tag:theconversation.com,2011:/uk/topics/alien-species-33313/articlesAlien species – The Conversation2023-09-21T12:03:56Ztag: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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<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>
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<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>
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<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/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>
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<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>
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<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>
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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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<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>
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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>
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<h2>1. Giant African land snail</h2>
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<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>
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<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>
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<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>
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<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>
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<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>
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<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>
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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>
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<h2>3. New tramp ants</h2>
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<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>
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<span class="caption">A red imported fire ant in the US.</span>
<span class="attribution"><span class="source">Alexander Wild/Wikimedia Commons</span></span>
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<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>
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<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>
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</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/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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<p>
<em>
<strong>
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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</em>
</p>
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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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<hr>
<p>
<em>
<strong>
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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<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>
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</p>
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<img src="https://counter.theconversation.com/content/211893/count.gif" alt="The Conversation" width="1" height="1" />
<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/2106442023-08-02T00:40:21Z2023-08-02T00:40:21ZUnique study shows we can train wild predators to hunt alien species they’ve never seen before<figure><img src="https://images.theconversation.com/files/540358/original/file-20230801-17770-u3qt9k.jpeg?ixlib=rb-1.1.0&rect=58%2C180%2C1937%2C1290&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bush rat eating a beetle.</span> <span class="attribution"><a class="source" href="https://www.inaturalist.org/observations/120888928">Larney Grenfell/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Humans have trained domestic animals for thousands of years, to help with farming, transport, or hunting.</p>
<p>But can we train wild animals to help us in conservation work? Wild animals can be <a href="https://www.newscientist.com/article/2358950-bandicoots-can-be-trained-to-flee-predators-more-quickly/">taught to recognise dangerous predators</a>, avoid <a href="https://www.bbc.com/news/science-environment-35235518">toxic food</a>, and <a href="https://theconversation.com/how-coyotes-and-humans-can-learn-to-coexist-in-cities-147738">stay away from people</a>.</p>
<p>However, there are few examples of using classical learning techniques to train free-living animals to act in a way that benefits their ecosystem. In our <a href="https://www.sciencedirect.com/science/article/pii/S0006320723003129">newly published study in Biological Conservation</a>, we trained wild Australian native predatory rats to recognise an unfamiliar species of cockroach prey. It worked – in a simulated cockroach invasion, this training increased predation rates by the rats.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pest-plants-and-animals-cost-australia-around-25-billion-a-year-and-it-will-get-worse-164969">Pest plants and animals cost Australia around $25 billion a year – and it will get worse</a>
</strong>
</em>
</p>
<hr>
<h2>Growing number of aliens</h2>
<p>As humans have engaged in global trade, various species have moved across otherwise impossible-to-cross geographical barriers and into new environments. These species are known as alien species, and <a href="https://www.nature.com/articles/ncomms14435">their number continues to grow</a>.</p>
<p>Some alien species are relatively harmless in their new environment, and can even <a href="https://theconversation.com/good-or-bad-some-invasive-species-can-help-native-ecosystems-thrive-200155">positively affect the ecosystem</a>. However, many others <a href="https://www.abc.net.au/news/science/2021-07-30/invasive-species-cost-billions-australia/100333710">have costly</a> and devastating <a href="https://www.theguardian.com/environment/2020/jul/15/increase-in-invasive-species-poses-dramatic-threat-to-biodiversity-report-aoe">impacts on biodiversity</a> and <a href="https://www.smh.com.au/environment/sustainability/everywhere-s-bad-farmers-eye-long-campaign-against-mouse-plague-20210607-p57yor.html">agriculture</a>.</p>
<p>Not all species that arrive in new environments become established or spread. Even fewer of these species become invasive. Yet we don’t really know why some species are successful and others aren’t, and <a href="https://doi.org/10.1111/j.1472-4642.2008.00521.x">there are many different theories</a>. One reason some species fail to thrive in new environments is when native species resist, either by eating or simply outcompeting the arrivals. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/540359/original/file-20230801-256057-g6z48f.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A pale brown elongated bug with darker specks on its wings" src="https://images.theconversation.com/files/540359/original/file-20230801-256057-g6z48f.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/540359/original/file-20230801-256057-g6z48f.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540359/original/file-20230801-256057-g6z48f.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540359/original/file-20230801-256057-g6z48f.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540359/original/file-20230801-256057-g6z48f.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540359/original/file-20230801-256057-g6z48f.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540359/original/file-20230801-256057-g6z48f.jpeg?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">Speckled cockroaches, the alien species chosen by the researchers for this study, don’t live in Sydney.</span>
<span class="attribution"><a class="source" href="https://www.inaturalist.org/photos/292216009">Belinda Forbes/iNaturalist</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>However, native species can only resist against alien species if they can respond appropriately, which they may not do if they’ve never encountered the invaders before (biologists call this being “naive”).</p>
<p>Naivete can occur when two species with no recent evolutionary or ecological history come into contact with one another. Prey naivete is well documented, and the effect of alien predators on native prey that can’t recognise or escape them is significant.</p>
<p>But the role of native predator naivete in biological invasions is less clear. Native predators may not recognise an alien prey species or lack the ability to hunt them effectively. Sometimes predators may simply prefer to hunt their natural prey. When predators are naive, alien prey can establish and spread unchecked.</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>
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</p>
<hr>
<h2>Speeding up a natural process</h2>
<p>Native predators do <a href="https://theconversation.com/eat-your-heart-out-native-water-rats-have-worked-out-how-to-safely-eat-cane-toads-123986">eventually learn to hunt alien prey</a>, but this process can take a long time when prey aren’t encountered often.</p>
<p>We wanted to know if we could speed up learning by exposing a free-living native predator to the scent of a novel prey species paired with a reward.</p>
<p>We conducted our study on bushland in the outskirts of Sydney, New South Wales, using <a href="https://australian.museum/learn/animals/mammals/bush-rat/">native bush rats</a> (<em>Rattus fuscipes</em>) as our model predator. Our chosen alien prey species, <a href="https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/c5dd2e9b-38ad-46f8-a309-0ae69b078f0e">speckled cockroaches</a> (<em>Nauphoeta cinerea</em>), don’t live in Sydney and surrounds, so rats have no experience with them.</p>
<p>We housed cockroaches in small boxes for days at a time with absorbent paper on the floor to collect odour. When using them as prey, we froze and tethered the cockroaches to tent pegs, to avoid accidental introduction of cockroaches in the area.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/540360/original/file-20230801-198210-c2smyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A grayscale image with a rodent in the top left corner sitting on leaf litter" src="https://images.theconversation.com/files/540360/original/file-20230801-198210-c2smyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/540360/original/file-20230801-198210-c2smyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540360/original/file-20230801-198210-c2smyp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540360/original/file-20230801-198210-c2smyp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540360/original/file-20230801-198210-c2smyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540360/original/file-20230801-198210-c2smyp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540360/original/file-20230801-198210-c2smyp.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 bush rat caught on camera interacting with the tea strainer and the tethered reward of a dead roach.</span>
<span class="attribution"><span class="source">Finn Cameron Gillies Parker</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We confirmed the presence of bush rats at 24 locations, and randomly allocated 12 as training sites and 12 as non-training (control) sites. At the training sites, we placed a metal tea strainer with the cockroach smell, and three dead cockroaches as a reward. The tea strainer and cockroaches were tethered to a tent peg in the ground so rats couldn’t carry them away.</p>
<p>We used cameras to observe the rat behaviour, and checked the training stations every one to two days. We also moved the stations so the rats wouldn’t just learn to associate the reward with the location.</p>
<h2>Trained for an invasion</h2>
<p>Immediately after training, we conducted a simulated invasion at all sites. The invasion involved ten dead and tethered cockroach “invaders”. The number of “surviving” (that is, uneaten) cockroaches was recorded each day for five days.</p>
<p>We compared prey survival rates in sites with trained and untrained rats, and found cockroach prey in training sites were 46% more likely to be eaten than prey in non-training sites.</p>
<p>We also found the number of cockroaches eaten during training was a significant predictor for how many were eaten on the first night of the “invasion”.</p>
<p>We also wanted to ensure we had not just attracted more rats to training sites during the training process. To do this, immediately after the invasion we used cameras to compare rat visits to all sites using a peanut oil attractant. There was no difference between training and non-training sites.</p>
<p>Our study is the first to train free-living predators to hunt species they’ve never seen before. It shows the potential for training our native species to fight biological invasions. More broadly, we think our study adds to the growing evidence that training animals can help to address a variety of problems, such as <a href="https://www.theguardian.com/environment/2022/feb/01/swedish-crows-pick-up-cigarette-butts-litter">birds picking up litter</a> and rats <a href="https://apopo.org/?v=6cc98ba2045f">sniffing out landmines</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/alien-invaders-the-illegal-reptile-trade-is-a-serious-threat-to-australia-68815">Alien invaders: the illegal reptile trade is a serious threat to Australia</a>
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</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/210644/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Banks receives funding from The Australian Research Council, The Herman Slade Foundation, Birdlife Australia, Northern Beaches Council and Manaaki Whenua. </span></em></p><p class="fine-print"><em><span>Finn Cameron Gillies Parker 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>What happens when wild native bush rats meet cockroaches they’ve never seen before?Finn Cameron Gillies Parker, PhD candidate, University of SydneyPeter Banks, Professor of Conservation Biology, School of Life and Environmental Sciences, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1886802022-09-13T17:43:35Z2022-09-13T17:43:35ZInvasive reptile and amphibian species are causing billions of dollars in damages globally<figure><img src="https://images.theconversation.com/files/482138/original/file-20220831-4764-z2dv88.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Invasive alien species are a growing concern for both the environment and economy.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Economic growth and globalization have connected the world’s most distant places. Rapid trade and transport have boosted economic growth globally, but not without consequences: many species have been introduced to new regions, far from where they evolved.</p>
<p>Alien species are those introduced by humans to regions outside their natural range. Invasive alien species are a growing concern for both the environment and economy. </p>
<p>In recent decades, alien herpetofauna — amphibians and reptiles — have increasingly gained attention on social media, with more information being circulated about the impacts these species have on native flora and fauna. </p>
<p>And yet, the number of invasive reptiles and amphibians is increasing, facilitated by the persistently high globalization of human activities. </p>
<h2>Detrimental effects</h2>
<p>Some invasive species arrive unintentionally as hitchhikers on planes, ships and cars. Others are sold intentionally as exotic pets, which then escape or are released into the wild. Of those that survive and establish, some are able to spread with severe negative impacts, giving them the title of “invasive.” </p>
<p><a href="https://doi.org/10.1016/j.scitotenv.2022.153404">These impacts can be massive</a>. Alien species are a leading cause of biodiversity loss and extinction worldwide, affecting human welfare and quality of life. </p>
<p>While alien species can also have detrimental effects on the economy, this is often complex to assess. Available information is often scattered, covers different scales or periods, recorded using variable measurements and currencies and presented in many languages. </p>
<p>The InvaCost database, <a href="https://doi.org/10.1038/s41597-020-00586-z">the most comprehensive database of the cost of alien species and a global initiative of scientists</a>, gathers this information and makes it accessible to researchers and the public.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/482402/original/file-20220901-9301-wcqbt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a Burmese python swimming through shallow water" src="https://images.theconversation.com/files/482402/original/file-20220901-9301-wcqbt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482402/original/file-20220901-9301-wcqbt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482402/original/file-20220901-9301-wcqbt7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482402/original/file-20220901-9301-wcqbt7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482402/original/file-20220901-9301-wcqbt7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482402/original/file-20220901-9301-wcqbt7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482402/original/file-20220901-9301-wcqbt7.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">The alien Burmese python has successfully established itself in the Everglades National Park in Florida, where it has decimated local mammal populations.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Surprising impacts</h2>
<p>The most common pathway for invasive reptiles and amphibians is the often-illegal trade of exotic snakes and frogs as pets. </p>
<p>Another common pathway is release for biological control, where a new species is introduced in an attempt to control a pest species. This is how <a href="https://doi.org/10.1111/j.1469-1795.2009.00319.x">the cane toad was introduced in Australia</a>. </p>
<p>Other pathways include aquaculture enterprises, such as those that raise <a href="https://doi.org/10.1007/s10530-007-9178-x">American bullfrogs for human consumption</a> and <a href="https://doi.org/10.2984/1534-6188(2007)61%5B307:BAIOPI%5D2.0.CO;2">species hitchhiking on planes or boats</a>.</p>
<p>Alien reptiles and amphibians can have quite unusual and surprising economic impacts. For instance, after the arrival of the coquí frog to Hawaii via contaminated nursery plants, <a href="https://ageconsearch.umn.edu/record/21313/">its very loud mating song caused severe declines in property values in infested areas</a>.</p>
<p>More typical economic impacts stem from programs for the control or eradication of these species. Management programs are needed due to the damage these invaders cause on biodiversity by eliminating native species, including at-risk amphibians and reptiles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/481903/original/file-20220830-37919-2ltj1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An American bullfrog with a large goldfish of approximately equal size in its mouth" src="https://images.theconversation.com/files/481903/original/file-20220830-37919-2ltj1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481903/original/file-20220830-37919-2ltj1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481903/original/file-20220830-37919-2ltj1a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481903/original/file-20220830-37919-2ltj1a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481903/original/file-20220830-37919-2ltj1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481903/original/file-20220830-37919-2ltj1a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481903/original/file-20220830-37919-2ltj1a.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">American bullfrogs have the largest reported economic impacts of any amphibian.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Bullfrog_tries_to_swallow_huge_Goldfish_-_Fish_survived.jpg">(Rusty Clark/Wikimedia Commons)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>This is the case for one of the most famous snakes in the pet trade, the California kingsnake, <a href="https://phys.org/news/2021-12-invasive-snake-gran-canaria-native.html">for which numerous eradication programs on the Canary Islands exist</a>.</p>
<h2>Quantifying the damage</h2>
<p>Our team of researchers quantified and synthesized, for the first time, <a href="https://doi.org/10.1038/s41598-022-15079-9">the economic costs of invasive reptiles and amphibians worldwide using the InvaCost database</a>. Between 1986 and 2020, we found that the cost of invasive reptiles and amphibians was massive, totalling approximately US$17 billion — with US$10.4 billion due to reptiles and US$6.3 billion due to amphibians. </p>
<p>Further, the bulk of these costs was from a small subset of highly impactful species. Most notably, the brown tree snake alone has resulted in a loss of US$4.5 million per year in Guam due to island-wide power outages and costing a total of US$10.34 billion during the study period (1986-2019).</p>
<p>The runner-up in terms of total impacts was the American bullfrog, whose impacts of US$6.04 billion accounted for approximately 97 per cent of the total amphibian cost, mostly due to control and eradication measures in Europe.</p>
<p>The types of costs incurred varied across species. In the case of amphibians, costs mostly originated from government expenditures — US$6.25 billion, or 99.6 per cent. These costs are derived from mitigating the spread or impacts of invaders through prevention, control, research, long-term management or eradication. </p>
<p>Reptile costs, however, mostly affected the public and social welfare sector, reportedly causing staggering damages — US$10.02 billion, or 96.6 per cent. These costs are incurred directly due to the impact of invaders, such as yield loss, infrastructure damage or income reduction.</p>
<p>Geographically, we found that economic impacts were present across all continents, except for amphibians in Africa, likely due to the lack of information. The geographic regions most affected were Europe by amphibians (US$6.04 billion), and Oceania and the Pacific Islands by reptiles (US$10.35 billion, 99.61 per cent).</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/BsR3Q1XgUjH","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Prevention is the better solution</h2>
<p>The economic costs of herpetofauna invasions are massive across all continents, but also underestimated. The vast part of our estimated total cost originated from only two species: the brown tree snake and the American bullfrog, which is likely, at least in part, due to missing data. </p>
<p>Further, only 21 species (six amphibians and 15 reptiles) were reported in InvaCost, out of 280 alien amphibians and reptiles recorded worldwide. </p>
<p>It should nevertheless be acknowledged that not all invasive reptiles and amphibians will have tangible monetary impacts, so some gaps are expected. Nonetheless, a greater research effort is needed to distinguish the true absence of economic cost from gaps in cost detection — especially for those species known to cause detrimental ecological impacts.</p>
<p>And as shown, investments in preventive measures can be <a href="https://doi.org/10.1016/j.scitotenv.2022.153404">an important money-saving measure for the public over the long term</a>, compared to reactive control approaches once a species has successfully invaded. </p>
<p>We propose the compilation of national lists for species facing import and selling bans, better screening for potentially harmful species and a more comprehensive effort to obtain information on the actual and species-specific costs. Our research highlights the importance of these measures to prevent future immense economic costs.</p><img src="https://counter.theconversation.com/content/188680/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>EJH was funded by a B3X postdoctoral fellowship from the Fonds de Recherche du Québec - Nature et Technologies.</span></em></p><p class="fine-print"><em><span>Ismael Soto Almena 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>New research has found that since the mid-1980s, the economic impact of invasive reptiles and amphibians totals more than US$17 billion.Ismael Soto Almena, PhD Student, Protection of Waters, University of South BohemiaEmma J. Hudgins, Postdoctoral fellow, Biology, Carleton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1765692022-02-22T14:11:23Z2022-02-22T14:11:23ZThe macaque monkeys of Mauritius: an invasive alien species, and a major export for research<figure><img src="https://images.theconversation.com/files/444780/original/file-20220207-17-1eqqbum.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Macaques are regarded as alien species in Mauritius. </span> <span class="attribution"><span class="source">Fabian Faber/Shutterstock</span></span></figcaption></figure><p><em>Macaque monkeys live as both captive and wild animals on the island of Mauritius. The wild population number is estimated at <a href="https://doi.org/10.1159/000156234">between 25,000 and 35,000</a> animals, it’s uncertain how many exist in captivity, but the figure is in the tens of thousands. The reason for a high captive number is that Mauritius is one of the world’s largest exporters of monkeys for the global research industry – primarily, to the US and Europe. <a href="https://www.aph.gov.au/DocumentStore.ashx?id=fa4e56d8-3755-40cc-8f69-4a2a19a39972&subId=408086">Up to 10,000</a> primates are exported by Mauritius each year. Ecologist Vincent Florens provides insights into how the animals first came to Mauritius and how their presence has affected the island’s natural environment.</em></p>
<h2>How long has Mauritius been involved?</h2>
<p>The macaques originally came from Southeast Asia and were introduced almost certainly as pets to Mauritius by the Dutch <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0053001">around</a> 1602. </p>
<p>In 1985, a private company, Bioculture, <a href="https://www.ncbi.nlm.nih.gov/books/NBK221770/">started to breed</a> the macaques for research. The government didn’t object. Macaques are closely related to humans and can help to provide data into medical issues. For instance, experimental trials in macaques <a href="https://onlinelibrary.wiley.com/doi/epdf/10.1111/jmp.12555#:%7E:text=Experimental%20trials%20in%20macaques%20have,influenza%2C%20smallpox%2C%20and%20hepatitis.">have led researchers</a> to understand the efficacy of novel drugs and vaccines against several infectious diseases, such as AIDS, influenza, smallpox, and hepatitis.</p>
<p>Macaques were first exported from Mauritius for research <a href="https://www.ncbi.nlm.nih.gov/books/NBK221770/">in 1985</a>. Initially feral animals had to be caught to supply research. These were typically caught in the islands’ forested areas, in the national parks, nature reserves, on mountains and in woods along rivers. </p>
<p>Today they are both caught from the wild and bred in captivity for research. <a href="https://www.traveldailynews.com/post/animal-protection-groups-outraged-as-mauritius-government-gives-permission-for-capture-of-wild-monkeys">In 2020</a>, 10,827 macaques were exported from the country. </p>
<p>Wild macaques are needed to support captive breeding, an intake of at least a few thousand females each year. This is to preclude problems of genetic inbreeding that may happen in captive populations. And because captive bred animals’ breeding capacity tends to drop, and other issues like ageing of breeding animals.</p>
<h2>How does the trade affect their numbers?**</h2>
<p>The intensity of trapping feral animals may vary through time depending on the needs of the breeding programs. In times of low to no trapping the feral macaque population generally grows gradually, something I’ve observed when carrying out <a href="https://scholar.google.com/citations?user=nDUJisIAAAAJ&hl=en">research</a> on vegetation dynamics in Mauritius over about 20 years. There are more frequent calls and sightings of animals during visits to forested areas, and also by the sizes of the groups seen.</p>
<p>Conversely, there have been times of intensive trapping, like when several companies were given permits to operate several years back. This led to a very marked drop in encounters where macaques were previously abundant. </p>
<h2>What impact do macaques have on the natural environment?</h2>
<p>To appreciate the impact of macaques on Mauritius’ natural environment, one must first remember that they were introduced by humans to the island. Macaques are not part of the natural environment of Mauritius, they are like rats in that respect. </p>
<p>The macaque is what is termed an ‘alien species’ in Mauritius. This means that the many native, and often unique, animals and plants of Mauritius – which occur in one of the world’s <a href="https://www.nature.com/articles/35002501">biodiversity hotspots</a> – had no previous exposure to animals like macaques. This means the plants and animals that lived there, the endemic species, have developed no evolutionary feature that would protect them from the alien monkeys. </p>
<p>Mauritius already has one of the highest <a href="https://portals.iucn.org/library/sites/library/files/documents/RL-2000-001.pdf">extinction rates</a> of endemic species worldwide. They are among the most threatened worldwide. For example, last year, the Botanical Gardens Conservation International ranked Mauritius as the <a href="https://mauritiushindinews.com/hindi-newspaper-in-mauritius/endemic-trees-mauritius-is-a-very-bad-student-scope/#:%7E:text=The%20new%20report%20State%20of,real%20observation%20is%20even%20worse.">second worst </a> country worldwide in terms of proportion of tree species threatened with extinction. Massive deforestation <a href="https://doi.org/10.1017/S0376892914000411">is the most direct and immediate driver of biodiversity loss</a>, removing 95.6% of the original native ecosystem. </p>
<p>Macaques have, and continue to, play a pivotal role in this situation. They are formidable predators capable of <a href="https://doi.org/10.1111/j.1474-919X.1997.tb08861.x">raiding bird</a> nests to eat <a href="https://www.iucnredlist.org/species/22696373/93557909">eggs</a> and <a href="https://www.iucnredlist.org/species/22690392/179390191">chicks</a>. Macaques also chew on the soft heart of many plants like <a href="https://doi.org/10.1007/978-3-030-11257-8_29-1">orchids</a>, especially the larger species, killing them. Today orchids are the plant family that have sustained the highest <a href="https://doi.org/10.1007/978-3-030-11257-8_29-1">extinction rate</a> – 20 of the 91 known species appear to have gone extinct since 1769 in Mauritius. Many of the macaque-vulnerable orchids now cling to survival in tiny numbers in places like steep cliffs, which are least accessible to macaques. </p>
<p>Macaques destroy the fruits of many native trees before they mature. This kills the seeds within, <a href="https://www.researchgate.net/publication/252932550_Current_decline_of_the_''Dodo_Tree''_a_case_of_broken-down_interactions_with_extinct_species_or_the_result_of_new_interactions_with_alien_invaders">like those</a> of the ‘Dodo-tree’ and many ebony species. This has made forests less hospitable for native frugivores such as the endangered flying fox. </p>
<p>Macaques also destroy flowers of many species, breaking branches, and chewing on seedlings. Their activities deprive native fauna of their natural foods, which in turn contribute to their further decline. For example, macaques <a href="https://www.academia.edu/14254707/Current_decline_of_the_Dodo_Tree_a_case_of_broken-down_interactions_with_extinct_species_or_the_result_of_new_interactions_with_alien_invaders">have destroyed</a> about 95% of fruits of certain endemic trees before the Mascarene endemic flying fox has a chance to feed on these fruits. This in turn pushes the flying fox to seek food elsewhere, including on commercial trees in gardens and orchards. Sadly, this resulted in the government of Mauritius taking action against flying foxes – <a href="https://doi.org/10.1038/530033a">killing them</a> by the thousands. This has worsened the conservation status of the flying fox to <a href="https://www.iucnredlist.org/species/18743/86475525">Endangered</a> on the Red List of the International Union for Conservation of Nature.</p>
<h2>How can they be better managed?</h2>
<p>Feral macaques in Mauritius are a formidably harmful invasive alien species, destructive to many animal and plant species which are heading towards extinction in part because of the macaques. </p>
<p>The ideal management in such a situation is eradication, just like goats and rabbits were eradicated from <a href="https://doi.org/10.1016/0006-3207(86)90086-8">Round Island</a> in the 1970s and 1980s. This saved its highly threatened flora and fauna from extinction. </p>
<p>However, macaque eradication may be difficult in Mauritius’ remaining forests, which are sizeable, covering 80 km2. It may be more feasible in the short run to eradicate them from isolated pockets of habitats or to control their numbers to far below what they are now. </p>
<p>This may be done through intensive trapping or construction of macaque proof fencing, particularly in and around the most biodiversity important areas respectively. </p>
<p>Each of the monkeys that are exported annually for research is subjected to a US$125 levy that contributes to raising funds for biodiversity conservation. However, more species will continue to go extinct if the level of conservation management is not seriously increased to face the threats, including those posed by the macaques.</p><img src="https://counter.theconversation.com/content/176569/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vincent Florens 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>Macaques are an alien species - and the endemic plants and animals of the island haven’t adapted to protect themselves against these monkeys.Vincent Florens, Associate Professor, Department of Biosciences at Faculty of Science, University of MauritiusLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1727562021-12-05T19:11:20Z2021-12-05T19:11:20ZWhy dingoes should be considered native to mainland Australia – even though humans introduced them<figure><img src="https://images.theconversation.com/files/435481/original/file-20211203-27-dx7620.jpg?ixlib=rb-1.1.0&rect=7%2C31%2C5168%2C3197&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>Dingoes are <a href="https://academic.oup.com/cz/article-abstract/57/5/668/5004458">often demonised</a> as a danger to livestock, while many consider them a natural and essential part of the environment. But is our most controversial wild species actually native to Australia? </p>
<p>Dingoes were brought to Australia by humans from Southeast Asia some 4,000 years ago. Technically, this means they are an introduced species, and an “alien” species by <a href="https://academic.oup.com/bioscience/article-abstract/68/7/496/5050532">classic ecological definitions </a>. By contrast, most legal definitions consider dingoes native, because they were here before Europeans arrived. </p>
<p>Though it sounds academic, the controversy has real consequences for this ancient dog lineage. In 2018, the Western Australian government declared dingoes <a href="https://theconversation.com/why-the-wa-government-is-wrong-to-play-identity-politics-with-dingoes-102344">were not native fauna</a> due to crossbreeding with domestic dogs. This potentially makes it easier to control their numbers.</p>
<p>In a <a href="https://meridian.allenpress.com/australian-zoologist/article-abstract/41/3/358/472935/An-eco-evolutionary-rationale-to-distinguish-alien">new research paper</a>, I find dingoes do indeed fit the bill as an Australian native species, using three new criteria I propose. These criteria can help us answer questions over whether alien species can ever be considered native, and if so, over what time frame.</p>
<h2>Why does alien or native status matter?</h2>
<p>Humans have been moving animal species around for millennia. Thousands of years ago, neolithic settlers <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2907.1992.tb00129.x">moved rabbits</a> to Mediterranean islands, traders unwittingly took black rats from India to Europe and Indigenous Southeast Asian people took pigs to Papua New Guinea. </p>
<p>The rate of species introductions has ramped up with the movement and spread of people, with many recent arrivals posing a major threat to biodiversity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/435486/original/file-20211203-25-eianud.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/435486/original/file-20211203-25-eianud.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/435486/original/file-20211203-25-eianud.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/435486/original/file-20211203-25-eianud.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/435486/original/file-20211203-25-eianud.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/435486/original/file-20211203-25-eianud.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/435486/original/file-20211203-25-eianud.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/435486/original/file-20211203-25-eianud.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">Pigs were introduced to Papua New Guinea by Indigenous people thousands of years ago. Does that make them native?</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Researchers often distinguish between alien and native using the year the species was introduced. There are obvious problems with this, given the dates used can be arbitrary and the fact perceptions of nativeness can be based on how much <a href="https://journals.sagepub.com/doi/abs/10.1177/0309132507079499">humans like the species</a>, rather than its ecological impact. For example, there has been strong opposition to killing “friendly” hedgehogs in areas of Scotland where they are introduced, but less cute animals like American mink get no such consideration.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-dingo-fence-from-space-satellite-images-show-how-these-top-predators-alter-the-desert-155642">The dingo fence from space: satellite images show how these top predators alter the desert</a>
</strong>
</em>
</p>
<hr>
<p>For conservationists, alien status certainly matters. <a href="https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2006.0444">Alien species act differently</a> to native species in their new environments, which can give them an advantage over locals in terms of competition for food, predation and spreading new diseases. This can cause native population declines and extinctions.</p>
<p>As a result, species considered alien in their ecosystems are often targets for control and eradication. But species considered native are usually protected even if they have extended their range significantly, like eastern water dragons or the Australian white ibis. </p>
<p>Native status is, of course, a human construct. Past definitions of nativeness have not directly considered the ecological reasons for concern about alien species. </p>
<p>This is what <a href="https://meridian.allenpress.com/australian-zoologist/article-abstract/41/3/358/472935/An-eco-evolutionary-rationale-to-distinguish-alien">my new research</a> seeks to address. </p>
<h2>An ecological definition of nativeness</h2>
<p>What I propose are three staged criteria to determine when an introduced species becomes native:</p>
<ol>
<li><p>has the introduced species evolved in its new environment? </p></li>
<li><p>do native species recognise and respond to the introduced species as they do other local species? </p></li>
<li><p>are the interactions between introduced and established native species similar to interactions between native species (that is, their impacts on local species are not negative and exaggerated)?</p></li>
</ol>
<p>For dingoes on mainland Australia, the answer is yes for all three criteria. We should consider them native. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/435474/original/file-20211203-23-1o19jql.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/435474/original/file-20211203-23-1o19jql.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/435474/original/file-20211203-23-1o19jql.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=482&fit=crop&dpr=1 600w, https://images.theconversation.com/files/435474/original/file-20211203-23-1o19jql.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=482&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/435474/original/file-20211203-23-1o19jql.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=482&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/435474/original/file-20211203-23-1o19jql.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=606&fit=crop&dpr=1 754w, https://images.theconversation.com/files/435474/original/file-20211203-23-1o19jql.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=606&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/435474/original/file-20211203-23-1o19jql.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=606&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dingoes on mainland Australia meet the criteria for native status.</span>
<span class="attribution"><span class="source">Peter Banks</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Firstly, dingoes are not the same dogs first brought here. Dingoes are now <a href="https://www.mapress.com/j/zt/article/view/zootaxa.4564.1.6">quite different</a> to their close ancestors in Southeast Asia, in terms of behaviour, how they reproduce and how they look. These <a href="https://www.nature.com/articles/s41467-020-14515-6">differences have a genetic basis</a>, suggesting they have evolved since their arrival in Australia. Their heads are now shaped differently, they breed less often and have better problem solving skills than other close dog relatives. </p>
<p>Second, it is well established that native prey species on mainland Australia <a href="https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2018.0857">recognise and respond to dingoes</a> as dangerous predators – which they are.</p>
<p>Finally, dingo impacts on prey species <a href="https://meridian.allenpress.com/australian-zoologist/article-abstract/41/3/338/447847/Introgression-does-not-influence-the-positive?redirectedFrom=fulltext">are not devastating</a> like those of alien predators such as feral cats and foxes. While hunting by dingoes does suppress prey numbers, they don’t keep them as low (and at greater risk of extinction) as do foxes and cats.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-dingo-is-a-true-blue-native-australian-species-111538">The dingo is a true-blue, native Australian species</a>
</strong>
</em>
</p>
<hr>
<p>Of course, dingo impacts were unlikely to have always been so benign. Dingoes are <a href="https://journals.sagepub.com/doi/abs/10.1191/0959683603hl682fa">linked to the extinction</a> of Tasmanian tigers (Thylacines), Tasmanian devils and the Tasmanian flightless hen, which disappeared from mainland Australia soon after the dingo arrived. </p>
<p>In my paper, I argue such impacts no longer occur because of evolutionary change in both dingoes and their prey. We can see this in Tasmania, which dingoes never reached. There, prey species like bandicoots still show <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161447">naiveté towards dogs</a>. That means we should not consider dingoes to be native to Tasmania.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/435484/original/file-20211203-23-101r65w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/435484/original/file-20211203-23-101r65w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/435484/original/file-20211203-23-101r65w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/435484/original/file-20211203-23-101r65w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/435484/original/file-20211203-23-101r65w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/435484/original/file-20211203-23-101r65w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/435484/original/file-20211203-23-101r65w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/435484/original/file-20211203-23-101r65w.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">Native prey species on the mainland recognise and respond to dingoes.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Alien today, native tomorrow?</h2>
<p>This idea challenges the dogma alien species remain alien forever. This is an unsettling concept for ecologists dealing with the major and ongoing damage done by newer arrivals. <a href="https://academic.oup.com/bioscience/article-abstract/62/3/217/358332">Some argue</a> we should never embrace alien species into natural ecosystems. </p>
<p>This makes no sense for long-established introduced species, which might now be playing a <a href="https://theconversation.com/the-dingo-fence-from-space-satellite-images-show-how-these-top-predators-alter-the-desert-155642">positive role</a> in ecosystems. But it’s a different story for recently introduced species like cats, given not enough time has passed to get past the exaggerated impacts on local species. </p>
<p>These ideas are not about considering all species present in an ecosystem to be native. Introduced species should still be considered alien until proven native.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/435482/original/file-20211203-27-1atm2p2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Cat sitting in the outback" src="https://images.theconversation.com/files/435482/original/file-20211203-27-1atm2p2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/435482/original/file-20211203-27-1atm2p2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/435482/original/file-20211203-27-1atm2p2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/435482/original/file-20211203-27-1atm2p2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/435482/original/file-20211203-27-1atm2p2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/435482/original/file-20211203-27-1atm2p2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/435482/original/file-20211203-27-1atm2p2.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">Cats are a bigger threat to Australian wildlife than dingoes.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This approach suggests ways of classifying species which might be native to a country but have moved to new places within the country through mechanisms like climate change or re-wilding. For example, we can’t simply assume returning Tasmanian devils to <a href="https://theconversation.com/bringing-devils-back-to-the-mainland-could-help-wildlife-conservation-43121">mainland Australia</a> more than 3,000 years after dingoes drove them extinct there would count as reintroducing a native species. </p>
<p>Defining nativeness in this ecological way will help resolve some of the heated and long-running debates over how to distinguish alien and native species. </p>
<p>How? Because it targets the key reason conservationists were worried about alien species in the first place – the damage they can do.</p><img src="https://counter.theconversation.com/content/172756/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Banks receives funding from the Australian Research Council and The Hermon Slade Foundation </span></em></p>Dingoes have evolved under Australian conditions. That’s just one step in the path the iconic dog has taken to become native.Peter Banks, Professor of Conservation Biology, School of Life and Environmental Sciences, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1649692021-07-29T19:59:09Z2021-07-29T19:59:09ZPest plants and animals cost Australia around $25 billion a year – and it will get worse<figure><img src="https://images.theconversation.com/files/413674/original/file-20210729-23-1xua4jp.jpg?ixlib=rb-1.1.0&rect=63%2C197%2C4185%2C2624&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">AAP</span></span></figcaption></figure><p>Shamefully, Australia has one of the <a href="https://theconversation.com/australias-threatened-species-plan-has-failed-on-several-counts-without-change-more-extinctions-are-assured-163434">highest extinction rates</a> in the world.
And the <a href="https://theconversation.com/invasive-species-are-australias-number-one-extinction-threat-116809">number one</a> threat to our species is invasive or “alien” plants and animals. </p>
<p>But invasive species don’t just cause extinctions and biodiversity loss – they also create a serious economic burden. Our <a href="http://doi.org/10.3897/neobiota.67.58834">research</a>, published today, reveals invasive species have cost the Australian economy at least A$390 billion in the last 60 years alone. </p>
<p>Our paper – the most detailed assessment of its type ever published in this country – also reveals feral cats are the worst invasive species in terms of total costs, followed by rabbits and fire ants.</p>
<p>Without urgent action, Australia will continue to lose billions of dollars every year on invasive species.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/412797/original/file-20210723-25-6b2d3n.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/412797/original/file-20210723-25-6b2d3n.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412797/original/file-20210723-25-6b2d3n.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412797/original/file-20210723-25-6b2d3n.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412797/original/file-20210723-25-6b2d3n.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412797/original/file-20210723-25-6b2d3n.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412797/original/file-20210723-25-6b2d3n.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412797/original/file-20210723-25-6b2d3n.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&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 cats are Australia’s costliest invasive species.</span>
<span class="attribution"><span class="source">Adobe Stock/240188862</span></span>
</figcaption>
</figure>
<h2>Huge economic burden</h2>
<p>Invasive species are those not native to a particular ecosystem. They are introduced either by accident or on purpose and become pests.</p>
<p>Some costs involve direct damage to agriculture, such as insects or fungi destroying fruit. Other examples include measures to control invasive species like feral cats and cane toads, such as paying field staff and buying fuel, ammunition, traps and poisons.</p>
<p>Our previous research put the global cost of invasive species at <a href="https://theconversation.com/attack-of-the-alien-invaders-pest-plants-and-animals-leave-a-frightening-1-7-trillion-bill-158628">A$1.7 trillion</a>. But this is most certainly a gross underestimate because so many data are missing.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/attack-of-the-alien-invaders-pest-plants-and-animals-leave-a-frightening-1-7-trillion-bill-158628">Attack of the alien invaders: pest plants and animals leave a frightening $1.7 trillion bill</a>
</strong>
</em>
</p>
<hr>
<p>As a wealthy nation, Australia has accumulated more reliable cost data than most other regions. These costs have increased exponentially over time – up to sixfold each decade since the 1970s.</p>
<p>We found invasive species now cost Australia around A$24.5 billion a year, or an average 1.26% of the nation’s <a href="https://www.abs.gov.au/statistics/economy/key-indicators">gross domestic product</a>. The costs total at least A$390 billion in the past 60 years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/412787/original/file-20210723-17-nfqpza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/412787/original/file-20210723-17-nfqpza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412787/original/file-20210723-17-nfqpza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412787/original/file-20210723-17-nfqpza.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412787/original/file-20210723-17-nfqpza.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412787/original/file-20210723-17-nfqpza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412787/original/file-20210723-17-nfqpza.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412787/original/file-20210723-17-nfqpza.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">Increase in annual costs of invasive species in Australia from 1960 to 2020. The predicted range for 2020 is shown in the upper left quadrant. Note the logarithmic scale of the vertical axis.</span>
<span class="attribution"><span class="source">CJA Bradshaw</span></span>
</figcaption>
</figure>
<h2>Worst of the worst</h2>
<p>Our analysis found feral cats have been the most economically costly species since 1960. Their A$18.7 billion bill is mainly associated with attempts to control their abundance and access, such as fencing, trapping, baiting and shooting.</p>
<p>Feral cats are a <a href="https://theconversation.com/australia-must-control-its-killer-cat-problem-a-major-new-report-explains-how-but-doesnt-go-far-enough-154931">main driver</a> of extinctions in Australia, and so perhaps investment to limit their damage is worth the price tag.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/412799/original/file-20210723-17-1sloenv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/412799/original/file-20210723-17-1sloenv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/412799/original/file-20210723-17-1sloenv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412799/original/file-20210723-17-1sloenv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412799/original/file-20210723-17-1sloenv.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412799/original/file-20210723-17-1sloenv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412799/original/file-20210723-17-1sloenv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412799/original/file-20210723-17-1sloenv.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>
<figcaption>
<span class="caption">Tasmania’s bane — ragwort (<em>Senecio jacobaea</em>)</span>
<span class="attribution"><span class="source">Adobe Stock/157770032</span></span>
</figcaption>
</figure>
<p>As a group, the management and control of invasive plants proved the worst of all, collectively costing about A$200 billion. Of these, <a href="https://www.agric.wa.gov.au/grains-research-development/annual-ryegrass">annual ryegrass</a>, <a href="https://weeds.dpi.nsw.gov.au/Weeds/PartheniumWeed">parthenium</a> and <a href="https://dpipwe.tas.gov.au/invasive-species/weeds/weeds-index/declared-weeds-index/ragwort">ragwort</a> were the costliest culprits because of the great effort needed to eradicate them from croplands.</p>
<p>Invasive mammals were the next biggest burdens, costing Australia A$63 billion.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/412655/original/file-20210722-23-4loggw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/412655/original/file-20210722-23-4loggw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412655/original/file-20210722-23-4loggw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412655/original/file-20210722-23-4loggw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412655/original/file-20210722-23-4loggw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412655/original/file-20210722-23-4loggw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412655/original/file-20210722-23-4loggw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412655/original/file-20210722-23-4loggw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&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 10 costliest invasive species in Australia.</span>
<span class="attribution"><span class="source">CJA Bradshaw</span></span>
</figcaption>
</figure>
<h2>Variation across regions</h2>
<p>For costs that can be attributed to particular states or territories, New South Wales had the highest costs, followed by Western Australia then Victoria.</p>
<p><a href="https://www.daf.qld.gov.au/business-priorities/biosecurity/invasive-plants-animals/ants/fire-ants">Red imported fire ants</a> are the costliest species in Queensland, and ragwort is the economic bane of Tasmania. </p>
<p>The <a href="https://weedsofmelbourne.org/common-heliotrope-or-potato-weed-heliotropium-europaeum">common heliotrope</a> is the costliest species in both South Australia and Victoria, and annual ryegrass tops the list in WA. </p>
<p>In the Northern Territory, the <a href="https://dothideomycetes.org">dothideomycete</a> fungus that causes <a href="https://nt.gov.au/industry/agriculture/food-crops-plants-and-quarantine/banana-freckle">banana freckle disease</a> brings the greatest economic burden, whereas cats and <a href="https://www.environment.nsw.gov.au/topics/animals-and-plants/pest-animals-and-weeds/pest-animals/foxes">foxes</a> are the costliest species in the ACT and NSW.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/412657/original/file-20210722-19-xptr2z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/412657/original/file-20210722-19-xptr2z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412657/original/file-20210722-19-xptr2z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=545&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412657/original/file-20210722-19-xptr2z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=545&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412657/original/file-20210722-19-xptr2z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=545&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412657/original/file-20210722-19-xptr2z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=684&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412657/original/file-20210722-19-xptr2z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=684&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412657/original/file-20210722-19-xptr2z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=684&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 three costliest species by Australian state/territory.</span>
<span class="attribution"><span class="source">CJA Bradshaw</span></span>
</figcaption>
</figure>
<h2>Better assessments needed</h2>
<p>Our study is one of 19 region-specific analyses <a href="https://doi.org/10.3897/neobiota.67.69971">released today</a>. Because the message about invasive species must get out to as many people as possible, our article’s abstract was translated into <a href="http://doi.org/10.3897/neobiota.67.58834">24 languages</a>.</p>
<p>This includes <a href="https://omniglot.com/writing/pitjantjatjara.htm">Pitjantjatjara</a>, <a href="https://www.welcometocountry.org/10-most-widely-spoken-aboriginal-languages-in-australia/">a widely spoken Indigenous language</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-threatened-species-plan-has-failed-on-several-counts-without-change-more-extinctions-are-assured-163434">Australia’s threatened species plan has failed on several counts. Without change, more extinctions are assured</a>
</strong>
</em>
</p>
<hr>
<p>Even the massive costs we reported are an underestimate. This is because of we haven’t yet surveyed all the places these species occur, and there is a lack of standardised reporting by management authorities and other agencies. </p>
<p>For example, our database lists several fungal plant pathogens. But no cost data exist for some of the worst offenders, such as the widespread <em>Phytophthora cinnamomi</em> pathogen that causes major <a href="https://doi.org/10.1071/BT07159">crop losses and damage to biodiversity</a>.</p>
<p>Developing <a href="https://news.microsoft.com/en-au/features/teaming-up-for-turtles/">better methods</a> to estimate the environmental impacts of invasive species, and the benefit of management actions, will allow us to use limited resources more efficiently.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/412956/original/file-20210724-27-120ky75.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/412956/original/file-20210724-27-120ky75.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412956/original/file-20210724-27-120ky75.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412956/original/file-20210724-27-120ky75.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412956/original/file-20210724-27-120ky75.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412956/original/file-20210724-27-120ky75.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412956/original/file-20210724-27-120ky75.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412956/original/file-20210724-27-120ky75.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>
<figcaption>
<span class="caption"><em>Phytophthora cinnamomi</em>, a widespread, but largely uncosted, fungal pathogen.</span>
<span class="attribution"><span class="source">Adobe Stock/272252666</span></span>
</figcaption>
</figure>
<h2>A constant threat</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/412955/original/file-20210724-15-1dfk65.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/412955/original/file-20210724-15-1dfk65.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/412955/original/file-20210724-15-1dfk65.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412955/original/file-20210724-15-1dfk65.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412955/original/file-20210724-15-1dfk65.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412955/original/file-20210724-15-1dfk65.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412955/original/file-20210724-15-1dfk65.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412955/original/file-20210724-15-1dfk65.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fall armyworm, a major crop pest.</span>
<span class="attribution"><span class="source">Adobe Stock/335450066</span></span>
</figcaption>
</figure>
<p>Many species damaging to <a href="https://www.agriculture.gov.au/pests-diseases-weeds/plant/national-priority-plant-pests-2019">agriculture</a> and the <a href="https://www.agriculture.gov.au/biosecurity/environmental/priority-list">environment</a> are yet to make it to our shores. </p>
<p>The recent arrival in Australia of fall armyworm, <a href="https://www.agriculture.gov.au/pests-diseases-weeds/plant/exotic-armyworm">a major agriculture pest</a>, reminds us how invasive species will <a href="https://doi.org/10.1038/ncomms14435">continue their spread</a> here and elsewhere.</p>
<p>As well as the economic damage, invasive species also bring <a href="https://doi.org/10.1038/ncomms12986">intangible costs</a> we have yet to measure adequately. These include the true extent of ecological damage, human health consequences, erosion of ecosystem services and the loss of cultural values.</p>
<p>Without better data, increased investment, a stronger biosecurity system and interventions such as animal culls, invasive species will continue to wreak havoc across Australia.</p>
<hr>
<p><em>The authors acknowledge the Traditional Owners of the lands on which they did this research.</em></p>
<p><em>Ngadlu tampinthi yalaka ngadlu Kaurna yartangka inparrinthi. Ngadludlu tampinthi, parnaku tuwila yartangka</em>.</p><img src="https://counter.theconversation.com/content/164969/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Corey J. A. Bradshaw receives funding from Australian Research Council. </span></em></p><p class="fine-print"><em><span>Andrew Hoskins receives funding from the Department of Agriculture, Water and the Environment. </span></em></p>Without urgent action, Australia will continue to lose billions of dollars every year on invasive species.Corey J. A. Bradshaw, Matthew Flinders Professor of Global Ecology and Models Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders UniversityAndrew Hoskins, Research scientist CSIRO Health and Biosecurity, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1618112021-06-13T20:07:22Z2021-06-13T20:07:22ZDo aliens exist? We asked five experts<figure><img src="https://images.theconversation.com/files/405853/original/file-20210611-17-1fcr2df.jpg?ixlib=rb-1.1.0&rect=170%2C89%2C5793%2C3880&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>Speculation has been rife about the contents of an unclassified report set to be released later this month from the Pentagon’s Unidentified Aerial Phenomena (UAP) task force. </p>
<p>The document, <a href="https://www.scientificamerican.com/article/experts-weigh-in-on-pentagon-ufo-report/">expected to drop</a> on June 25, will supposedly provide a comprehensive summary of what the US government knows about UAPs — or, to use the more popular term, UFOs.</p>
<p>While the report is not yet public, the New York Times recently <a href="https://www.nytimes.com/2021/06/03/us/politics/ufos-sighting-alien-spacecraft-pentagon.html">published</a> what it claimed was a preview of the findings, provided by unnamed senior officials who were privy to the report’s contents. </p>
<p>According to the Times’s sources, the report does not provide any clear link or association between more than 120 incidents of UFO sightings from the past two decades, and a possibility of Earth having been visited by aliens.</p>
<p>If the Times’s sources are to be believed, there’s clearly still no good reason to interpret an unexplained object in the sky as evidence of aliens. But does that mean aliens aren’t out there, somewhere else in the universe? And if they are, could we ever find them? Or might they be so different to us that “finding” them is impossible in any meaningful sense?</p>
<p>We asked five experts. </p>
<h2>Four out of five experts said aliens do exist</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/315871/original/file-20200218-11005-1x9b2hg.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/315871/original/file-20200218-11005-1x9b2hg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/315871/original/file-20200218-11005-1x9b2hg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=99&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315871/original/file-20200218-11005-1x9b2hg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=99&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315871/original/file-20200218-11005-1x9b2hg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=99&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315871/original/file-20200218-11005-1x9b2hg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=125&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315871/original/file-20200218-11005-1x9b2hg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=125&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315871/original/file-20200218-11005-1x9b2hg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=125&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"></span>
</figcaption>
</figure>
<p><strong>Here are their detailed responses:</strong></p>
<p><iframe id="tc-infographic-587" class="tc-infographic" height="400px" src="https://cdn.theconversation.com/infographics/587/04f8cf2f024c65ae2010dc729c28c7600cecda2d/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-us-military-has-officially-published-three-ufo-videos-why-doesnt-anybody-seem-to-care-137498">The US military has officially published three UFO videos. Why doesn't anybody seem to care?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/161811/count.gif" alt="The Conversation" width="1" height="1" />
Even if aliens exist, are intelligent like humans and interested in making contact with us, what are the chances they’ll be close enough for us to hear them screaming their presence into the cosmos?Noor Gillani, Digital Culture EditorChynthia Wijaya-Kovac, Social Media Producer, The Conversation AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1523202021-03-10T19:07:56Z2021-03-10T19:07:56ZScientists used ‘fake news’ to stop predators killing endangered birds — and the result was remarkable<figure><img src="https://images.theconversation.com/files/388691/original/file-20210310-15-korh1e.jpg?ixlib=rb-1.1.0&rect=4%2C12%2C2713%2C1723&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>Animals, including humans, depend on accurate information to navigate the world. But we can easily succumb to deliberate misinformation or “fake news”, fooling us into making a poor choice. </p>
<p>The concept of fake news <a href="https://www.bbc.com/news/av/world-us-canada-46175024">came to the fore</a> during the term of former US president Donald Trump. It became so prevalent, it was named the Macquarie Dictionary’s <a href="https://www.smh.com.au/culture/books/fake-news-no-it-really-is-the-macquarie-dictionary-s-word-of-the-decade-20210204-p56zfa.html">word of the decade</a></p>
<p>In a <a href="https://advances.sciencemag.org/content/7/11/eabe4164">new paper</a> out today we show how a form of fake news can be deployed to help save vulnerable wildlife. We protected endangered shorebirds by spreading misinformation — in the form of bird smells — to deceive predators. This helped reduce the number of birds lost, without using lethal force.</p>
<p>To be honest, when we began working on the idea ten years ago it seemed a little crazy. But after seeing how fake news messes with the minds of both humans and animals, it now makes a lot of sense.</p>
<figure class="align-center ">
<img alt="A newly hatched banded dotterel" src="https://images.theconversation.com/files/388693/original/file-20210310-17-1u3bsfo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/388693/original/file-20210310-17-1u3bsfo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=292&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388693/original/file-20210310-17-1u3bsfo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=292&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388693/original/file-20210310-17-1u3bsfo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=292&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388693/original/file-20210310-17-1u3bsfo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=367&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388693/original/file-20210310-17-1u3bsfo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=367&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388693/original/file-20210310-17-1u3bsfo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=367&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The authors used ‘fake news’ odours to protect vulnerable birds and their offspring, including the banded dotterel, above.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>The problem with predators</h2>
<p>Introduced or “alien” predators are species such as rats, cats and foxes, which have been introduced to new environments and kill local wildlife. If local species have not evolved with such predators — and so learned to evade them or ward them off — the damage can be devastating. </p>
<p>Alien predators have far more impact than native ones and are a <a href="https://doi.org/10.1098/rspb.2006.0444">major driver</a> of extinctions. In <a href="https://www.publish.csiro.au/pc/Fulltext/PC18024">Australia alone</a>, cats threaten the survival of more than 120 listed species, while foxes threaten 95 species. In the South Pacific the threat is <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsbl.2015.0623">even greater</a>.</p>
<p>But killing predators is a blunt and often ineffective tool. Too often, control techniques such as baiting, trapping and shooting <a href="https://www.sciencedirect.com/science/article/pii/S0006320715300380">can’t</a> reduce predator numbers enough to protect vulnerable prey. </p>
<p>In other circumstances, lethal control may not be possible or <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320718313533">socially acceptable</a>. This might occur when the problem predator is a native species (such as foxes in the United Kingdom) or where alien predators such as feral pigs are also a <a href="https://link.springer.com/article/10.1007/s10531-009-9680-9">food resource</a> for local people.</p>
<p>That’s why it’s important to examine alternative ways to protect vulnerable species.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-threatened-birds-declined-by-59-over-the-past-30-years-128114">Australia's threatened birds declined by 59% over the past 30 years</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="Cat with bird in mouth" src="https://images.theconversation.com/files/388696/original/file-20210310-21-4mbxhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/388696/original/file-20210310-21-4mbxhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388696/original/file-20210310-21-4mbxhp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388696/original/file-20210310-21-4mbxhp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388696/original/file-20210310-21-4mbxhp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388696/original/file-20210310-21-4mbxhp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388696/original/file-20210310-21-4mbxhp.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">Killing introduced predators such as cats may not be possible, or socially acceptable.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>New Zealand’s precious shorebirds</h2>
<p>In New Zealand, 59 bird species have <a href="https://protect-au.mimecast.com/s/0DXSClx1NjiY8QRMtGtaJs?domain=doc.govt.nz">become extinct</a> since humans arrived and many more close to being lost. Introduced predators contribute <a href="https://newzealandecology.org/nzje/2911">substantially</a> to this problem.</p>
<p>Predators such as hedgehogs, cats and ferrets were <a href="https://hilo.hawaii.edu/campuscenter/hohonu/volumes/documents/Vol10x09TransportedFaunaanditsEffects-NewZealandAReviewoftheLiterature.pdf">introduced to New Zealand</a> in the 1800s. They are especially common in our study area, the braided riverbed landscapes of the Mackenzie Basin on New Zealand’s South Island. There, they eat eggs and kill endangered shorebirds such as banded dotterel, plovers, wrybill and the South Island pied oystercatcher. </p>
<p>The birds evolved with avian predators, and have learnt to hide from them by building camouflaged nests among pebbles on the river shores.</p>
<p>But this tactic does not work against introduced predators. Odours emanating from the shorebirds’ feathers and eggs attract these scent-hunting mammals, which easily find the nests. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/PLOy-bdhSBg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Tricked you!</h2>
<p>Our research set out to undermine the predators’ tactics. We worked closely with Grant Norbury and others from Manaaki Whenua Landcare Research in New Zealand.</p>
<p>We distributed fake news — in the form of nest-like odours — that suggested to predators the shorebirds had begun to nest, even though they were yet to arrive. </p>
<p>First, we distilled odours extracted from the feathers and preen glands of three bird species — chickens, quails and gulls. In this case, any bird species could be used to produce the scent. (Watch a video of the process <a href="https://www.youtube.com/watch?v=Ac5uhBiW4MQ">here</a>). The result smelled a lot like a chicken coup or aviary — unmistakable to the human nose.</p>
<p>Five weeks before the shorebirds arrived for their breeding season in 2016, we mixed the odours with Vaseline and smeared the concoction on hundreds of rocks over two 1,000-hectare study sites. We did this every three days, for three months.</p>
<p>The predators were initially attracted to the odours. But within days, after realising the scent would not lead to food, they lost interest and stopped visiting the site.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/387626/original/file-20210304-14-gjq6xo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/387626/original/file-20210304-14-gjq6xo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=154&fit=crop&dpr=1 600w, https://images.theconversation.com/files/387626/original/file-20210304-14-gjq6xo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=154&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/387626/original/file-20210304-14-gjq6xo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=154&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/387626/original/file-20210304-14-gjq6xo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=193&fit=crop&dpr=1 754w, https://images.theconversation.com/files/387626/original/file-20210304-14-gjq6xo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=193&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/387626/original/file-20210304-14-gjq6xo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=193&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cat, hedgehog and ferret investigating odour treatments.</span>
</figcaption>
</figure>
<p>The shorebirds then arrived at Mackenzie Basin at their normal breeding time, and began building nests and laying eggs. At control sites where our “fake news” had not been deployed, the predators ate eggs and birds at the usual rate. But at sites where we put out unrewarding bird odours, the results were dramatic.</p>
<p>The number of nests destroyed by predators almost halved. As a result, chick production was 1.7 times higher at treated sites compared to control sites over the 25-35 days of the nesting season.</p>
<p>We wanted to be sure our results were not due to lower predator numbers or different behaviour in some areas. So the next year, we flipped treatments at our sites and got the same result. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/predators-prey-and-moonlight-singing-how-phases-of-the-moon-affect-native-wildlife-140556">Predators, prey and moonlight singing: how phases of the Moon affect native wildlife</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/387604/original/file-20210303-21-weitfv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/387604/original/file-20210303-21-weitfv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/387604/original/file-20210303-21-weitfv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/387604/original/file-20210303-21-weitfv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/387604/original/file-20210303-21-weitfv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/387604/original/file-20210303-21-weitfv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/387604/original/file-20210303-21-weitfv.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">A predator monitoring tunnel at a study site. The scientists replicated their results the following year.</span>
</figcaption>
</figure>
<h2>Using fake news for good, not evil</h2>
<p>Our modelling predicts this fake news tactic would increase plover populations by about 75% over 25 years. By comparison, an absence of intervention would lead to a population decline of more than 40%.</p>
<p>Our results show the profound conservation potential of fake news tactics. The approach cost no more than a traditional lethal control program and delivered comparable benefits. </p>
<p>We hope the work will encourage others to consider manipulating the behaviour of introduced predators when lethal control options are too difficult or ineffective.</p><img src="https://counter.theconversation.com/content/152320/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Banks receives funding from the Australian Research Council and the New Zealand Ministry of Business Innovation</span></em></p><p class="fine-print"><em><span>Catherine Price receives funding from the Australian Research Council. </span></em></p>When scientists first thought to deceive predators with bird smells, the idea seemed crazy. But after seeing how fake news messes with the minds of both humans and animals, it now makes sense.Peter Banks, Professor of Conservation Biology, School of Life and Environmental Sciences, University of SydneyCatherine Price, Postdoctoral Researcher in Conservation Biology, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1464072020-09-20T19:42:37Z2020-09-20T19:42:37ZIf there is life on Venus, how could it have got there? Origin of life experts explain<figure><img src="https://images.theconversation.com/files/358781/original/file-20200918-18-1xkxztj.jpg?ixlib=rb-1.1.0&rect=71%2C35%2C5919%2C3458&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>The <a href="https://theconversation.com/life-on-venus-traces-of-phosphine-may-be-a-sign-of-biological-activity-146093">recent discovery of phosphine</a> in the atmosphere of Venus is exciting, as it may serve as a potential sign of life (among other possible explanations). </p>
<p>The researchers, who <a href="https://www.nature.com/articles/s41550-020-1174-4">published their findings in Nature Astronomy</a>, couldn’t really explain how the phosphine got there. </p>
<p>They explored all conceivable possibilities, including lightning, volcanoes and even delivery by meteorites. But each source they modelled couldn’t produce the amount of phosphine detected.</p>
<p>Most phosphine in Earth’s atmosphere is produced by living microbes. So the possibility of life on Venus producing phosphine can’t be ignored. </p>
<p>But the researchers, led by UK astronomer Jane Greaves, say their discovery “is not robust evidence for life” on Venus. Rather, it’s evidence of “anomalous and unexplained chemistry”, of which biological processes are just one possible origin.</p>
<p>If life were to exist on Venus, how could it have come about? Exploring the origins of life on Earth might shed some light.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/life-on-venus-traces-of-phosphine-may-be-a-sign-of-biological-activity-146093">Life on Venus? Traces of phosphine may be a sign of biological activity</a>
</strong>
</em>
</p>
<hr>
<h2>The ingredients for life (as we know it)</h2>
<p>Understanding how life formed on Earth not only helps us understand our own origins, but could also provide insight into the key ingredients needed for life, as we know it, to form. </p>
<p>The details around the origins of life on Earth are still shrouded in mystery, with <a href="https://www.scientificamerican.com/article/lifes-origins-by-land-or-sea-debate-gets-hot/">multiple competing scientific theories</a>. But most theories include a common set of environmental conditions considered vital for life. These are: </p>
<p><strong>Liquid water</strong></p>
<p>Water is needed to dissolve the molecules needed for life, to facilitate their chemical reactions. Although other solvents (such as methane) have been suggested to potentially support life, water is most likely. This is because it <a href="http://sitn.hms.harvard.edu/uncategorized/2019/biological-roles-of-water-why-is-water-necessary-for-life/">can dissolve a huge range of different molecules</a> and is found throughout the universe.</p>
<p><strong>Mild temperatures</strong> </p>
<p>Temperatures higher than 122°C destroy most complex organic molecules. This would make it almost impossible for carbon-based life to form in very hot environment. </p>
<p><strong>A process to concentrate molecules</strong> </p>
<p>As the origin of life would have required a large amount of organic molecules, a process to concentrate organics from the diluted surrounding environment would be required – either through absorption onto mineral surfaces, evaporation or floating on top of water in oily slicks. </p>
<p><strong>A complex natural environment</strong></p>
<p>For life to have originated, there would have had to be a complex natural environment wherein a diverse range of conditions (temperature, pH and salt concentrations) could create chemical complexity. Life itself is incredibly complex, so even the most primitive versions would need a complex environment to originate.</p>
<p><strong>Trace metals</strong></p>
<p>A range of trace metals, amassed through water-rock interactions, would be needed to promote the formation of organic molecules.</p>
<p>So if these are the conditions required for life, what does that tell us about the likelihood of life forming on Venus? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/358787/original/file-20200918-14-6vka30.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of Venus" src="https://images.theconversation.com/files/358787/original/file-20200918-14-6vka30.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/358787/original/file-20200918-14-6vka30.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=615&fit=crop&dpr=1 600w, https://images.theconversation.com/files/358787/original/file-20200918-14-6vka30.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=615&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/358787/original/file-20200918-14-6vka30.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=615&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/358787/original/file-20200918-14-6vka30.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=773&fit=crop&dpr=1 754w, https://images.theconversation.com/files/358787/original/file-20200918-14-6vka30.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=773&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/358787/original/file-20200918-14-6vka30.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=773&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Venus has 90 times the atmospheric pressure of Earth.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<h2>It’s unlikely today …</h2>
<p>The possibility of life as we know it forming on the surface of present-day Venus is incredibly low. An average surface temperature above 400°C means the surface can’t possibly have liquid water and this heat would also destroy most organic molecules. </p>
<p>Venus’s milder upper atmosphere, however, has temperatures low enough for water droplets to form and thus could potentially be suitable for the formation of life. </p>
<p>That said, this environment has its own limitations, such as clouds of sulfuric acid which would destroy any organic molecules not protected by a cell. For example, on Earth, molecules such as DNA are rapidly destroyed by acidic conditions, although some <a href="https://sciencing.com/types-bacteria-living-acidic-ph-9296.html">bacteria can survive</a> in extremely acidic environments.</p>
<p>Also, the constant falling of water droplets from Venus’s atmosphere down to its extremely hot surface would destroy any unprotected organic molecules in the droplets. </p>
<p>Beyond this, with no surfaces or mineral grains in the Venusian atmosphere on which organic molecules could concentrate, any chemical building blocks for life would be scattered through a diluted atmosphere – making it incredibly difficult for life to form. </p>
<h2>… but possibly less unlikely in the past</h2>
<p>Bearing all this in mind, if atmospheric phosphine is indeed a sign of life on Venus, there are three main explanations for how it could have formed. </p>
<p>Life may have formed on the planet’s surface when its conditions were very different to now. </p>
<p>Modelling suggests the surface of early Venus was very similar to early Earth, with lakes (or even oceans) of water and <a href="https://www.nasa.gov/feature/goddard/2016/nasa-climate-modeling-suggests-venus-may-have-been-habitable">mild conditions</a>. This was before a runaway greenhouse effect turned the planet into the hellscape it is today.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/358782/original/file-20200918-16-1s8z2gp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Computer generated surface view of Eistla Regio region on Venus." src="https://images.theconversation.com/files/358782/original/file-20200918-16-1s8z2gp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/358782/original/file-20200918-16-1s8z2gp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/358782/original/file-20200918-16-1s8z2gp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/358782/original/file-20200918-16-1s8z2gp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/358782/original/file-20200918-16-1s8z2gp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=587&fit=crop&dpr=1 754w, https://images.theconversation.com/files/358782/original/file-20200918-16-1s8z2gp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=587&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/358782/original/file-20200918-16-1s8z2gp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=587&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This is a computer-generated picture of the Eistla Regio region on Venus’s surface.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<p>If life formed back then, it might have adapted to spread into the clouds. Then, when intense climate change boiled the oceans away – killing all surface-based life – microbes in the clouds would have become the last outpost for life on Venus.</p>
<p>Another possibility is that life in Venus’s atmosphere (if there is any) came from Earth. </p>
<p>The planets of our inner solar system have been documented to exchange materials in the past. When meteorites crash into a planet, they can send that planet’s rocks hurtling into space where they occasionally intersect with the orbits of other planets.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meteorites-from-mars-contain-clues-about-the-red-planets-geology-130104">Meteorites from Mars contain clues about the red planet's geology</a>
</strong>
</em>
</p>
<hr>
<p>If this happened between Earth and Venus at some point, the rocks from Earth may have contained microbial life that could have adapted to Venus’s highly acidic clouds (similar to Earth’s acid-resistant bacteria).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/358784/original/file-20200918-16-7blw0k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Rendered image of meteorite hitting Earth." src="https://images.theconversation.com/files/358784/original/file-20200918-16-7blw0k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/358784/original/file-20200918-16-7blw0k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/358784/original/file-20200918-16-7blw0k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/358784/original/file-20200918-16-7blw0k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/358784/original/file-20200918-16-7blw0k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=483&fit=crop&dpr=1 754w, https://images.theconversation.com/files/358784/original/file-20200918-16-7blw0k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=483&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/358784/original/file-20200918-16-7blw0k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=483&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">If rocks from Earth containing microbial life entered Venus’s orbit in the past, this life may have adapted to Venus’s atmospheric conditions.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>A truly alien explanation</h2>
<p>The third explanation to consider is that a truly alien form of life (life as we <em>don’t</em> know it) could have formed on Venus’s 400°C surface and survives there to this day. </p>
<p>Such a foreign life probably wouldn’t be carbon-based, as nearly all complex carbon molecules break down at extreme temperatures. </p>
<p>Although carbon-based life produces phosphine on Earth, it’s impossible to say <em>only</em> carbon-based life can produce phosphine. Therefore, even if totally alien life exists on Venus, it may produce molecules that are still recognisable as a potential sign of life. </p>
<p>It’s only through further missions and research that we can find out whether there is, or was, life on Venus. As prominent scientist Carl Sagan <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3114207/#:%7E:text=non%2Dlocal%20perception-,Introduction,et%20al.%2C%201999">once said</a>: “extraordinary claims require extraordinary evidence”. </p>
<p>Luckily, two of the <a href="https://www.nasa.gov/press-release/nasa-selects-four-possible-missions-to-study-the-secrets-of-the-solar-system">four finalist proposals</a> for NASA’s next round of funding for planetary exploration are focused on Venus.</p>
<p>These include VERITAS, an orbiter proposed to map the surface of Venus, and DAVINCI+, proposed to drop through the planet’s skies and sample different atmospheric layers on the way down.</p><img src="https://counter.theconversation.com/content/146407/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Steller receives funding from a Research Training Program scholarship provided by the Australian government. </span></em></p><p class="fine-print"><em><span>Martin Van Kranendonk receives funding from the Australian Research Council and BHP. </span></em></p>Considering what we know about the key ingredients for life’s formation on Earth, here are three explanations for how this process may have occurred on our sister planet.Luke Steller, PhD Student, UNSW SydneyMartin Van Kranendonk, Professor and Head of School, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1188582019-07-14T10:51:34Z2019-07-14T10:51:34ZKenya faces devastating Prosopis invasion: What can be done<figure><img src="https://images.theconversation.com/files/279662/original/file-20190616-158917-12ogmwk.jpg?ixlib=rb-1.1.0&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>Woody plant species <a href="https://academic.oup.com/bioscience/article/49/8/619/254611">have been deliberately introduced</a> into many arid and semi-arid regions across the world as they can help combat desertification and provide resources - like fuelwood - to the rural poor. But some of these <a href="https://academic.oup.com/bioscience/article/49/8/619/254611">alien trees and shrubs</a> have become invasive, having devastating effects on other species as well as people.</p>
<p>This is big problem in the mainly arid Baringo County, in Kenya’s Rift valley as well as other counties north, east and south of the country.</p>
<p>The guilty party is <a href="https://www.researchgate.net/publication/262884950_Prosopis_A_global_assessment_of_the_biogeography_benefits_impacts_and_management_of_one_of_the_world's_worst_woody_invasive_plant_taxa"><em>Prosopis</em></a>, also known as Mesquite or “Mathenge” (Kenya) or “Promi” (Baringo). It is a thorny shrub or small tree native to Mexico, other South American countries and the Caribbean. <a href="https://www.cabi.org/news-and-media/2019/scientists-recommend-measures-to-contain-rapid-woody-weed-spread-in-baringo-county-kenya/">It was introduced</a> in Baringo in the 1980s as part of a project to prevent desertification and provide firewood and livestock fodder for local communities. It is deep-rooted, multi-stemmed and produces numerous highly nutritious pods with strongly embedded seeds. </p>
<p>The species is currently naturalised in parts of East Africa, South Africa, Asia and Australia. It provides wood, shade and helps to control soil erosion in degraded areas. Its fruit <a href="https://academic.oup.com/bioscience/article/49/8/619/254611">is used</a> mainly as livestock fodder and occasionally for food. </p>
<p><em>Prosopis</em> has no natural enemies in East Africa, such as herbivorous insects and plant pathogens. It has spread rapidly from the original plantations and invaded the surrounding natural grasslands, shrublands, and croplands. </p>
<p>The shrub is particularly difficult to manage because it bears fruit prolifically. Seeds germinate and grow very fast when in contact with moisture. This causes high densities of invasion that easily outcompete other species. When cut, its stems regrow rapidly. Today, the plant is regarded as one of the <a href="http://www.issg.org/pdf/publications/worst_100/english_100_worst.pdf">world’s 100 worst</a> invasive alien species.</p>
<p>We set out <a href="https://www.mdpi.com/2072-4292/11/10/1217/htm">to assess</a> what impact it has had in Baringo County since its introduction. We analysed land-use and land-cover changes and dynamics using a combination of dry and wet season satellite data acquired between 1988 and 2016. We then quantified the changes that took place by calculating the extent of <em>Prosopis</em> invasion, rates of spread, gains and losses of different vegetation. And the importance of <em>Prosopis</em> in these changes.</p>
<p>The study established that the rate of invasion is a major threat to the environment and rural people’s livelihoods because it suppresses or replaces native biodiversity and alters ecosystem functions and services. In particular, it severely limits livestock production, increases costs of crop production, and depletes the groundwater table, thereby causing significant economic damage.</p>
<h2>What we found</h2>
<p>We <a href="https://www.mdpi.com/2072-4292/11/10/1217/htm">found</a> that the shrub expanded from 882 hectares in 1988 to 18 792 hectares in 2016. During the same period grasslands declined by 86% irrigated cropland by 57%, and rainfed cropland by 37%. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/pVNL1HWf7RQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The spread of Prosopis in Kenya.</span></figcaption>
</figure>
<p>We concluded that the <em>Prosopis</em> invasion was the cause of over 30% of these negative changes and the biggest driving force behind shrinking grasslands and croplands in the region. Besides the invasion, human activities such as deforestation, land clearing, and overgrazing, as well as changes in the weather were also likely to have contributed to the changes.</p>
<p>By 2005, <em>Prosopis</em> invasion in Baringo had intensified. Pastoralists perceived it as the main cause of dwindling grazing lands. This prompted <a href="http://kenyalaw.org/caselaw/cases/view/51663">a legal suit</a> between the affected pastoral community and the Kenyan government. </p>
<p>In response, the government began a programme to train affected communities on <em>Prosopis</em> management, through an approach famously known as “Management by Utilisation”. This involved encouraging communities to harvest the trees and produce charcoal, poles and other commercial products as a source of income. At the same time they were encouraged to reseed the reclaimed areas with grass species to sustain livestock. </p>
<p>This practice is now widely used and could partly explain the fact that there was an increase in grassland cover in the area between 2009 and 2016.</p>
<p>But our results show that management by utilisation approach in Baringo has not been effective in stopping or slowing the spread of the plant. This is because most households don’t completely remove its stumps because it’s tedious and costly. The result is that the plant simply regrows. </p>
<h2>What next</h2>
<p>Australia uses a combination of techniques to control <em>Prosopis</em>. These include physical, chemical and biological control. It also includes follow-up control work, which is essential to avoid recolonisation. </p>
<p>A key lesson learned in Australia is that management activities across privately and communally managed land and across administrative units should be organised and supervised by commissioned coordinators.</p>
<p>Likewise, sustainable and effective <em>Prosopis</em> management in Kenya and neighbouring countries – such as Tanzania, Somalia, Ethiopia and Sudan – can only be achieved by combining different practices. This should include:</p>
<ul>
<li><p>physical and chemical control to kill stems and rootstocks;</p></li>
<li><p>introducing quarantine measures for livestock, where animals are kept a few days to empty their digestive system before moving them from an invaded to an uninvaded area;</p></li>
<li><p>introducing natural enemies, and; </p></li>
<li><p>using biological control agents that feed only on the target species to reduce seed production.</p></li>
</ul>
<p>Experience shows that early detection and rapid response are crucial. This entails a regular inspection of areas at risk of invasion and the targeted removal of small invading populations at the invasion front. It requires the development, together with scientists and practitioners, of a national strategic plan that provides guidance on best practices for weed management.</p>
<p>Kenya is in the process of developing such a plan. It aims to coordinate efforts across various jurisdictions and affected stakeholders, including national and local government, communities, community based organisations, non-governmental organisations and other environmental agencies, as well as by the private sector and landholders.</p>
<p><em>Additional contributors: Urs Schaffner; Simon Choge; Albrecht Ehrensperger; Sandra Eckert.</em></p><img src="https://counter.theconversation.com/content/118858/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Purity Rima Mbaabu works at Chuka University, Kenya. She receives funding from CABI Switzerland, under the Project “Woody invasive alien species in East Africa: Assessing and mitigating their negative impact on ecosystem services and rural livelihood” (<a href="http://www.woodyweeds.org">www.woodyweeds.org</a>). The project is funded by the Swiss National Science Foundation (SNSF) and the Swiss Agency for Development and Cooperation (SDC) as part of the Swiss Programme for Research on Global Issues for Development (r4d), for the project Grant Number: 400440_152085. She is affiliated with Kenya Forestry Research Institute (KEFRI), Institute for Climate Change and Adaptation (ICCA) - University of Nairobi, Kenya and Faculty of Humanities and Social Sciences - Chuka University, Kenya. </span></em></p>The rapid invasion is a major threat to the environment and rural people’s livelihoods.Purity Rima Mbaabu, PhD candidate, University of NairobiLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1027232018-09-13T07:38:05Z2018-09-13T07:38:05ZThe Predator: you’re gonna need a bigger rope to tie down this alien hunter<figure><img src="https://images.theconversation.com/files/235166/original/file-20180906-190662-1rxqhj8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A prettier predator we have not seen.</span> <span class="attribution"><span class="source">20th Century Fox / Davis Entertainment</span></span></figcaption></figure><p><a href="https://www.imdb.com/title/tt3829266/">The Predator</a> blasts into cinemas today. While newcomers will enjoy the ride, there are some sly references for those lifelong fans who have watched all the way back to 1987’s original <a href="https://www.imdb.com/title/tt0093773/">Predator</a> film, and the sequel and crossover films since then.</p>
<p>This is a modern-day Predator film, shiny and slick and updated – with even the mention of climate change as a plot point.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/50_Ala5BKBo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">I’m glad there’s a chopper to get to in this film.</span></figcaption>
</figure>
<p>But how does the science of new evolved predators stack up? Some spoilers and slightly macabre calculations follow.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-meg-when-the-giant-prehistoric-shark-bites-the-science-bites-back-101105">The Meg! When the (giant prehistoric) shark bites, the science bites back</a>
</strong>
</em>
</p>
<hr>
<h2>Invisibility cloaking</h2>
<p>We see some interesting details on the invisibility cloaking technology of the predators. </p>
<p>Their ship appears to have an external physical field that wraps around the outside of its normal exterior. Personal cloaks appear to vary from being completely invisible to slightly visible, shimmering transparent patterns in the air.</p>
<figure>
<img src="https://cdn.theconversation.com/static_files/files/279/gif2.gif?1536756455" width="100%">
<figcaption>
<span class="caption">Now you see him, now you don’t.</span>
<span class="attribution"><span class="source">20th Century Fox / Davis Entertainment.
</span></span>
</figcaption>
</figure>
<p>While some progress has been made, most current invisibility experiments have only worked on <a href="https://theconversation.com/ten-years-on-invisibility-cloaks-are-close-to-becoming-a-manufacturable-reality-47663">tiny micrometre-scale objects</a>, and only for certain wavelengths. </p>
<p>For larger objects, most techniques <a href="https://www.nature.com/articles/ncomms1176">reflect incident light back</a>, which obscures the object but doesn’t show the viewer what is behind it – unlike in the movie. </p>
<p><a href="https://www.youtube.com/watch?v=6GNGfse9ZK8&feature=youtu.be">“See-through” trucks</a> are currently being developed that use forward-looking cameras and rear displays to show cars what’s in front.</p>
<p>The main challenge with achieving invisibility using this technique is multiple viewers, which was nicely highlighted in the film <a href="https://www.youtube.com/watch?v=ydIPKkjBlMw">Mission Impossible: Ghost Protocol</a>. While it’s possible to simulate the background behind the invisible person for one viewer, it becomes progressively more complex to simultaneously simulate multiple backgrounds for multiple viewers at different locations.</p>
<p>One piece of current human technology suggests a possible solution: new OLED TV monitors with <a href="https://www.smithsonianmag.com/innovation/people-can-now-simultaneously-watch-different-shows-on-the-same-tv-180947762/">extremely fast refresh rates</a>. Multiple viewers wearing 3D glasses can watch different shows at the same time on the same TV. Perhaps some future technology will enable this effect without the need for glasses.</p>
<p><strong>Verdict:</strong> Some slight stretching of science.</p>
<h2>Will someone please tie up that monster properly</h2>
<p>People doing a shoddy job of restraining monsters is one of the most frequently used “stupidity drives the plot” elements of movies. This movie is no different, with a supposedly sedated (because these brilliant scientists know the exact dose for the animal, of course) predator held down by some dubiously thin restraints.</p>
<figure>
<img src="https://cdn.theconversation.com/static_files/files/277/gif1.gif?1536753130" width="100%">
<figcaption>
<span class="caption">Pred is not a happy hotel guest.</span>
<span class="attribution"><span class="source">20th Century Fox / Davis Entertainment.
</span></span>
</figcaption>
</figure>
<p>The wire rope appear to have a diameter of about 6mm, <a href="https://www.engineeringtoolbox.com/wire-rope-strength-d_1518.html">suggesting a breaking strength</a> of about 24.4kN, equivalent to a load of about 2,500kg.</p>
<p>But the “safe load” given for that diameter is only 4.89kN (498kg static load), to allow for factors like dynamic loading: something the escaping predator would definitely be applying.</p>
<p>Given that the predator is shown to be able to smash deep dents in solid steel tables and squash cars, it seems unlikely that this cabling (even allowing for the three cables in some places) provides a sufficient safety margin for restraining an angry predator.</p>
<p><strong>Verdict:</strong> Shoddy subduing.</p>
<h2>Depictions of autism and memory</h2>
<p>The son of the main character is presented as being on the <a href="https://theconversation.com/memory-and-sense-of-self-may-play-more-of-a-role-in-autism-than-we-thought-63210">autism spectrum</a>. In one character-establishing scene, he correctly sets the pieces back on at least six in-progress chess games from memory after two bullies sweep the pieces onto the floor.</p>
<p>Top chess players have reported they can <a href="http://www.chesshistory.com/winter/extra/memory.html">remember thousands of games</a>. So it’s plausible that a good chess player could remember the configuration of six boards: it’s implied that he is a good player by his watching of other games.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/236002/original/file-20180912-133892-1ira2u1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/236002/original/file-20180912-133892-1ira2u1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/236002/original/file-20180912-133892-1ira2u1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=346&fit=crop&dpr=1 600w, https://images.theconversation.com/files/236002/original/file-20180912-133892-1ira2u1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=346&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/236002/original/file-20180912-133892-1ira2u1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=346&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/236002/original/file-20180912-133892-1ira2u1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=435&fit=crop&dpr=1 754w, https://images.theconversation.com/files/236002/original/file-20180912-133892-1ira2u1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=435&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/236002/original/file-20180912-133892-1ira2u1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=435&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Are the memory feats demonstrated by young Rory McKenna possible?</span>
<span class="attribution"><span class="source">20th Century Fox / Davis Entertainment</span></span>
</figcaption>
</figure>
<p>Special interests are also a <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/aur.1931">key characteristic of autism</a>. It’s plausible that he has developed a special interest in chess (it’s portrayed that he’s part of a chess club), and that level of attention has resulted in him being able to reconstruct the board configurations.</p>
<p><strong>Verdict:</strong> Care is needed with condition characterisations.</p>
<h2>Spoiler alert! I got you, you got me</h2>
<p>In the climactic final battle, two mortally injured best buddy soldiers decide to go out on their own terms and shoot each other simultaneously from a range of about ten metres.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/236008/original/file-20180912-133898-9g9lz8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/236008/original/file-20180912-133898-9g9lz8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/236008/original/file-20180912-133898-9g9lz8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/236008/original/file-20180912-133898-9g9lz8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/236008/original/file-20180912-133898-9g9lz8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/236008/original/file-20180912-133898-9g9lz8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/236008/original/file-20180912-133898-9g9lz8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/236008/original/file-20180912-133898-9g9lz8.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">At its heart The Predator is part buddy flick.</span>
<span class="attribution"><span class="source">20th Century Fox / Davis Entertainment</span></span>
</figcaption>
</figure>
<p>On first impressions, this doesn’t seem possible because the minimum human reaction speed is <a href="https://www.iaaf.org/news/news/iaaf-sprint-start-research-project-is-the-100">no better than 100 miliseconds</a>, during which time a handgun bullet travelling at a speed of around <a href="http://www.gunnersden.com/index.htm.handgun-ballistics.html">300 metres per second</a> would move 30 metres, more than the distance between them (much faster than the <a href="https://theconversation.com/why-blasters-miss-their-mark-and-other-science-stunners-in-solo-a-star-wars-story-96631">blasters in Star Wars</a>)</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/when-ai-meets-your-shopping-experience-it-knows-what-you-buy-and-what-you-ought-to-buy-101737">When AI meets your shopping experience it knows what you buy – and what you ought to buy</a>
</strong>
</em>
</p>
<hr>
<p>But this act of bravado is co-ordinated: one buddy isn’t waiting for the other but rather they pull the triggers at the same time. If cued off a shared wink, head nod or other visual cue, they would only need to get the delay after that consistent, still difficult but not impossible.</p>
<p><strong>Verdict:</strong> Tricky timing but possible.</p>
<h2>The verdict</h2>
<p>The Predator is surprisingly fun. It has its ups and downs but there’s some great humour and an entertaining cast that on the whole works well together. </p>
<p>Most of the science – if you allow the overall premise of a super alien species that trawls the galaxy for hunting challenges – holds up reasonably well, with a few exceptions that I think we can allow for the purpose of plot progression.</p>
<p>Most importantly, in a nod to the <a href="https://www.youtube.com/watch?v=-9-Te-DPbSE">1987 film</a>, it’s good to see the characters don’t forget to <a href="https://www.imdb.com/title/tt0093773/quotes/qt0490135">get to the chopper</a>.</p>
<hr>
<p><em>Dr Kate Sofronoff, Associate Professor in the School of Psychology at the University of Queensland, was consulted for advice on autism as part of this article.</em></p><img src="https://counter.theconversation.com/content/102723/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Professor Michael Milford is a Chief Investigator at the Australian Centre for Robotic Vision, an Australian Research Council Future Fellow, Microsoft Research Faculty Fellow and Founding Director of the education startup Math Thrills Pty Ltd. He receives funding from the Australian Research Council, the Queensland Government, Caterpillar Corporation, Mining3, Microsoft, the Asian Office of Aerospace Research and Development and AMP. He has board director and advisory roles at Motor Trades Association of Queensland and Queensland AI.</span></em></p><p class="fine-print"><em><span>Peter Stratton receives funding from the Queensland Brain Institute, the Asia-Pacific Centre for Neuromodulation and the Massachusetts Institute of Technology. He is affiliated with the American Association for the Advancement of Science (AAAS).
</span></em></p>Scientists and soldiers deal with alien invaders in the new Predator movie, but how does the science stack up? With brains and brawn you’d think they’d know how to keep an alien tied down to a table.Michael Milford, Professor, Queensland University of TechnologyPeter Stratton, Postdoctoral Research Fellow, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/794442017-06-22T13:20:06Z2017-06-22T13:20:06ZInvasive species have a massive impact, but wise policy can keep them out<figure><img src="https://images.theconversation.com/files/174706/original/file-20170620-30812-1yhyxff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The American red swamp crayfish was intentionally introduced to parts of Africa to control snails and as a pet.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><em>This article is the second in a <a href="https://theconversation.com/topics/invasive-species-africa-40566">series</a> The Conversation Africa is running on invasive species</em></p>
<p>Invasive alien species harm ecosystems, economies and human health across the globe. In Africa, alien trees <a href="http://www.sciencedirect.com/science/article/pii/S0921800907006167">reduce water yield</a> in regions that are severely water stressed. Fishes introduced for aquaculture <a href="http://www.nationalgeographic.org/media/impact-invasive-species/">reduce native biodiversity</a> and alien whiteflies spread <a href="http://www.apsnet.org/publications/apsnetfeatures/Pages/cassava.aspx">diseases in cassava</a> that can lead to famine.</p>
<p>Many of these species were introduced intentionally for use as pets, crops, livestock, garden plants or for forestry. Overall trade between countries has greatly improved human welfare by giving access to useful species. In Africa, these intentionally introduced species include the food staples cassava and maize, which are both native to the Americas.</p>
<p>But the continent has learned the hard way. A subset of imported species have become invasive, and by the time they become established in the wild it’s almost always too late to eradicate them. </p>
<p>More species than ever are being moved intentionally around the world as the pace of trade between countries continues to grow. Most countries still operate with what is essentially an open door policy, allowing in any species that commercial interests want to import.</p>
<p>But there is a better way. Invasive alien species are different from alien species that don’t cause harm. Scientists have the techniques and the know how to track these differences and to predict which species are likely to become invasive in the future. This makes it possible to decide wisely which species are safe to import. The impact of invasive species can be massively reduced if policies are developed based on these insights.</p>
<p>Developing these policies would be financially and environmentally beneficial for all countries. But there are significant challenges to implementation, particularly in developing countries, where resources for assessing species and then monitoring borders are scarce. These challenges could be overcome by sharing the results of assessments on species among countries, and through cooperation between importing and exporting nations to prevent the transport of harmful ones.</p>
<h2>A basic biology</h2>
<p>It’s possible to predict the behaviour of species by looking at their basic biology, how they interact with the environment, and how they spread. Using basic analysis, it’s possible to predict which invasive species will be bad, and which benign.</p>
<p>Not all are bad. Take the mollusc populations of the US Great Lakes which is home to a number of alien snails and mussels. But only a few are harmful – like the notorious zebra mussel which causes hundreds of millions in damage by clogging pipes and has fundamentally rearranged the Great Lakes ecosystems.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?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>
<figcaption>
<span class="caption">Zebra mussels, an invasive species of fresh water mussels, on the propeller and shaft of a
sailing yacht.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This and other harmful non-native molluscs in the Great Lakes are characterised by having <a href="https://www.researchgate.net/profile/David_Lodge4/publication/6505938_Fecundity_as_a_Basis_for_Risk_Assessment_of_Nonindigenous_Freshwater_Molluscs/links/53dab7350cf2631430cb10a8.pdf">much higher production of offspring</a> than their harmless counterparts. </p>
<p>And in South Africa, <a href="https://www.researchgate.net/profile/Richard_Cowling/publication/227677415_Assessing_the_risk_of_invasive_success_in_Pinus_and_Banksia_in_South_African_mountain_fynbos/links/56fd3ec708ae3c85c0c9bf8e.pdf">invasive pine trees</a> mature faster and produce small seeds that can be blown long distances to colonise new habitats. These harmful pines are out competing native species in some habitats, while species without these characteristics rarely spread from where they’re planted.</p>
<p>Alien species with a history of being harmful in one area are likely to <a href="https://www.researchgate.net/profile/Keith_Hayes2/publication/225567176_Are_there_any_consistent_predictors_of_invasion_success_Biol_Inv/links/00b49532d0d139e018000000.pdf">cause harm in another</a>. </p>
<p>Transferring this scientific knowledge to policy helps to make predictions about how imported species are likely to act in the future. Risk assessment tools have been developed to do this. Some countries -– notably <a href="http://www.environment.gov.au/biodiversity/wildlife-trade/live">Australia</a> and <a href="https://www.mpi.govt.nz/law-and-policy/legal-overviews/biosecurity/">New Zealand</a> -– have been implementing these for over a decade. They ban all species that have the characteristics of invaders, including most reptiles. </p>
<p>Many others, including the US, European Union, and South Africa, are moving in this direction. But progress is slow and there is opposition from companies concerned about regulations that restrict what they can buy and sell.</p>
<h2>Policy is crucial for developing nations</h2>
<p>Progress has been made in managing the import of species in developed countries, but there’s been less in developing nations. Poorer countries face big challenges in, for example, developing policies and monitoring borders. </p>
<p>But developing nations have the most to gain from keeping invasive species out because invaders have a big impact on agricultural production and fisheries that make up a large portion of their economies. For example, the American <a href="http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-64972015000100002">red swamp crayfish</a> was intentionally introduced to Africa to control snails and as a pet. But it soon escaped into the wild where it reduces harvests of aquatic plants and fishes, and can even destabilise dam walls with its burrowing. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=896&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=896&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=896&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1126&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1126&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1126&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 red swamp crayfish escaped into the wild where it can reduce harvests of aquatic plants and fishes.</span>
<span class="attribution"><span class="source">Reuben Keller</span></span>
</figcaption>
</figure>
<p>There are ways round the problem. Developing nations can use simpler methods to determine which species are likely to become invasive. The US <a href="https://www.fws.gov">Fish and Wildlife Service</a> has developed a useful approach to <a href="https://www.fws.gov/injuriouswildlife/pdf_files/ERSS-SOP-Final-Version.pdf">risk assessment</a> that relies primarily on determining whether a species is suited to climates in the new region, and whether it has become invasive elsewhere. The assessment can be adapted for any region, applied to any plant or animal, and has reasonable accuracy. </p>
<p>Another way to reduce the cost is for countries to share predictions. This would mean that the burden of assessing species was spread out. </p>
<p>And better coordination between exporting and importing countries could help improve border controls and ensure compliance. </p>
<p>Policies that predict which species are likely to become invasive and then keep them out would have huge environmental and economic <a href="http://onlinelibrary.wiley.com/doi/10.1111/conl.12071/full">benefits</a>. South Africa is <a href="http://www.abcjournal.org/index.php/ABC/article/view/2136/0">developing regulations</a>. It should consider using one of the risk assessment approaches that have already been shown to be effective. </p>
<p>Other countries in sub-Saharan Africa need to take action too. Acting together, countries will be able to keep out the next invaders, protect biodiversity, reduce future financial costs, and lessen future losses of vital ecosystem services.</p><img src="https://counter.theconversation.com/content/79444/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Reuben P. Keller receives funding from United States Environmental Protection Agency.</span></em></p><p class="fine-print"><em><span>Sabrina Kumschick receives funding from the South African National Department of Environment Affairs through its funding of the South African National Biodiversity Institute’s Invasive Species Programme and from the DST-NRF Centre of Excellence for Invasion Biology. </span></em></p>Developing countries have been slow to react to the alien species problem. Its impact can be massively reduced if policies are developed to deal with the issue.Reuben P. Keller, Assistant Professor Freshwater Ecology, Invasive Species, Bioeconomics, Loyola University ChicagoSabrina Kumschick, Researcher and core team member Centre for Invasion Biology, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/786842017-06-14T15:26:34Z2017-06-14T15:26:34ZAlien animals and plants are on the rise in Africa, exacting a growing toll<figure><img src="https://images.theconversation.com/files/173342/original/file-20170612-10193-b97g43.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The larger grain borer beetle attacks crops like maize and cassava, threatening food security.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><em>This article is the first in a series The Conversation Africa is running on invasive species.</em></p>
<p>Let’s say you’re travelling from Uganda to South Africa for business. You finally arrive at your hotel after a long day and decide to change before dinner. You unlock and unzip your luggage, but there’s something in your bag that you didn’t pack. As you reach for a clean shirt, a moth flies out. Did that come with you all the way from Uganda? It’ll be fine, right? Surely, something so small won’t cause any harm.</p>
<p>Species are intentionally or accidentally transported by humans between continents to regions where they are not native. With the help of humans or by natural means like flight, these alien species can also spread within continents.</p>
<p>Their spread within continents can be rapid, affecting both the ecology as well as societies and the economy. Unfortunately, it’s really challenging to prevent species from spreading. Given the vast amount of people and goods that are transported between and around continents they can easily be moved across oceans as well as between countries.</p>
<p>The spread of alien species within Africa is increasing. Since 2000 more alien insect pests of eucalyptus trees have spread to other African countries from South Africa, than have been introduced to these African countries <a href="http://www.abcjournal.org/index.php/ABC/article/view/2157">from other continents</a>. To manage the spread of these alien species countries need to <a href="http://www.abcjournal.org/index.php/ABC/article/view/2157">co-operate, communicate and share information and skills.</a>. </p>
<h2>The spread of alien species</h2>
<p>Many alien plants and animals have been introduced to Africa from other regions and then have spread from country to country, often having devastating effects.</p>
<p>Take the larger grain borer beetle, (<em>Prostephanus truncatus</em>) which is thought to have arrived on the continent in imported grain from Mexico and central America. The beetle was introduced to Tanzania before 1984, Togo before 1981 and <a href="http://www.abcjournal.org/index.php/ABC/article/view/2157">Guinea before 1987</a>. It then spread across the continent and within 20 years could be found further south in South Africa. </p>
<p>The beetle attacks crops such as maize and cassava, threatening food security and the <a href="http://www.cabi.org/isc/datasheet/44524">livelihoods of the poor</a>. Infestations often destroy maize that’s been stored by farmers, forcing them to buy maize as well as lose income they could have earned from selling any excess.</p>
<p>But alien species don’t just arrive from abroad. Many that are native to parts of Africa have also spread to countries on the continent where they are not native.</p>
<p>An example is the fish commonly known as the Mozambique tilapia (<em>Oreochromis mossambicus</em>) which is native to rivers on the east coast of southern Africa. Fishermen have transported the Mozambique tilapia to other areas and it is now found in river systems in southern and western South Africa and Namibia. </p>
<p>The Mozambique tilapia is a popular species for fishing but it can pose a threat to native <a href="http://www.iucngisd.org/gisd/speciesname/Oreochromis+mossambicus">fish</a> and has been responsible for the disappearance of native species in some <a href="https://www.fws.gov/fisheries/ans/erss/highrisk/Oreochromis-mossambicus-ERSS-revision-July-2015.pdf">regions</a>.</p>
<p>The spread of alien species within Africa is by no means a new thing. For instance, the bur clover (<em>Medicago polymorpha</em>), a plant from northern Africa, might have been accidentally transported by humans to South Africa <a href="http://www.abcjournal.org/index.php/ABC/article/view/2157">as early as 760 AD.</a></p>
<h2>A high and increasing threat</h2>
<p>Recently a number of alien species have spread extremely rapidly across the continent, posing a particularly high threat to food security and livelihoods.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/173341/original/file-20170612-10258-1rjje5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/173341/original/file-20170612-10258-1rjje5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/173341/original/file-20170612-10258-1rjje5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/173341/original/file-20170612-10258-1rjje5i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/173341/original/file-20170612-10258-1rjje5i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/173341/original/file-20170612-10258-1rjje5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/173341/original/file-20170612-10258-1rjje5i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/173341/original/file-20170612-10258-1rjje5i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&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 fall armyworm, native to the Americas, was first recorded in west and central Africa in early 2016 and then in South Africa in January 2017.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>One is a caterpillar known as the fall armyworm (<em>Spodoptera frugiperda</em>). The species, native to the Americas, was first recorded in west and central Africa in early 2016 and then in <a href="http://www.arc.agric.za/arc-ppri/Fact%20Sheets%20Library/The%20new%20Invasive%20Fall%20Armyworm%20(FAW)%20in%20South%20Africa.pdf">South Africa in January 2017</a>. </p>
<p>The moths of the armyworm are strong fliers and the species may have spread through flight to South Africa from other African countries. Although the species attacks a wide range of crops, it poses a particularly serious threat <a href="https://theconversation.com/armyworms-are-wreaking-havoc-in-southern-africa-why-its-a-big-deal-72822">to grain farmers</a>. It is extremely <a href="https://theconversation.com/why-its-hard-to-control-the-fall-armyworm-in-southern-africa-72890">difficult to manage</a>. </p>
<p>Another example is a wasp known as the bluegum chalcid (<em>Leptocybe invasa</em>), which is native to Australia. In 2000 it was <a href="http://www.fabinet.up.ac.za/publication/pdfs/1952-kelly_et_al_selitrichodes_neseri.pdf">detected in Israel</a> and shortly afterwards it was reported in <a href="http://www.forestry.co.za/uploads/File/home/notices/2011/ICFR%20IS01-2011gallwasp.pdf">Uganda and Kenya</a>. From there it spread rapidly to many African countries including Zimbabwe, Mozambique, and Tanzania and was finally detected in <a href="http://www.forestry.co.za/uploads/File/home/notices/2011/ICFR%20IS01-2011gallwasp.pdf">South Africa in 2007.</a> The insect probably reached Israel on live plant material and spread into Africa the same way, or was carried by people travelling between countries. </p>
<p>The wasp causes swelling or growths on eucalyptus trees, which can lead to <a href="http://www.fao.org/forestry/13569-05912e0e2fe9054c3ed4904ae597e3310.pdf">decreased growth and tree death.</a> As eucalyptus trees are an important source of income and fuel, this species could have an impact on the livelihoods of locals in these countries.</p>
<h2>Preventing the introduction and spread</h2>
<p>Once a species is introduced to one African country it’s highly likely it will spread to others on the continent because borders checks are weak.</p>
<p>The introduction and spread of species could be reduced if countries introduced biosecurity systems. These are used extensively in countries like Australia and New Zealand and involve using technology to check for alien species when people and goods enter a country. In Australia this involves inspecting goods, vehicles and luggage before they enter the country.</p>
<p>But even these systems aren’t a guarantee that species won’t spread. African countries would need to work together and share information and skills. This would also allow countries to prepare for the arrival of species, and to draw up plans to reduce their impact.</p>
<p>This is a tall order. But as a country’s defence against alien species introductions is only as strong as that of its neighbours, such action would benefit all of the countries involved.</p><img src="https://counter.theconversation.com/content/78684/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katelyn Faulkner receives funding from South African National Biodiversity Institute's Invasive Species Programme. </span></em></p><p class="fine-print"><em><span>Mark Robertson receives funding from the DST-NRF Centre for Invasion Biology. </span></em></p><p class="fine-print"><em><span>Brett Hurley 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>Many alien plants and animals have been introduced to Africa from other regions and spread from country to country, often having devastating effects.Katelyn Faulkner, Postdoctoral research fellow, University of PretoriaBrett Hurley, Senior Lecturer Zoology and Entomology, University of PretoriaMark Robertson, Associate Professor Zoology & Entomology, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/683442016-11-20T19:04:45Z2016-11-20T19:04:45ZIf we find ET, don’t talk to it, says the man who wants to find ET<figure><img src="https://images.theconversation.com/files/146316/original/image-20161117-13503-1jdue5v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Should we make contact with alien life?</span> <span class="attribution"><span class="source">Shutterstock/adike</span></span></figcaption></figure><p>The question of whether there is <a href="https://theconversation.com/the-search-for-et-has-been-going-on-for-years-so-what-do-we-know-so-far-44966">intelligent life elsewhere in the universe</a> has been asked by people for many years.</p>
<p>But if we hear something, should we answer? In the absence of any signal from them, should we try to make our presence known?</p>
<p>One of those asking these questions is Stephen Hawking, the British cosmologist with many deep thoughts and a good sense of humour. </p>
<p>Unlike many celebrity scientists, Hawking’s provocative, news-grabbing statements almost always have some content worth pondering.</p>
<h2>Looking for ET</h2>
<p>Hawking is part of a <a href="http://breakthroughinitiatives.org/Initiative/1">Breakthrough Listen</a> project to develop more sensitive radio receivers and listen in on the alien civilisations of the cosmos.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/146321/original/image-20161117-13367-acgoi4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/146321/original/image-20161117-13367-acgoi4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/146321/original/image-20161117-13367-acgoi4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/146321/original/image-20161117-13367-acgoi4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/146321/original/image-20161117-13367-acgoi4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/146321/original/image-20161117-13367-acgoi4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/146321/original/image-20161117-13367-acgoi4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/146321/original/image-20161117-13367-acgoi4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Stephen Hawking.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/lwpkommunikacio/16227395801/https://www.flickr.com/photos/lwpkommunikacio/16227395801/">Flickr/Lwp Kommunika</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>There is another project called <a href="http://breakthroughinitiatives.org/Initiative/2">Breakthrough Message</a> to design a digital message that could be transmitted from Earth to an extraterrestrial civilisation. The message should be “representative of humanity and planet Earth”.</p>
<p>The program pledges:</p>
<blockquote>
<p>[…] not to transmit any message until there has been a global debate at high levels of science and politics on the risks and rewards of contacting advanced civilisations.</p>
</blockquote>
<p>But Hawking wants us <a href="https://www.theguardian.com/science/2016/sep/23/stephen-hawking-warns-against-seeking-out-aliens-in-new-film">to listen, and not to talk</a> – use our ears, not our mouth. He wants us to eavesdrop but not join the conversation. He wants us to keep our head low.</p>
<p>That sounds like a reasonable idea. Better safe than sorry. But in the spectrum between, paranoia and unjustifiable fear on one side, and reasonable caution on the other, where does keeping your head low fit in?</p>
<h2>What kind of ET could we find?</h2>
<p>Hawking’s comments are motivated by a fear of what the aliens would do to us if they find us. In his mind, the aliens are the Spanish Conquistador Cortez and we are the Aztecs he made contact with in central America.</p>
<p>Tribal warfare, genocide and ethnic cleansing have been part of our history for thousands of years. Hawking’s fear is a fear of what we have done to ourselves.</p>
<p>Would advanced alien civilisations be as barbaric as we are? Are our genocidal tendencies at all representative of advanced alien civilisations? Maybe.</p>
<p>Hawking <a href="http://www.independent.co.uk/news/science/stephen-hawking-warns-that-humanity-should-not-respond-to-aliens-in-case-they-kill-us-all-a7326256.html">says he worries</a> that any aliens “will be vastly more powerful and may not see us as any more valuable than we see bacteria”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/146324/original/image-20161117-13361-oo8ksp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/146324/original/image-20161117-13361-oo8ksp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/146324/original/image-20161117-13361-oo8ksp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/146324/original/image-20161117-13361-oo8ksp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/146324/original/image-20161117-13361-oo8ksp.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/146324/original/image-20161117-13361-oo8ksp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/146324/original/image-20161117-13361-oo8ksp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/146324/original/image-20161117-13361-oo8ksp.JPG?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"></a>
<figcaption>
<span class="caption">Under the microscope: cyanobacteria.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Tolypothrix_(Cyanobacteria).JPG">Wikimedia/Matthewjparker</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>But Stephen, bacteria ARE valuable. Our bacterial biomes keep us alive and healthy. They have been here for about 4 billion years. They invented the ability to harvest sunlight for energy. They produced the oxygen we breathe, and as mitochondria, they do our breathing.</p>
<p>Life on Earth would do fine without people, but without bacteria no other life forms would exist. So Hawking is over-estimating our importance and under-estimating our insignificance to aliens. We will be much less valuable to aliens, than bacteria are to us.</p>
<h2>Advanced civilisation</h2>
<p>The age distribution of Earth-like planets in the universe tells us that the average Earth-like planet is about 2 billion years older than our Earth.</p>
<p>If life has formed on these other Earths, it has had, on average, 2 billion years longer to evolve than we have had. This is the fact that has Hawking worried.</p>
<p>If you imagine that the pace of biological and technological evolution on these other Earths is about the same as it has been on our Earth, then alien civilisations are on average two billion years more advanced than we are.</p>
<p>To put that time frame into perspective, two billion years ago, our ancestors on Earth were amoebas or parameciums – single-celled <a href="http://www.nature.com/scitable/topicpage/eukaryotic-cells-14023963">eukaryotes</a> of some kind.</p>
<p>I agree with Hawking that we should keep our heads low. But we have already opened our mouths and started coughing – betraying our existence to any big-eared aliens.</p>
<p>Via television broadcasts we have already sent the 1936 Berlin Olympics and the I Love Lucy show to the stars.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/uhIEfxRLiPI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Discovering one of the earliest television broadcasts from 1936.</span></figcaption>
</figure>
<p>Currently our strongest emissions into the cosmos – emissions that are making our presence known to the aliens – are the emissions that we think are protecting us from terrestrial aliens.</p>
<p>Those emissions are military radar. The unintended consequence of this protective radar is that it is simultaneously shouting out to the aliens “here we are”.</p>
<p>So the biggest threat to humanity is humanity – our nuclear weapons, our guns, our big brains and our powerful radar systems.</p>
<h2>Contact or not?</h2>
<p>While discussing the value of searching for extraterrestrial intelligence <a href="http://www.seti.org/">SETI</a>, a colleague told me that it was dangerous to even listen to aliens. He thought the message would be like a Trojan horse. If we let the message into our minds, it would kill us.</p>
<p>It would be like sticking a virus-contaminated USB stick into your computer. The militaristic generals in the movie <a href="http://www.imdb.com/title/tt0118884/">Contact</a> should come to mind here: “Ellie Arroway! Don’t build that machine!”</p>
<p>Science fiction writer <a href="http://www.clarkefoundation.org/about-sir-arthur/">Arthur C. Clarke</a> <a href="https://www.goodreads.com/quotes/14885-any-sufficiently-advanced-technology-is-indistinguishable-from-magic">once said</a> that any sufficiently advanced technology would be indistinguishable from magic. But futurist <a href="http://www.kschroeder.com/weblog/the-deepening-paradox">Karl Schroeder thinks</a> that any sufficiently advanced technology will be indistinguishable from nature.</p>
<p>I don’t know. Maybe Schroeder’s right and advanced aliens have made their peace with the universe. But even if there aren’t any advanced alien civilisations elsewhere in the universe, keeping your head down is probably a good exercise in humility.</p><img src="https://counter.theconversation.com/content/68344/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charley Lineweaver 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>We continue to search for intelligent life elsewhere in the universe. But if we find ET there are those who question whether we should make contact or not.Charley Lineweaver, Researcher at Research School of Astronomy and Astrophysics and the Research School of Earth Sciences, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/688152016-11-16T19:09:21Z2016-11-16T19:09:21ZAlien invaders: the illegal reptile trade is a serious threat to Australia<figure><img src="https://images.theconversation.com/files/146152/original/image-20161116-31144-7s0w25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Boa constrictors are frequently found at large in Australia, despite being banned.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/56361113@N00/74821060">Marcos André/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Australians are <a href="https://www.environment.gov.au/biodiversity/wildlife-trade/exotics">banned from keeping non-native reptiles as pets</a>, but there is a nevertheless a thriving illegal trade in these often highly prized animals. We have documented the threat that these species – many of them venomous or potentially carrying exotic diseases – pose to people and wildlife in Australia.</p>
<p>In a study published in <a href="http://onlinelibrary.wiley.com/doi/10.1111/conl.12301/full">Conservation Letters</a>, we estimate that of 28 alien reptile species illegally traded in Victoria between 1999 and 2012, 5 of them (18%) would have the potential to establish themselves in the wild if they escape or are released. Our findings also indicate that smaller alien reptiles are more likely to establish in the wild in Australia.</p>
<p>Worryingly, more than a third of these illegal reptile species are highly venomous snakes (10 out of the 28 species). The presence of 10 alien venomous snakes represents a serious human health hazard, even in Australia which is already home to <a href="http://www.australiangeographic.com.au/topics/science-environment/2012/07/australias-10-most-dangerous-snakes">some of the most venomous snakes in the world</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/146180/original/image-20161116-13555-ugbrun.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/146180/original/image-20161116-13555-ugbrun.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/146180/original/image-20161116-13555-ugbrun.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=856&fit=crop&dpr=1 600w, https://images.theconversation.com/files/146180/original/image-20161116-13555-ugbrun.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=856&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/146180/original/image-20161116-13555-ugbrun.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=856&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/146180/original/image-20161116-13555-ugbrun.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1075&fit=crop&dpr=1 754w, https://images.theconversation.com/files/146180/original/image-20161116-13555-ugbrun.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1075&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/146180/original/image-20161116-13555-ugbrun.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1075&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Our warning of the dangers posed by the illegal reptile trade.</span>
<span class="attribution"><span class="source">Environment Institute, University of Adelaide</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Previous research has focused on the <a href="http://www.nature.com/news/biodiversity-the-ravages-of-guns-nets-and-bulldozers-1.20381">overharvesting of wild populations</a> to meet the demand for illegal wildlife products such as traditional medicine ingredients and other commodities, as well as live animals themselves. </p>
<p>But the trade in illegal wildlife poses a risk not just to the species being trafficked, but also to the people and ecosystems potentially exposed to new hazardous alien species as a result. Unfortunately, these risks are often overlooked or underestimated by wildlife agencies.</p>
<h2>Frogs take their diseases with them</h2>
<p>Effective biosecurity measures are crucial for tackling these threats. Are Australia’s biosecurity activities as good as they are made out to be in <a href="https://au.tv.yahoo.com/plus7/border-security/">popular television shows</a> about customs officers policing our borders? </p>
<p>Let’s look at the example of ranaviruses, an emerging disease that kills huge numbers of amphibians around the world. The introduction of these viruses to Australia could be catastrophic for native frogs. Alien frogs transported as unintentional stowaways can carry ranavirus, so intercepting those alien frogs will also prevent the spread of these pathogens. </p>
<p>In an <a href="http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12749/full">earlier study</a>, we examined the effectiveness of Australian biosecurity activities for stopping the introduction of dangerous alien ranaviruses. Our main conclusion was that existing biosecurity measures have significantly reduced the likelihood of introduction of alien ranaviruses. </p>
<p>Moreover, biosecurity activities do not need to intercept every single incoming alien frog in order to reduce significantly the likelihood that new diseases will be introduced. This is particularly good news for threatened <a href="https://www.environment.gov.au/biodiversity/threatened/publications/factsheet-frogs-australia">native frogs</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/146147/original/image-20161115-31132-vaq520.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/146147/original/image-20161115-31132-vaq520.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/146147/original/image-20161115-31132-vaq520.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/146147/original/image-20161115-31132-vaq520.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/146147/original/image-20161115-31132-vaq520.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/146147/original/image-20161115-31132-vaq520.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/146147/original/image-20161115-31132-vaq520.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/146147/original/image-20161115-31132-vaq520.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">Puff adders have been illegally kept in Victoria, despite being a seriously dangerous pet.</span>
<span class="attribution"><span class="source">Julius Rückert/Wikimedia Commons</span></span>
</figcaption>
</figure>
<h2>A way forward</h2>
<p>Unfortunately, many other countries seem to have <a href="http://www.nature.com/articles/ncomms12485">inadequate systems for keeping unwanted species out</a>, despite the many <a href="https://theconversation.com/global-agriculture-study-finds-developing-countries-most-threatened-by-invasive-pest-species-61280">social, economic and ecological impacts</a> that alien species cause across the world. </p>
<p>This situation paints a bleak picture for the future of biodiversity, with alien species increasingly wreaking havoc across all environments. But we believe there is <a href="http://bioscience.oxfordjournals.org/content/60/8/626.full">hope and a way forward</a> – as long as countries are willing to work much harder to combat the threats posed by alien species. </p>
<p>Foremost, we need to improve our understanding of the importance and drivers of transport pathways through which alien species travel. Armed with that knowledge, we can plan more effective management – although a lack of data is <a href="http://www.nature.com/nature/journal/v539/n7627/full/539031e.html">no excuse for delay in the meantime</a>. Prevention is always <a href="http://link.springer.com/article/10.1007/s10530-016-1332-x">better than cure</a>, so our number one goal should be to prevent the introduction of alien species, rather than simply tackling the problems they cause.</p>
<p>Some important lessons emerge from our research. The illegal wildlife trade and the transport of stowaways are global issues. Therefore no country, however effective its biosecurity, can solve its problems on its own. Multilateral biosecurity agreements will be necessary to manage both stowaways and the illegal wildlife trade. </p>
<p>In Australia, we need to raise public awareness about alien species. We have to <a href="https://theconversation.com/the-rise-of-citizen-science-is-great-news-for-our-native-wildlife-63866">enlist the public</a> in reporting suspicious activities and the presence of alien species at large. Meanwhile, <a href="https://theconversation.com/explainer-why-australia-needs-biosecurity-20105">supporting biosecurity activities is a no-brainer</a>. Biosecurity is a responsibility shared by all Australians, and the general public have a role to support biosecurity activities, even if that means a few more minutes to clear biosecurity ports and airports. Be on the lookout for potential alien species, and if you spot anything unusual, report it to the <a href="http://www.agriculture.gov.au/pests-diseases-weeds/report">Department of Agriculture and Water Resources</a>.</p><img src="https://counter.theconversation.com/content/68815/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Pablo Garcia-Diaz receives funding from the Invasive Animals CRC and the Department of Education and Training (Australian Government). </span></em></p><p class="fine-print"><em><span>Joshua Ross receives funding from the ARC, NHMRC, and D2D CRC.</span></em></p><p class="fine-print"><em><span>Phill Cassey receives funding from Australian Research Council and the Invasive Animals CRC. </span></em></p>Keeping non-native reptiles as pets is against the law – with good reason. Alien species traded on the black market can potentially establish themselves in the wild if they are released or escape.Pablo García-Díaz, PhD candidate in invasion ecology, University of AdelaideJoshua Ross, Associate Professor in Applied Mathematics, University of AdelaidePhill Cassey, Assoc Prof in Invasion Biogeography and Biosecurity, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.