs and pigs</h2>
<p>So can we say these invasives are useful in some sense? Exotic prey can help boost numbers of some native predators. Saltwater crocodiles in the Northern Territory are rapidly bouncing back <a href="https://theconversation.com/the-northern-territory-does-not-have-a-crocodile-problem-and-salties-do-not-need-culling-209863">after widespread, severe culling</a>. </p>
<p>Using the bones of crocodiles collected through time, <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2021.0676">researchers have shown</a> that over roughly half a century, salties have shifted from a diet largely based on fish to a more terrestrial diet, including feral water buffalo and pigs. </p>
<p>This seems like a much-needed good news story for the environment – a natural way to limit feral pigs, one of Australia’s <a href="https://theconversation.com/one-of-the-most-damaging-invasive-species-on-earth-wild-pigs-release-the-same-emissions-as-1-million-cars-each-year-163250">most widespread and damaging invasive species</a>. At present, though, we don’t know for sure that crocs keep pig numbers down. </p>
<p>Pigs and crocodiles live in the fast and slow lanes, respectively. <a href="https://pestsmart.org.au/toolkit-resource/feral-pig-biology-ecology-and-behaviour/#:%7E:text=Favourable%20conditions%20allow%20feral%20pigs,leads%20to%20diverse%20genetic%20mixing.">Feral pigs</a> feed and breed, and <a href="https://www.dcceew.gov.au/environment/invasive-species/feral-animals-australia/feral-pigs">few things are off the menu</a>. Sows can give birth from around 6 months of age, and produce <a href="https://pestsmart.org.au/wp-content/uploads/sites/3/2020/06/Pig.pdf">ten or more piglets in litters</a> once or twice every 12 or so months. </p>
<p>On the other hand, <a href="https://environment.des.qld.gov.au/wildlife/animals/living-with/crocodiles/about-crocodiles/estuarine">female estuarine crocodiles</a> begin reproducing at around 12 years of age, and do so once a year under the right conditions. Crocodiles cut back on hunting and other activity during cooler months. Together, this means feral pigs can endure relatively high predation rates and still persist in ecosystems in large numbers.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/eat-locals-swapping-sheep-and-cows-for-kangaroos-and-camels-could-help-our-environment-57349">Eat locals: swapping sheep and cows for kangaroos and camels could help our environment</a>
</strong>
</em>
</p>
<hr>
<h2>Of quolls and rabbits</h2>
<p>The largest of Australia’s four predatory marsupial quoll species, the spotted-tailed quoll, is known to enjoy <a href="https://www.publish.csiro.au/AM/AM19069">rabbit</a> even when there is a diverse and abundant selection of native mammals within the same area. </p>
<p>Unfortunately, quolls are now absent or still <a href="https://www.publish.csiro.au/zo/ZO14029">declining in many places</a>, due likely to competition or predation with the bigger, heavier predators Europeans introduced: feral cats and foxes. In the bush, male cats can be sizeable – exceeding 6 kilos, roughly double the size of your average spotted-tailed quoll. </p>
<p>As quolls have disappeared, rabbits <a href="https://doi.org/10.1071/ZO12129">may have taken advantage</a> of the predatory void and expanded. Fast-breeding rabbits are now arguably Australia’s <a href="https://www.publish.csiro.au/PC/PC18024">worst invasive alien species</a>. Their sheer numbers support cat and fox populations. </p>
<p>This begs the question – if cats and foxes could be eradicated or greatly reduced in some areas, could we reintroduce quolls to help manage rabbit populations or prevent their return? </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/TEZEYpDxCZs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Quolls also like the taste of rats.</span></figcaption>
</figure>
<h2>Dangerous dinners</h2>
<p>Not all introduced prey make safe meals. </p>
<p>Cane toads have devastated some native species such as northern quolls, which naturally prey on native amphibians but cannot survive toad toxin. </p>
<p>Regrettably, a <a href="https://www.abc.net.au/news/science/2023-10-31/doubts-raised-over-effectiveness-of-cane-toad-sausages/103003684">recent attempt to train quolls</a> not to eat cane toads appears to have failed. </p>
<p>But other species have learnt to safely eat cane toads, including the rakali (Australian water rat), which removes and eats <a href="https://theconversation.com/eat-your-heart-out-native-water-rats-have-worked-out-how-to-safely-eat-cane-toads-123986">toad hearts and livers with surgical precision</a>. The humble bin chicken (white ibis) has also figured out how to make toads safer <a href="https://www.bbc.com/news/world-australia-63699884">by washing them</a>. </p>
<p>European house mice and introduced rats can be easy prey for owls, snakes, and many other native predators. Unfortunately, these easy pickings can become their <a href="https://theconversation.com/mouse-plague-bromadiolone-will-obliterate-mice-but-itll-poison-eagles-snakes-and-owls-too-160995">last suppers</a> – not because the rodents are toxic, but because they may well have eaten rodenticide which makes them easier to hunt. Once a sick, dying rodent is eaten, the predator can in turn be <a href="https://theconversation.com/rat-poison-is-killing-our-beloved-native-owls-and-tawny-frogmouths-and-thats-the-tip-of-the-iceberg-212184">poisoned and die</a>. Scavengers who eat poisoned predators can also die, affecting entire <a href="https://theconversation.com/australias-reptiles-may-be-spreading-rat-poison-through-the-food-chain-94922">food chains and ecosystems</a>.</p>
<p>Sometimes predators can find themselves prey, depending on their <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/brv.12468">age and size</a>. In Australia, large pythons, goannas and monitor lizards <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2010.2103">eat foxes and cats</a>, but these same reptiles are preyed upon by cats and foxes when younger and smaller. </p>
<h2>Invasive prey aren’t going away</h2>
<p>As time goes on, invasive prey species can become regular meals for native predators – and part of the food web. </p>
<p>When we try to remove invasive prey species from ecosystems, we must take a <a href="https://theconversation.com/a-numbers-game-killing-rabbits-to-conserve-native-mammals-97078">big picture view</a> and <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2011.01673.x">proceed with great caution</a>. </p>
<p>When feral cats were <a href="https://www.pnas.org/doi/10.1073/pnas.0707414105">killed off</a> on New Zealand’s Little Barrier island, it was done with the best intentions: protect the seabirds nesting there. But with the cats gone, invasive rat populations surged and soon began killing the seabird chicks. </p>
<p>In Australia’s arid regions, we now have experimental evidence to suggest biological controls such as <a href="https://theconversation.com/releasing-a-virus-against-rabbits-is-effective-but-can-make-them-immune-if-let-loose-at-the-wrong-time-176028">rabbit haemorrhagic disease</a> do keep rabbit numbers down, alongside culling and destroying warrens. With the rabbits suppressed, plants and native herbivores can <a href="https://onlinelibrary.wiley.com/doi/10.1111/rec.13552">bounce back</a>. This, in turn, <a href="https://link.springer.com/article/10.1007/s10530-019-02131-5">pushes cat</a> and fox populations lower, as these two predators maintain their high numbers in arid regions in part due to an abundance of rabbits. </p>
<p>But this doesn’t work in the wetter, more vegetated south-east. Here, there’s little evidence <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.13253">rabbit control greatly affects fox populations</a>. </p>
<p>So should we celebrate crocs chomping on pigs and rakali eating cane toads? Of course – it’s a sign that some of our native predators can adapt to these introduced species. But it’s not true for all native wildlife. Our quolls are doing far worse with the new arrivals. </p>
<p>And for every native predator finding new tucker, there are far more cats and foxes eating birds, reptiles, frogs, and small marsupials, while pigs, deer, camels, horses, donkeys, and water buffalo run amok. We have already set these creatures loose – we must use all means possible to try and rein them in. </p>
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Read more:
<a href="https://theconversation.com/australias-least-wanted-8-alien-species-and-diseases-we-must-keep-out-of-our-island-home-212850">Australia’s least wanted – 8 alien species and diseases we must keep out of our island home</a>
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<img src="https://counter.theconversation.com/content/211904/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Euan Ritchie receives funding from the Australian Research Council and the Department of Energy, Environment, and Climate Action. Euan is a Councillor within the Biodiversity Council, and a member of the Ecological Society of Australia and the Australian Mammal Society.</span></em></p>Invasive species such as deer, pigs and rabbits might help boost native predator populations.Euan Ritchie, Professor in Wildlife Ecology and Conservation, School of Life & Environmental Sciences, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2155302023-12-20T19:07:17Z2023-12-20T19:07:17ZInvasive grasses are worsening bushfires across Australia’s drylands<p>As the semi-arid <a href="https://explorenarrabriregion.com.au/narrabri-directory/pilliga-forest/">Pilliga Scrub</a> burns in New South Wales, many of us are thinking about fire once again. It’s an El Niño summer in the hottest year on record. And there’s a remarkable amount of grass drying out and ready to burn. </p>
<p>Over the past few years, more rain than usual has fallen over vast regions of Australia’s rangelands, the arid and semi-arid regions that account for most of our land mass.</p>
<p>These rains have triggered an enormous boom in native grasses. But it’s also boom time for introduced species such as buffel grass (<em>Cenchrus ciliaris</em>) in the deserts, and Gamba grass (<em>Andropogon Gayanus</em>) in the savannas. These fast-growing grasses have outcompeted native grasses in many areas. </p>
<p>As they dry out, they become fuel for grass fires. Fuel loads have become extreme, especially in areas where invasive grasses are abundant. Already this fire season, enormous tracts of rangelands have burned, covering an area the <a href="https://www.theguardian.com/news/datablog/ng-interactive/2023/nov/15/bushfires-in-australias-north-this-year-have-burned-an-area-larger-than-the-size-of-spain">size of Spain</a>. </p>
<p>Our <a href="https://www.firenorth.org.au/nafi3/">bushfire-mapping site</a> has captured the rangeland fire season so far. Fast-moving grassfires <a href="https://www.adelaidenow.com.au/news/south-australia/grass-fires-rage-as-sas-extreme-heat-sets-in/news-story/2d783aeb4b6c1cbe9c1c69519bb90966">recently hit</a> South Australia. These grassfires can have fronts hundreds of kilometres wide. Yet this is only the beginning of the summer fire season. </p>
<h2>Arid lands and buffel grass</h2>
<p>When we think of fire in Australia, we often think of bushfires raging through a forest. But grassfires are very common once you leave the coast. </p>
<p>In Australia’s northern savannas, research has shown the <a href="https://www.tandfonline.com/doi/full/10.1080/14693062.2023.2239758">direct link</a> between fires, dried grass fuel at the end of the dry season in October, and how much rain fell over the year. Put simply, more rain leads to more grass, which usually leads to more fire. </p>
<p>These past few La Niña years have dumped enough rain to trigger major grass growth in the deserts – producing enough fuel to carry very widespread fire. </p>
<p>Buffel grass has made the problem far worse. This tussock grass native to parts of Africa and Asia was introduced for pasture, as it grows fast, roots deeply, spreads easily and needs less rain than other grasses. But these traits have now made it the biggest risk to biodiversity in arid Australia. Buffel has been a declared weed in South Australia since 2015, and the Northern Territory <a href="https://www.abc.net.au/news/2023-03-31/nt-buffel-grass-working-group-central-australia/102164504">is considering</a> whether to follow suit. </p>
<p>Management burns are needed to reduce the hazard but are increasingly difficult to implement. Buffel grass grows right up to trees and regrows quickly, promoting hotter and more frequent fires. Fire encourages buffel to regrow, which creates a grass-fire cycle. Native plants and fauna can’t adapt to this. </p>
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Read more:
<a href="https://theconversation.com/the-buffel-kerfuffle-how-one-species-quietly-destroys-native-wildlife-and-cultural-sites-in-arid-australia-149456">The buffel kerfuffle: how one species quietly destroys native wildlife and cultural sites in arid Australia</a>
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<p>Buffel also grows more evenly across a landscape, rather than in patches like many natives. At a fine scale, this means fire damage is worse, with more trees and shrubs killed. At a broader scale, areas invaded by buffel grass create links between flammable native plant communities previously separated by open patches.</p>
<p>The result? Fires can spread across larger tracts of land from a single ignition point, <a href="https://fireecology.springeropen.com/articles/10.1186/s42408-021-00121-4">as we saw</a> in Tjoritja National Park (West MacDonnell) in 2019.</p>
<p>Because fires spread so easily, management burns become much more risky and also more damaging to native shrubs and trees – <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/aec.12039">even in winter</a>. That’s a problem, because we need these burns to reduce fuel loads. More intense and wide-ranging fires are likely to injure or kill more native animals, both directly and from the loss of shelter and food after the fire.</p>
<p>Fires can start from lightning – or from <a href="https://www.abc.net.au/news/2023-10-23/mount-isa-spinifex-fires-amid-record-heat/103002454">simply driving through</a> long, dry grass. Historical weather and fire information indicates central Australia is in for a long hot summer. </p>
<p>How much fire might we see? In 2011, a year when we saw similar fuel loads, about 45% of arid and semi-arid lands had burned by the end of the summer. </p>
<h2>Gamba grass on the savanna</h2>
<p>In northern Australia’s tropical savannas, there’s a similar problem: fast-growing Gamba grass. This African tussock grass can grow up to four metres high. It’s invading new areas rapidly – government surveys show it increased from about 1,500 sites to more than 9,000 sites in six years in the Greater Darwin Region.</p>
<p>When Gamba dries out, the fuel loads it creates are <a href="https://d1wqtxts1xzle7.cloudfront.net/48784189/The_impacts_of_Andropogon_gayanus_gamba20160912-15138-d6tjy0-libre.pdf?1473724225=&response-content-disposition=inline%3B+filename%3DThe_impacts_of_Andropogon_gayanus_gamba.pdf&Expires=1700290794&Signature=OGCR8-I6Oeh3s9fanfsC2E0tsoc9oRmY2v6yqQ0HSnEQdOwr0b%7EviJ9fr0Hg7Pu6cyanNcfwbcEFUfd%7ET-DGiTYGb0VKaRrvlhZe08%7EsnuFr0S1eNh8QgddZ4ckMg03xfXSs2WzYjteubn5sxaxgAKdyNroNEr0DV3vjqi2lCqfxybTXVaM76Wk6c-IPyTfXzHiLRfPsKxSNNGOOLJI8Q-wjv2NQ4mFKUScyQmEP9ysF2sO1NAo5AHG7aA35vA93yfm5g52MrykmmedY1doOEV1Ob27uvHhJF3pqoYM70evNIdvV4xgxJn-p0oFAGhrb8hDSbkY49pX201FK9zLvCA__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA">many times greater</a> than native grasses. Gamba is now widespread throughout the greater Darwin rural area, including large areas of Litchfield National Park.</p>
<p>When Gamba grass burns, the fire runs so hot it can kill tall trees and devastate biodiversity. It’s also more dangerous for firefighters. The high fuel loads produce <a href="https://link.springer.com/article/10.1007/s13280-022-01745-9">very high greenhouse gas emissions</a> and harmful pollutants such as particulate matter. </p>
<p>Unlike Buffel, Gamba is a declared weed in the NT. The territory government is putting in <a href="https://depws.nt.gov.au/__data/assets/pdf_file/0007/1287799/gamba-grass-annual-report-2023.pdf">considerable effort</a> to reduce the damage it does through prescribed burning and requiring property owners to control Gamba.</p>
<p>Unfortunately, these control efforts have a cost. Days with very high levels of air pollution in Darwin are increasing each year, caused by the burning of Gamba to reduce fuel load and the chance of big fires later in the dry season. Polluted air is damaging <a href="https://link.springer.com/article/10.1007/s13280-022-01745-9">human health</a>.</p>
<p>To combat this, we need to use weather forecasting to advise volunteer firefighters (who do most of the prescribed burns) of the best time to burn.</p>
<p>As the heat of summer continues, we can expect to see more extensive grassfires in central and northern Australia. Highly flammable invasive grasses will make them worse still. We cannot ignore the changes they are making to central and northern fire regimes. </p>
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Read more:
<a href="https://theconversation.com/the-summer-bushfires-you-didnt-hear-about-and-the-invasive-species-fuelling-them-112619">The summer bushfires you didn't hear about, and the invasive species fuelling them</a>
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<img src="https://counter.theconversation.com/content/215530/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Edwards receives funding from the Australian Research Council and Charles Darwin University. </span></em></p><p class="fine-print"><em><span>Christine Schlesinger receives funding from the Australian Research Council</span></em></p><p class="fine-print"><em><span>Ellen Ryan-Colton has received funding from the Ecological Society of Australia (Holsworth wildlife research endowment, and Jill Landsberg Trust), Ten Deserts Project and Alinytjara Wilurara Landscape Board. </span></em></p><p class="fine-print"><em><span>Peter Jacklyn receives funding from the Clean Energy Regulator and National Emergency Management Agency. </span></em></p><p class="fine-print"><em><span>Greg Barber does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Grassfires are normal in central and northern Australia. But fast-growing invasive grasses are supercharging grassfires – and this summer looks like it will be big.Andrew Edwards, Research Fellow Bushfires, Charles Darwin UniversityChristine Schlesinger, Associate Professor in Environmental Science, Charles Darwin UniversityEllen Ryan-Colton, PhD candidate, Charles Darwin UniversityGreg Barber, PhD student, Charles Darwin UniversityPeter Jacklyn, NAFI Service Manager and Knowledge and Adoption Coordinator, Charles Darwin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2146882023-12-19T18:13:36Z2023-12-19T18:13:36ZShipwrecks teem with underwater life, from microbes to sharks<figure><img src="https://images.theconversation.com/files/555600/original/file-20231024-25-xo8h4f.jpg?ixlib=rb-1.1.0&rect=30%2C15%2C5061%2C3534&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A school of grunts on a sunken World War II German submarine in the Atlantic Ocean off North Carolina.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/diver-and-schooling-tomtates-on-wwii-u-352-german-royalty-free-image/153943111">Karen Doody/Stocktrek Images via Getty Images</a></span></figcaption></figure><p>Humans have sailed the world’s oceans for thousands of years, but they haven’t all reached port. Researchers estimate that there are <a href="https://unesdoc.unesco.org/ark:/48223/pf0000152883">some three million shipwrecks</a> worldwide, resting in shallow rivers and bays, coastal waters and the deep ocean. Many sank during catastrophes – some during storms or after running aground, others in battle or collisions with other vessels.</p>
<p>Shipwrecks like <a href="https://www.britannica.com/topic/Titanic">the RMS Titanic</a>, <a href="https://www.britannica.com/topic/Lusitania-British-ship">RMS Lusitania</a> and <a href="https://www.britannica.com/technology/monitor-ship-type#ref51448">USS Monitor</a> conjure tales of human courage and sacrifice, sunken treasure and unsolved mysteries. But there’s another angle to their stories that doesn’t feature humans. </p>
<p>I have <a href="https://scholar.google.com/citations?user=wZ-kv2AAAAAJ&hl=en">studied the biology of shipwrecks</a> in the United States and internationally for 14 years. From this work, I have learned that shipwrecks are not only cultural icons but can also be biological treasures that create habitat for diverse communities of underwater life. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/FTYyzAxt3JI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The USS Monitor, which sank off Cape Hatteras, North Carolina, in a storm on Dec. 31, 1862, is now a center for sea life.</span></figcaption>
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<p>Recently, I led an international team of biologists and archaeologists in disentangling the mysteries of how this transformation happens. Drawing on scientific advances from our team and international colleagues, our <a href="https://academic.oup.com/bioscience/article-lookup/doi/10.1093/biosci/biad084">new study</a> describes how wrecked vessels can have second lives as seabed habitats.</p>
<h2>A new home for underwater life</h2>
<p>Ships are typically made of metal or wood. When a vessel sinks, it adds foreign, artificial structure to the seafloor. </p>
<p>For example, the World War II tanker <a href="https://monitor.noaa.gov/shipwrecks/clark.html">E.M. Clark</a> sank on a relatively flat, sandy seabed in 1942 when it was torpedoed by a German submarine. To this day, the intact metal wreck looms over the North Carolina seafloor like an underwater skyscraper, creating an island oasis in the sand. </p>
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<figcaption><span class="caption">In this video narrated by NOAA research scientist Avery Paxton, sand tiger sharks hover above the wreck of the E.M. Clark off North Carolina, with vermilion snapper schooling nearby. Jacks and an invasive lionfish also appear.</span></figcaption>
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<p>The creatures that reside on and around sunken ships are so diverse and abundant that scientists often colloquially call these sites “<a href="https://3d-shipwreck-data-viewer-noaa.hub.arcgis.com/">living shipwrecks</a>.” Marine life ranging from microscopic critters to some of the largest animals in the sea use shipwrecks as homes. Brilliantly colored corals and sponges blanket the wrecks’ surfaces. Silvery schools of baitfish dart and shimmer around the structures, chased by sleek, fast-moving predators. Sharks sometimes cruise around wrecks, likely resting or looking for prey. </p>
<h2>The origin of a second life</h2>
<p>A ship’s transformation from an in-service vessel into a thriving metropolis for marine life can seem like a fairy tale. It has a once-upon-a-time origin story – the wrecking event – and a sequence of life arriving on the sunken structure and beginning to blossom.</p>
<p>Tiny microbes invisible to the naked human eye initially settle on the wreck’s surface, forming a carpet of cells, called a <a href="https://www.britannica.com/science/biofilm">biofilm</a>. This coating helps to <a href="https://doi.org/10.3389/fmars.2019.00048">make the wreck structure suitable</a> for larval animals like sponges and corals to settle and grow there.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Shellfish, deepwater coral and anemones cling to the surface of a sunken wreck." src="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Diverse sea creatures living on the 19th-century, wooden-hulled Ewing Bank wreck, which lies 2,000 feet (610 meters) deep in the Gulf of Mexico.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/explorations/19microbial-stowaways/background/archaeology/media/img2-hires.jpg">NOAA</a></span>
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<p>Larger animals like fish sometimes appear within minutes after a ship sinks. <a href="https://coastalscience.noaa.gov/news/artificial-reefs-may-help-tropical-fish-expand-geographic-range-video/">Small fish</a> hide in the structure’s cracks and crevices, while <a href="https://doi.org/10.1016/j.fooweb.2020.e00147">large sharks</a> glide around it. <a href="https://doi.org/10.1016/j.marenvres.2020.104916">Sea turtles</a> and marine mammals such as <a href="https://doi.org/10.1371/journal.pone.0130581">fur seals</a> have also been spotted on wrecks.</p>
<h2>Hot spots for biodiversity</h2>
<p>Shipwrecks host quantities and varieties of marine life that can make them hot spots for biodiversity. The microbes that transform the wreck structure into habitat also enrich the surrounding sand. Evidence from deep Gulf of Mexico wrecks shows that a <a href="https://doi.org/10.1038/s41396-021-00978-y">halo of increased microbial diversity</a> radiates outward anywhere from 650 to 1,000 feet (200-300 meters) from the wreck. In the Atlantic Ocean, <a href="https://doi.org/10.1111/faf.12548">thousands of grouper</a>, a type of reef fish highly valued by fishers, congregate around and inside shipwrecks.</p>
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<a href="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Fish hover above a wrecked ship's surface." src="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Groupers and a conger eel, bottom center, on the wreck of the German submarine U-576 off the coast of North Carolina.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/explorations/16battlefield/logs/sept7/sept7.html">NOAA</a></span>
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</figure>
<p>Shipwrecks can also serve as stepping stones across the ocean floor that animals use as temporary homes while moving from one location to another. This has been documented in areas of the world with dense concentrations of shipwrecks, such as off North Carolina, where storms and war have sunk hundreds of ships.</p>
<p>In this part of the ocean, popularly known as the “<a href="https://www.ncpedia.org/graveyard-atlantic">Graveyard of the Atlantic</a>,” reef fish likely <a href="https://doi.org/10.1038/s42003-019-0398-2">use the islandlike shipwrecks as corridors</a> when moving north or south away from the equator to find favorable water temperatures as climate change <a href="https://theconversation.com/ocean-heat-is-at-record-levels-with-major-consequences-174760">warms the oceans</a>. Scientists have also observed <a href="https://doi.org/10.1002/ecy.2687">sand tiger sharks</a> traveling from one wreck to another, possibly using the shipwrecks like rest stops during migration.</p>
<p>In the deep sea, life growing on shipwrecks can even generate energy. Tube worms that grow on organic shipwreck materials such as paper, cotton and wood host symbiotic bacteria that produce chemical energy. Such tube worm colonies have been documented in the Gulf of Mexico on the steel <a href="https://www.boem.gov/sites/default/files/boem-newsroom/Library/Ocean-Science/Ocean-Science-Jul-Aug-Sep-2014.pdf">luxury yacht Anona</a>. </p>
<h2>Biological mysteries abound</h2>
<p>Despite their biological value, shipwrecks can also threaten underwater life by altering or destroying natural habitats, causing pollution and spreading invasive species.</p>
<p>When a ship sinks, it can damage existing seafloor habitats. In a well-documented case in the Line Islands of the central Pacific, an <a href="https://doi.org/10.1038/ismej.2011.114">iron shipwreck</a> sank on a healthy coral reef. The iron infusion substantially decreased coral cover, and the reef was overcome by algae.</p>
<p>Ships may carry pollutants as fuel or cargo. As shipwrecks deteriorate in seawater, there is a risk that these pollutants may be released. The <a href="https://doi.org/10.1016/j.marpolbul.2021.112087">level of risk</a> depends on how much of the pollutant the ship was carrying and how intact the wreck is. One recent investigation revealed that effects from shipwreck pollutants can be detected in microbes up to <a href="https://doi.org/10.3389/fmars.2022.1017136">80 years after the wreck</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/JTq4b9c3Z00?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Ships and planes wrecked in wartime can leak toxic materials for decades after they come to rest in the ocean.</span></figcaption>
</figure>
<p>Shipwrecks may also inadvertently assist the spread of invasive plants and animals that wreak biological havoc. Wrecks are new structures that invasive species can settle on, grow and use as a hub to expand to other habitats. <a href="https://doi.org/10.1016/j.marpolbul.2020.111394">Invasive cup coral</a> has spread on World War II shipwrecks off Brazil. In Palmyra Atoll in the Pacific, a type of anemone called a corallimorph <a href="https://doi.org/10.1371/journal.pone.0002989">rapidly invaded</a> a shipwreck and now <a href="https://doi.org/10.1007/s10530-018-1696-1">threatens healthy coral reefs</a>.</p>
<h2>The future of shipwreck exploration</h2>
<p>Shipwrecks create millions of study sites that scientists can use to ask questions about marine life and habitats. One of the greatest challenges is that many wrecks are undiscovered or in remote locations. Advances in technology can help researchers see into the most inaccessible areas of the ocean, not only to find shipwrecks but to better understand their biology. </p>
<p>Maximizing discovery will require biologists, archaeologists and engineers to work together to explore these special habitats. Ultimately, the more we learn, the more effectively we can conserve these historical and biological gems.</p><img src="https://counter.theconversation.com/content/214688/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Avery Paxton is affiliated with NOAA National Centers for Coastal Ocean Science. </span></em></p>When ships sink, they add artificial structures to the seafloor that can quickly become diverse, ecologically important underwater communities.Avery Paxton, Research Marine Biologist, National Oceanic and Atmospheric AdministrationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2188992023-12-19T13:16:50Z2023-12-19T13:16:50ZWild ‘super pigs’ from Canada could become a new front in the war on feral hogs<figure><img src="https://images.theconversation.com/files/566082/original/file-20231215-23-irn2uo.jpg?ixlib=rb-1.1.0&rect=8%2C4%2C2986%2C1958&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Feral hogs' long snouts and tusks allow them to rip and root their way across the landscape in search of food. </span> <span class="attribution"><a class="source" href="https://flic.kr/p/ehmMiS">USDA/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>They go by many names – pigs, hogs, swine, razorbacks – but whatever you call them, <a href="https://www.invasivespeciesinfo.gov/profile/wild-boar">wild pigs</a> (<em>Sus scrofa</em>) are one of the <a href="https://www.washingtonpost.com/science/2019/08/06/think-feral-hogs-is-joke-millions-more-are-rampaging-across-us/">most damaging invasive species</a> in North America. They cause millions of dollars in crop damage yearly and harbor dozens of pathogens that threaten humans and pets, as well as meat production systems.</p>
<p>Although wild pigs have been <a href="https://www.aphis.usda.gov/aphis/ourfocus/wildlifedamage/operational-activities/feral-swine/sa-fs-history">present in North America for centuries</a>, their populations have rapidly expanded over the past several decades. Recent studies estimate that since the 1980s the wild pig population in the United States has <a href="https://doi.org/10.1007/s10530-019-01983-1">nearly tripled</a> and <a href="https://doi.org/10.1002/wsb.808">expanded from 18 to 35 states</a>. More recently, they have <a href="https://www.cbc.ca/news/canada/british-columbia/invasive-pigs-canada-1.5136431">spread rapidly across Canada</a>, and these populations are <a href="https://apnews.com/article/wild-pigs-feral-swine-canada-minnesota-border-e59a542efb3c64d5f4b136fc137b7665">threatening to invade the U.S. from the north</a>.</p>
<p>The wild pigs in Canada are unique because they were originally crossbred by humans to be larger and more cold-hardy than their feral cousins to the south. This suite of traits has earned them the name “super pigs” for good reason. Adults can reach weights exceeding 500 pounds, which is twice the size of the largest wild pigs sampled across many U.S. sites in <a href="http://dx.doi.ORG/10.1002/ece3.9853">a 2022 study</a>. </p>
<p>As a <a href="https://www.researchgate.net/profile/Marcus_Lashley">wildlife ecologist</a>, I study how wild pigs alter their surroundings and affect other wildlife species. <a href="https://www.doi.gov/invasivespecies/early-detection-and-rapid-response">Early detection and rapid response</a> is of utmost importance in eradicating an invasive species, because invasions are more manageable when populations are small and geographically restricted. This is especially true for species like wild pigs that have a high reproductive rate, can readily move into new areas and can change their behavior to avoid being captured or killed.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/RpwHJT4t-Zo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Minnesota wildlife experts are keeping a wary eye on their northern border for signs of wild ‘super pigs’ moving down from Canada.</span></figcaption>
</figure>
<h2>Omnivores on the hoof</h2>
<p>Much concern over the spread of wild pigs has focused on economic damage, which was recently estimated at <a href="https://www.usatoday.com/story/news/nation/2023/11/21/which-states-have-the-worst-wild-hog-problem/71658126007/">about US$2.5 billion annually</a> in the United States.</p>
<p>Wild pigs have a unique collection of traits that make them problematic to humans. When we told one private landowner about the results from our studies, he responded: “That makes sense. Pigs eat all the stuff the other wildlife do – they just eat it first, and then they go ahead and eat the wildlife, too. They pretty much eat anything with a calorie in it.” </p>
<p>More scientifically, wild pigs are called extreme generalist foragers, which means they can survive on many different foods. A <a href="https://doi.org/10.1111/mam.12015">global review of their dietary habits</a> found that plants represent 90% of their diet – primarily agricultural crops, plus the fruits, seeds, leaves, stems and roots of wild plants.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566078/original/file-20231215-23-4f6gba.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A male lesser prairie-chicken inflates his orange throat sacs to call potential mates." src="https://images.theconversation.com/files/566078/original/file-20231215-23-4f6gba.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566078/original/file-20231215-23-4f6gba.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566078/original/file-20231215-23-4f6gba.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566078/original/file-20231215-23-4f6gba.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566078/original/file-20231215-23-4f6gba.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566078/original/file-20231215-23-4f6gba.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566078/original/file-20231215-23-4f6gba.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lesser prairie chickens are a ground-nesting species – found in parts of Colorado, Kansas, New Mexico, Oklahoma and Texas – that is listed under the Endangered Species Act. Feral hogs prey on the birds and their eggs and damage the birds’ habitat by rooting up and consuming native plants and spreading invasive plant seeds.</span>
<span class="attribution"><a class="source" href="https://www.fws.gov/media/lesser-prairie-chicken-lek">Greg Kramos/USFWS</a></span>
</figcaption>
</figure>
<p>Wild pigs also eat most small animals, along with fungi and invertebrates such as insect larvae, clams and mussels, particularly in places where pigs are not native. For example, a 2019 study reported that wild pigs were digging up eggs laid by endangered loggerhead sea turtles on an island off the coast of South Carolina, <a href="https://doi.org/10.1016/j.actao.2019.103442">reducing the turtles’ nesting success to zero in some years</a>.</p>
<p>And these pigs do “just eat it first.” They compete for resources that other wildlife need, which can have <a href="http://dx.doi.org/10.1007/s10530-012-0229-6">negative effects on other species</a>. </p>
<p>However, they likely do their most severe damage through predation. Wild pigs kill and eat rodents, deer, birds, snakes, frogs, lizards and salamanders. This probably best explains why colleagues and I found in <a href="https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/ece3.5360">one study</a> that forest patches with wild pigs had 26% fewer mammal and bird species than similar forest patches without pigs. </p>
<p>This decrease in diversity was similar to that found with <a href="https://doi.org/10.1016/bs.aecr.2016.10.002">other invasive predators</a>. And our findings are consistent with a global analysis showing that invasive mammalian predators that have no natural predators themselves – especially generalist foragers like wild pigs – <a href="https://doi.org/10.1073/pnas.1602480113">cause by far the most extinctions</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1734983386941333818"}"></div></p>
<h2>Altering ecosystems</h2>
<p>Many questions about wild pigs’ ecological impacts have yet to be answered. For example, they may harm other wild species indirectly, rather than eating them or depleting their food supply. </p>
<p>Our work shows that wild pigs <a href="https://doi.org/10.1016/j.fooweb.2022.e00270">can alter the behavior of common native wildlife species</a>, such as raccoons, squirrels and deer. Using trail cameras, we found that when wild pigs were present, other animals altered their activity patterns in various ways to avoid them. Such shifts may have additional cascading effects on ecosystems, because they change how and when species interact in the food web.</p>
<p>Another major concern is wild pigs’ potential to spread disease. They carry numerous pathogens, including brucellosis and tuberculosis. However, little ecological research has been done on this issue, and scientists have not yet demonstrated that an increasing abundance of wild pigs reduces the abundance of native wildlife via disease transmission. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/vIHbFQFdyaM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Feral hogs can be seen rooting up the soil in this trail camera footage from Alabama.</span></figcaption>
</figure>
<p>Interestingly, in their native range in Europe and Asia, pigs do not cause as much ecological damage. In fact, some studies indicate that they may <a href="http://biozoojournals.ro/nwjz/content/v13n2/nwjz_e161706_Baruzzi.pdf">modify habitat in important ways</a> for species that have evolved with them, such as frogs and salamanders. </p>
<p>So far, however, there is virtually no scientific evidence that feral pigs provide any benefits in North America. One <a href="http://dx.doi.org/10.1007/s10530-012-0229-6">review of wild pig impacts</a> discussed the potential for private landowners plagued with pigs to generate revenue from selling pig meat or opportunities to hunt them. And it’s possible that wild pigs could serve as an alternative food source for imperiled large predators, or that their wallowing and foraging behavior in some cases could mimic that of locally eradicated or extinct species. </p>
<p>But the scientific consensus today is that in North America, wild pigs are a growing threat to both ecosystems and the economy. It is unclear how invading super pigs would contribute to the overall threat, but bigger pigs likely cause more damage and are generally better predators and competitors. </p>
<p>While efforts to control wild pigs <a href="https://www.nrcs.usda.gov/feral-swine-eradication-and-control-pilot-program">are well underway</a> in the U.S., incursions by Canadian super pigs may complicate the job. Invasive super pigs make for catchy headlines, but their potential effects are no joke.</p>
<p><em>This is an updated version of <a href="https://theconversation.com/feral-pigs-harm-wildlife-and-biodiversity-as-well-as-crops-120066">an article</a> originally published on Aug. 26, 2019.</em></p><img src="https://counter.theconversation.com/content/218899/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marcus Lashley receives funding from USDA Wildlife Services.</span></em></p>Feral hogs are one of the most destructive invasive species in North America, harming land, crops and wildlife.Marcus Lashley, Associate Professor of Wildlife Ecology, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2171312023-11-07T16:51:30Z2023-11-07T16:51:30ZExtreme weather may help invasive species outcompete native animals – new study<figure><img src="https://images.theconversation.com/files/558037/original/file-20231107-22-7023v6.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C2998%2C1994&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Invasive species can capitalise on disturbances like this. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/forest-fire-pinus-pinaster-guadalajara-spain-1065315416">FJAH / shutterstock</a></span></figcaption></figure><p>Non-native species appear to be better able to resist extreme weather, threatening native plants and animals and potentially creating more favourable conditions for invasive species under climate change. That’s the conclusion of a new study in the scientific journal <a href="https://www.nature.com/articles/s41559-023-02235-1">Nature Ecology and Evolution</a>.</p>
<p>Wildfires, droughts, heavy rainfall and storms are all <a href="https://www.nature.com/articles/nclimate1452">increasing</a>, and predicted to become more frequent throughout the <a href="https://www.nature.com/articles/s43247-023-00826-1">next century</a> due to human-driven climate change. </p>
<p>At the same time, humans are transporting <a href="https://www.nature.com/articles/ncomms14435/">more species</a> into new areas, despite concerted global efforts to increase <a href="https://www.sciencedirect.com/science/article/pii/S1462901119311669">biosecurity across borders</a> and to target the <a href="https://www.nature.com/articles/s41598-022-14982-5">eradication of specific species</a>. Some of these non-native species can go on to become invasive, damaging native <a href="https://zenodo.org/records/10004329">ecosystems</a>. </p>
<h2>Capitalising on opportunities</h2>
<p>Invasive species introduced by humans often possess traits that help them survive or even thrive when ecosystems are disturbed (perhaps by wildfire, a storm or human buildings). </p>
<p>Invasive plants are <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1461-0248.2009.01418.x">generally fast-growing</a>, for instance, allowing them to quickly fill gaps before native species can recover from disturbances. They are also often very good at dispersing their seeds, allowing them to quickly colonise disturbed areas.</p>
<p>This is why scientists have long suspected that extreme weather and the success of non-native species could be <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/110137?casa_token=4_TVjhddeUAAAAAA%3AIAHZQqTWf7Q3F1-LY6-R2HiVHW5qwsdtkW1aumwAXtc3aYDdGJf9wuhkTzmH1TlP6xxqnuBdqtCWMoud">linked</a>. </p>
<p>If extreme weather removes native plants and animals, that increases the availability of resources such as water and space. Non-native species can then capitalise on these new resources to establish themselves.</p>
<p>Even more concerning is the potential for extreme weather and non-native species to interact, exacerbating their effect on native biodiversity. For instance, in a recent <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ele.13974">field experiment in the US</a>, scientists deliberately started a fire which killed about 10% of the longleaf pine trees in the area studied. </p>
<p>But in areas where an invasive grass – <a href="https://theconversation.com/invasive-grasses-are-fueling-wildfires-across-the-us-126574">cogongrass, an Asian native</a> – was allowed to establish itself alongside the pines, the fires had more fuel and were larger, hotter and burned for longer. </p>
<p>Where the scientists had added rain shelters to simulate drought conditions, the grass dried out further and the fires became much more lethal. A combination of drought and the invasive species meant longleaf pine mortality soared to 44%.</p>
<p>Similarly, on the small Macquarie Island in the south west Pacific, a combination of extreme rainfall and the presence of invasive European rabbits reduced the breeding success of nesting <a href="https://www.nature.com/articles/s41598-020-64662-5">black-browed albatrosses</a>. Heavy grazing by the invasive rabbits reduced plant cover, exposing the albatross chicks to the harsh weather conditions. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558038/original/file-20231107-17-yrnh31.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Penguins on grassy surface, sea in background" src="https://images.theconversation.com/files/558038/original/file-20231107-17-yrnh31.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558038/original/file-20231107-17-yrnh31.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558038/original/file-20231107-17-yrnh31.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558038/original/file-20231107-17-yrnh31.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558038/original/file-20231107-17-yrnh31.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558038/original/file-20231107-17-yrnh31.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558038/original/file-20231107-17-yrnh31.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Macquarie’s grass makes excellent bird nests – and rabbit food.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/gentoo-penguins-macquarie-islands-australia-111279710">BMJ / shutterstock</a></span>
</figcaption>
</figure>
<p>This relationship between extreme weather and invasive species – two human-driven drivers of global change – threatens native plants and animals and could cost countries <a href="https://enveurope.springeropen.com/articles/10.1186/s12302-023-00750-3">billions of dollars</a> in coming decades. Ecologists must identify priority areas and species that can be targeted in efforts to minimise costs and prevent the loss of native biodiversity.</p>
<h2>Bad weather, good for non-natives</h2>
<p>To better understand how native and non-native species respond to extreme weather events, the scientists behind the new study reanalysed information from 443 peer-reviewed studies on how species responded to wildfires, droughts and storms. In all, they gathered data on 187 non-native species and 1,852 native species from all major animal groups.</p>
<p>Their results suggest that native and non-native species may indeed respond differently to extreme weather. Across all studies, a total of 24.8% of non-native species benefited from extreme weather events compared to only 12.7% of native species.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558048/original/file-20231107-29-vra3jw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="'attention invasive plant' sign" src="https://images.theconversation.com/files/558048/original/file-20231107-29-vra3jw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558048/original/file-20231107-29-vra3jw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558048/original/file-20231107-29-vra3jw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558048/original/file-20231107-29-vra3jw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558048/original/file-20231107-29-vra3jw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558048/original/file-20231107-29-vra3jw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558048/original/file-20231107-29-vra3jw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Japanese knotweed is an invasive species in much of Europe and North America. Like many invasive plants, it grows quickly and can handle extreme weather.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/attention-sign-invasive-plant-japanese-knotweed-1777590785">Leon_Brouwer / shutterstock</a></span>
</figcaption>
</figure>
<p>For example, while native species in both freshwater and land-based ecosystems were harmed by droughts, their non-native counterparts showed no significant response. Notably, marine ecosystems were comparatively more resistant to extreme weather events, with fewer differences between native and non-native species. </p>
<p>The authors did find marine heatwaves harmed native coral species, however, a relationship that has been documented in other <a href="https://www.nature.com/articles/s41586-018-0041-2">scientific studies</a>.</p>
<h2>Identifying global hotspots</h2>
<p>The authors took this information and combined it with known global hotspots of extreme weather, to identify areas where native species may be particularly vulnerable to the combination of extreme weather and invasive species.</p>
<p>They found high latitude areas such as northern US and Europe, for instance, are both vulnerable to extreme cold spells and possess non-native species that benefit from cold spells. Alternatively, areas of the western Amazon in Brazil and east Asia were identified as vulnerable to flooding and possessing flood-resistant non-native species. </p>
<p>In these regions, non-native species could benefit from increasing cold spells or flooding respectively, posing a greater threat to native plants and animals.</p>
<p>Studies like this are very useful. Regions that are identified as vulnerable can be targeted with early preventative measures to stop the spread of invasive species, or with measures to help native biodiversity cope with climate change.</p>
<p>This research could also allow targeted restoration to remove <a href="https://www.nature.com/articles/s41598-022-14982-5">non-native species</a> and produce <a href="https://www.nature.com/articles/s42003-023-05485-8">invasion-resistant native communities</a> that could better withstand future conditions. This is what happened on Macquarie Island, where invasive rabbits and rats were eventually eliminated and the <a href="https://www.theguardian.com/environment/2022/aug/10/rats-and-rabbits-invasive-species-macquarie-island-southern-ocean-aoe">whole ecosystem soon bounced back</a>. </p>
<p>Such action could be critical as we adapt to a changing climate and a greater mixing of the world’s plants and animals. </p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<hr><img src="https://counter.theconversation.com/content/217131/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Harry Shepherd receives funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme. </span></em></p>Non-native species tend to be better at exploiting the disturbance caused by storms, fires or droughts.Harry Shepherd, Postdoctoral Research Associate, King's College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2143892023-11-03T08:15:53Z2023-11-03T08:15:53ZCan we eat our way through an exploding sea urchin problem?<figure><img src="https://images.theconversation.com/files/557013/original/file-20231101-21-pz1lh7.PNG?ixlib=rb-1.1.0&rect=3%2C11%2C2583%2C1082&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">John Keane on an extensive urchin barren</span> <span class="attribution"><span class="source">John Keane</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Longspined sea urchins are native to temperate waters around New South Wales. But as oceans heat up, their range has expanded more than 650km, through eastern Victoria and south to Tasmania. Their numbers are exploding in the process, clear-felling kelp forests and leaving “urchin barrens” behind.</p>
<p>The species (<em>Centrostephanus rodgersii</em>) is now the single largest and most <a href="https://www.sciencedirect.com/science/article/pii/S0022098111000803">urgent threat</a> to kelp forests along the southeastern coast of Australia’s <a href="https://greatsouthernreef.com/learn">Great Southern Reef</a>. </p>
<p>What can we do? Here’s one excellent solution: eat their roe, a buttery delicacy that can fetch hundreds of dollars per kilogram. Tasmania already has a government-backed urchin fishery. When combined with a mix of other tools, as outlined in <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0011/1623593/IMAS-Submission-to-the-senate-inquiry-on-climate-related-marine-and-invasive-species_Final.pdf">our submission</a> to the invasive marine species <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/Invasivemarinespecies">Senate inquiry</a>, harvesting urchins can put the brakes on this overabundant, range-extending marine species. </p>
<p>Today, the <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/Invasivemarinespecies/Report">Senate handed down its findings</a>, identifying <a href="https://parlinfo.aph.gov.au/parlInfo/download/committees/reportsen/RB000056/toc_pdf/Win-winunderouroceansClimate-relatedmarineinvasivespecies.pdf">investment in commercial harvesting</a> as a frontline climate-ready tool to combat the urchin. It presents a win-win opportunity by maximising socioeconomic and environmental returns for kelp ecosystems, while lessening the ongoing cost of control.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/nsLLLT908Kk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Strategies for urchin control.</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-great-southern-reef-is-in-more-trouble-than-the-great-barrier-reef-201235">The Great Southern Reef is in more trouble than the Great Barrier Reef</a>
</strong>
</em>
</p>
<hr>
<h2>Dealing with urchins is urgent</h2>
<p><a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15634">Almost 200 marine species</a> have been documented shifting range in Australian seas as climate change heats the oceans. But longspined sea urchins are the most damaging so far. </p>
<p>The waters along hundreds of kilometres of coastline have now warmed above a winter average of 12°C. This is the temperature at which <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2486.2008.01543.x">urchin larvae can develop</a> during spawning. The ocean is warming faster than land, heating at a rate of <a href="https://www.sciencedirect.com/science/article/pii/S0079661123000897">4°C per century</a>.</p>
<p>The Senate inquiry shows the government is listening. The inquiry and accompanying <a href="https://www.aph.gov.au/DocumentStore.ashx?id=7ceb303f-b642-4674-82cc-0195ba034fb3">five-year plan</a> for control methods are based on more than <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0011/1623593/IMAS-Submission-to-the-senate-inquiry-on-climate-related-marine-and-invasive-species_Final.pdf">two decades</a> of scientific research. </p>
<h2>The tragedy of the barrens</h2>
<p>Urchins chew through entire forests of kelp. Once the big kelp is gone, they switch to feeding on tiny encrusting seaweeds that can regrow rapidly and persist in the face of intensive grazing. This creates <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.2013.0269">“hyper-stable” urchin barrens</a>. </p>
<p>The damage is dramatic, with the local loss of <a href="https://link.springer.com/article/10.1007/s00442-008-1043-9">hundreds of kelp-associated species</a> ranging from valuable abalone to the iconic leafy seadragon. </p>
<p>Barrens in southern NSW, eastern Victoria and Tasmania can now be measured in the scale of kilometres, with whole reefs turned into <a href="https://hiddendeserts.com/the-project/">underwater deserts</a>. </p>
<p>They expand fast, too. In Tasmania, early sightings off the northeast in 1978 have turned into a population <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0005/1176026/129569-Resurvey-of-the-Longspined-Sea-Urchin-Centrostephanus-rodgersii-and-associated-barren-reef-in-Tasmania.pdf">estimated at 20 million</a> around the eastern coastline. Barren areas now cover 15% of Tasmanian reefs. If left unchecked, 50% of reef habitat could be lost by the 2030s, as we’ve seen in southern NSW and eastern Victoria. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="diver in a kelp forest looking for sea urchins" src="https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Research divers assessing sea urchin spread off St Helens in Tasmania’s northeast.</span>
<span class="attribution"><span class="source">Matt Testoni</span></span>
</figcaption>
</figure>
<h2>Correcting an imbalance of nature</h2>
<p>Rock lobsters are a natural predator of urchins. They boost <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0008/1556522/Centro_lobster_exp_site_resurvey_final_report.pdf">kelp bed resilience</a> and even prevent barren expansion in some areas off limits to lobster fisheries. </p>
<p>The Tasmanian East Coast Rock Lobster Rebuilding Strategy focuses on rebuilding stocks to help combat the urchin. However, the lobsters’ strong preference for <a href="https://academic.oup.com/icesjms/article/79/4/1353/6565266">local prey</a> such as abalone, their <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0008/1556522/Centro_lobster_exp_site_resurvey_final_report.pdf">negligible capacity to rehabilitate extensive barrens</a> once urchins reach hyperabundance, and high recreational and commercial fisheries value, constrains the scale of effectiveness. </p>
<p>Another option is culling, where divers kill urchins underwater. The upshot is that kelp can grow back quickly, within just 18 months, if all visible urchins are culled. But it’s <a href="https://www.frdc.com.au/sites/default/files/products/2011-087-DLD.pdf">extremely expensive</a> and urchins can reemerge, meaning culling needs to be ongoing. </p>
<h2>An affordable, scalable, long-term solution?</h2>
<p>Yes. Make it profitable. The main game here isn’t the urchins themselves but their roe, known as “uni” in Japan. Urchin roe is a delicacy, renowned for its sweet, buttery, umami flavours and bright golden colour. Premium roe returns top dollar in markets from across South East Asia, the United States and the Middle East.</p>
<p>If commercial fisheries are viable, we can remove vast quantities of urchins from reefs in a low-cost urchin control program over large areas. </p>
<p>But there are challenges here too. Extracting the roe is labour-intensive. Roe quality can vary greatly, dropping as overgrazing ensues. To date, infrastructure, access to markets, and detailed knowledge of processing techniques has been a limiting factor. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A commercial diver bags a haul of sea urchins destined for international markets" src="https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A commercial diver removes a haul of sea urchins destined for international markets.</span>
<span class="attribution"><span class="source">Matt Testoni</span></span>
</figcaption>
</figure>
<p>Tasmania is showing it can be done. In 2018, the state government invested in a <a href="https://fishing.tas.gov.au/community/long-spined-sea-urchin-management/abalone-industry-reinvestment-fund">fledgling urchin fishery</a> in conjunction with the abalone industry by offering <a href="https://tasfisheriesresearch.org/wp-content/uploads/2022/11/Cresswell-et-al.-Centrostephanus-Subsidy-Program-Initial-Evaluatio.pdf">harvest subsidies</a>.</p>
<p>These gave urchin processors the financial certainty to invest. In a few years, annual urchin fishery yields have grown from <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0010/1659268/TASMANIAN-LONGSPINED-SEA-URCHIN-FISHERY-ASSESSMENT-2021-22.pdf">40 tonnes to 500 tonnes</a>, all harvested by hand by divers.</p>
<p>To date, the fishery has created more than 100 jobs and boosted regional economies. It’s <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0011/1623593/IMAS-Submission-to-the-senate-inquiry-on-climate-related-marine-and-invasive-species_Final.pdf">starting to work too</a>. The fishery has not only slowed the expansion of urchin barrens, but allowed recovery of kelp habitats in some heavily fished areas. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sea-urchins-have-invaded-tasmania-and-victoria-but-we-cant-work-out-what-to-do-with-them-194534">Sea urchins have invaded Tasmania and Victoria, but we can’t work out what to do with them</a>
</strong>
</em>
</p>
<hr>
<h2>Expanding urchin fisheries</h2>
<p>Tasmania’s example shows the potential of fishery-led control of overabundant, problematic species. Making the most of it means adding value, such as by expanding the international market, developing new uses for low-grade urchin roe and <a href="https://www.mdpi.com/2073-4395/12/12/2919">selling waste products</a>. If it’s more profitable, divers will be able to travel farther from port and fish down urchin stocks.</p>
<p>We can also direct fishery efforts for better urchin control by offering subsidies to <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0010/1659268/TASMANIAN-LONGSPINED-SEA-URCHIN-FISHERY-ASSESSMENT-2021-22.pdf">fish high priority areas</a>. </p>
<p>Other states hit hard by urchins too, such as Victoria, could benefit from control-by-fishery. </p>
<p>Achieving national, widespread urchin control will require challenging coordination. We need to:</p>
<ul>
<li>support dive fisheries to become the heavy lifter of urchin control</li>
<li>add <a href="https://www.youtube.com/watch?v=vFbB0bPHUDQ">extra urchin control measures</a> on high-value reefs</li>
<li>begin restoring degraded barrens to a mosaic of urchin fisheries or kelp forests</li>
<li>boost populations of urchin predators on healthy reefs, to increase resilience in the first place.<br></li>
</ul>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo showing a healthy kelp ecosystem" src="https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Healthy kelp ecosystems are vital for abalone.</span>
<span class="attribution"><span class="source">Matt Testoni</span></span>
</figcaption>
</figure>
<p>If we do this right, Australia’s control of the longspined sea urchin could be a global exemplar of <a href="https://www.climatereadyaustralia.com.au/">climate-ready</a> management of overabundant and range extending species, boosting <a href="https://www.frdc.com.au/project/2014-301">rural economies</a> and <a href="https://www.csiro.au/en/research/natural-environment/land/regional-prosperity">social wellbeing</a>. As species keep moving, finding low- or zero-cost control measures will be essential to keeping ecosystems intact. </p>
<p>Controlling troublesome species is often seen as a major cost to government. Our work and the work of many others has shown it doesn’t have to be. Creating viable urchin fisheries turns a cost into a benefit. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/marine-species-are-being-pushed-towards-the-poles-from-dugong-to-octopuses-here-are-8-marine-species-you-might-spot-in-new-places-207115">Marine species are being pushed towards the poles. From dugong to octopuses, here are 8 marine species you might spot in new places</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/214389/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Keane receives funding from the Fisheries Research Development Corporation and the Tasmanian Government.</span></em></p><p class="fine-print"><em><span>Scott Ling receives funding from the Australian Research Council. </span></em></p>Controlling invasive sea urchins is expensive. Why not make it profitable by fishing for them and selling their roe as a delicacy?John Keane, Research Fellow (Dive Fisheries), University of TasmaniaScott Ling, Associate professor, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2056262023-10-02T12:28:48Z2023-10-02T12:28:48ZThere’s a thriving global market in turtles, and much of that trade is illegal<figure><img src="https://images.theconversation.com/files/549993/original/file-20230925-24-nz5ob8.jpg?ixlib=rb-1.1.0&rect=11%2C3%2C2422%2C1912&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Smuggled rare Mexican box turtles intercepted by U.S. officials at the Port of Memphis.</span> <span class="attribution"><a class="source" href="https://www.fws.gov/story/2021-05/us-fish-and-wildlife-service-works-partners-rescue-rare-turtles-memphis-port-entry">USFWS</a></span></figcaption></figure><p>Hatchling turtles are cute, small and inexpensive. Handled improperly, they also can make you sick. </p>
<p>Turtles are well-known carriers of <a href="https://www.mayoclinic.org/diseases-conditions/salmonella/symptoms-causes/syc-20355329">salmonella, a common bacterial disease</a> that causes fever, stomach cramps and dehydration and can lead to severe illness, especially in young children and elderly people. In August 2023, the Centers for Disease Control and Prevention <a href="https://www.cdc.gov/salmonella/turtles-08-23/index.html">released an advisory</a> about an 11-state outbreak of salmonella bacteria linked to pet turtles.</p>
<p>“Don’t kiss or snuggle your turtle, and don’t eat or drink around it. This can spread Salmonella germs to your mouth and make you sick,” the agency warned.</p>
<p>Global trade in turtles is big business, and the U.S. is a leading <a href="https://doi.org/10.1641/0006-3568(2005)055%5B0256:CIETIO%5D2.0.CO;2">source, destination and transit country</a>. Some of this commerce is legal, some is not. For example, it has been illegal in the U.S. since 1975 to sell turtles with shells less than 4 inches (10 centimeters) in diameter because young children often contract salmonella from them. But it’s easy to <a href="https://doi.org/10.1371/journal.pone.0278443">find them for sale</a> nonetheless. </p>
<p>However, humans are a much bigger threat to turtles than vice versa. Over half of the world’s turtle species are <a href="https://iucn-tftsg.org/checklist/">classified as threatened or endangered</a>, and <a href="https://doi.org/10.1016/j.cub.2020.04.088">overharvesting of wild turtles</a> is a major cause. Turtles also face other threats, including habitat loss, climate change, pollution, diseases, invasive species and death or injury while <a href="https://theconversation.com/by-helping-wild-animals-you-could-end-their-freedom-or-even-their-lives-heres-why-you-should-keep-your-distance-207188">trying to cross roads</a>.</p>
<p>As a <a href="https://www.linkedin.com/in/jennifer-sevin-a38b4b89/">conservation biologist</a>, I work with colleagues from academia, nonprofit organizations and state and federal agencies to protect threatened species and combat wildlife trafficking. I also use the global wildlife trade to teach important ecological concepts and research skills. Here’s what we know about trade in turtles and how it threatens their survival.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/fdnQ7Kd8czk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">U.S. zoos and aquariums are working with government agencies to detect and reduce illegal trade in turtles.</span></figcaption>
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<h2>Life in the slow lane</h2>
<p>It’s <a href="https://doi.org/10.1371/journal.pone.0229689">hard to harvest turtles sustainably</a> because they are so long-lived. Individual turtles of some species can survive for more than 100 years. Most turtles reach reproductive maturity late in life and have relatively few eggs, not all of which produce successful offspring.</p>
<p>To put this in context, compare a common female snapping turtle from the northern U.S. with a female white-tailed deer. Begin at the start of their lives and fast-forward 17 years. At this point, the snapping turtle will just be ready to reproduce for the first time; the deer will already be dead, but it may have produced <a href="https://www.fws.gov/story/2022-11/turtles-face-unique-challenges-cites-can-help">over 600 descendants</a>. It can take a female turtle her entire life to generate one or two offspring that in turn reach adulthood and replace her in the population.</p>
<p>Turtles are valuable because they play diverse roles in <a href="https://doi.org/10.1093/biosci/biy095">land, freshwater and ocean ecosystems</a>. For example, tortoise burrows provide refuge for hundreds of other species, including <a href="https://myfwc.com/wildlifehabitats/profiles/reptiles/gopher-tortoise">birds, mice, snakes and rabbits</a>. Box turtles – the type you may encounter in your garden – consume practically any kind of plant material and excrete the seeds as they move around, <a href="https://doi.org/10.1002/ece3.6487">helping plants spread</a>. Some seeds even germinate more readily <a href="https://www.bbg.org/article/box_turtles">after passing through a box turtle’s gut</a>.</p>
<p>In lakes and ponds, freshwater turtles serve as both predator and prey, and they help maintain good water quality by consuming decaying organisms. Terrapins reside in brackish water zones, where rivers flow into oceans and bays, and feed heavily on snails. Without terrapins present, the snails would quickly consume all underwater seagrasses, which would harm fish, shellfish, sea urchins and other organisms that <a href="https://ocean.si.edu/ocean-life/plants-algae/seagrass-and-seagrass-beds">rely on seagrasses for their survival</a>.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CCUOnx7ggav/?utm_source=ig_web_copy_link\u0026igshid=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>In global demand</h2>
<p>Humans have long been fascinated with turtles. Revered in many cultures, turtles have <a href="https://www.britannica.com/topic/Kurma">symbolized strength</a> and <a href="https://blog.nativehope.org/native-american-animals-turtle-k%C3%A9ya">longevity</a> for centuries. Today, people use turtles as pets; sources of food, <a href="https://flic.kr/p/Rwc4mu">jewelry and other curios</a>; and in traditional medicines and <a href="https://news.mongabay.com/2017/05/balinese-rituals-fuel-spike-in-trafficking-of-endangered-sea-turtles/">religious and cultural practices</a>.</p>
<p>International trade in turtles takes place on a massive scale. According to the U.S. Fish and Wildlife Service, nearly 127 million turtles were exported just from the U.S. between 2002 and 2012. About one-fifth (24 million) <a href="https://doi.org/10.1371/journal.pone.0086478">came from the wild</a>.</p>
<p>More recent data indicates that exports declined between 2013 and 2018, but <a href="https://www.fishwildlife.org/application/files/7815/9352/0162/Case_Study_U.S._Freshwater_Turtles_and_Tortoises_CITES_2020_FINAL.pdf">trade in particular species increased</a>. Commercial freshwater turtle farming is still a <a href="https://doi.org/10.1371/journal.pone.0139053">multimillion-dollar industry</a> in the southeastern U.S.; a small number of native turtle species, <a href="https://www.nass.usda.gov/Publications/AgCensus/2017/Online_Resources/Aquaculture/aqua_1_0020_0020.pdf">largely bred on turtle farms</a>, now make up the bulk of legal U.S. exports, for use as both pets and food.</p>
<p>There’s no good way to quantify how many native turtles are harvested from the wild. But history shows what happens when they are hunted without limits. Historic demand for <a href="https://www.nationalgeographic.com/animals/article/sea-turtles-are-surviving-despite-threats-from-humans-feature">sea turtles</a>, <a href="https://www.npr.org/sections/thesalt/2019/07/18/742326830/our-taste-for-turtle-soup-nearly-wiped-out-terrapins-then-prohibition-saved-them">diamondback terrapins</a> and <a href="https://doi.org/10.1016/j.jnc.2016.11.003">snapping turtles</a> as food led to such crashes in populations that management agencies had to regulate their harvesting.</p>
<p>Turtles also are gaining popularity as pets, <a href="https://www.forbes.com/advisor/pet-insurance/pet-ownership-statistics/">particularly for younger adults</a>. Surveys indicate that <a href="https://www.americanpetproducts.org/press_releasedetail.asp?v=ALL&id=1229">more than 2 million Americans own turtles</a>. To curb pressure on wild populations, state agencies are <a href="https://biologicaldiversity.org/w/news/press-releases/south-carolina-governor-signs-bill-protect-wild-turtles-poaching-trade-2020-10-22/">prohibiting or limiting</a> personal collection and possession of native turtles. </p>
<h2>Black market turtles</h2>
<p>Despite existing regulations, demand for some native North American turtle species is so strong that people collect, smuggle and sell the animals illegally. For example, in 2019 a Pennsylvania man was sentenced to six months in prison and fined $250,000 for trafficking <a href="https://www.justice.gov/opa/pr/pennsylvania-man-sentenced-trafficking-protected-turtles">thousands of protected diamondback terrapins</a>. </p>
<p>Rare species such as wood turtles and Blanding’s turtles, as well as uniquely patterned individual turtles, <a href="https://doi.org/10.1111/1365-2664.12797">command top value on the black market</a>. Internet commerce, social media apps and online payment mechanisms make it easy for illegal buyers and sellers to connect.</p>
<p>Between 1998 and 2021, U.S. enforcement agencies intercepted at least 24,000 protected freshwater turtles and tortoises <a href="https://doi.org/10.1002/pan3.10448">from 34 native species</a> that were being illegally traded across the U.S. These animals may be held without food and water and in crowded spaces, sometimes wrapped in tape and stuffed in socks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/549998/original/file-20230925-25-zzb9mu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A turtle roughly 10 inches in diameter, wrapped in duct tape." src="https://images.theconversation.com/files/549998/original/file-20230925-25-zzb9mu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/549998/original/file-20230925-25-zzb9mu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549998/original/file-20230925-25-zzb9mu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549998/original/file-20230925-25-zzb9mu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549998/original/file-20230925-25-zzb9mu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549998/original/file-20230925-25-zzb9mu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549998/original/file-20230925-25-zzb9mu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A live smuggled Mexican box turtle intercepted by U.S. officials at the Port of Memphis in 2021.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/2kZn2Af">USFWS</a></span>
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<h2>How to help</h2>
<p>To curtail the illegal turtle trade, regulators are working to <a href="https://www.fws.gov/story/joining-forces-combat-turtle-trafficking">strengthen regulations and increase enforcement</a>. Private citizens can also help reduce the demand and protect wild turtles. Here are some simple steps:</p>
<ul>
<li><p>Before you purchase any live animal or wildlife-related product, review relevant local, state, national and international regulations. Just because something is for sale doesn’t mean it’s legal.</p></li>
<li><p>Make an informed decision about owning a turtle. Consider the size it will reach as an adult, its care requirements and its life span. Prioritize adopting one from a reputable rescue organization, and seek out a captive-bred turtle instead of a wild one.</p></li>
</ul>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/550000/original/file-20230925-27-u1z8wx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small terrapin with a red streak on the side of its head." src="https://images.theconversation.com/files/550000/original/file-20230925-27-u1z8wx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/550000/original/file-20230925-27-u1z8wx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550000/original/file-20230925-27-u1z8wx.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550000/original/file-20230925-27-u1z8wx.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550000/original/file-20230925-27-u1z8wx.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550000/original/file-20230925-27-u1z8wx.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550000/original/file-20230925-27-u1z8wx.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The red-eared slider (<em>Trachemys scripta elegans</em>) is a terrapin that has become highly invasive in the U.S., outcompeting native species.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Red-eared_slider#/media/File:Tortue_floride_france.JPG">Galano~commonswiki/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<ul>
<li><p>Don’t release an animal that you no longer want or can’t care for into the wild. This is illegal and can have serious ecological impacts. The <a href="https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=1261">red-eared slider</a> (<em>Trachemys scripta elegans</em>), a freshwater turtle that’s native to the Mississippi River basin, was sold by the millions in recent decades and released by many pet owners. Now it is considered one of the <a href="https://www.invasivespeciesinfo.gov/aquatic/fish-and-other-vertebrates/red-eared-slider">world’s most invasive species</a> because it <a href="https://portals.iucn.org/library/sites/library/files/documents/2000-126.pdf">outcompetes native turtles for food and space</a>.</p></li>
<li><p>If you encounter illegal wildlife collection, smuggling or sales, report them to your state fish and wildlife agency or the <a href="https://www.fws.gov/form/refuge-law-enforcement">U.S. Fish and Wildlife Service</a> for investigation.</p></li>
<li><p>Support efforts to conserve and restore turtle habitat and minimize other threats, such as pollution and <a href="https://daily.jstor.org/road-density-threatens-turtle-populations/">road traffic</a>.</p></li>
</ul><img src="https://counter.theconversation.com/content/205626/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer Sevin is a co-founder and serves on the steering committee of the Collaborative to Combat the Illegal Trade in Turtles.</span></em></p>More than half of the world’s turtle species are endangered or threatened, and overhunting of wild species is a major cause.Jennifer Sevin, Director of Biological Instruction, University of RichmondLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2131202023-09-21T22:07:48Z2023-09-21T22:07:48ZHow the Peach Blossom Jellyfish is spreading across North America<figure><img src="https://images.theconversation.com/files/548221/original/file-20230914-17-v07w3f.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4000%2C3000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Peach Blossom Jellyfish (Craspedacusta sowerbii) is native to China and an invasive species in Canada.</span> <span class="attribution"><span class="source">(Florian Lüskow)</span>, <span class="license">Author provided</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/how-the-peach-blossom-jellyfish-is-spreading-across-north-america" width="100%" height="400"></iframe>
<p>Invasive species <a href="https://www.canada.ca/en/environment-climate-change/services/biodiversity/invasive-alien-species-strategy.html">are a real problem in Canada</a>, and one species in particular, the freshwater jellyfish species of the genus <em>Craspedacusta sowerbii</em> — <em>C. sowerbii</em>, or the Peach Blossom Jellyfish — are as widespread as they are also poorly understood. </p>
<p>There is anecdotal evidence that the invasive jellyfish had been present in British Columbia lakes and ponds for decades. Still, compiled data suggest that the number of sightings has increased considerably since the year 2000. </p>
<p>Unfortunately, however, we still have very limited information about the range of its presence in Canada, how it got here, how it spreads and what its essential impact on freshwater ecosystems across Canada may be. No mitigation and management strategy has yet been developed and many fundamental questions about the species ecology are unanswered.</p>
<h2>Climate change and species introductions</h2>
<p>The <em>Craspedacusta</em> species is a subtropical but adaptable organism which favours moderate- to high-water temperatures. While cold water temperatures have acted as a historical check on their growth and expansion, warming temperatures around the globe are helping to expand their territory.</p>
<p>Recent increases in sightings of <em>C. sowerbii</em> in B.C., across Canada and worldwide are therefore indicative of an expanding suitable habitat for the jellyfish as a result of global warming, alongside a <a href="https://www.int-res.com/articles/ab2021/30/b030p069.pdf">growing public awareness and increased observational efforts</a> leading to more effective recognition.</p>
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Read more:
<a href="https://theconversation.com/invasive-species-cause-billions-of-dollars-in-damage-worldwide-4-essential-reads-212924">Invasive species cause billions of dollars in damage worldwide: 4 essential reads</a>
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<p>Current modelling shows that the Peach Blossom Jellyfish will expand to ever higher latitudes in both hemispheres over this century and be <a href="https://doi.org/10.3354/ab00742">present in freshwater systems longer in the year from spring to late autumn</a>. </p>
<p>Unfortunately, the species has rarely been the focus of research. Currently, as far as I am aware, only biological oceanographer Evgeny Pakhomov and I are now researching the species and its significance for Canada.</p>
<p>Our research shows that this trend is not restricted to B.C., but is expected to happen in other provinces such as Alberta, Ontario and Québec too. <em>Craspedacusta sowerbii</em> irregularly occurs in the Great Lakes area on both sides of the Canada-United States border since the 1930s.</p>
<h2>Small invader, unpredictable occurrence</h2>
<p>The current state of provincial monitoring and reporting on this species is, unfortunately, lacklustre. </p>
<p>While a number of tools and data have been shown to be effective <a href="https://doi.org/10.1002/rra.3947">in monitoring populations in North America and Europe</a>, no province currently includes these in annual reports and statistics. </p>
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<a href="https://theconversation.com/a-battlefield-for-ants-new-study-on-ant-warfare-shows-we-could-manipulate-their-fights-211127">A battlefield for ants? New study on ant warfare shows we could manipulate their fights</a>
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<p>For example, the <a href="https://bcinvasives.ca/">Invasive Species Council of British Columbia’s annual report</a> does not cunduct large-scale data synthesis on the Peach Blossom Jellyfish. As a result of this lack of data, no evidence of seasonal or long-term population trends exists.</p>
<p>Compounding these difficulties is the fact that the <em>C. sowerbii</em> is known as a species complex, meaning that there are likely several species going undetected under the same name. The nuances of these species distinctions are not only of academic interest, but also hold the key to identifying how these species move across and between ecosystems.</p>
<p>Understanding all of these aspects is crucial for us to start seriously thinking about mitigation and management strategies.</p>
<h2>We cannot manage what we don’t understand</h2>
<p>While the species is harmless to humans, it is unknown how the freshwater jellyfish interact with other lake and pond inhabitants. There is evidence that these jellyfish are a potentially rich source of food for juvenile fish and they could <a href="https://doi.org/10.3390/biology12060814">compete with other native species as food</a>.</p>
<p>Meanwhile, not enough up-to-date information is available about the various life stages of the jellyfish and the particular impacts of each stage. Indeed, <a href="https://doi.org/10.3390/biology11081100">while polyps and other juvenile stages are present year-round</a>, their exact locations, abundance and activity levels are entirely unknown.</p>
<p>While governmental reporting infrastructure does exist in some provinces and territories, large-scale data have not yet been analyzed. Efforts are hampered by the lack of inclusion of the Peach Blossom Jellyfish in regular monitoring programs. </p>
<p>We hope to stimulate interest and motivation to better understand this problem at all levels from federal to provincial governments and local municipalities.</p>
<p>This lack of data, and effort by provinces to collect them, has serious consequences for Canada’s ecological security and limits the effectiveness of any management or adaptation plan in the years to come.</p><img src="https://counter.theconversation.com/content/213120/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Florian Lüskow does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The Peach Blossom Jellyfish is an invasive species in Canada, and a lack of data is hampering efforts to control populations.Florian Lüskow, Postdoctoral research fellow, Faculty of Science, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2137782023-09-21T12:03:56Z2023-09-21T12:03:56ZInvasive alien species are a serious threat to the planet: 4 key messages for Africa<p>Climate change has negatively – and irreversibly, in some cases – affected ecosystems around the globe. Sadly, though, it is not the only phenomenon that’s altering our natural world.</p>
<p>In 2019, the Intergovernmental Science Policy Platform on Biodiversity and Ecosystem Services (IPBES) Global Assessment Report <a href="https://www.ipbes.net/sites/default/files/inline/files/ipbes_global_assessment_report_summary_for_policymakers.pdf">confirmed</a> invasive alien species as one of the five most important direct drivers of biodiversity loss. The others were climate change, land and sea use, direct exploitation of species, and pollution. </p>
<p><a href="https://www.ipbes.net/">IPBES</a>, an independent intergovernmental body, was established in 2012. It now has 144 member countries; Somalia, the newest member, joined in mid-September. Its major objective is to strengthen the interface between science and policy to conserve and sustainably use biodiversity. </p>
<p>The 2019 assessment found that more than 37,000 alien species had been introduced by many human activities to regions and biomes around the world, most in the past 100 years. A <a href="https://www.ipbes.net/IASmediarelease">new report</a> by the organisation, focused on alien invasive species, suggests this number is rising fast, with new alien species being recorded at an unprecedented rate of approximately 200 annually. It also reveals that the global economic cost of invasive alien species exceeded US$423 billion annually. Costs have at least quadrupled every decade since 1970.</p>
<p>But the new report doesn’t just concentrate on problems. It also offers solutions. It outlines key responses and policy options that governments may take for prevention, early detection and effective control of invasive alien species. Doing so will help to safeguard nature and its contributions to people. This will ensure a better quality of life for all.</p>
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Read more:
<a href="https://theconversation.com/the-true-damage-of-invasive-alien-species-was-just-revealed-in-a-landmark-report-heres-how-we-must-act-211893">The true damage of invasive alien species was just revealed in a landmark report. Here's how we must act</a>
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<p>I am an invasion biologist whose <a href="https://www.ru.ac.za/centreforbiologicalcontrol/people/researchstaff/juliecoetzee/">research</a> focuses on the ecology and management of invasive aquatic plants. Here, I elaborate on the four key messages highlighted by the report that African countries should heed if the continent is to successfully tackle the threats posed by invasive species.</p>
<h2>Key messages</h2>
<p><em><strong>1: Invasive alien species are a major threat to nature, its contributions to people, and good quality of life.</strong></em></p>
<p>In Africa, invasive species threaten food security by negatively affecting fish production, agricultural productivity, grazing and water supplies. </p>
<p>The introduction of the Nile perch, <em>Lates niloticus</em>, into East Africa’s Lake Victoria in 1954 is one of the most extreme examples. Predation by this species caused the extinction of approximately 200 species of cichlids from the lake. It <a href="https://www.jstor.org/stable/2386700">is considered</a> to represent the largest extinction event among vertebrates during the 20th century. </p>
<p>The invasion also resulted in the shallow lake becoming enriched with nutrients as people came to fish for Nile perch. This resulted in the widespread invasion of the lake by water hyacinth. The plant restricted access to the lake, which prevented transport and fishing. </p>
<p><em><strong>2: Globally, invasive alien species and their impacts are increasing rapidly and are predicted to continue rising in the future. Accurate data is crucial.</strong></em></p>
<p>A <a href="https://www.sciencedirect.com/science/article/pii/S0048969721003041">2021 research study</a> highlighted that the reported economic costs of invasive aquatic species were unevenly distributed across geographic regions. Africa, the Oceania-Pacific Islands and the Antarctic-Subantarctic, combined, accounted for only 0.6% of the US$345 billion global estimate. That’s not because the costs are really that low. The data simply isn’t being recorded, so we’re not getting the full picture. </p>
<p>African countries need to <a href="https://healthtimes.co.zw/2023/09/19/zim-scales-up-efforts-to-control-invasive-alien-species/">partner with their neighbours</a> in better quantifying the situation. </p>
<p><em><strong>3: Invasive alien species and their negative impact can only be prevented and mitigated through effective management.</strong></em></p>
<p>In 2011 the Convention on Biological Diversity released its <a href="https://www.cbd.int/sp/targets/">Aichi Biodiversity Targets</a>. The 20 targets were designed to address and mitigate biodiversity loss across the globe. Target 9 stated that, by 2020, invasive alien species and pathways should be identified and prioritised. Priority species should be controlled or eradicated, and measures taken to block new pathways.</p>
<p>But none of those targets were met. And there has been little or no progress recorded in some African countries. Today, invasive species <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(20)30174-1/fulltext">are reported</a> to be adversely affecting livelihoods in more than 70% of African countries. </p>
<p>Constrained financial resources and the lack of legal frameworks and related operational systems are largely to blame for the lack of progress. For example, there is a <a href="https://link.springer.com/chapter/10.1007/978-3-030-32394-3_12">huge lack of capacity</a>, mainly at ports of entry – which are the most crucial step in preventing invasions. </p>
<p>Many regions still have to enhance their management plans for effective control of invasive species, starting with identification of common invasive species.</p>
<p><em><strong>4: There are success stories on the continent – lessons should be shared across borders.</strong></em></p>
<p>In South Africa, the management of alien plant invasions has been actively supported by the government’s <a href="https://www.dws.gov.za/wfw/">Working for Water</a> programme since 1995. </p>
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Read more:
<a href="https://theconversation.com/invasive-alien-plants-in-south-africa-pose-huge-risks-but-they-can-be-stopped-94186">Invasive alien plants in South Africa pose huge risks, but they can be stopped</a>
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<p>A study in 2022 <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320722002944">estimated</a> that an average of R310 million (adjusted to 2020 values) had been spent every year on work that covered 2.7 million hectares across more than 76,000 sites. This doesn’t mean plant invasions are totally under control. But it is clear that, without this kind of programme, the situation would be far worse.</p>
<p>The study recommended that the programme’s future efforts must focus on clearly defined priority sites, improving planning and monitoring, and increasing operational efficiency. These are all valuable lessons for other African countries.</p>
<h2>An African lens</h2>
<p>Its new report did not focus on any one part of the world, but IPBES has previously been clear about the importance of biodiversity to African nations. In a 2018 <a href="https://www.ipbes.net/assessment-reports/africa">regional assessment</a> on Biodiversity and Ecosystem Services For Africa, the organisation wrote that</p>
<blockquote>
<p>biodiversity and nature’s contributions in Africa are economically, socially and culturally important, essential in providing the continent’s food, water, energy, health and secure livelihood, and represent a strategic asset for sustainable development and achievement of the Sustainable Development Goals.</p>
</blockquote>
<p>Most of the data in the newest report comes from the northern hemisphere, as this is where most of the research is conducted, and where the majority of funding comes from. </p>
<p>Different countries and regions will have different needs. That’s where the value of regional coordination and knowledge-sharing becomes clear.</p><img src="https://counter.theconversation.com/content/213778/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julie Coetzee receives funding from the National Research Foundation SARCHi and the Natural
Resource Management Programme of the South African Department of Forestry, Fisheries, and the Environment. Any opinion, conclusion or recommendation in this material is that of the authors and the NRF does not accept any liability in this regard.</span></em></p>The new report on alien invasive species doesn’t just concentrate on problems. It also offers solutions.Julie Coetzee, Researcher, Rhodes UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2125012023-09-19T14:47:51Z2023-09-19T14:47:51ZWhy invasive ants are a silent threat to our ecosystems<figure><img src="https://images.theconversation.com/files/548832/original/file-20230918-27-85srij.jpg?ixlib=rb-1.1.0&rect=0%2C13%2C3113%2C2316&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The yellow crazy ant (Anoplolepis gracilipes) is a notorious invasive ant species.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/yellow-crazy-ant-anoplolepis-gracilipes-1960533274">Lukman_M/Shutterstock</a></span></figcaption></figure><p>Invertebrates are often described by <a href="https://faculty.washington.edu/timbillo/Readings%20and%20documents/ABRIDGED%20READINGS%20for%20PERU/Wilson_1987_Little_things_that_run.pdf">experts</a> as the “little things that run the world”, and ants are certainly one of the top contenders for this role. Ants help ecosystems to function normally and the <a href="https://www.pnas.org/doi/full/10.1073/pnas.2201550119">total weight</a> of all ants on Earth is roughly equivalent to 1.4 billion people, or 33 Empire State Buildings. </p>
<p>Unfortunately, some ants have become invasive species – organisms transported to a new ecosystem that cause damage. These introductions typically happen accidentally by people but can have dire consequences, as my team’s <a href="https://resjournals.onlinelibrary.wiley.com/doi/10.1111/icad.12672">new research</a> shows. </p>
<p>Invasive species are thought to be the <a href="https://link.springer.com/article/10.1007/s10531-018-1595-x">second largest</a> threat to biodiversity after habitat destruction. They are a <a href="https://doi.org/10.1016/j.tree.2005.01.003">leading cause</a> of animal extinctions, potentially leading to species extinction and ecosystem failure. </p>
<p>The International Union for the Conservation of Nature includes <a href="https://portals.iucn.org/library/sites/library/files/documents/2000-126.pdf">five different ant species</a> on its list of 100 of the world’s worst invasive alien species. But while invasive ants have dramatically transformed some of the areas they have been able to invade, other areas appear to be far less affected, or even totally unaffected.</p>
<h2>How bad are invasive ants, really?</h2>
<p>My team’s <a href="https://resjournals.onlinelibrary.wiley.com/doi/10.1111/icad.12672">study</a> draws from research conducted around the world to provide a measure of how bad or good invasive ants are for biodiversity loss. The results show us that invasive ants are every bit as bad as we had assumed.</p>
<p>We extracted data from 46 different research articles that studied how animal communities reacted to invasive ants, and combined the results. We only selected research that was done in relatively “undisturbed” natural environments, free from intensive human activity. </p>
<p>These are areas that invasive ants have dispersed to from more degraded habitats or urban environments. This allows us to more confidently claim that any negative or positive effects on animal communities are because of invasive ants, rather than other invasive species or some form of human disturbance such as agriculture or deforestation.</p>
<p>Our results show that animal communities respond overwhelmingly negatively to invasive ants. We found there were on average 50% fewer individual animals and species in areas invaded by ants, which is a dramatic fall in biodiversity. It is also important to remember these results are averages and, therefore, invasive ants may spell doom for some animal communities above and beyond these numbers.</p>
<figure class="align-center ">
<img alt="A close up of an ant with a large head crawls along a mossy piece of bark." src="https://images.theconversation.com/files/548020/original/file-20230913-19-n2k3ar.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548020/original/file-20230913-19-n2k3ar.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548020/original/file-20230913-19-n2k3ar.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548020/original/file-20230913-19-n2k3ar.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548020/original/file-20230913-19-n2k3ar.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548020/original/file-20230913-19-n2k3ar.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548020/original/file-20230913-19-n2k3ar.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The <em>Pheidole megacephala</em> or big-headed ant.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/macro-image-bigheaded-ant-2215004569">Alen thien/Shutterstock</a></span>
</figcaption>
</figure>
<p>We also found that certain animal types, such as birds, reptiles and beetles, reacted more strongly than others. Native ants were the most strongly affected group. </p>
<p>This makes sense because many native ants will not only be directly attacked by invasive ants but they will also need to compete with them for food and nest sites. This is also bad news because of the general importance of native ants to the wider ecosystem. </p>
<p>Other groups that were badly affected were birds, beetles, butterflies, moths and reptiles. </p>
<p>We also found that the number of individuals in one insect group – bugs such as scale insects, aphids and mealybugs – increased. This group forms “mutualisms” with ants, which is where each species has a net benefit. </p>
<p>These insects are sap-sucking and exude a sugary liquid called “honeydew”, which ants love. Ants will defend these insects from their predators and parasites in return for this sugary secretion, enabling their populations to mutually increase. In some cases, these mutualisms can facilitate invasion – and to disastrous effect. </p>
<h2>How can something so small cause such a big problem?</h2>
<p>Although ants are small relative to how people perceive the world, they are numerous and tend to interact with a wide range of other organisms. This means they may be able to influence the ecosystem from multiple angles of attack. Invasive ants probably actively hunt down other species but competition for food or space is also important. </p>
<p>Ultimately, we need more research that can tease apart how ants are interacting with other species when they invade a location. What do they eat? Who do they compete with for food? Which habitats do they prefer and why? These questions urgently need answers so we can understand, prioritise and optimise how to minimise the negative effects of invasive ants.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-red-fire-ants-and-yellow-crazy-ants-have-given-themselves-a-green-light-to-invade-australia-208479">Why red fire ants and yellow crazy ants have given themselves a green light to invade Australia</a>
</strong>
</em>
</p>
<hr>
<p>Overall, our research is worrying. The reduction in animal diversity may have severe consequences for ecosystem functioning and the long-term future of rare species. Although there are crucial considerations to mitigate or reverse these effects, the conservation implications are not straightforward. </p>
<p>Ant eradication regimes are logistically complex and financially expensive, for example, and more than half <a href="https://doi.org/10.1016/j.biocon.2016.03.036">fail</a>. Early detection technology, as well as control measures such as toxic baits, can help conservationists prevent or reverse the effects of invasive ants on our ecosystems.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<hr><img src="https://counter.theconversation.com/content/212501/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Maximillian Tercel receives funding from Natural Environment Research Council and Durrell Wildlife Conservation Trust.</span></em></p>Invasive ants are a major threat to biodiversity, according to a study.Maximillian Tercel, PhD Candidate in Entomology, Cardiff UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2129042023-09-13T15:39:32Z2023-09-13T15:39:32ZAsian hornets make UK their latest target – here’s why they’re such a threat to European bees<figure><img src="https://images.theconversation.com/files/547827/original/file-20230912-15-32q28z.jpg?ixlib=rb-1.1.0&rect=0%2C29%2C5000%2C3285&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Asian hornet is a species of hornet indigenous to south-east Asia.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vespa-velutina-known-yellowlegged-hornet-asian-1973172431">ThomasLENNE/Shutterstock</a></span></figcaption></figure><p>A staggering increase in the <a href="https://www.bbc.co.uk/news/science-environment-66697968">number of Asian hornet sightings</a> in the UK has beekeepers and wildlife lovers there reeling. But the invasive species poses a substantial threat to beekeeping and honey production across Europe.</p>
<p>Asian hornets (<em>Vespa velutina</em>), which are native to south-east Asia, are a top predator of <a href="https://www.britannica.com/animal/honeybee">honeybees</a>. Just one Asian hornet reputedly can hunt down and eat <a href="https://www.exmoor-nationalpark.gov.uk/Whats-Special/exmoor-non-native-invasive-species-ennis/exmoors-invasives/asian-hornets">up to 50 honeybees</a> a day. </p>
<p><a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969723041992%C2%A0">Research</a> estimates that Asian hornets could cost the French economy €30.8 million (£26.4 million) every year in a worst case scenario.</p>
<p>But their menace extends beyond bees in a hive. Asian hornets also <a href="https://link.springer.com/article/10.1007/s10530-020-02275-9">prey on native pollinators</a> such as <a href="https://www.britannica.com/animal/bumblebee">bumblebees</a>, so can have a <a href="https://www.sciencedirect.com/science/article/pii/S1439179123000415?via%3Dihub%C2%A0">serious impact</a> on the pollination services these creatures provide.</p>
<p>Asian hornets don’t just eat other bees. They also scare them away from flowers. <a href="https://link.springer.com/article/10.1007/s10530-020-02275-9">One study</a> found that flower visits by bumblebees and hoverflies dropped substantially in the presence of these predators.</p>
<p>Asian hornets were <a href="https://www.nature.com/articles/s41598-017-06212-0">first recorded</a> in the UK in 2016 when worker hornets were seen foraging at an apiary near Tetbury in Gloucestershire. Since then, vigilant members of the public and beekeepers have found and identified 43 Asian hornet nests in the UK – mainly in southern counties such as Kent, Hampshire and Devon. </p>
<p>So far, there have been more confirmed UK sightings of the Asian hornet in 2023 than there were in all the previous years combined. Despite the <a href="https://www.theguardian.com/environment/2023/sep/04/asian-hornet-likely-become-established-uk-say-experts#:%7E:text=Asian%20hornets%20first%20came%20to,or%20under%20their%20own%20steam.">occasional suggestion</a> that the Asian hornet may have become established in the UK, there is no evidence yet that these insects can survive British winters.</p>
<p>The spread of invasive Asian hornets mirrors a global trend. According to a <a href="https://www.ipbes.net/ias">recent report</a> by the Intergovernmental Platform on Biodiversity and Ecosystem Services, invasive species are linked to 60% of global plant and animal extinctions. Their implicit economic cost stands at around US$420 billion (£335 billion) each year.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/un-invasive-species-report-reveals-scale-of-threat-to-nature-and-people-and-how-to-manage-it-212832">UN invasive species report reveals scale of threat to nature and people – and how to manage it</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547842/original/file-20230912-19-syivh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An Asian hornet mid-flight." src="https://images.theconversation.com/files/547842/original/file-20230912-19-syivh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547842/original/file-20230912-19-syivh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547842/original/file-20230912-19-syivh6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547842/original/file-20230912-19-syivh6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547842/original/file-20230912-19-syivh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547842/original/file-20230912-19-syivh6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547842/original/file-20230912-19-syivh6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Asian hornets were first spotted in the UK in 2016.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vespa-velutina-nigrithorax-chinese-hornet-foraging-1956309706">DKeith/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Crossing the border</h2>
<p>The Asian hornet (also known as the yellow-legged hornet) <a href="https://www.nationalbeeunit.com/diseases-and-pests/asian-hornet/">first came to Europe</a> in 2004, where it was spotted in the Lot-et-Garonne region of south-western France. It was supposedly brought to Europe by mistake in a <a href="https://www.persee.fr/doc/bsef_0037-928x_2006_num_111_4_16372">shipment of imported pottery</a> from China.</p>
<p>Asian hornets have since spread into several neighbouring countries, including Spain, Portugal, Germany <a href="https://www.nature.com/articles/s41598-017-06212-0">and the UK</a>. The UK sightings so far in 2023 are clustered around the coast in Kent, Dorset, Hampshire, Plymouth and Weymouth. </p>
<p>Genetic analyses carried out by the National Bee Unit, which runs bee health programmes in England and Wales, suggest that the Asian hornets found in the UK all have <a href="https://www.nationalbeeunit.com/diseases-and-pests/asian-hornet/#:%7E:text=As%20of%20January%202023%2C%20genetic,a%20new%20incursion%20from%20Asia.">the same heritage</a> as the population on mainland Europe. This implies that they are crossing the channel from France on maritime winds with regular re-invasions each year. </p>
<p>It’s plausible that the <a href="https://climate.copernicus.eu/summer-2023-hottest-record">higher summer temperatures</a> seen throughout Europe in 2023 may have driven the recent increase in sightings in the UK. Hornets need warm weather, like they have in Asia, to survive. So warmer summers make it more likely that they will cross over to the UK from Europe and survive long enough to be spotted by people.</p>
<p>Scientists aren’t yet sure what has caused 2023’s mass invasion. But a study, led by the <a href="https://www.ceh.ac.uk/">UK Centre for Ecology and Hydrology</a>, to investigate the underlying factors is underway. </p>
<h2>Why they’re a threat</h2>
<p>Beekeeping is not just a European enterprise. There are over <a href="https://www.destatis.de/EN/Themes/Countries-Regions/International-Statistics/Data-Topic/AgricultureForestryFisheries/Bees.html">45 million honeybee hives</a> across Asia, housing nearly half of the world’s honeybees. All of these bees are living with the Asian hornet without much issue.</p>
<p>So why are European beekeepers so concerned about an insect that is mostly a piece of everyday life for beekeepers in Asia? The secret is in the breeding.</p>
<p>European beekeeping has never had to account for a significant predatory threat like the Asian hornet. The <a href="https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/other-garden-wildlife/insects-and-other-invertebrates/bees-wasps-ants/hornet/">European hornet</a> (<em>Vespa crabro</em>), for example, looks similar to the Asian hornet and is nearly double the size. But this species poses very little threat to people or to bees.</p>
<p>The <a href="https://www.wildlifetrusts.org/wildlife-explorer/invertebrates/bees-and-wasps/giant-horntail">giant woodwasp</a> (<em>Urocerus gigas</em>) is found throughout Europe too, and can grow to about 5cm long (roughly the size of a house key). However, this species is completely harmless and quite gentle-mannered.</p>
<figure class="align-center ">
<img alt="A close-up of a giant woodwasp on a branch." src="https://images.theconversation.com/files/548045/original/file-20230913-17-9uynd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548045/original/file-20230913-17-9uynd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548045/original/file-20230913-17-9uynd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548045/original/file-20230913-17-9uynd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548045/original/file-20230913-17-9uynd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548045/original/file-20230913-17-9uynd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548045/original/file-20230913-17-9uynd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The giant woodwasp can grow to the size of a house key.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-giant-woodwasp-uroceras-gigas-drilling-2093538256">Stefan Rotter/Shutterstock</a></span>
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</figure>
<p>Due to the scarcity of native predators, European beekeepers have been intentionally breeding bees that are easier to handle and capable of producing larger quantities of honey. Consequently, these bees are defenceless against a formidable predator like the Asian hornet.</p>
<p>Several bee species throughout Japan, China and South Korea are significantly more adept at warding off Asian hornet attacks than their European counterparts. The <a href="https://beeaware.org.au/archive-pest/giant-honey-bees/#ad-image-0">giant honeybee</a> (<em>Apis dorsata</em>) is so large that it uses its body mass to smother a hornet. Meanwhile, her sisters <a href="https://www.nhm.ac.uk/discover/are-murder-hornets-really-as-scary-as-they-sound.html">swarm the invader</a>, gradually heating it up and cooking it alive – quite an effective defence.</p>
<h2>How to spot them</h2>
<p>Asian hornets are slightly smaller than the European hornet. They have a dark brown thorax, yellow-tipped legs, a black head and an orange face. However, the Asian hornet’s potentially most distinctive characteristic is its abdomen, which is dark brown with a fourth segment that is almost entirely orange. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547472/original/file-20230911-16-qwicrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="How the abdominal section of the European and Asian hornets compare." src="https://images.theconversation.com/files/547472/original/file-20230911-16-qwicrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547472/original/file-20230911-16-qwicrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=478&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547472/original/file-20230911-16-qwicrp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=478&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547472/original/file-20230911-16-qwicrp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=478&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547472/original/file-20230911-16-qwicrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=600&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547472/original/file-20230911-16-qwicrp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=600&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547472/original/file-20230911-16-qwicrp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=600&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">(1) The abdominal section of a European hornet. (2) The abdominal section of an Asian hornet.</span>
<span class="attribution"><span class="source">Philip Donkersley</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>If you suspect you have an Asian hornet in your area, the UK Centre for Ecology and Hydrology has been spearheading a <a href="https://risc.brc.ac.uk/alert.php?species=asian_hornet">national monitoring programme</a>. Remember to include full location details.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Philip Donkersley receives funding from the EPSRC, ESRC, Lancaster Univeristy and the BBKA.</span></em></p>Invasive Asian hornets are a top predator of bees in the UK – and sightings are starting to soar.Philip Donkersley, Senior Research Associate in Entomology, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2129242023-09-06T12:26:36Z2023-09-06T12:26:36ZInvasive species cause billions of dollars in damage worldwide: 4 essential reads<p>Invasive species – including plants, animals and fish – cause heavy damage to crops, wildlife and human health worldwide. Some prey on native species; other out-compete them for space and food or spread disease. A new United Nations report estimates the losses generated by invasives at <a href="https://zenodo.org/record/8314303">more than US$423 billion yearly</a> and shows that these damages have at least quadrupled in every decade since 1970.</p>
<p>Humans regularly move animals, plants and other living species from their home areas to new locations, either accidentally or on purpose. For example, they may import plants from faraway locations to <a href="https://theconversation.com/invasive-grasses-are-fueling-wildfires-across-the-us-126574">raise as crops</a> or bring in a nonnative animal to <a href="https://theconversation.com/everyone-agreed-cane-toads-would-be-a-winner-for-australia-19881">prey on a local pest</a>. Other invasives <a href="https://theconversation.com/the-invasive-emerald-ash-borer-has-destroyed-millions-of-trees-scientists-aim-to-control-it-with-tiny-parasitic-wasps-158403">hitch rides in cargo</a> or <a href="https://theconversation.com/ballast-water-management-is-reducing-the-flow-of-invasive-species-into-the-great-lakes-190880">ships’ ballast water</a>.</p>
<p>When a species that is not native to a particular area becomes established there, reproducing quickly and causing harm, it has become invasive. These recent articles from The Conversation describe how several invasive species are causing economic and ecological harm across the U.S. They also explain steps that people can take to avoid contributing to this urgent global problem.</p>
<h2>1. The best intentions: Callery pear trees</h2>
<p>Many invasive species were introduced to new locations because people thought they would be useful. One example that’s widely visible across the U.S. Northeast, Midwest and South is the Callery pear (<em>Pyrus calleryana</em>), a flowering tree that botanists brought to the U.S. from Asia more than 100 years ago. </p>
<p>Horticulturists loved the Callery pear for landscaping and wanted to produce trees that all grew and bloomed in the same way. As University of Dayton plant ecologist <a href="https://scholar.google.com/citations?user=uRA-SZ0AAAAJ&hl=en&oi=sra">Ryan W. McEwan</a> explained, they created identical clones from cuttings of trees with the desired characteristics – a process called grafting. Unlike some trees, a Callery pear can’t fertilize its flowers with its own pollen, so plant experts thought it wouldn’t spread.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/1i8hL2mhCpM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Missouri state foresters explain why Callery pear trees became so popular and the problems they cause.</span></figcaption>
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<p>However, “as horticulturalists tinkered with Callery pears to produce new versions, they made the individuals different enough to <a href="https://theconversation.com/once-the-callery-pear-tree-was-landscapers-favorite-now-states-are-banning-this-invasive-species-and-urging-homeowners-to-cut-it-down-198724">escape the fertilization barrier</a>,” McEwan wrote. As wind and birds spread the trees’ seeds, wild populations of the trees became established and started crowding out native species. </p>
<p>Today, Callery pear trees are such scourges that several states have banned them. Others are paying residents to cut them down and replace them with native plants. </p>
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<p>
<em>
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Read more:
<a href="https://theconversation.com/once-the-callery-pear-tree-was-landscapers-favorite-now-states-are-banning-this-invasive-species-and-urging-homeowners-to-cut-it-down-198724">Once the Callery pear tree was landscapers' favorite – now states are banning this invasive species and urging homeowners to cut it down</a>
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<h2>2. Tiny organisms, big impacts: Zebra and quagga mussels</h2>
<p>Invasive species don’t have to be large to cause outsized damage. Zebra and quagga mussels – shellfish the size of a fingernail – invaded the Great Lakes in the 1980s, clogging water intake pipes and out-competing native mollusks for food. Now they’re spreading west via rivers, lakes and bays, threatening waters all the way to the Pacific coast and Alaska.</p>
<p>As Rochester Institute of Technology environmental historian <a href="https://www.researchgate.net/scientific-contributions/Christine-Keiner-2071802254">Christine Keiner</a> wrote, it took several decades for the U.S. and Canada to regulate ships’ management of their ballast water tanks, which was the route by which the mussels were introduced to North America. </p>
<p>“Now, however, other human activities are increasingly contributing to harmful freshwater introductions – and with shipping regulated, the main culprits are <a href="https://theconversation.com/the-westward-spread-of-zebra-and-quagga-mussels-shows-how-tiny-invaders-can-cause-big-problems-185286">thousands of private boaters and anglers</a>,” Keller wrote. Limiting the destructive impacts of invasive species “requires scientific, technological and historical knowledge, political will and skill to persuade the public that everyone is part of the solution.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Infographic showing locations on a motorboat to check for invasive mussels." src="https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Many states require boaters to clean and dry their boats after use to avoid spreading zebra and quagga mussels.</span>
<span class="attribution"><a class="source" href="https://neinvasives.com/stop-aquatic-hitchhikers">Nebraska Invasive Species Program</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-westward-spread-of-zebra-and-quagga-mussels-shows-how-tiny-invaders-can-cause-big-problems-185286">The westward spread of zebra and quagga mussels shows how tiny invaders can cause big problems</a>
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</em>
</p>
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<h2>3. Threatening entire ecosystems: Lionfish</h2>
<p>When an invasive species is especially successful at spreading and reproducing, it can threaten the health of entire ecosystems. Consider the Pacific red lionfish (<em>Pterois volitans</em>), which has spread throughout the Caribbean and now is <a href="https://theconversation.com/invasive-lionfish-have-spread-south-from-the-caribbean-to-brazil-threatening-ecosystems-and-livelihoods-199229">moving south along Brazil’s coast</a>. </p>
<p>Lionfish thrive in many ocean habitats, from coastal mangrove forests to deepwater reefs, and they prey on numerous smaller fish species. In the Caribbean, they have reduced the number of small juvenile fish on reefs by up to 80% within as little as five weeks. </p>
<p>“Scientists and environmental managers widely agree that the lionfish invasion in Brazil is a potential ecological disaster,” warned Brazilian marine ecologist <a href="https://scholar.google.com.au/citations?user=_ArEYYMAAAAJ&hl=en">Osmar J. Luiz</a> of Charles Darwin University. “Brazil’s northeast coast, with its rich artisanal fishing activity, stands on the front line of this invasive threat.”</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1692994189099700515"}"></div></p>
<p>Although the Brazilian government was slow to address the lionfish threat, Luiz asserted that “with strategic, swift action and international collaboration, it can mitigate the impacts of this invasive species and safeguard its marine ecosystems.” That will require many techniques, from recruiting coastal residents to monitor for the invaders to tracking lionfish subpopulations using DNA analysis. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/invasive-lionfish-have-spread-south-from-the-caribbean-to-brazil-threatening-ecosystems-and-livelihoods-199229">Invasive lionfish have spread south from the Caribbean to Brazil, threatening ecosystems and livelihoods</a>
</strong>
</em>
</p>
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<h2>4. The value of acting locally</h2>
<p>Public awareness is critical for stemming the spread of many invasive plants and animals. That can involve actions as simple as cleaning your shoes and socks after a hike. </p>
<p>“Certain species of nonnative invasive plants produce seeds <a href="https://theconversation.com/those-seeds-clinging-to-your-hiking-socks-may-be-from-invasive-plants-heres-how-to-avoid-spreading-them-to-new-locations-195697">designed to attach to unsuspecting animals or people</a>. Once affixed, these sticky seeds can be carried long distances before they fall off in new environments,” explains Boise State University ecology Ph.D. candidate <a href="https://scholar.google.com/citations?user=nmAblPEAAAAJ&hl=en&oi=ao">Megan Dolman</a>. </p>
<p>Research shows that recreational trails promote the introduction of invasive plant species into natural and protected areas, including national parks and scenic trails.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CkgNbwptsgc/?utm_source=ig_web_copy_link\u0026igshid=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>In her research, Dolman found that few Appalachian Trail hikers were aware of the risk of carrying invasive plant seeds on their shoes or socks, so they typically did not take steps such as cleaning their gear before and after hiking. By knowing about invasive species in their areas and ways to manage them, people can help protect special places and keep invasive species from spreading.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/those-seeds-clinging-to-your-hiking-socks-may-be-from-invasive-plants-heres-how-to-avoid-spreading-them-to-new-locations-195697">Those seeds clinging to your hiking socks may be from invasive plants – here's how to avoid spreading them to new locations</a>
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</em>
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<p><em>Editor’s note: This story is a roundup of articles from The Conversation’s archives.</em></p><img src="https://counter.theconversation.com/content/212924/count.gif" alt="The Conversation" width="1" height="1" />
According to a new UN report, invasive species do more than US$423 billion in damage worldwide every year. Four articles explore examples, from mollusks to poisonous fish.Jennifer Weeks, Senior Environment + Cities Editor, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2128182023-09-06T08:18:52Z2023-09-06T08:18:52ZInvasive species risk a biodiversity disaster – but there is still time to stop it<figure><img src="https://images.theconversation.com/files/546422/original/file-20230905-28-non40r.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5472%2C3645&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Native to South and Central America, cane toads are an invasive species in most regions they have been introduced.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cane-toad-bufo-marinus-giant-neotropical-429662245">Seregraff/Shutterstock</a></span></figcaption></figure><p>Earth’s habitats are facing a big increase in the number of alien species they have to deal with. </p>
<p>These are organisms transported beyond their original habitats as a result of human activities, where they survive and establish new populations. They’re sometimes called exotic, non-native or introduced species.</p>
<p>If current trends continue, there could be as much as <a href="https://doi.org/10.1111/gcb.15333">a 36% increase</a> in global alien species numbers by 2050, compared with 2005. The relentless pace at which alien species are being transported and introduced globally will alter ecosystems for centuries, if not millennia.</p>
<p>A subset of these species, termed invasive alien species, can have a catastrophic effect on biodiversity, human wellbeing and the economy. </p>
<p>But research by me and my colleagues suggests that there is still time to avoid the worst outcomes for Earth’s biodiversity and bring the rate of new biological invasions under control.</p>
<p>Once introduced, many alien species can thrive in their new environments and become integral parts of the local biodiversity, <a href="https://theconversation.com/european-colonialism-has-had-a-lasting-legacy-on-how-plants-are-distributed-around-the-world-192660">reshaping ecosystems for generations</a>. </p>
<p>In some extreme cases, alien species can eventually dominate ecosystems. Data from <a href="https://doi.org/10.1038/s41559-017-0186">a 2017 study</a> revealed that Hawaiian flora comprised 1,586 native plant species and 1,488 <a href="https://www.fs.usda.gov/research/publications/book/invasiveSpecies/invasiveSpeciesAppendixHawaiiPacificIslands.pdf">aliens</a>. </p>
<p>Unlike alien species, native species cannot increase in number beyond time scales set by their evolution. This ensures it is only a matter of time before alien plants outnumber native Hawaiian flora.</p>
<figure class="align-center ">
<img alt="A person in camouflage fatigues holding a tropical plant's leaf aloft." src="https://images.theconversation.com/files/546252/original/file-20230904-25-m22sf7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546252/original/file-20230904-25-m22sf7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546252/original/file-20230904-25-m22sf7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546252/original/file-20230904-25-m22sf7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546252/original/file-20230904-25-m22sf7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546252/original/file-20230904-25-m22sf7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546252/original/file-20230904-25-m22sf7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An invasive miconia plant in Tahiti (French Polynesia), where it has been called ‘the green cancer’.</span>
<span class="attribution"><span class="source">Eloise Killgore</span></span>
</figcaption>
</figure>
<p>Invasive species in particular are the <a href="https://doi.org/10.1038/s41467-022-30339-y">main driver</a> of extinctions on islands. Over the past 50 years, they have cost <a href="https://doi.org/10.1038/s41586-021-03405-6">over US$1.2 trillion</a> (£1 trillion) in damage and management worldwide and led to <a href="https://doi.org/10.3897/neobiota.67.59743">between £5.4 billion and £13.7 billion</a> in reported losses for the UK alone. </p>
<p>Invasive mosquitoes, such as the tiger and yellow fever mosquitoes, <a href="https://www.cabidigitallibrary.org/doi/book/10.1079/9781786390981.0000">transmit deadly diseases</a> including West Nile fever, dengue, Zika and Chikungunya.</p>
<p>The introduction of the Nile perch in Africa’s Lake Victoria in the 1950s was intended to boost local fisheries. It killed off multiple native species, <a href="https://doi.org/10.1111/lre.12192">spurred</a> the increased transmission of HIV amongst local populations from fishers following the perch’s seasonal migration, and generated more frequent border conflicts for fishing rights.</p>
<figure class="align-center ">
<img alt="A stripy mosquito drawing blood from someone's skin." src="https://images.theconversation.com/files/546253/original/file-20230904-27-yhne36.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546253/original/file-20230904-27-yhne36.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546253/original/file-20230904-27-yhne36.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546253/original/file-20230904-27-yhne36.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546253/original/file-20230904-27-yhne36.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546253/original/file-20230904-27-yhne36.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546253/original/file-20230904-27-yhne36.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Invasive tiger and yellow fever mosquitoes are important vectors of disease.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Aedes_albopictus#/media/File:CDC-Gathany-Aedes-albopictus-1.jpg">James Gathany/CDC</a></span>
</figcaption>
</figure>
<p>Given how much damage invasive species can do to ecosystems and multiple aspects of society, it is important to understand what’s behind their proliferation so we can stem their spread and prevent them becoming entrenched. Like other environmental changes, biological invasions are largely determined by how people live and how society is organised.</p>
<p>Alien species were sometimes <a href="https://doi.org/10.1111/j.1365-2664.2007.01442.x">brought into new environments</a> intentionally, for example to serve as game or to control other species. Sometimes they were brought unintentionally as stowaways or contaminants, such as seeds in the dirt clinging to boots or small organisms within a ship’s ballast. Sometimes human activity destroyed natural barriers, allowing species to spread through new corridors like the Suez and Panama canals.</p>
<h2>What happens next?</h2>
<p><a href="https://doi.org/10.1007/s11625-022-01166-3">A recent study</a> I led found that international trade was the biggest driver of biological invasions, but that a country’s ability to implement policies to prevent and counteract them was also critical. </p>
<p>Effective governance meant alien species richness fell across most classifications of organisms. Past levels of trade and governance predicted present levels of biological invasions better than recent ones, which underlines the abiding consequences of decisions taken today.</p>
<p>Addressing biological invasions requires comprehensive action within and between countries. A new <a href="https://www.ipbes.net/ias">report</a> by the UN’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services has concluded that invasive alien species are likely to thrive unless there is international collaboration and coordination, driven by effective governance within countries and robust institutions.</p>
<p>Whereas climatologists can use computer models to project <a href="https://unfccc.int/sites/default/files/part1_iiasa_rogelj_ssp_poster.pdf">future scenarios</a> for the climate based on CO₂ emissions, biologists have no equivalent for invasive species. <a href="https://doi.org/10.1007/s11625-022-01166-3">In our study</a>, we observed that while trade increased almost everywhere between 1996 and 2015, governance changes varied substantially between countries and continents, making it hard to pre-empt the unfolding invasive species problem with a high degree of accuracy.</p>
<p>To account for these uncertainties, we developed several scenarios for invasive species based on different sets of socio-economic changes <a href="https://doi.org/10.1007/s11625-021-00963-6">globally</a> and <a href="https://doi.org/10.1101/2022.09.13.507777">in Europe</a>. </p>
<p>These range from scenarios in which countries eschew cooperation but maintain lightly regulated trade and preside over a rising number of invasions to high levels of regulation and regional and global governance, fostering low or stable levels of biological invasions. These scenarios will be tailored to the different regions of the world in the future.</p>
<p>This suggests that while invasions have already caused substantial damage, the future outcome is still largely ours to decide.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
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</figcaption>
</figure>
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<hr><img src="https://counter.theconversation.com/content/212818/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Guillaume Latombe was funded through the 2017-2018 Belmont Forum and BiodivERsA joint call for research proposals, under the BiodivScen ERA-Net COFUND programme and with the funding organisation FWF (project no I 4011-B32).</span></em></p>Modern ecosystems are very different to how they were just a few centuries ago.Guillaume Latombe, Lecturer in Environmental Change Biology, The University of EdinburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2128502023-09-06T06:10:34Z2023-09-06T06:10:34ZAustralia’s least wanted – 8 alien species and diseases we must keep out of our island home<figure><img src="https://images.theconversation.com/files/546390/original/file-20230905-17-lal73z.jpg?ixlib=rb-1.1.0&rect=48%2C64%2C5343%2C3758&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Solenopsis_invicta1.jpg">Alexander Wild/Wikimedia Commons</a></span></figcaption></figure><p>This week’s landmark report on the impact of <a href="https://www.ipbes.net/ias">invasive alien species</a> revealed costs to the global economy exceeded US$423 billion (A$654 billion) a year in 2019. Costs have at least <a href="https://www.ipbes.net/IASmediarelease#:%7E:text=Approved%20on%20Saturday%20in%20Bonn,%24423%20billion%20annually%20in%202019%2C">quadrupled</a> every decade since 1970 and that trend is set to continue. </p>
<p>Prevention is better than a cure. Stopping pests and diseases arriving and establishing in Australia is not only better for the environment, it’s much <a href="https://cebra.unimelb.edu.au/__data/assets/pdf_file/0020/3535013/CEBRA_Value_Docs_KeyResultSummary_v0.6_Endorsed.pdf">cheaper</a> too. </p>
<p>The biosecurity system is our front line against invasion. Species that pose a significant <a href="https://www.igb.gov.au/sites/default/files/documents/environmental-biosecurity-risk_2.pdf">risk to agriculture</a> have historically received more attention, but we also need to defend our borders against threats to nature. </p>
<p>Here we take a closer look at some pests and diseases we need to keep out at all costs, to protect our biodiversity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graph showing how the cost of managing an invasive alien species gets much larger once it is established." src="https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=374&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=374&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=374&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=470&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=470&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546391/original/file-20230905-15-598vx2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=470&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The invasion curve shows the cost of managing an incursion at various stages. Prevention is much cheaper than dealing with invaders after they arrive, and early eradication is much cheaper than longer-term containment or control.</span>
<span class="attribution"><span class="source">Invasive Species Council</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-true-damage-of-invasive-alien-species-was-just-revealed-in-a-landmark-report-heres-how-we-must-act-211893">The true damage of invasive alien species was just revealed in a landmark report. Here's how we must act</a>
</strong>
</em>
</p>
<hr>
<h2>One of the biggest threats to biodiversity</h2>
<p>Alien species are those deliberately or accidentally introduced to areas where they are not native. If they cause problems, we call them invasive.</p>
<p>Invasive alien species include weeds, feral animals, exotic pests and diseases. </p>
<p>Those that have already arrived have taken a huge toll. Introduced predators were largely responsible for most of <a href="https://www.sciencedirect.com/science/article/pii/S000632071930895X">Australia’s mammal extinctions</a>. And introduced diseases have decimated <a href="https://theconversation.com/we-name-the-26-australian-frogs-at-greatest-risk-of-extinction-by-2040-and-how-to-save-them-166339">our frogs</a>.</p>
<p>Invasive species are pushing <a href="https://www.publish.csiro.au/PC/PC18024">most (82%)</a> of Australia’s 1,914 nationally listed threatened species closer to extinction. </p>
<p>Imagine if those invasive species had been kept out of Australia. Here are eight of the <a href="https://www.agriculture.gov.au/biosecurity-trade/policy/environmental/priority-list">pests and diseases</a> we really need to keep out. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/1-7-million-foxes-300-million-native-animals-killed-every-year-now-we-know-the-damage-foxes-wreak-177832">1.7 million foxes, 300 million native animals killed every year: now we know the damage foxes wreak</a>
</strong>
</em>
</p>
<hr>
<h2>1. Giant African land snail</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A very large brown snail on a hand" src="https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546378/original/file-20230905-29-vftj6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A giant African snail in Hong Kong, where it is invasive.</span>
<span class="attribution"><span class="source">Thomas Brown/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><a href="https://www.publish.csiro.au/PC/PC18024">Giant African snails</a> have a ferocious appetite. They feed on more than 500 species of plants including agricultural crops and eucalyptus trees. The shells of these giants can be 20cm long and females typically lay 1,200 eggs a year. Adult snails could sneak into shipping containers or machinery and their eggs could be transported in soil or goods. They are now present on Christmas Island. </p>
<h2>2. Avian influenza</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Faces of two pelicans close up, showing their red gullets." src="https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546379/original/file-20230905-23-cno6xu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Thousands of Dalmatian pelicans were killed by highly pathenogenic Avian influenza in Europe in 2022.</span>
<span class="attribution"><span class="source">Birger Strahl/Unsplash</span></span>
</figcaption>
</figure>
<p><a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/avian-influenza#what-is-avian-influenza">Avian influenza</a> or bird-flu is a viral disease found in birds. Some strains can kill farmed poultry and <a href="https://wildlifehealthaustralia.com.au/Portals/0/Documents/FactSheets/Avian/Avian_Influenza_in_Wild_Birds_in_Australia.pdf">susceptible wild birds</a>. Such highly pathogenic strains are thought to have killed millions of wild birds globally in the past few years. The virus can also jump across to mammals, recently knocking off <a href="https://www.nhm.ac.uk/discover/news/2023/march/bird-flu-kills-thousands-south-american-sea-lions-outbreak-continues.html">3,500 sea lions Peru</a>.</p>
<p>Migratory birds could bring the virus here but it could also be carried in imported birds and poultry products, including contaminated eggs, feathers, poultry feed and equipment. Our biosecurity system is responsible for <a href="https://wildlifehealthaustralia.com.au/ProgramsProjects/WildBirdSurveillance.aspx">surveillance</a> and early detection, preparedness and management to protect our vulnerable wildlife. In California, preparation includes <a href="https://www.aphis.usda.gov/aphis/newsroom/stakeholder-info/SA_By_Date/SA-2023/ca-condor-hpai">vaccinating</a> endangered condors.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/migrating-birds-could-bring-lethal-avian-flu-to-australias-vulnerable-birds-204793">Migrating birds could bring lethal avian flu to Australia's vulnerable birds</a>
</strong>
</em>
</p>
<hr>
<h2>3. New tramp ants</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close up of an ant's head" src="https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=535&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=535&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546383/original/file-20230905-17-non40r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=535&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A red imported fire ant in the US.</span>
<span class="attribution"><span class="source">Alexander Wild/Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>We’re already battling some species of <a href="https://www.dcceew.gov.au/environment/invasive-species/insects-and-other-invertebrates/tramp-ants#:%7E:text=Key%20threatening%20processes&text=Loss%20of%20biodiversity%20and%20ecosystem,%2C%20Solenopsis%20invicta%20(fire%20ant)">tramp ants</a>, but there’s more where that came from - there are at least 16 different species. So far six species including <a href="https://www.outbreak.gov.au/current-outbreaks/red-imported-fire-ant">red imported fire ants</a> have been detected, with efforts underway to contain or eradicate them at their incursion points. On Christmas Island, another tramp ant species (<a href="https://www.dcceew.gov.au/sites/default/files/env/resources/898583db-b929-491a-8448-73fb652bca66/files/brochure-detail-crazy-ant-control-options.pdf">yellow crazy ants</a>) formed “super colonies”, killing every animal in their path, including tens of millions of the island’s iconic red and robber crabs. Ants are easily transported to new areas in dirt, plants and cargo. Tramp ants threaten Australian ecosystems, agriculture and human health. </p>
<h2>4. Bat white nose syndrome</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small bat hanging from a cave roof with a white face" src="https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546385/original/file-20230905-21-y5cwgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A little brown bat displaying white nose syndrome in the US.</span>
<span class="attribution"><span class="source">Moriarty Marvin/USFWS/WikimediaCommons</span></span>
</figcaption>
</figure>
<p><a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/white-nose-syndrome#:%7E:text=Australia%20is%20free%20of%20WNS,causing%20fungus%20could%20enter%20Australia.">White nose syndrome</a> is a bat disease caused by a fungus. In less than 20 years it has killed more than five million bats across North America, causing local extinctions and reducing the beneficial services performed by bats such as eating harmful insects. The fungus could be introduced to Australian caves on the shoes, clothing and equipment of people who had previously visited caves in Europe or North America. </p>
<h2>5. Crayfish plague</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small crayfish in an aquarium" src="https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546386/original/file-20230905-23-6joum6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dwarf Cajun crayfish can be carriers of crayfish plague.</span>
<span class="attribution"><span class="source">Chris Lukhaup/USDA-FS/Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>A highly infectious fungal disease, <a href="https://www.agriculture.gov.au/sites/default/files/sitecollectiondocuments/animal/ahl/ANZSDP-Crayfish-plague.pdf">crayfish plague</a> is the main cause of crayfish declines across Europe. It has the potential to devastate Australian freshwater crayfish populations. North American crayfish can be carriers of the disease and the illegal trade of crayfish, such as the dwarf Cajun crayfish for aquariums, also threatens to introduce the disease. </p>
<h2>6. New myrtle rust strains</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Leaves covered in a yellow powdery bloom." src="https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546387/original/file-20230905-25-j3j5if.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The plant disease myrtle rust killing native rose apple leaves in Hawaii.</span>
<span class="attribution"><span class="source">Pest Plants and Animals/Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>When a strain of myrtle rust arrived in Australia in 2010, it spread quickly along the east coast, <a href="https://www.nespthreatenedspecies.edu.au/media/njzno05b/1-4-3-imminent-extinction-of-australian-myrtaceae-trees-and-shrubs-by-myrtle-rust-findings-factsheet_v5.pdf">infecting 358</a> different native plant species including eucalypts, bottle brushes and lilly pillies. It has caused major declines and local extinctions of many species. Other <a href="https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/plant/myrtle-rust#:%7E:text=Myrtle%20rust%20(exotic%20strains)%20is,damaging%20to%20our%20eucalyptus%20trees.">exotic myrtle rust strains</a> occur outside Australia. These present serious threats to Australia’s natural environment and to commercial native forest plantations. Importing infected plant material is the main risk of introduction. </p>
<h2>7. Savannah cats</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close up of a patterned black and tan cat with large pointy ears." src="https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546388/original/file-20230905-15-sjem6n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Savannah cats are bred by crossing a domestic cat with an African serval.</span>
<span class="attribution"><span class="source">Jason Douglas/Wikimedia Commons</span></span>
</figcaption>
</figure>
<p><a href="https://www.nespthreatenedspecies.edu.au/news-and-media/media-releases/banning-savannah-cats-in-australia-was-good-science">Savannah cats</a> are two to three times the size of domestic cats. In 2008 the federal government banned the importation of savannah cats. A <a href="https://www.mdpi.com/2076-2615/9/10/795">scientific assessment</a> found pet savannah cats had the potential to establish and roam across 97% of the country if they escaped or were released. They can take down prey twice as large as feral cats, so 90% of Australia’s native land mammals would be at risk. Demand for the species from the pet trade raises the risk of smuggling or illegal trade.</p>
<h2>8. Black spined toad</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A brown toad with black markings on dried orange leaves." src="https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546389/original/file-20230905-24-tyy3v6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A black spined toad in Taiwan.</span>
<span class="attribution"><span class="source">LiCheng Shih/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.agriculture.gov.au/biosecurity-trade/import/arrival/pests/black-spined-toad">black spined toad</a> is potentially more damaging than the cane toad because it could survive across a bigger region including in the colder parts of Australia. It would prey on native frogs and other small animals, be toxic to larger animals, and probably carry exotic parasites or disease. It is a common stowaway in shipping cargo. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/97-of-australians-want-more-action-to-stop-extinctions-and-72-want-extra-spending-on-the-environment-207811">97% of Australians want more action to stop extinctions and 72% want extra spending on the environment</a>
</strong>
</em>
</p>
<hr>
<h2>Prioritising nature</h2>
<p>Australia’s biosecurity system has generally served our country well, but it is under constant and <a href="https://www.igb.gov.au/sites/default/files/documents/environmental-biosecurity-risk_2.pdf">growing strain</a>. Historically, the environment has also been the <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/biosecurity/Report/c03">poor cousin of agriculture</a> at the biosecurity table.</p>
<p>Preparedness and responses for environmental threats remain <a href="https://www.mdpi.com/1999-4907/10/4/336">chronically underfunded</a>, especially when compared to those developed for industry.</p>
<p>A well-resourced independent body focused on the prevention and early elimination of new environmental pests and diseases would be a major step toward achieving our <a href="https://www.dcceew.gov.au/sites/default/files/documents/threatened-species-action-plan-2022-2032.pdf">global commitments</a> to end extinction.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hear-me-out-we-could-use-the-varroa-mite-to-wipe-out-feral-honey-bees-and-help-australias-environment-185959">Hear me out – we could use the varroa mite to wipe out feral honey bees, and help Australia's environment</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/212850/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaana Dielenberg is based at The University of Melbourne and works for the Biodiversity Council. She is a member of Invertebrates Australia and the Ecological Society of Australia. She previously worked for the now ended Threatened Species Recovery Hub of the Australian Government's National Environmental Science Program. She thanks James Trezise for his contribution to this article. </span></em></p><p class="fine-print"><em><span>Patrick O'Connor receives funding from the Australian Research Council and Australian and State Governments. He is a councilor on the Biodiversity Council and affiliated with the Nature Conservation Society of South Australia and the Australian Landcare movement. </span></em></p>Australia’s biosecurity system is on high alert for alien invaders. Here’s a hit list of eight baddies we believe pose the greatest threat to Australia’s biodiversity.Jaana Dielenberg, University Fellow, Charles Darwin UniversityPatrick O'Connor, Associate Professor, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2128322023-09-05T17:28:57Z2023-09-05T17:28:57ZUN invasive species report reveals scale of threat to nature and people – and how to manage it<figure><img src="https://images.theconversation.com/files/546410/original/file-20230905-27-bxidl0.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3177%2C2125&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lionfish are an invasive species in the Caribbean.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/red-lionfish-invasive-species-caribbean-pretty-666337033">Drew McArthur/Shutterstock</a></span></figcaption></figure><p>More than 3,500 invasive alien species are seriously compromising human wellbeing and causing irreversible damage to ecosystems, according to the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). While some alien species actually benefit humans, the UN organisation estimates 10% threaten nature and people.</p>
<p>Alien species are plants, animals or other organisms that are introduced to new regions by human activities. A subset of them, known as invasive alien species, can make native species go extinct, spread diseases such as malaria, Zika and West Nile fever, and damage food crops.</p>
<p>The IPBES, a body of experts tasked with assessing the state of nature and its contributions to society, has <a href="https://www.ipbes.net/global-assessment">identified</a> invasive alien species as a significant cause of the declining variety of lifeforms on Earth. Other threats include the loss and degradation of habitats, pollution, climate change and the overharvesting of species for food, their body parts and the pet trade.</p>
<p><a href="https://www.ipbes.net/IASmediarelease">A new report</a> by the IPBES, created by 86 experts from 49 countries over four years, drawing on over 13,000 scientific studies and including contributions from indigenous peoples, highlights the particular threat of invasive species.</p>
<h2>Growing threat</h2>
<p>Invasive alien species affect all world regions, including Antarctica. The IPBES assessment says that 34% of the impacts are reported in the Americas, 31% in Europe and Central Asia, 25% in <a href="https://link.springer.com/article/10.1007/s10531-009-9755-7">Asia and the Pacific</a>, and 7% in Africa.</p>
<p>Most impacts are reported on land (75%), with fewer in freshwater (14%) and marine (10%) habitats. Islands are particularly vulnerable, with alien plants outnumbering natives on more than 25% of the world’s islands.</p>
<figure class="align-center ">
<img alt="A tropical island." src="https://images.theconversation.com/files/546409/original/file-20230905-19-qppr0s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546409/original/file-20230905-19-qppr0s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546409/original/file-20230905-19-qppr0s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546409/original/file-20230905-19-qppr0s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546409/original/file-20230905-19-qppr0s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546409/original/file-20230905-19-qppr0s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546409/original/file-20230905-19-qppr0s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Island species evolve in relative isolation and struggle to compete with introduced wildlife.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/desert-island-blue-paradise-383289268">Vibrant Image Studio/Shutterstock</a></span>
</figcaption>
</figure>
<p>The assessment highlights that indigenous peoples, who are more likely to have deep cultural ties to the lands on which they live, are particularly vulnerable. More than 2,300 invasive alien species occur in indigenous territories, threatening the quality of life and cultural identities of millions of people.</p>
<p>The report also reveals that invasive alien species are linked to 60% of global plant and animal extinctions. Their implicit economic cost exceeded US$423 billion (£361 billion) annually in 2019 and has quadrupled each decade since 1970.</p>
<p>The threat of invasive alien species will loom larger in future due to <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ecog.01893">increasing trade and travel</a>. Their impacts could be amplified as they interact with other drivers of biodiversity loss, such as climate change.</p>
<h2>Taking control</h2>
<p>An effective response to each invasive species will depend on <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.3744">where it is happening</a> and how it is spreading. But it should combine efforts across countries and sectors. Raising awareness among the public will also be necessary.</p>
<p>Although 80% of countries have targets for managing invasive alien species, only 17% have specific national laws or regulations. The IPBES assessment also highlights that 45% of countries do not invest in the management of biological invasions, which puts their national neighbours at risk.</p>
<p>The assessment calls for effective management to address the growing threat. Its recommendations include:</p>
<ul>
<li><p>increasing preparedness and prevention through pre-border quarantines and strict import controls, which are generally the most cost-effective solutions</p></li>
<li><p>early detection of invasions and rapid responses through general surveillance strategies, especially in aquatic environments</p></li>
<li><p>eradicating invasive species where possible – this is most feasible for small, slow-spreading species (for example, feral cats) and particularly in isolated ecosystems such as islands</p></li>
<li><p>containment, which can be effective for invasive alien species that cannot be eradicated.</p></li>
</ul>
<figure class="align-center ">
<img alt="A white cat lying among shrubs." src="https://images.theconversation.com/files/546407/original/file-20230905-18915-quus11.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546407/original/file-20230905-18915-quus11.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546407/original/file-20230905-18915-quus11.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546407/original/file-20230905-18915-quus11.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546407/original/file-20230905-18915-quus11.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546407/original/file-20230905-18915-quus11.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546407/original/file-20230905-18915-quus11.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Feral cats can devastate wildlife which haven’t evolved to defend against them.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cats-hanging-out-montserrat-monastery-spain-1627761805">Todamo/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Invasive aliens can be beneficial</h2>
<p>Alien species can also <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.5020">benefit people</a>. The recent assessment acknowledged that perceptions of their threat can vary depending on who you ask, which can complicate their management. The report does not offer guidance for these cases, but assessing the benefits and costs of each alien species is a good place to start.</p>
<p>For example, feral cattle, sheep, goats and pigs on the Caribbean island of Montserrat provide meat for local cuisines. Another <a href="https://link.springer.com/article/10.1007/s10530-014-0743-9">assessment</a> by the Montserrat Department of Environment (which I helped with) found that discontinuing management of these feral animals could halve the island’s nature-based tourism revenue. This ongoing control programme provides a steady supply of wild meat, which would fall by 36% in its absence.</p>
<p>Having an accurate understanding of the damage caused by invasive species, as well as their potential benefits and the cost of controlling them, is essential for properly tackling one of the biggest threats to Earth’s biodiversity.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<p class="fine-print"><em><span>Kelvin S.-H. Peh does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Not all alien species are a significant hazard to people and ecosystems.Kelvin S.-H. Peh, Associate Professor of Conservation Science, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2118932023-09-04T12:01:47Z2023-09-04T12:01:47ZThe true damage of invasive alien species was just revealed in a landmark report. Here’s how we must act<figure><img src="https://images.theconversation.com/files/546132/original/file-20230904-17-cgmyf9.jpg?ixlib=rb-1.1.0&rect=53%2C53%2C3932%2C2181&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/aerial-top-view-container-cargo-ship-708817909">Avigator Fortuner. Shutterstock</a></span></figcaption></figure><p>Invasive alien species are driving biodiversity loss and extinctions in every country, all over the world. </p>
<p>Responding to the challenge, the United Nations is today releasing the <a href="https://doi.org/10.5281/zenodo.7430692">first global assessment</a> of invasive alien species and their control. </p>
<p>It comes from the <a href="https://www.ipbes.net">Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services</a> (IPBES), which represents almost 140 member states. </p>
<p>Over four years, 86 expert authors from 49 countries gathered the latest scientific evidence and Indigenous and local knowledge on invasive alien species. The report draws on more than 13,000 references, including governmental reports. We were among the authors. Here are some of the key insights for Australia and Aotearoa New Zealand. </p>
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Read more:
<a href="https://theconversation.com/invasive-species-are-australias-number-one-extinction-threat-116809">Invasive species are Australia's number-one extinction threat</a>
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<h2>Hope in the face of increasing threats</h2>
<p>In 2019, IPBES released a <a href="https://www.ipbes.net/global-assessment">global biodiversity assessment</a> that placed invasive alien species in the top five drivers of biodiversity loss - alongside changing land- and sea-use, over-exploitation of natural resources, climate change, and pollution. </p>
<p>This triggered further assessment to determine the current global state of biological invasions, the effectiveness of our existing responses, and recommended management and policy options. </p>
<p>The result, released today, is the most comprehensive overarching policy-relevant report on biological invasions to date. </p>
<p>It promises to help us meet our international obligations under the recently adopted UN <a href="https://www.cbd.int/">Convention on Biological Diversity</a>. In particular, one of the targets in the Kunming-Montreal <a href="https://www.cbd.int/article/cop15-final-text-kunming-montreal-gbf-221222">Global Biodiversity Framework</a> is to “eliminate, minimise, reduce and/or mitigate the impacts of invasive alien species on biodiversity and ecosystem services”.</p>
<p>The world faces increasing biosecurity threats, but effective management can prevent or lessen the extent of subsequent biological invasions. Ambitious progress can be achieved with an integrated approach.</p>
<h2>The experience in Australia and Aotearoa New Zealand</h2>
<p>Australia already has close to <a href="https://www.gbif.org/dataset/15147db1-27c3-49b5-9c69-c78d55a4b8ff">3,000</a> introduced alien species. Aotearoa New Zealand has almost <a href="https://www.gbif.org/dataset/b286f8ee-1e29-4f8a-a041-9106bb1796f3">900</a>.</p>
<p>Globally, we observe around 200 new alien species every year, and many of these species (>10%) have negative impacts, including threats to native species, the health of natural vegetation, or the way ecosystems work. </p>
<p>Australian examples include <a href="https://theconversation.com/1-7-million-foxes-300-million-native-animals-killed-every-year-now-we-know-the-damage-foxes-wreak-177832">foxes</a>, <a href="https://theconversation.com/why-red-fire-ants-and-yellow-crazy-ants-have-given-themselves-a-green-light-to-invade-australia-208479">red imported fire ants</a> and <a href="https://theconversation.com/field-of-nightmares-gamba-grass-in-the-top-end-12178">gamba grass</a>. </p>
<p>Aotearoa New Zealand suffers from invasive Australian <a href="https://www.doc.govt.nz/nature/pests-and-threats/animal-pests/possums/">possums</a>. And the Māori cultural icon the Kauri tree is under siege from a deadly <a href="https://theconversation.com/lord-of-the-forest-new-zealands-most-sacred-tree-is-under-threat-from-disease-but-response-is-slow-100447">dieback disease</a>.</p>
<p>The assessment reveals that invasive alien species have contributed to 60% of global extinctions, and have been the sole driver of 16% of recorded extinctions. </p>
<p><a href="https://theconversation.com/invasive-species-are-australias-number-one-extinction-threat-116809">Australia</a> and <a href="https://www.doc.govt.nz/nature/pests-and-threats/predator-free-2050/">Aotearoa New Zealand</a> have among the highest modern global native species extinction rates. Australia is the worst in the world <a href="https://theconversation.com/gut-wrenching-and-infuriating-why-australia-is-the-world-leader-in-mammal-extinctions-and-what-to-do-about-it-192173">for mammals</a>, while Aotearoa New Zealand has experienced tragic loss in <a href="https://theconversation.com/call-of-the-huia-how-nzs-bird-of-the-century-contest-helps-us-express-ecological-grief-210698">endemic birds</a>, largely due to invasive species. </p>
<p>The economies of both countries rely heavily on agriculture, trade and eco-tourism. These sectors are highly susceptible to threats from invasive alien species. The cost to Australia is <a href="https://theconversation.com/pest-plants-and-animals-cost-australia-around-25-billion-a-year-and-it-will-get-worse-164969">A$24.5 billion a year</a> out of an estimated global cost of $654 billion (<a href="https://doi.org/10.5281/zenodo.7430692">US$423 billion a year</a>). </p>
<p>The cost of biological invasions is quadrupling every decade, but stringent biosecurity policies and practices can protect our environment and economies. They also safeguard our wellbeing and cultural and social livelihoods. </p>
<p>Continued cooperation and investment across our region is paramount to preventing future impacts from increasing threats. These include <a href="https://theconversation.com/to-lock-out-foot-and-mouth-disease-australia-must-help-our-neighbour-countries-bolster-their-biosecurity-188010">foot and mouth disease</a> and <a href="https://theconversation.com/avian-influenza-how-bird-flu-affects-domestic-and-wild-flocks-and-why-a-one-health-approach-matters-182497">avian influenza</a>. </p>
<p>At the same time, already established invasive alien species can supercharge environmental disasters. For example, the wildfire-promoting properties of introduced <a href="https://theconversation.com/feed-or-weed-new-pastures-are-sowing-problems-for-the-future-33733">African pasture grasses</a> exacerbated <a href="https://time.com/6305735/invasive-plants-from-colonists-fueled-maui-wildfires">bushfires in Hawaii</a> this year. </p>
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Read more:
<a href="https://theconversation.com/new-expose-of-australias-exotic-pet-trade-shows-an-alarming-proliferation-of-alien-threatened-and-illegal-species-203354">New exposé of Australia's exotic pet trade shows an alarming proliferation of alien, threatened and illegal species</a>
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<h2>Coordinate, consult and prioritise</h2>
<p>An effective biosecurity system can mitigate the threats from invasive species. But to do so, we’ll need coherent policy across primary production and logistic sectors, better education and greater public awareness.</p>
<p>We need to coordinate and prioritise our efforts, from offshore ports to border control and quarantine, through to eradication or containment of any new pests and weeds.</p>
<p>Government-industry partnerships are leading to trusted “green-lane” trade supply chains. This cuts red tape for businesses that manage import risks and produce pre-costed and co-designed emergency response agreements.</p>
<p>Prevention will not stop arrivals altogether. We will still have to contend with blow-ins on storm winds, <a href="https://theconversation.com/debris-from-the-2011-tsunami-carried-hundreds-of-species-across-the-pacific-ocean-84773">ocean waves</a> and boat hulls. There’s also the $23 billion a year <a href="https://theconversation.com/alien-invaders-the-illegal-reptile-trade-is-a-serious-threat-to-australia-68815">illegal pet trade</a>.</p>
<p>Biosecurity tools work best alongside strong public support, regulation and governance. We share a proud history of effective biological control programs for many <a href="https://theconversation.com/explainer-how-biocontrol-fights-invasive-species-31298">weeds and pests</a>. Australia’s approach to <a href="https://theconversation.com/releasing-a-virus-against-rabbits-is-effective-but-can-make-them-immune-if-let-loose-at-the-wrong-time-176028">rabbit control using a virus</a> was a world-first and it remains in use 70 years later. This has delivered benefits worth more than <a href="https://www.csiro.au/en/research/natural-environment/biodiversity/fighting-plagues-and-predators">$70 billion</a>. </p>
<p>Despite strong biosecurity measures, highly engaged primary industries agricultural industries, excellent research infrastructure and a high level of public awareness, invasive alien species continue to <a href="https://theconversation.com/new-zealand-needs-to-up-its-biosecurity-game-to-protect-the-country-from-the-next-devastating-pest-threat-207104">slip through our borders</a> and multiply. </p>
<p>We tried to defend our countries against recent invasions from the <a href="https://theconversation.com/the-fall-armyworm-invasion-is-fierce-this-year-and-scientists-are-researching-how-to-stop-its-destruction-of-lawns-football-fields-and-crops-167098">fall armyworm</a>, <a href="https://theconversation.com/what-is-myrtle-rust-and-why-has-this-disease-closed-lord-howe-island-to-visitors-202045">myrtle rust</a> and the <a href="https://theconversation.com/australia-is-in-a-unique-position-to-eliminate-the-bee-killing-varroa-mite-heres-what-happens-if-we-dont-205926">varroa mite</a>. But they have still managed to establish. </p>
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<h2>One world, ‘One Biosecurity’</h2>
<p>The rising pressure of trade will likely outpace the resourcing dedicated to biosecurity measures. Frequent interceptions of pests, weeds, and diseases at our border highlight the pressure we are under. We will have to simply become smarter, more effective, and better coordinated across the <a href="https://www.nzherald.co.nz/the-listener/new-zealand/the-new-billion-dollar-biosecurity-threats-at-our-borders/F6AQFEQCE5GUZDMSJM6B5ZSMUI/">human, animal, plant and ecosystem health sectors</a>. </p>
<p>We encourage governments to recognise the threats invasive alien pests pose and mobilise their resources and capability to combat these threats – in regions where a species is first recognised as going rogue, rather than simply monitoring its progressive global spread. This is the <a href="https://www.nzherald.co.nz/the-country/news/covid-19-coronavirus-expert-calls-for-holistic-approach-to-biosecurity/WOWPH22RSVCHIE5D3NDXL6ZZII/">One Biosecurity concept</a>. </p>
<p>Australia and Aotearoa New Zealand can play a much stronger leadership role in <a href="https://www.cookislandsnews.com/internal/national/regional/environment/economy/pacific-islands/pacific-island-countries-meet-in-rarotonga-to-discuss-biosecurity-and-trade/">managing biosecurity risks in the Pacific</a>. After all, lax border protocols in our neighbourhood help pests and diseases end up on our doorstep. </p>
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Read more:
<a href="https://theconversation.com/why-red-fire-ants-and-yellow-crazy-ants-have-given-themselves-a-green-light-to-invade-australia-208479">Why red fire ants and yellow crazy ants have given themselves a green light to invade Australia</a>
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<p class="fine-print"><em><span>Andy Sheppard, as a chief research scientist with CSIRO, receives funding from the Australian federal government. This included funding to participate in the IPBES Assessment process as a coordinating lead author from 2019-2023, where he co-led Chapter 5 and made contributions to three other chapters. He is therefore well connected to the IPBES process, corporate, assessment team and media team. However, as a CSIRO employee he respects all the values of the organisation and does not undertake any commentary that would be seen to criticise Australian government policy or in any way lobby for additional research funding from governments. </span></em></p><p class="fine-print"><em><span>Melodie McGeoch receives funding from the Australian Research Council - ARC SRIEAS Grant SR200100005 Securing Antarctica’s Environmental Future. She is affiliated with La Trobe University and Monash University. She is 1st Vice Chair of the Science Committee of the Global Biodiversity Information Facility, Fellow of the African Academy of Sciences, Member of the Implementation Committee of the Group on Earth Observations Biodiversity Observation Network, Independent Board Member of the National Computation Infrastructure and on the Editorial Board of Global Ecology and Biogeography.</span></em></p><p class="fine-print"><em><span>Philip Hulme receives research funding from the New Zealand government. He is affiliated with Lincoln University, New Zealand. and is a member of the Canterbury-Aoraki Conservation Board and a Director of the QEII Trust. He is a member of the Biosecurity Advisory Groups of both Environment Canterbury and Zespri.</span></em></p><p class="fine-print"><em><span>Phill Cassey receives funding from the Centre for Invasive Species Solutions and the Australian Research Council. </span></em></p>Alien invaders are penetrating the borders of every country in the world. Now the full extent of the problems and potential solutions have been exposed, in a new United Nations report.Andy Sheppard, Research Director CSIRO Health & Biosecurity, CSIROMelodie McGeoch, Professor, La Trobe UniversityPhilip Hulme, Distinguished Professor in Pest Management and Conservation, Lincoln University, New ZealandPhill Cassey, Australian Research Council Industry Laureate Fellow, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2121082023-08-29T04:26:14Z2023-08-29T04:26:14ZHow a lethal fungus is shrinking living space for our frogs<p>In 1993, frogs were found dying <a href="https://www.pnas.org/doi/full/10.1073/pnas.95.15.9031">en masse</a> in Far North Queensland. When scientists analysed their bodies, they found something weird. Their small bodies were covered in spores. </p>
<p>It was an epidemic. An aquatic fungus had eaten the keratin in their skin, compromising its function and leading to cardiac arrest. And worse, the amphibian chytrid fungus (<em>Batrachochytrium dendrobatidis</em>) had been quietly spreading around the world, from South America to Europe, killing frogs wherever it went. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/545151/original/file-20230829-19-2sjqta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/545151/original/file-20230829-19-2sjqta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/545151/original/file-20230829-19-2sjqta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=481&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545151/original/file-20230829-19-2sjqta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=481&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545151/original/file-20230829-19-2sjqta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=481&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545151/original/file-20230829-19-2sjqta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=605&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545151/original/file-20230829-19-2sjqta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=605&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545151/original/file-20230829-19-2sjqta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=605&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">It doesn’t look lethal – but looks can be deceiving. This is a chytrid zoosporangium, which will release zoospores that propel themselves through water in search of amphibian hosts.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Batrachochytrium_dendrobatidis#/media/File:CSIRO_ScienceImage_1392_Scanning_Electron_Micrograph_of_Chytrid_Fungus.jpg">CSIRO/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Likely native to the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6311102/">Korean Peninsula</a>, it was first detected in Australia in the <a href="https://www.sciencedirect.com/science/article/pii/S0006320716310126">late 1970s</a>. As it spread, it <a href="https://www.sciencedirect.com/science/article/pii/S0006320716310126">caused the extinction</a> of at least four Australian frog species and probably three others. </p>
<p>This lethal pathogen is a selective killer. As our <a href="https://www.nature.com/articles/s41559-023-02155-0">new research</a> shows, it effectively makes some areas a no-go zone for susceptible frog species. The fungus doesn’t like hot conditions. But in cooler environments – such as in southern Australia and higher up in mountain ranges – it flourishes. Mortality rates in these environments can approach 100% for some frog species. </p>
<h2>Pushed from the highlands</h2>
<p>Australia is rich in frogs, with 247 surviving species at last count. Most are endemic to the continent – and many are spectacularly beautiful or, like the <a href="https://www.theguardian.com/culture/2022/feb/21/the-15-most-interesting-australian-frogs-sorted">turtle frog</a>, bizarre. </p>
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<a href="https://images.theconversation.com/files/545161/original/file-20230829-30-f0vm7l.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="turtle frog" src="https://images.theconversation.com/files/545161/original/file-20230829-30-f0vm7l.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545161/original/file-20230829-30-f0vm7l.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545161/original/file-20230829-30-f0vm7l.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545161/original/file-20230829-30-f0vm7l.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545161/original/file-20230829-30-f0vm7l.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545161/original/file-20230829-30-f0vm7l.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545161/original/file-20230829-30-f0vm7l.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The turtle frog (Myobatrachus gouldii) is one of Australia’s strangest.</span>
<span class="attribution"><span class="source">Stephen Zozaya/Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>The gorgeous Australian lace-lid treefrog was once widespread across the rainforests of Queensland’s Wet Tropics, which run from Townsville to Cooktown, stretching from sea level up to Queensland’s highest mountain, the 1,622 metre Mt Bartle Frere. </p>
<p>Lace-lid treefrogs once lived throughout these forests, whether on mountains or down near sea level. But they have been driven from rainforests above 400 metres. Down lower, the heat makes it harder for chytrid to kill, and the frog’s higher breeding rate can outpace deaths from the disease. </p>
<h2>No-go zones</h2>
<p>Australians know full well about the damage introduced species can do. Cane toads kill native predators like quolls who aren’t used to their toxin. Cats and foxes have driven many small mammals to extinction. </p>
<p>But even when a species survives contact with an introduced species, it can be forever changed. </p>
<p>That’s because of less visible effects introduced species like chytrid fungus can have, such as shrinking the areas where native species can survive. When this happens, our species can be pushed into smaller parts of their original range, known as environmental refuges. </p>
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Read more:
<a href="https://theconversation.com/the-worlds-worst-animal-disease-is-killing-frogs-worldwide-a-testing-breakthrough-could-help-save-them-205872">The world's worst animal disease is killing frogs worldwide. A testing breakthrough could help save them</a>
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<p>As our research shows, it’s not just geographic range that changes. It also changes their niche – the set of environmental conditions where species can survive. Introduced species can actually force much larger contractions to a native species’ niche than to its geographic range. </p>
<p>You might wonder how that can be. It’s because the damage done by introduced species can vary a lot depending on the environment. Introduced species have their own niche – climates and environments where they thrive, and areas where they don’t. </p>
<p>Frog species that survived the initial epidemics don’t just persist in random parts of their old range. Hotter, wetter areas or those with less temperature variability become refuges. Chytrid is still widespread here, but it’s less lethal. </p>
<p>Part of the puzzle is also the fact these refuge areas are naturally easier places for frogs to survive and reproduce. Where populations thrive, they have greater resilience and stand a better chance of surviving the fungus. </p>
<h2>Pushed into refuges</h2>
<p>The pattern we document isn’t just seen in frogs. Researchers suspect similar changes have been forced on many native species impacted by introduced species. </p>
<p>Consider the bush-stone curlew – a long-legged, endearing bird with eerie <a href="https://www.youtube.com/watch?v=gqZsdBF-eKg&ab_channel=Janegrowsgardenrooms">night cries</a>. Many of us will have seen them haunting parks and beer gardens across northern Australia. But the same bird is now extinct or critically endangered in southern Australia, where it used to roam. Why? </p>
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<a href="https://images.theconversation.com/files/545164/original/file-20230829-15-qleqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="bush-stone curlew" src="https://images.theconversation.com/files/545164/original/file-20230829-15-qleqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545164/original/file-20230829-15-qleqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545164/original/file-20230829-15-qleqn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545164/original/file-20230829-15-qleqn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545164/original/file-20230829-15-qleqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545164/original/file-20230829-15-qleqn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545164/original/file-20230829-15-qleqn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Bush-stone curlews are lanky, unusual birds with a distinctive call.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<p>Habitat loss has played a role, but this species is <a href="https://www.publish.csiro.au/mu/mu02029">highly susceptible</a> to foxes. Foxes don’t much like the humidity of tropical and subtropical Australia. As a result, the curlew has been pushed out of the drier parts of its niche. </p>
<p>Niche contractions due to introduced species are likely to be widespread but little-studied. </p>
<p>If a species has a shrinking niche, it may change where conservationists direct their efforts. To give threatened species the best chance of survival, we might have to direct our energies to safeguarding them in their environmental refuges, safe from introduced predators or diseases.</p>
<p>When scientists assess how a species is going, we often look at changes in geographic range to gauge the level of risk to the species, from vulnerable through to extinct in the wild. </p>
<p>But this can have limitations. What our work has shown is that the survivable niche for species can shrink much more than its geographic range, reducing resilience to new environmental challenges. If frog species are forced out of upland areas, they may be at more risk from climate change, given higher elevations are likely to be <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/eap.1824">most resilient</a> to climate change. </p>
<p>There’s a silver lining here, though. Species can be more resilient than we assume in the face of new threats. Some populations may be hard hit, while others escape. Understanding why that is will be key to give our native species the best chance of surviving an uncertain future. </p>
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Read more:
<a href="https://theconversation.com/a-deadly-disease-has-driven-7-australian-frogs-to-extinction-but-this-endangered-frog-is-fighting-back-189491">A deadly disease has driven 7 Australian frogs to extinction – but this endangered frog is fighting back</a>
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<p class="fine-print"><em><span>Geoffrey Heard is a member of the Terrestrial Ecosystem Research Network at the University of Queensland, which is funded under the National Collaborative Research Infrastructure Strategy (NCRIS). The Threatened Species Index, of which Geoffrey Heard is a Science Advisor, has received co-funding from the Department of Climate Change, Energy, the Environment and Water of the Australian Government.</span></em></p><p class="fine-print"><em><span>Benjamin Scheele receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Conrad Hoskin receives funding from the Department of Environment and Science (Queensland Government) and the Australian Research Council (ARC). He is affiliated with the College of Science and Engineering, James Cook University (Townsville, Australia).</span></em></p><p class="fine-print"><em><span>Jarrod Sopniewski is supported by a Hackett Postgraduate Research Scholarship at the University of Western Australia.</span></em></p><p class="fine-print"><em><span>Jodi Rowley has received funding from the Department of Agriculture, Water and the Environment, the Australian Museum Foundation and other state, federal and philanthropic agencies.</span></em></p>Introduced species and diseases can drive native species into smaller environmental niches – and that could mean change to how we work to conserve them.Geoffrey Heard, Research fellow, Australian National University and, The University of QueenslandBenjamin Scheele, Research Fellow in Ecology, Australian National UniversityConrad Hoskin, Senior Lecturer, College of Science & Engineering, James Cook UniversityJarrod Sopniewski, PhD student, The University of Western AustraliaJodi Rowley, Curator, Amphibian & Reptile Conservation Biology, Australian Museum, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.