tag:theconversation.com,2011:/africa/topics/weeds-6713/articlesWeeds – The Conversation2024-01-25T20:46:32Ztag:theconversation.com,2011:article/2206532024-01-25T20:46:32Z2024-01-25T20:46:32ZThe botanical imperialism of weeds and crops: how alien plant species on the First Fleet changed Australia<figure><img src="https://images.theconversation.com/files/570269/original/file-20240119-22-lcj7rr.jpg?ixlib=rb-1.1.0&rect=34%2C22%2C7618%2C3774&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://collection.sl.nsw.gov.au/record/Ydma46R9/8pg0LrwplLmxJ">Dixson Library, State Library of New South Wales</a></span></figcaption></figure><p>Locally grown produce fills Australian shops, but almost all of these species were imported, as native as cane toads. Icons of Australian agriculture, like the Big Banana and Big Pineapple, proudly display the regions’ crops, but these are newcomers to the continent.</p>
<p>British ships carrying plants and seeds from around the world arrived in Botany Bay on <a href="https://firstfleetfellowship.org.au/ships/the-voyage/">January 20 1788</a>. This story is overshadowed by convict ships and Royal Navy vessels, but the cargo on board also had a lasting impact. Colonists, convicts and Indigenous Australians were all affected when new species transformed the landscape.</p>
<p>British colonists introduced plants as foreign as the people who carried them. Some of these plants, ranging from <a href="https://firstfleetfellowship.org.au/wp-content/uploads/2013/11/PLANTS-AND-SEEDS-FROM-RIO-DE-JANEIRO-pdf.pdf">bananas to wheat</a>, were food sources, promoting self-sufficiency. Others were attempts to expand the British Empire. Could the new territory be exploited as a tropical plantation? </p>
<h2>Botanical imperialism</h2>
<p>In the parliamentary debate over destinations for convict transportation, Sir Joseph Banks and James Matra, both members of James Cook’s 1770 expedition, spruiked the potential of the new colony as an extension of the empire. </p>
<p><a href="https://www.google.com.au/books/edition/Historical_Records_of_New_South_Wales_pa/ML4NAAAAYAAJ?hl=en&gbpv=1">Matra claimed</a> the colony was “fitted for production” of “sugar-cane, tea, coffee, silk, cotton, indigo and tobacco”. </p>
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<a href="https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=898&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=898&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=898&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1129&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1129&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570273/original/file-20240119-27-gv172q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1129&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Sir Joseph Banks.</span>
<span class="attribution"><a class="source" href="https://victoriancollections.net.au/items/64a215525a416af5117dd67e">Victorian Collections</a></span>
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<p><a href="https://australian.museum/learn/first-nations/unsettled/recognising-invasions/plans-for-a-colony/">Banks claimed</a> Botany Bay was an “advantageous” site, with fertile soil – and virtually no inhabitants. </p>
<p>Two plants carried by the First Fleet stand out as examples of botanical imperialism: prickly pear cactus (Opuntia) and sugarcane. Banks, as head of the Royal Society of London, selected these species as experiments to compete with European trade rivals. </p>
<p>His goal was to break a Spanish monopoly in producing fabric dye and to expand British cultivation of sugar outside the West Indies.</p>
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Read more:
<a href="https://theconversation.com/from-captain-cook-to-the-first-fleet-how-botany-bay-was-chosen-over-africa-as-a-new-british-penal-colony-128002">From Captain Cook to the First Fleet: how Botany Bay was chosen over Africa as a new British penal colony</a>
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<h2>The secret of the colour scarlet</h2>
<p>Prickly pear cactus was imported because it is the preferred food of the cochineal insect. Dried <a href="https://www.webexhibits.org/causesofcolor/7.html#google_vignette">cochineal</a> were crushed to make a vibrant, colourfast scarlet dye for textiles. Discovered in the New World by Spanish colonists, cochineal replaced kermes, another insect that had provided red dye since antiquity. </p>
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<a href="https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and White Photo" src="https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=805&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=805&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=805&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1012&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1012&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570260/original/file-20240118-19-o7bfu4.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1012&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Man standing in an invasive prickly pear forest in Queensland, 1935.</span>
<span class="attribution"><a class="source" href="https://www.archivessearch.qld.gov.au/items/ITM1143347">Queensland State Archives</a></span>
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<p>Cochineal dye was ten times stronger than kermes or vegetable dyes. From cardinals’ capes to British officers’ red coats, cochineal was a product for elite consumers signifying power, wealth and prestige.</p>
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<a href="https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and white photo, looks like a haystack" src="https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=945&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=945&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=945&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1187&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1187&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570265/original/file-20240118-21-557i3j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1187&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">2,200,000 eggs of cactus moth, collected to combat the invasive prickly pear in 1928.</span>
<span class="attribution"><a class="source" href="https://onesearch.slq.qld.gov.au/permalink/61SLQ_INST/1dejkfd/alma99183712416402061">State Library of Queensland</a></span>
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<p>New Spain, based in Mexico, had a monopoly on cochineal. Banks wanted to break the stranglehold on the scarlet dye by establishing production in New South Wales. Plants infested with the precious insects were imported from Brazil in 1788. </p>
<p>The project soon failed when the cochineal died, but the cacti survived. Colonists used cacti as natural fences and drought-resistant animal fodder. Without insects to feed on them the plants spread, uncontrolled, to cover more than <a href="https://www.nma.gov.au/defining-moments/resources/prickly-pear-eradication">60 million acres</a> of eastern Australia by the 1920s. Poison, crushing and fire failed to stop the cactus.</p>
<p>In 1926, a moth species from Argentina was introduced to eradicate the plants, but Opuntia cacti remain an environmental hazard. Trade in the plants, classified as <a href="https://weeds.dpi.nsw.gov.au/WeedListPublics/CategoryResults?showImages=True&categoryId=1&pageTitle=Weeds%20of%20National%20Significance">weeds of national significance</a>, is banned in most states.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/exposing-australias-online-trade-in-pest-plants-weve-found-thousands-of-illegal-advertisements-212647">Exposing Australia's online trade in pest plants – we've found thousands of illegal advertisements</a>
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<h2>The first sugar grown in Australia</h2>
<p>Sugarcane was imported from the Cape Colony, now South Africa. Before sugar was planted in Queensland, or even Port Macquarie, in the 19th century, sugar was grown in a small garden plot in Sydney and as an experimental crop on Norfolk Island in 1788.</p>
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<a href="https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration of a house on Sydney Harbour" src="https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=501&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=501&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=501&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=630&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=630&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570266/original/file-20240118-15-dz0fjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=630&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Sugarcane was first grown in garden plots in Sydney.</span>
<span class="attribution"><a class="source" href="https://archival.sl.nsw.gov.au/Details/archive/110316551">Mitchell Library, State Library of New South Wales</a></span>
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<p>The Royal Navy targeted Norfolk Island as a source of flax and timber, but it also served as an agricultural laboratory, testing tropical crops like sugar and coffee for Banks.</p>
<p>Philip Gidley King, lieutenant-governor of Norfolk Island, reported in his correspondence with Banks in 1790 that his four canes had multiplied into more than 100 plants. Within a few years he sent <a href="https://transcripts.sl.nsw.gov.au/page/letter-received-banks-philip-gidley-king-8-may-1792-series-39004-no-0004">samples</a> of sugar, rum and molasses to Sydney. By 1798, the cane was declared “prolific” and Norfolk Island was in “a state of cultivation equal to the West Indies”.</p>
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<a href="https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Black and white photo" src="https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570262/original/file-20240118-17-iojl9b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">South Sea Islander workers standing in a sugarcane field in Queensland.</span>
<span class="attribution"><a class="source" href="https://onesearch.slq.qld.gov.au/permalink/61SLQ_INST/tqqf2h/alma99183799211402061">State Library of Queensland</a></span>
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<p>This favourable comparison with the West Indies ignores the use of convict labour in producing sugar, and foreshadows the advent of “<a href="https://theconversation.com/from-the-caribbean-to-queensland-re-examining-australias-blackbirding-past-and-its-roots-in-the-global-slave-trade-158530">blackbirding</a>”, a euphemism for the abduction or coercion of Melanesian workers. Blackbirding was introduced in Queensland canefields in <a href="https://www.nma.gov.au/defining-moments/resources/islander-labourers">1863</a> as penal transportation ended and cheap convict labour became unavailable. </p>
<p>Once essential to the sugar industry, in 1901 Pacific Islanders in Australia were deemed undesirable, competing unfairly with white workers. As part of the White Australia Policy, many were deported under the <a href="https://humanrights.gov.au/our-work/race-discrimination/publications/australian-south-sea-islanders-century-race">Pacific Island Labourers Act 1901</a>.</p>
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Read more:
<a href="https://theconversation.com/from-the-caribbean-to-queensland-re-examining-australias-blackbirding-past-and-its-roots-in-the-global-slave-trade-158530">From the Caribbean to Queensland: re-examining Australia's 'blackbirding' past and its roots in the global slave trade</a>
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<h2>The fruits of empire</h2>
<p>Reconsidering the impact of alien plant species on Australia gives us additional insight into the process of colonisation. </p>
<p>Transplanting species from around the world to create a new environment was a major endeavour in the 18th century, and a manifestation of imperial power and control. </p>
<p>Indigenous connections with Country were disrupted when foreign botanical landscapes displaced native species. The roots of these early imperial projects are deeply embedded in Australian culture and history, with an enduring legacy.</p><img src="https://counter.theconversation.com/content/220653/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Garritt C. Van Dyk does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It wasn’t just colonists and convicts who invaded Australia in 1788 – invasive plant species arrived too.Garritt C. Van Dyk, Lecturer in History, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2126472023-09-08T00:25:14Z2023-09-08T00:25:14ZExposing Australia’s online trade in pest plants – we’ve found thousands of illegal advertisements<figure><img src="https://images.theconversation.com/files/546310/original/file-20230905-25-ejpcy3.jpg?ixlib=rb-1.1.0&rect=107%2C83%2C7832%2C5214&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/new-plants-delivery-woman-opening-shipping-1836099568">Shutterstock</a></span></figcaption></figure><p>Do you buy plants online? You might be breaking the law without even knowing it.</p>
<p>We found hundreds of different invasive plants and prohibited weeds advertised on a popular online marketplace. </p>
<p>For the first time, <a href="https://neobiota.pensoft.net/article/104472/">our research</a> has exposed the frequent, high volume trade in pest plants across Australia. </p>
<p>State and territory governments are adopting our automated surveillance approach to help regulate the online trade in plants and <a href="https://theconversation.com/buying-bugs-and-beetles-or-shopping-for-scorpions-and-snails-australias-pet-trade-includes-hundreds-of-spineless-species-207932">other wildlife</a>. Biosecurity officers can receive automatic alerts for suspected illegal trade, rather than manually monitoring websites or relying on reports from the public. </p>
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<a href="https://images.theconversation.com/files/547090/original/file-20230907-23-fsbn22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of someone shopping for plants online, showing hands on the laptop keyboard and plants on screen." src="https://images.theconversation.com/files/547090/original/file-20230907-23-fsbn22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547090/original/file-20230907-23-fsbn22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547090/original/file-20230907-23-fsbn22.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547090/original/file-20230907-23-fsbn22.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547090/original/file-20230907-23-fsbn22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547090/original/file-20230907-23-fsbn22.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547090/original/file-20230907-23-fsbn22.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Australians love online shopping and that passion extends to plants.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hands-searching-plants-buy-online-shop-746765218">Rawpixel.com, Shutterstock</a></span>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-true-damage-of-invasive-alien-species-was-just-revealed-in-a-landmark-report-heres-how-we-must-act-211893">The true damage of invasive alien species was just revealed in a landmark report. Here's how we must act</a>
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</p>
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<h2>What’s the problem and why all the fuss?</h2>
<p>Certain plants are prohibited in Australia because they are harmful to our unique natural environment and agricultural industries. These weeds can threaten native species, <a href="https://www.theguardian.com/australia-news/2023/mar/29/environmental-tragedy-as-fires-burn-through-one-fifth-of-northern-territory-national-park">fuel severe fires</a> and choke rivers. </p>
<p>Weeds are also a <a href="https://theconversation.com/the-buffel-kerfuffle-how-one-species-quietly-destroys-native-wildlife-and-cultural-sites-in-arid-australia-149456">social and cultural threat for First Nations people</a>, because they can compete with traditional food and medicine plants, causing them to decline.</p>
<p>Overall, invasive plants are estimated to have <a href="https://theconversation.com/pest-plants-and-animals-cost-australia-around-25-billion-a-year-and-it-will-get-worse-164969">cost Australia A$200 billion since 1960</a>. </p>
<p>Weeds that are controlled under state and territory laws are referred to as “noxious” or declared plants. Each state and territory has different laws prohibiting the sale and cultivation of these declared plants. </p>
<p>Compliance is generally high within the horticultural industry, save for the occasional <a href="https://www.abc.net.au/news/2016-09-22/bunnings-caught-selling-declared-weed-sagittaria-to-customers/7869226">high profile blunder</a>. The main problem for Australia is the widespread invasive plant trade on public online marketplaces.</p>
<p>Trade of ornamental plants, which are the kinds popularly grown in homes and gardens, is the <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.12953">major current pathway</a> enabling invasion and spread of weeds into new areas. They’re travelling long distances, to homes in new places. </p>
<p>Invasive cacti and ornamental pond plants are among the most frequently advertised plants, but many are banned from sale and distribution in Australia. </p>
<p>Internet trade has historically been tricky to monitor and regulate, which has led to a variety of invasive species being <a href="https://theconversation.com/new-expose-of-australias-exotic-pet-trade-shows-an-alarming-proliferation-of-alien-threatened-and-illegal-species-203354">widely traded</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547091/original/file-20230907-23-xlg0k9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo showing the invasive nature of water hyacinth, with purple flowers in a field of green." src="https://images.theconversation.com/files/547091/original/file-20230907-23-xlg0k9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547091/original/file-20230907-23-xlg0k9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547091/original/file-20230907-23-xlg0k9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547091/original/file-20230907-23-xlg0k9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547091/original/file-20230907-23-xlg0k9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547091/original/file-20230907-23-xlg0k9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547091/original/file-20230907-23-xlg0k9.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">Water hyacinth is considered the world’s worst water weed.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/flowers-water-hyacinth-purple-lined-according-583320415">KEEP GOING, Shutterstock</a></span>
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<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>
</strong>
</em>
</p>
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<h2>Scraping the web</h2>
<p>We used specialised software called “web scrapers” to monitor trade on a public classifieds website. These automated web tools can be used to rapidly harvest information from advertisements. This allowed us to detect thousands of advertisements for weeds over a 12-month period.</p>
<p>We found 155 declared plant species traded on one website, and we suspect there could be more. </p>
<p>Prickly pear cacti were among the most frequently traded declared plants. This is concerning given their history in Australia. In the 1920s, about 25 million hectares of land became unusable due to prickly pear invasion. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/546312/original/file-20230905-27-quus11.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black and white photo of a farmer standing in a field of prickly pear, it's more than double his height." src="https://images.theconversation.com/files/546312/original/file-20230905-27-quus11.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/546312/original/file-20230905-27-quus11.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=805&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546312/original/file-20230905-27-quus11.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=805&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546312/original/file-20230905-27-quus11.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=805&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546312/original/file-20230905-27-quus11.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1012&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546312/original/file-20230905-27-quus11.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1012&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546312/original/file-20230905-27-quus11.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1012&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The invasion of prickly pear was so dense in areas of Queensland and New South Wales that farming became impossible.</span>
<span class="attribution"><a class="source" href="https://www.archivessearch.qld.gov.au/items/ITM1143347">Queensland Government</a></span>
</figcaption>
</figure>
<p>Aquatic weeds were another popular group. That includes water hyacinth, which is the world’s most widespread invasive alien species according to a recently published <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">global assessment</a>. </p>
<p>We found some sellers advertised uses for the declared plants they were trading, including for food and medicinal properties. </p>
<p>Aquatic weeds were often stated to have water-filtering properties and provide habitat for fish. Those traits make Amazon frogbit a popular choice for aquariums and ponds, but if the weed enters creeks and rivers it can have <a href="https://www.abc.net.au/news/2021-11-25/amazon-frogbit-statewide-declaration/100648506">devastating consequences</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/buying-bugs-and-beetles-or-shopping-for-scorpions-and-snails-australias-pet-trade-includes-hundreds-of-spineless-species-207932">Buying bugs and beetles, or shopping for scorpions and snails? Australia's pet trade includes hundreds of spineless species</a>
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<hr>
<h2>Everyone can do their bit</h2>
<p>Better surveillance is not the only solution. Public awareness is key to reducing invasive plant trade. We can all make informed decisions about the plants we buy.</p>
<p>A significant hurdle is a phenomenon called “<a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1002/ppp3.51">plant blindness</a>”. People tend to find plants harder to recognise than animals. We found many weeds sold using generic names such as lily, cactus or pond plant. Some people may not even know the true identity of a plant they are selling, let alone that it is a weed and illegal to trade.</p>
<p>Another complication is the fact that laws differ between states. Plants that might be legal for an interstate trader, might still be illegal for you to buy. This is why caution should be taken when sending or receiving plants by post. Always check your local regulations before buying or selling a plant online. You can find out what is declared on your state or territory’s biosecurity website or on <a href="https://weeds.org.au/">Weeds Australia</a>. </p>
<p>Online marketplaces must also cooperate with local policies. These platforms should be enforced to self-regulate trade and include measures to prevent illegal advertisements from being posted in the first place. Failure to act may result in significant penalties from governments. Last year the <a href="https://www.science.org/doi/10.1126/science.ade0843#:%7E:text=%E2%80%9CFacebook%20fined%20U%242%20million,animals%2Din%2Dbrazil%2F.">Brazilian government fined Meta</a> for failing to remove illegal wildlife trade from Facebook and WhatsApp. </p>
<p>For now, monitoring tools such as the web scrapers we have developed will help to prevent some weeds escaping backyards and into bushland. As plant lovers, it’s important to be mindful of the plants we choose to buy and keep. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lickable-toads-and-magic-mushrooms-wildlife-traded-on-the-dark-web-is-the-kind-that-gets-you-high-201180">Lickable toads and magic mushrooms: wildlife traded on the dark web is the kind that gets you high</a>
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</em>
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<img src="https://counter.theconversation.com/content/212647/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jacob Maher receives funding from the Centre for Invasive Species Solutions. </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>Australians are trading pest plants online, potentially breaking the law without even realising it.Jacob Maher, PhD Candidate, University of AdelaidePhill Cassey, Australian Research Council Industry Laureate Fellow, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1898522023-08-10T14:34:34Z2023-08-10T14:34:34ZProtecting boreal plant species is a critical part of reconciliation efforts<figure><img src="https://images.theconversation.com/files/482447/original/file-20220902-19-pnlr93.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4594%2C3456&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Labrador Tea is one of the boreal plants that are classified as pests or weeds. The plant is important to Indigenous communities for its healing properties.</span> <span class="attribution"><span class="source">(J. Baker)</span>, <span class="license">Author provided</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/protecting-boreal-plant-species-is-a-critical-part-of-reconciliation-efforts" width="100%" height="400"></iframe>
<p>Labrador Tea, fireweed, chokecherry and raspberry are some of the boreal plants that are <a href="https://weedscience.ca/biology-of-canadian-weeds/">classified as weeds</a> by the Canadian Weed Science Society. These plants are targeted with herbicide by logging companies across the Canadian boreal forest.</p>
<p>However, these boreal plant species are important traditional plants for many Indigenous peoples in Canada and around the world. In addition to their <a href="https://www.fao.org/3/ai215e/ai215e.pdf">use as food</a>, these traditional native plants hold tremendous <a href="https://doi.org/10.1186/1746-4269-8-7">medicinal, ceremonial and material value</a>.</p>
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<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><strong>This article is part of <em>La Conversation Canada’s</em> series <a href="https://theconversation.com/ca-fr/topics/foret-boreale-138017">The boreal forest: A thousand secrets, a thousand dangers</a></strong></p>
<p><br><em>La Conversation Canada invites you to take a virtual walk in the heart of the boreal forest. In this series, our experts focus on management and sustainable development issues, natural disturbances, the ecology of terrestrial wildlife and aquatic ecosystems, northern agriculture and the cultural and economic importance of the boreal forest for Indigenous peoples. We hope you have a pleasant — and informative — walk through the forest!</em></p>
<hr>
<p>These plant species thrived before the arrival of Europeans and are respected and cared for by Indigenous communities, in ways that help increase <a href="https://www.cbd.int/portals/culturaldiversity/docs/north-american-regional-declaration-on-biocultural-diversity-en.pdf">biocultural diversity</a>. </p>
<p>As a cultural and environmental anthropologist, I have been working for and with First Nations communities in the boreal forests in Alberta since 2006. In my recently published paper, I reveal how the misappropriation of these plants from traditional territories is <a href="https://doi.org/10.1215/22011919-9712467">grounded in a colonial bias for the economic value of plants</a>.</p>
<h2>Boreal forests under threat</h2>
<p>Over recent decades, boreal forests in Canada have been facing numerous threats, including attempts to extract plants for economic gain or <a href="https://hdl.handle.net/10214/27311">eradicate them using herbicides</a>. </p>
<p>The issue lies in what gets referred to as “<a href="https://open.alberta.ca/publications/timber-harvest-planning-and-ogr-2023">merchantable timber</a>” versus the abundance of boreal forest plants that cover the ground below the trees. </p>
<p>When government agencies and logging companies follow their <a href="https://www.alberta.ca/indigenous-consultations-in-alberta.aspx">Duty to Consult First Nations</a>, they tend to overlook expressed concerns about the destruction of traditional plants that grow in abundance. </p>
<p>For example, balsam and aspen poplar trees, birch trees, Labrador Tea, blueberries and wild mint are all plants that grow in abundance in the boreal forest that have high cultural value. </p>
<p>In the consultation process, when an Elder or community member identifies these plants for protection, company representatives often respond saying that these plants grow throughout the forest, so their destruction has <a href="https://doi.org/10.1016/j.exis.2017.12.008">no significant impact</a> on inherent rights protected by treaty. </p>
<p>This outside ruling can affect First Nation members’ access to their particular familial stewardship area. </p>
<p>The loss of access to seemingly abundant plants is exacerbated by the use of <a href="https://open.alberta.ca/dataset/2008d812-65eb-4608-9c00-54999149c2a1/resource/2a40a300-d391-4440-b870-e3b632588e92/download/af-forest-management-herbicide-reference-manual-2021-01.pdf">the herbicide glyphosate in the reforestation process</a>, and along roads, pipelines and power lines. </p>
<p>Plants with great nutritional and medicinal value like Labrador Tea are sprayed so that they do not compete with monocropping reforestation practices that focus on timber. This reflects a bias toward merchantable timber rather than a <a href="https://mothertreeproject.org/mother-tree-experiment/">biodiverse and healthy forest</a>. </p>
<h2>Boreal destruction impacts Indigenous communities</h2>
<p>When people lose their collecting areas, they have to search larger areas for the same plants, request access in other people’s areas and risk collecting plants contaminated by volatile organic compounds, heavy metals or herbicides. </p>
<p>Research in the boreal forest has revealed that <a href="https://doi.org/10.1016/j.foreco.2021.119259">glyphosate remains in plant tissues for at least a decade</a>. The communities I collaborate with during my research continue to be very concerned about the use of herbicides in their territories, and with reason. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541815/original/file-20230808-17-jgodur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="rows of leaves drying on a flat surface" src="https://images.theconversation.com/files/541815/original/file-20230808-17-jgodur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541815/original/file-20230808-17-jgodur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541815/original/file-20230808-17-jgodur.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541815/original/file-20230808-17-jgodur.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541815/original/file-20230808-17-jgodur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541815/original/file-20230808-17-jgodur.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541815/original/file-20230808-17-jgodur.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">Wild mint — used as food and medicine — from the boreal forest laid out to dry.</span>
<span class="attribution"><span class="source">(J. Baker)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Elders from First Nations communities are also concerned about the impacts of bioaccumulation — the gradual accumulation of substances such as pesticides or other chemicals through the food chain. These concerns are based on Elders’ own systems of natural law, oral traditions and enacting <a href="https://doi.org/10.1080/00141844.2020.1765829">respect and reciprocity in the forest</a>.</p>
<h2>Reconciliation includes plant species</h2>
<p>As Canada attempts to reconcile with Indigenous communities through the Truth and Reconciliation Commission of Canada <a href="https://www2.gov.bc.ca/assets/gov/british-columbians-our-governments/indigenous-people/aboriginal-peoples-documents/calls_to_action_english2.pdf">Calls to Action</a>, the recognition of species of traditional value is critical in this process.</p>
<p>Calls to Action for improvements in Indigenous-centred education, youth programs, language and culture, and health supports are connected to people’s abilities to participate in land-based activities. Plant species must be available for these activities to be possible. </p>
<p>The availability of these species means that they need to be respected and conserved based on Indigenous approaches and ecological knowledge.</p>
<p>Not caring for plant species in the context of Indigenous natural legal systems ignores the ancient and ongoing stewardship by Indigenous Peoples living within the boreal forests. Ignoring native species results in the continued misappropriation of traditional territories, one plant at a time.</p><img src="https://counter.theconversation.com/content/189852/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Janelle Marie Baker receives funding from ECCC, the Arctic Connections Fund, CIHR, SSHRC, NSERC, and Athabasca University.</span></em></p>Some boreal plant species are classified — and treated — as weeds, affecting Indigenous communities’ access to important cultural, medicinal and ceremonial resources.Janelle Marie Baker, Associate professor, Anthropology, Athabasca UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2064102023-06-15T01:06:55Z2023-06-15T01:06:55ZAre tree-changers bad at managing their rural properties? A new study wades into the weeds to find the answer<figure><img src="https://images.theconversation.com/files/529517/original/file-20230601-15-k0dgno.jpg?ixlib=rb-1.1.0&rect=25%2C0%2C5725%2C3837&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>Tree-changers opting for a rural lifestyle can get a bad rap for not managing their properties well. The COVID-19 pandemic prompted <a href="https://www.smh.com.au/politics/federal/city-slickers-use-covid-for-sea-and-tree-change-20220726-p5b4r7.html">thousands</a> more city-based Australians to buy property in the regions. So will this lead to more absentee neighbours who, in the eyes of some, don’t know what they’re doing?</p>
<p>If you buy rural land, you are buying into a community. You’re also expected to take on certain responsibilities, such as managing weeds on the property. This helps both the environment and your neighbours. </p>
<p>Tensions about weeds can be <a href="https://www.sciencedirect.com/science/article/abs/pii/S0264837708000628">especially high</a> in areas with many tree-changers. Farmers, for example, may think new arrivals don’t care about how weeds affect agriculture, creating an “us and them” mentality. But are these perceptions warranted? </p>
<p>Our <a href="https://doi.org/10.1080/09640568.2023.2217338">new paper</a> examined this question. We found almost everyone, including absentee landowners, were concerned about weeds and spent a lot of time managing them. But their motivations for doing so were different. These insights can help communities deal with the threat of invasive plants.</p>
<h2>Tree-changers: friend or foe?</h2>
<p>An estimated <a href="https://researchoutput.csu.edu.au/en/publications/absentee-ownership-of-rural-land-7">22-45% of landowners</a> in Australia are absentee. They might be corporations, Indigenous groups or farmers leasing their land to others. They can also be tree-changers who are generally more interested in rural lifestyles and “getting into nature” than farming the land. This group may visit their properties only on weekends or for holidays. </p>
<p>Of all absentee landowners, tree-changers can readily attract complaints because of the significant changes they bring to the look and culture of rural areas. They often occupy former farmland and may cease farming, engage in conservation work, build new houses or just ride motorbikes all weekend.</p>
<p>Absentee landholders can own vast swathes of land. So the way they manage their properties, including managing weeds, can have big consequences. </p>
<p>Weeds <a href="https://www.csiro.au/en/research/natural-environment/biodiversity/fighting-plagues-and-predators">can cause</a> economic and environmental harm. They may lower crop productivity and damage pastures. They can also out-compete native vegetation and disrupt ecosystems.</p>
<p>Weed control methods include herbicides, intensive grazing with goats, or removal by hand or with machinery. </p>
<p>Government agencies <a href="http://dx.doi.org/10.1080/08941920801998893">say</a> absentee landholders can be hard to contact and lack knowledge about weeds. They can also be time-poor and absent at times when weed spraying or removal is most effective. </p>
<p>But <a href="https://conbio.onlinelibrary.wiley.com/doi/full/10.1111/cobi.13266">weed control</a> requires all landowners to pull their weight. People can feel their efforts are wasted if neighbours do little. </p>
<p>In places such as the Southern Tablelands in New South Wales, absentee landholders have been <a href="https://www.abc.net.au/news/2016-03-09/concerns-about-weed-expansion-on-nsw-southern-tablelands/7232272">blamed</a> for enabling the spread of a noxious weed known as serrated tussock. The species damages pastures and is difficult for stock to digest.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-botanical-detective-story-shedding-light-on-the-journey-out-of-africa-for-one-of-australias-worst-weeds-205183">A botanical detective story: shedding light on the journey out of Africa for one of Australia's worst weeds</a>
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<h2>The evidence is mixed</h2>
<p>So what does the research say on the matter? One <a href="https://www.sciencedirect.com/science/article/abs/pii/S026483771200049X">literature review</a> in the United States found absentee owners, as compared with resident owners, were less likely to actively manage their land and had less scientific knowledge.</p>
<p>But another <a href="https://link.springer.com/article/10.1007/s00267-021-01454-1">US study</a> did not identify residential status as a factor in weed management.</p>
<p>In Australia, research tends to note absentee owners as an issue for weed management. One small <a href="https://doi.org/10.1016/j.ecoser.2019.100988">study</a>, however, found absentee landholders in Central West NSW were engaged, interested in collaboration on weed management, and reasonably knowledgeable.</p>
<p>Another <a href="http://dx.doi.org/10.5751/ES-05071-170405">study</a> found length of ownership was a greater influence on land management than residential status.</p>
<p>Our research aimed to better understand whether absentee land ownership in Australia makes a difference to how weeds were managed.</p>
<figure class="align-center ">
<img alt="african love grass fronds" src="https://images.theconversation.com/files/529527/original/file-20230601-15-pr7e4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529527/original/file-20230601-15-pr7e4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529527/original/file-20230601-15-pr7e4i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529527/original/file-20230601-15-pr7e4i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529527/original/file-20230601-15-pr7e4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529527/original/file-20230601-15-pr7e4i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529527/original/file-20230601-15-pr7e4i.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">Does absentee land ownership influence weed management? Pictured: African love grass, which can quickly overtake pasture.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Our results</h2>
<p>Our research focused on the Shoalhaven and Bega Valley in southeastern NSW. These regions have experienced an influx of tree-changers in recent decades. They include towns such as Bega, Bowral, Candelo, Berry, Kangaroo Valley and Nowra. </p>
<p>We surveyed 439 landowners about their behaviours and attitudes toward weeds and their management. We then compared the responses of residential owners (88% of respondents) and absentee landowners (12%). We excluded responses from farmers and focused on “lifestylers”, which are themselves a significant group.</p>
<p>Both groups said weeds negatively affected them due to how they looked and the environmental damage they caused. Similar proportions of each group were trying to eradicate or control weeds. </p>
<p>Almost everyone was concerned about weeds. Both groups said weed management was a priority and said being a good neighbour was a primary motivation for taking action.</p>
<p>An overwhelming number of people in both groups managed weeds (and spent one to five hours per week doing so). One of the few significant differences between the groups was that residential landowners prioritised weeds that damaged agriculture, while absentee landowners prioritised weeds that threatened the environment.</p>
<p>This shows how values and interests, rather than indifference, shapes attitudes to weed management.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/trees-can-be-weeds-too-heres-why-thats-a-problem-182599">Trees can be weeds too – here's why that's a problem</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="house and shed in rural setting" src="https://images.theconversation.com/files/529528/original/file-20230601-23-2n4eeh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529528/original/file-20230601-23-2n4eeh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529528/original/file-20230601-23-2n4eeh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529528/original/file-20230601-23-2n4eeh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529528/original/file-20230601-23-2n4eeh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529528/original/file-20230601-23-2n4eeh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529528/original/file-20230601-23-2n4eeh.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">
<figcaption>
<span class="caption">Values and interests, rather than indifference, shapes attitudes to weed management.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Look beyond where people live</h2>
<p>Weed management is determined by our varying <a href="https://www.science.org.au/academy-newsletter/mar-2020-136/managing-wild-and-weedy-australia">social relationships</a> with the land. This must be recognised in both research and policy.</p>
<p>Landowners are diverse and own land for a variety of reasons. Our approach to weed management should take account of these differences. Absenteeism is just one part of the puzzle – and perhaps not as important as we might think.</p>
<p>More research is needed. This should involve in-depth case studies to tease out the issues underpinning community tensions about weed management and identify common ground. Then, we can develop steps towards more effective weed management across fence lines.</p><img src="https://counter.theconversation.com/content/206410/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicholas Gill receives funding from the NSW Government via the Bushfire and Natural Hazards Research Centre and has previously received funding from the Australian Research Council and the NSW Department of Planning and Environment </span></em></p><p class="fine-print"><em><span>Laurie Chisholm has previously received funding from the Australian Research Council and the NCRIS Australian National Data Service.</span></em></p><p class="fine-print"><em><span>Anna Lewis 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>Tree-changers can get a bad rap for not managing their properties well. So will this lead to more absentee neighbours who let weeds run rampant?Nicholas Gill, Associate Professor in Geography, University of WollongongAnna Lewis, Research Program Manager, University of WollongongLaurie Chisholm, Associate Professor in Remote Sensing, University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2051832023-05-21T20:00:34Z2023-05-21T20:00:34ZA botanical detective story: shedding light on the journey out of Africa for one of Australia’s worst weeds<figure><img src="https://images.theconversation.com/files/526989/original/file-20230518-15-gzmuv8.jpg?ixlib=rb-1.1.0&rect=34%2C97%2C4604%2C2865&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">John K. Scott, CSIRO</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The scrubby harbour-side hills of a South African city recently revealed details of an historical event that transformed Australian coastlines. That event led to the arrival in Australia of a native South African shrub, bitou bush. The invader went on to become one of <a href="https://lists.ala.org.au/speciesListItem/list/dr823">Australia’s worst weeds</a>, smothering coastal dune vegetation.</p>
<p>While bitou bush has been widespread along Australia’s east coast for decades, the weed arrived in Western Australia relatively recently. The species (<em>Chrysanthemoides monilifera</em> subspecies <em>rotundata</em>) was <a href="https://doi.org/10.1614/IPSM-D-13-00052.1">discovered in 2012 at Kwinana</a>, a port and industrial area south of Perth. This new invasion <a href="https://doi.org/10.3897/neobiota.50.35070">required urgent attention</a>.</p>
<figure class="align-right ">
<img alt="A closeup of a bitou bush flower" src="https://images.theconversation.com/files/527179/original/file-20230519-17-k14689.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/527179/original/file-20230519-17-k14689.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527179/original/file-20230519-17-k14689.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527179/original/file-20230519-17-k14689.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527179/original/file-20230519-17-k14689.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527179/original/file-20230519-17-k14689.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527179/original/file-20230519-17-k14689.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Bitou bush (<em>Chrysanthemoides monilifera</em> subspecies <em>rotundata</em>) is a weed targeted for eradication in Western Australia. The flowers are bright yellow daisies.</span>
<span class="attribution"><span class="source">Kathryn L. Batchelor, CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Knowing where a weed has come from is fundamental to <a href="https://theconversation.com/attack-of-the-alien-invaders-pest-plants-and-animals-leave-a-frightening-1-7-trillion-bill-158628">managing it well</a>. Understanding how plants are introduced to new regions can enable effective biosecurity measures to be put in place. Establishing a weed’s origin also reveals where to look for its natural enemies, such as insects or fungi, that can be used as classical <a href="https://theconversation.com/explainer-how-biocontrol-fights-invasive-species-31298">biological control</a> agents.</p>
<p>Our research set out to decipher how bitou bush originally entered Australia and then spread from east to west. We reveal how the chance of new bitou bush arrivals in Australia is low and better biological control is possible.</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>
<h2>Establishing relationships between populations</h2>
<p>Earlier <a href="https://doi.org/10.1002/ece3.9179">research</a> on bitou bush established Australian populations went through “genetic bottlenecks”, meaning only a few plants, seeds or parts of plants arrived to begin with. However, the work was unable to identify a population in South Africa that was a genetic match to the bitou bush found in Australia.</p>
<p><a href="https://doi.org/10.1007/s10530-023-03017-3">Our new research</a> took a more comprehensive approach to reveal plants from the South African port of East London were the likely source. Our findings suggested there was a single introduction of bitou bush to eastern Australia, with subsequent movement of material to establish the population in Western Australia more than a century later.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/524856/original/file-20230508-15-ra6lqy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A historical image of the South African port of East London in 1905" src="https://images.theconversation.com/files/524856/original/file-20230508-15-ra6lqy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524856/original/file-20230508-15-ra6lqy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=379&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524856/original/file-20230508-15-ra6lqy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=379&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524856/original/file-20230508-15-ra6lqy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=379&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524856/original/file-20230508-15-ra6lqy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=476&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524856/original/file-20230508-15-ra6lqy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=476&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524856/original/file-20230508-15-ra6lqy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=476&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 South African port of East London (c. 1905) was the likely source of Australia’s bitou bush.</span>
<span class="attribution"><span class="source">East London Museum</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Travel by ballast</h2>
<p>To build confidence in our results, we scoured historical archives in Australia and South Africa for records that could support or refute these findings. Could we turn a plausible hypothesis into a feasible smoking gun?</p>
<p>In the storage racks of the National Herbarium of New South Wales lies a pressed sheet of dried plant material. Collected in 1908, this sample – later identified as bitou bush – was from the port-side suburb of Stockton in Newcastle. Newspaper reports revealed Stockton’s local government had been complaining for at least ten years about a weed threat from dry ballast, making it likely the introduction of bitou bush to Australia occurred even earlier.</p>
<p>Dry ballast consists of sand, soil, rocks and other matter used to provide stability to wooden sailing ships that had to travel without a heavy cargo load. This material was usually quarried at the port of departure. At the time, an increasingly large area in Stockton was reclaimed land comprised of ship’s ballast.</p>
<p>We found historical shipping records that showed ships were regularly leaving the South African Port of East London after taking on dry ballast, then sailing directly to Newcastle to collect coal. Before taking on coal, these ships discharged their dry ballast onto the ballast field at Stockton. We found documents showing that in 1904, more than half the ballast arriving in Australia was dumped at Stockton. </p>
<figure class="align-center ">
<img alt="Map of harbour and inset photo of docked sailing ships" src="https://images.theconversation.com/files/524840/original/file-20230508-230622-hnfek9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524840/original/file-20230508-230622-hnfek9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=249&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524840/original/file-20230508-230622-hnfek9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=249&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524840/original/file-20230508-230622-hnfek9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=249&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524840/original/file-20230508-230622-hnfek9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=313&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524840/original/file-20230508-230622-hnfek9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=313&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524840/original/file-20230508-230622-hnfek9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=313&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The location of the first introduction of bitou bush into Australia showing the reclaimed ballast field (red shading, c. 1902) at Stockton, New South Wales and right, barques (sailing ships) waiting to be loaded with coal, having discarded the ballast (c. 1900).</span>
<span class="attribution"><span class="source">Newcastle University and Ralph Snowball</span></span>
</figcaption>
</figure>
<p>Historical maps revealed a ballast quarry on the west side of the Port of East London. This quarry existed in 1902 and exposed remnants can still be seen today. Bitou bush can still be found across the vegetation-covered hillsides near the old quarry. Their seeds are therefore likely to have been contaminants in dry ballast.</p>
<figure class="align-center ">
<img alt="Historical map of the Port of East London, South Africa." src="https://images.theconversation.com/files/524842/original/file-20230508-19-nu8t9n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524842/original/file-20230508-19-nu8t9n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=198&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524842/original/file-20230508-19-nu8t9n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=198&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524842/original/file-20230508-19-nu8t9n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=198&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524842/original/file-20230508-19-nu8t9n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=249&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524842/original/file-20230508-19-nu8t9n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=249&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524842/original/file-20230508-19-nu8t9n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=249&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Likely source location of bitou bush in and around the quarry at the Port of East London (circa 1920).</span>
<span class="attribution"><span class="source">East London Museum</span></span>
</figcaption>
</figure>
<h2>To Newcastle and beyond!</h2>
<p>The arrival of bitou bush at Stockton was the beginning of a wider invasion of the eastern Australian coastline. The plants now cover 1,600 km <a href="https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/2908997#overview">from Victoria to Queensland</a>.</p>
<p>This spread included deliberate plantings for dune stabilisation in the 1950s. Our molecular work revealed these dune plantings were enabled by the local collection of seed from a limited number of plants, rather than new material from South Africa or widely sourced seed.</p>
<p>We were not able to conclusively identify the introduction pathway from New South Wales to Western Australia. However, contamination of steel shipments between Newcastle or Port Kembla and Kwinana, or landscape plantings for the companies involved, are considered most likely.</p>
<h2>Why does this matter?</h2>
<p>The discovery of a potential source population and pathway into Australia for bitou bush reveals two avenues for improved invasive species management.</p>
<p>First, it opens the door to improved biological control. Earlier ineffective agents were sourced in South Africa from <a href="https://doi.org/10.2307/2404788">populations distantly related</a> to the material introduced into Australia. Many effective agents, particularly pathogens, are highly host specific. New surveys around East London could discover a more effective biological control agent.</p>
<p>Second, the work has clarified the ongoing risk of new introductions following the same pathway. Thankfully the use of dry ballast ceased with the move to steel-hulled ships carrying wet ballast, although the latter has its own <a href="https://doi.org/10.1098/rsos.150039">biosecurity concerns</a>.</p>
<p>More generally, the case of bitou bush in Australia highlights the problem of inadvertent outcomes from introducing plants, either accidentally or deliberately, without rigorous risk assessment. We must remain vigilant to the risk of introductions facilitated by global trade and maintain <a href="https://theconversation.com/yes-wash-your-shoes-at-the-airport-but-we-can-do-more-to-stop-foot-and-mouth-disease-ravaging-australia-187602">strict border biosecurity</a> protocols.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/yes-wash-your-shoes-at-the-airport-but-we-can-do-more-to-stop-foot-and-mouth-disease-ravaging-australia-187602">Yes, wash your shoes at the airport – but we can do more to stop foot-and-mouth disease ravaging Australia</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/205183/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bruce Webber receives funding from Fremantle Ports Authority and CSIRO Health & Biosecurity. </span></em></p><p class="fine-print"><em><span>John Scott 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>Knowing where a weed has come from can improve its management, but this quest can be challenging. CSIRO detective work revealed an unusual pathway for the introduction of South African bitou bush.Bruce Webber, Principal Research Scientist, CSIROJohn Scott, Honorary Fellow, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2045042023-04-27T15:02:39Z2023-04-27T15:02:39ZDandelions are a lifeline for bees on the brink – we should learn to love them<figure><img src="https://images.theconversation.com/files/523208/original/file-20230427-961-e42c9v.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4500%2C2997&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/dandelion-grass-yellow-flower-green-close-1950501952">Elvira Tursynbayeva/Shutterstock</a></span></figcaption></figure><p><a href="https://www.rhs.org.uk/weeds/dandelion">Dandelions</a>, love them or hate them, are <a href="https://www.wildlifetrusts.org/news/make-yours-dandelion-spring">blooming in abundance</a> all over the UK this spring. As an ecologist who studies the insects which visit these flowers, so redolent of sunshine, I have never been able to understand why anyone might hate them. </p>
<p>Why do some people despair when they see a dandelion poking through the grass in their garden, or through the concrete on their drive? Most see dandelions as “weeds”: they don’t want them around their house and will reach for the lawnmower, or worse still, a <a href="https://www.sciencedirect.com/science/article/abs/pii/S1618866719309628">can of weed killer</a>, when one dares to rear its yellow head. </p>
<p>Perhaps I’m strange for rejoicing at the sight of a street, lawn or field blooming with dandelion heads. But as these flowers make fantastic food for a wide range of endangered bees, I’d like to convince you to love these flowers as I do, and to care for them as you would any other wildflower in a meadow.</p>
<figure class="align-center ">
<img alt="A roadside verge filled with flowering dandelions." src="https://images.theconversation.com/files/522971/original/file-20230426-20-ch94a4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/522971/original/file-20230426-20-ch94a4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522971/original/file-20230426-20-ch94a4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522971/original/file-20230426-20-ch94a4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522971/original/file-20230426-20-ch94a4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522971/original/file-20230426-20-ch94a4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522971/original/file-20230426-20-ch94a4.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">
<figcaption>
<span class="caption">The dandelion (<em>Taraxacum officiale</em>) can grow almost anywhere.</span>
<span class="attribution"><span class="source">Philip Donkersley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Flowers in the city</h2>
<p>The last 50 years have seen urban areas and farms expand across the UK. What few places were set aside to provide for wildlife have been eroded. We have pushed nature to the brink, but nature adapts, changes and overcomes these obstacles. </p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>Many people think of plants as nice-looking greens. Essential for clean air, yes, but simple organisms. A step change in research is shaking up the way scientists think about plants: they are far more complex and more like us than you might imagine. This blossoming field of science is too delightful to do it justice in one or two stories.</em> </p>
<p><em><a href="https://theconversation.com/topics/plant-curious-137238?utm_source=TCUK&utm_medium=linkback&utm_campaign=PlantCurious2023&utm_content=InArticleTop">This article is part of a series, Plant Curious</a>, exploring scientific studies that challenge the way you view plantlife.</em></p>
<hr>
<p>Studies of bee feeding patterns in cities, where much of their original food sources have been covered with concrete and tarmac, show a shift in their <a href="https://link.springer.com/article/10.1007/s00442-017-3968-3">wild, diverse diet</a> to one dominated by <a href="https://link.springer.com/article/10.1007/s10841-014-9694-9/">dandelions, clover</a> and <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.9490">brambles</a>.</p>
<p>Dandelions are an abundant source of nectar and pollen for bees flying around an environment in which the diversity of food options continues to shrink. These plants grow in very little soil, flower from <a href="https://www.sciencedirect.com/science/article/abs/pii/S0169534707001541">early spring to just before winter</a> and offer sustenance for bees all year round.</p>
<p>What makes dandelions so successful in feeding a wide variety of pollinators is the shape of their flowers.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/522982/original/file-20230426-20-20upgr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small bee nestled in the middle of a dandelion flower." src="https://images.theconversation.com/files/522982/original/file-20230426-20-20upgr.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/522982/original/file-20230426-20-20upgr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=531&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522982/original/file-20230426-20-20upgr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=531&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522982/original/file-20230426-20-20upgr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=531&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522982/original/file-20230426-20-20upgr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=667&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522982/original/file-20230426-20-20upgr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=667&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522982/original/file-20230426-20-20upgr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=667&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 common carder bee (<em>Bombus pascorum</em>).</span>
<span class="attribution"><span class="source">Philip Donkersley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The evolution of bees is a dance between the changing shapes of flowers and the corresponding length of bee tongues. Complicated flowers, like <a href="https://www.kew.org/plants/vanilla">vanilla</a>, evolved to make sure only a certain bee species could pollinate them, whereas others have evolved simple, open flowers that anyone can get pollen and nectar from.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/522981/original/file-20230426-186-sob7tw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bumblebee perched on a dandelion flower." src="https://images.theconversation.com/files/522981/original/file-20230426-186-sob7tw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/522981/original/file-20230426-186-sob7tw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522981/original/file-20230426-186-sob7tw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522981/original/file-20230426-186-sob7tw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522981/original/file-20230426-186-sob7tw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522981/original/file-20230426-186-sob7tw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522981/original/file-20230426-186-sob7tw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A buff tailed bumblebee (<em>Bombus terrestris</em>).</span>
<span class="attribution"><span class="source">Philip Donkersley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Dandelions fall into this second camp. Take a look at a patch of dandelion flowers and you’ll be amazed at the diversity of visitors. Over just 10 minutes in my garden I spotted at least 10 different bee and fly species: the ever abundant <a href="https://www.wildlifetrusts.org/wildlife-explorer/invertebrates/bees-and-wasps/buff-tailed-bumblebee">buff-tailed bumblebee</a>, as well as the common <a href="https://www.wildlifetrusts.org/wildlife-explorer/invertebrates/bees-and-wasps/common-carder-bee">carder bee</a> and a <a href="https://www.wildlifetrusts.org/wildlife-explorer/invertebrates/bees-and-wasps/honey-bee">honeybee</a> from one of my own hives working hard to collect pollen for the colony.</p>
<p>Among the many threats to pollinators (pesticides, the destruction of nest habitat, invasive species), <a href="https://www.mdpi.com/2306-7381/7/3/119">lack of food</a> is one of the most important. Highly abundant dandelions can go a long way to bridging this gap – at least in terms of <a href="https://www.mdpi.com/2075-4450/11/5/304">nectar</a>.</p>
<figure class="align-center ">
<img alt="A close-up image of a honeybee bestriding a dandelion flower." src="https://images.theconversation.com/files/522984/original/file-20230426-20-sag6mc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/522984/original/file-20230426-20-sag6mc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=587&fit=crop&dpr=1 600w, https://images.theconversation.com/files/522984/original/file-20230426-20-sag6mc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=587&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/522984/original/file-20230426-20-sag6mc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=587&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/522984/original/file-20230426-20-sag6mc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=738&fit=crop&dpr=1 754w, https://images.theconversation.com/files/522984/original/file-20230426-20-sag6mc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=738&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/522984/original/file-20230426-20-sag6mc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=738&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A honeybee (<em>Apis mellifera</em>) feeding on a dandelion, its leg baskets full of pollen.</span>
<span class="attribution"><span class="source">Philip Donkersley</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Some scientists have argued that dandelion pollen is not the best for bees. Research suggests that it may contain high levels of the essential amino acid <a href="https://www.frontiersin.org/articles/10.3389/fcell.2021.728576/full">proline</a> (which bees can only get from food and cannot make themselves), but lack several others, like <a href="https://academic.oup.com/jee/article-abstract/80/1/14/757976">isoleucine and valine</a>. A diet lacking in these elements can <a href="https://www.sciencedirect.com/science/article/abs/pii/S002220111200167X">hamper</a> a bee’s ability to grow, resist disease and raise its young. </p>
<p>But in a world where bees are stressed by a lack of any food at all, I would argue that any source that can proliferate under the toughest conditions like dandelions is a worthwhile thing to preserve.</p>
<h2>Dandelion dawn</h2>
<p><a href="https://www.plantlife.org.uk/campaigns/nomowmay/">No Mow May</a> approaches: a campaign sponsored by the charity <a href="https://www.plantlife.org.uk/campaigns/nomowmay/">Plantlife</a> to let weeds grow in gardens. Sadly, at the end of May, all that lovely wildflower habitat could be cut down and sprayed with herbicides.</p>
<p>Manicured lawns are essentially green deserts: ostensibly full of plants but with nothing to nourish bees or other wildlife.</p>
<p>Not everyone wants a lawn full of wildflowers. So I would recommend, rather than setting aside the whole garden for nature a month, trying to set aside a patch forever. </p>
<figure class="align-center ">
<img alt="A row of poppies and other wildflowers." src="https://images.theconversation.com/files/523210/original/file-20230427-16-tdsmla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523210/original/file-20230427-16-tdsmla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=244&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523210/original/file-20230427-16-tdsmla.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=244&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523210/original/file-20230427-16-tdsmla.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=244&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523210/original/file-20230427-16-tdsmla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=306&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523210/original/file-20230427-16-tdsmla.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=306&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523210/original/file-20230427-16-tdsmla.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=306&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Even a strip of wildflowers will benefit bugs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/beautiful-wildflowers-on-lovely-sunny-day-1441015007">Liz Miller/Shutterstock</a></span>
</figcaption>
</figure>
<p>Dandelions are amazing plants that can survive anywhere, as long as we allow them. They are a lifeline for pollinators on the brink and need protecting as part of our environment in car parks, roads and lawns. The next time you see a dandelion, try to see it as a bee would.</p><img src="https://counter.theconversation.com/content/204504/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Philip Donkersley 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>Before you reach for the weed killer, spare a thought for struggling pollinators.Philip Donkersley, Senior Research Associate in Entomology, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1825992023-02-15T19:06:20Z2023-02-15T19:06:20ZTrees can be weeds too – here’s why that’s a problem<figure><img src="https://images.theconversation.com/files/510000/original/file-20230214-16-h13uwj.jpg?ixlib=rb-1.1.0&rect=55%2C77%2C3601%2C2329&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/124930081@N08/19069175689/">John Jennings/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>When we think of weeds, often what comes to mind are small, quick-growing plants such as the dandelions or couch grass we might find in our gardens. You may not think of trees as being weedy. </p>
<p>But trees can be weeds too. They can spread quickly, showering an area in seeds and pushing out other species. Even species native to Australia can be a problem when they’re introduced to other areas. </p>
<p>It’s worth knowing the most common weedy trees so you can avoid planting them – or take them out before they get large and expensive to remove.</p>
<h2>Which overseas trees can be weeds?</h2>
<p>In many parts of Australia, the common <a href="https://profiles.ala.org.au/opus/weeds-australia/profile/Pinus%20radiata">Monterey pine</a> (<em>Pinus radiata</em>) is a serious weed. Native to the United States, it’s widely planted in forestry plantations and as windbreaks on farms. Renowned for rapid growth, these pines seed prolifically and spread easily. Their needles contain chemicals that stop other plants growing beneath them.</p>
<p><a href="https://profiles.ala.org.au/opus/weeds-australia/profile/Cinnamomum%20camphora">Camphor laurel</a> (<em>Cinnamomum camphora</em>), a tree native to China, Japan and Taiwan, can dominate moist environments and force out other species. It was once planted widely to give shade, especially in southeastern Queensland. Cities such as Toowoomba still have streets <a href="https://gumtreesandgalaxies.com/2020/09/23/a-green-embrace/">lined with them</a>. But these trees are major weeds on farms. Every part of the plant is toxic to aquatic life.</p>
<figure class="align-center ">
<img alt="Sunlight shining on the leaves of a desert ash (Fraxinus angustifolia)" src="https://images.theconversation.com/files/510214/original/file-20230214-28-3qmy8o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510214/original/file-20230214-28-3qmy8o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510214/original/file-20230214-28-3qmy8o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510214/original/file-20230214-28-3qmy8o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510214/original/file-20230214-28-3qmy8o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510214/original/file-20230214-28-3qmy8o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510214/original/file-20230214-28-3qmy8o.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">Desert ash (Fraxinus angustifolia) is a common European tree that spreads readily.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/o_0/51137416482/in/photolist-oVa5Zz-62Hjix-nyJanC-2niEMtA-8SNfsg-6vhoGr-2niDtPt-2niCfVr-7ZmGUW-9f6NgD-2niCqtX-2kUQCjw-5os56h-2niCfXR-2niwSGQ-2niCfUp-6vhn1a-82b4Gg-MPtrT2">Guilhem Vellut/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Similarly, <a href="https://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_trees_desert_ash">desert ash</a> (<em>Fraxinus angustifolia</em>) was once planted as a street tree across Australia’s southeast. But this common European tree showers spiralling wind-borne seeds over a wide area, and can spread by suckers too. It outcompetes native trees and invades nature reserves.</p>
<p><a href="https://theconversation.com/why-theres-a-lot-more-to-love-about-jacarandas-than-just-their-purple-flowers-150851">Jacarandas</a> are hugely popular with many Australians, especially when they are in full flower, but they can be hard to control in South Africa and parts of Australia.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pulling-out-weeds-is-the-best-thing-you-can-do-to-help-nature-recover-from-the-fires-130296">Pulling out weeds is the best thing you can do to help nature recover from the fires</a>
</strong>
</em>
</p>
<hr>
<p>Not all weedy trees are prolific seeders. Some reproduce from suckers to create dense thickets of woody growth. Many of our native Acacia or wattle species sucker prolifically after fire and floods. A single tree in your garden can give rise to a thicket of hundreds of small trees that are difficult to eradicate.</p>
<p>The iconic <a href="https://weeds.dpi.nsw.gov.au/Weeds/Willows">willow</a> (<em>Salix</em>) was once widely planted along waterways to stop erosion. Unfortunately, they grow very rapidly from pieces of a tree that break off and take root in moist soil. These thirsty trees quickly spread along thousands of kilometres of creeks and rivers. It’s now illegal to sell almost any willow species, except for less-invasive ones such as the weeping willow.</p>
<h2>Our trees can be pests overseas</h2>
<p>Australia’s own <a href="https://myfwc.com/wildlifehabitats/habitat/invasive-plants/weed-alerts/melaleuca/#:%7E:text=In%20the%20Everglades%2C%20melaleuca%20trees,that%20create%20hot%20crown%20fires">broad-leafed paperbark</a> (<em>Melaleuca quinquenervia</em>) has become a major weed tree in Florida’s famous Everglades, creating dense thickets and crowding out native species. It’s similarly devastating in Madagascar.</p>
<figure class="align-center ">
<img alt="A dense thicket of broad-leafed paperbark (Melaleuca quinquenervia)" src="https://images.theconversation.com/files/510217/original/file-20230214-18-a3d929.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510217/original/file-20230214-18-a3d929.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510217/original/file-20230214-18-a3d929.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510217/original/file-20230214-18-a3d929.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510217/original/file-20230214-18-a3d929.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510217/original/file-20230214-18-a3d929.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510217/original/file-20230214-18-a3d929.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">
<figcaption>
<span class="caption">Broad-leafed paperbark (Melaleuca quinquenervia) is a native Australian plant causing issues in Florida.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/starr-environmental/24580743671/">Forest and Kim Starr/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Even our beloved river red gum <a href="https://theconversation.com/south-africa-needs-a-fresh-approach-to-managing-invasive-trees-like-eucalyptus-126777">is a problem</a> in southern Africa, where it spreads easily, while the Tasmanian blue gum has spread so widely in California that its <a href="https://www.theguardian.com/us-news/2019/dec/16/california-eucalyptus-trees-environment-comic">detractors</a> dub it the “gasoline tree” for its ability to intensify fires.</p>
<h2>Even native trees can be pests</h2>
<p>Trees don’t have to come from overseas to be considered weeds. <a href="https://keyserver.lucidcentral.org/weeds/data/media/Html/pittosporum_undulatum.htm#:%7E:text=Sweet%20pittosporum%20(Pittosporum%20undulatum)%20is,and%20on%20Lord%20Howe%20Island">Sweet pittosporum</a> (<em>Pittosporum undulatum</em>) occurs naturally in Victoria and New South Wales. Even so, it’s considered weedy in parts of both states, as well as in Western Australia, New Zealand, parts of Africa, and the United States.</p>
<p>This tree engages in chemical warfare, its fallen leaves suppressing rival species. Currawongs and common mynahs eat its fruit and spread the seeds in their droppings.</p>
<figure class="align-center ">
<img alt="A sweet pittosporum (Pittosporum undulatum) ladden with orange fruits" src="https://images.theconversation.com/files/510221/original/file-20230214-16-89zg5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510221/original/file-20230214-16-89zg5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510221/original/file-20230214-16-89zg5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510221/original/file-20230214-16-89zg5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510221/original/file-20230214-16-89zg5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510221/original/file-20230214-16-89zg5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510221/original/file-20230214-16-89zg5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sweet pittosporum (Pittosporum undulatum) is native to Australia but is causing issues in other parts of Australia where it does not occur naturally.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/jakub303/3138349787/in/photolist-5MjS46-5Lq5tG-5PvJHH-DJSChk-EzV2N-5Lq68S-EBaAX-7YGL6X-2kh52xh-X9dGXT-2kh9fKv-2kh9fGK-5NayMt-2nUNYmx-MHv9DX-2bp7cdQ-28HeiNU-mwLGN8-SP2znA-8SVJyd-6UVbgM-SwAvZd-5NAh9Q-68Y6dZ-5Lq4Nf-qrdbD2-2m8T5ig-37g5w9-2jJmtHS-6cCn9W-2jJhUJ8-DyWo1Q-8SSQLN-5PA1PL-2mzR7fb-8SPKEM-8SSQAW-8SSQzC-mwL8De-8rjWWb-avJdHq-avFySv-avFza4-9dhkb3-M5uT3t-4HkpSg-msYUY-9V2Pr3-8Bq1oR-vvHY9E">jakub303/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>The once widely loved <a href="https://weedsbluemountains.org.au/weeds/cootamundra-wattle/">Cootamundra wattle</a> (<em>Acacia baileyana</em>), with its golden orb flowers and grey leaves, is now considered a weed outside its native range in NSW. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/planning-to-plant-an-australian-native-like-wattle-read-this-first-you-might-be-spreading-a-weed-165165">Planning to plant an Australian native like wattle? Read this first — you might be spreading a weed</a>
</strong>
</em>
</p>
<hr>
<h2>What can be done about these trees?</h2>
<p>Which trees are most likely to <a href="https://www.environment.vic.gov.au/invasive-plants-and-animals/weed-risk-ratings">become weeds</a>? Those that reproduce quickly, grow fast, tolerate different soils and climates, have fruit or seeds dispersed by animals and birds, and are able to force out native tree species.</p>
<p>It’s far better we stop new species from becoming weeds rather than to try to control them once they’re here. </p>
<p>But for those species already in the soil, we’re left with control measures. In many places, government agencies can direct you <a href="https://agriculture.vic.gov.au/biosecurity/weeds/invasive-plant-classifications">to remove</a> weed species. Local governments can ban the planting of certain weedy species and require land owners to remove such species at their own expense.</p>
<p>Our efforts here often have had little effect. Some plants regulated as weeds in the 1800s never became weedy; others long considered weeds remain so and some have become even bigger problems. Some Northern Hemisphere thistles were proclaimed weeds more than a century ago, but have since proved not to be a major problem. African boxthorn (<em>Lycium ferocissimum</em>) is still a problem, despite being a listed and controlled weed for more than a century. </p>
<p>Botanists have tried to tackle the issue by <a href="https://www.whatgrowsthere.com/grow/2018/01/04/tree-cultivars-varietiesthat-do-not-produce-seeds-or-fruits">breeding varieties</a> of attractive but weedy trees with far fewer fruit and seeds. You can now buy safer varieties of maple (<em>Acer</em>), black locust (<em>Robinia pseudoacacia</em>), white cedar (<em>Melia azedarach</em>) and liquidambar.</p>
<p>So next time you’re looking to plant a new tree in your garden, look into whether the species is OK for the area. You could also consider joining a local group involved in caring for parks and reserves and help remove any weedy trees.</p><img src="https://counter.theconversation.com/content/182599/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gregory Moore 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>From pine trees to camphor laurel and even the Cootamundra wattle, trees can be weeds too.Gregory Moore, Senior Research Associate, School of Ecosystem and Forest Sciences, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1970142022-12-22T06:29:34Z2022-12-22T06:29:34ZThe peculiar history of thornapple, the hallucinogenic weed that ended up in supermarket spinach<figure><img src="https://images.theconversation.com/files/502496/original/file-20221222-17-jd44zw.jpg?ixlib=rb-1.1.0&rect=0%2C1%2C1000%2C664&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/white-flower-poisonous-vespertineflowering-thornapple-plant-2199701639">Shutterstock</a></span></figcaption></figure><p>The agent that contaminated baby spinach, prompting the recent <a href="https://www.foodstandards.gov.au/industry/foodrecalls/recalls/Pages/Baby-spinach-recall.aspx">national recall</a>, has been <a href="https://www.theguardian.com/world/2022/dec/21/weed-responsible-for-hallucinogenic-spinach-recall-identified-as-applethorn">revealed</a>. It’s a weed, not deliberate misadventure or a chemical contaminant. </p>
<p>The culprit is <a href="https://weeds.dpi.nsw.gov.au/Weeds/Commonthornapple">thornapple</a>, otherwise known as jimsonweed or, to give it its scientific name, <em>Datura stramonium</em>.</p>
<p>Multiple cases of poisoning, now extending <a href="https://www.foodstandards.gov.au/industry/foodrecalls/recalls/Pages/Baby-spinach-recall.aspx">into their hundreds</a>, have been reported across numerous Australian jurisdictions in the past couple of weeks, following the consumption of baby spinach.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1605509424260517889"}"></div></p>
<h2>From blurred vision to hallucinations</h2>
<p><a href="https://www.foodstandards.gov.au/industry/foodrecalls/recalls/Pages/Baby-spinach-recall.aspx">Symptoms included</a> blurred vision, dry mouth, abdominal cramps – and quite significant hallucinations. These are all classic symptoms of “<a href="https://www.ncbi.nlm.nih.gov/books/NBK534798/">anticholinergic poisoning</a>”. </p>
<p>“Toxidromes” are patterns of symptoms that give medical responders clues to what agent might be responsible for a poisoning. Not all types of poisoning come with their own toxidrome, but of those that do, anticholinergic poisoning is one of the most colourful and well-characterised.</p>
<p>There would be very few medical students who would not be familiar with some version of the <a href="https://www.rch.org.au/clinicalguide/guideline_index/Anticholinergic_Syndrome/">mnemonic</a></p>
<blockquote>
<p>red as a beet, dry as a bone, blind as a bat, mad as a hatter, hot as a hare, full as a flask. </p>
</blockquote>
<p>This reflects the characteristic flushing, drying up of sweating and saliva, dilation of pupils, “altered mental state”, fever and, in some occasions, urinary retention. Additional features can include stomach cramps. An “altered mental state” can manifest as delirium, hallucinations, agitation, restlessness or confusion, together with possible changes in speech and gait, among other effects.</p>
<p>All of these effects are due to toxins that block the action of an essential neurotransmitter (chemical messenger in the nervous system), <a href="https://www.ncbi.nlm.nih.gov/books/NBK11143/">acetylcholine</a> and its receptor.</p>
<p>These are vital cogs in the autonomic nervous system, the maintenance janitor of our nervous system. Fundamental as it is to our survival, it is hardly a surprise that any disturbance of its function results in fairly dramatic effects.</p>
<p>It is also similarly not that surprising that humans have known about plant materials that exert these effects for as long as humans have been interested in using plants for either therapeutic or nefarious purposes.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/i-have-always-wondered-why-are-some-fruits-poisonous-83210">I have always wondered: why are some fruits poisonous?</a>
</strong>
</em>
</p>
<hr>
<h2>A rich history of using these plants</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/502518/original/file-20221222-26-76w7a3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Woman with a mirror" src="https://images.theconversation.com/files/502518/original/file-20221222-26-76w7a3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/502518/original/file-20221222-26-76w7a3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=702&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502518/original/file-20221222-26-76w7a3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=702&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502518/original/file-20221222-26-76w7a3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=702&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502518/original/file-20221222-26-76w7a3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=882&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502518/original/file-20221222-26-76w7a3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=882&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502518/original/file-20221222-26-76w7a3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=882&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Titian’s Woman with a Mirror is thought to depict use of deadly nightshade to dilate the pupils.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Tiziano,_donna_allo_specchio,_1515_ca._01.JPG">Sailko/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412926/">Tropane alkaloids</a> are both valuable, and potentially dangerous, compounds with a rich history.</p>
<p>Ancient Egyptians reportedly burned <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2844275/">henbane</a> and inhaled its smoke as one of the earliest treatments for asthma.</p>
<p><a href="https://www.rcpe.ac.uk/heritage/deadly-nightshade-botanical-biography">Deadly nightshade</a> was used in Renaissance Italy as both a poison and as a cosmetic agent, with drops of extract used to dilate the pupils of wealthy ladies. Titian’s <a href="https://www.fs.usda.gov/wildflowers/ethnobotany/Mind_and_Spirit/belladonna.shtml">Woman with a Mirror</a> is thought to depict this. </p>
<h2>Then there were the naked soldiers</h2>
<p>Thornapple has its own peculiar story, which is impossible to confirm but may give us clues to the origin of its other name, jimsonweed.</p>
<p>There is a <a href="https://wydaily.com/news/local/2021/10/22/oddities-curiosities-the-colonial-case-of-the-mysterious-jimson-weed/">widely reported story</a> from colonial times in Jamestown, Virginia, where British soldiers were sent to quell an uprising in Bacon in the 1600s. </p>
<p>The soldiers prepared a meal from the plant and shortly afterwards, were entirely incapacitated. They were, <a href="https://docsouth.unc.edu/southlit/beverley/beverley.html">apparently</a> “stark naked … sitting up in a corner, like a monkey, grinning and making mows at them”. Another of the affected soldiers would “fondly kiss, and paw his companions”. </p>
<p>This was regarded as a something of a worry in an armed expeditionary force. So the plant earned the additional names “devil’s snare” or “devil’s trumpet”.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/little-shop-of-horrors-the-australian-plants-that-can-kill-you-50842">Little shop of horrors: the Australian plants that can kill you</a>
</strong>
</em>
</p>
<hr>
<h2>Back in Australia</h2>
<p>Plants from the <em>Datura</em> genus and the closely related, woody cousin, angel’s trumpet, are widely grown for their decorative flowers around Australia. Occasionally some people deliberately consume them for their hallucinogenic effects, with misadventure requiring medical intervention not uncommon.</p>
<p>Every year, poisons centres and emergency departments around the country are involved in managing these recreational overdoses. </p>
<p>Accidental overdoses, such as the one affecting the baby spinach crop, are less common but not unheard of. One such outbreak was reported <a href="https://www.napolike.com/pozzuoli-pianta-velenosa-venduta-come-spinaci-8-intossicati-uno-e-grave">in Italy</a> earlier this year. </p>
<p>Unfortunately, thornapple is a hardy plant, with seeds that can reputedly last several decades. Without constant agricultural vigilance, contamination of plants meant for human consumption remains a possibility.</p>
<p>For those not anticipating the effects, poisoning can be quite disturbing, not just from the obvious physical effects, but from the disconcerting hallucinations. Fortunately, the treatment of such exposures, once identified, is usually relatively straightforward. </p>
<p>Given the characteristic toxidrome, and the efficiency of modern poisons information centres, outbreaks and sources can be identified very rapidly, and the public protected from further exposure, as has been the case here.</p><img src="https://counter.theconversation.com/content/197014/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Caldicott has previously been the recipient of an NH&MRC partnership grant.</span></em></p>Thornapple or jimsonweed and related plants have an interesting history – from an early asthma treatment to intoxicated British soldiers.David Caldicott, Senior lecturer, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1922322022-10-11T12:20:17Z2022-10-11T12:20:17Z‘Silent Spring’ 60 years on: 4 essential reads on pesticides and the environment<figure><img src="https://images.theconversation.com/files/489065/original/file-20221010-16-58644.jpg?ixlib=rb-1.1.0&rect=38%2C0%2C5153%2C3470&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spraying from either a ground-based vehicle or an airplane is a common method for applying pesticides.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/aerial-of-spray-application-in-green-agricultural-field-on-news-photo/687564922">Edwin Remsburg/VW Pics via Getty Images</a></span></figcaption></figure><p>In 1962 environmental scientist Rachel Carson published “<a href="http://www.rachelcarson.org/SilentSpring.aspx">Silent Spring</a>,” a bestselling book that asserted that overuse of pesticides was harming the environment and threatening human health. Carson did not call for banning DDT, the most widely used pesticide at that time, but she argued for using it and similar products much more selectively and paying attention to their effects on nontargeted species. </p>
<p>“Silent Spring” is widely viewed as <a href="https://www.nytimes.com/2012/09/23/magazine/how-silent-spring-ignited-the-environmental-movement.html">an inspiration for the modern environmental movement</a>. These articles from The Conversation’s archive spotlight ongoing questions about pesticides and their effects.</p>
<h2>1. Against absolutes</h2>
<p>Although the chemical industry attacked “Silent Spring” as <a href="https://www.penguinrandomhouse.com/books/170448/on-a-farther-shore-by-william-souder/">anti-science and anti-progress</a>, Carson believed that chemicals had their place in agriculture. She “favored <a href="https://theconversation.com/would-rachel-carson-eat-organic-94967">a restrained use of pesticides, but not a complete elimination</a>, and did not oppose judicious use of manufactured fertilizers,” writes Harvard University sustainability scholar <a href="https://wcfia.harvard.edu/people/robert-l-paarlberg">Robert Paarlberg</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/489066/original/file-20221010-12-j4yhcg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman seated at a microphone delivers a statement to a Congressional committee." src="https://images.theconversation.com/files/489066/original/file-20221010-12-j4yhcg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489066/original/file-20221010-12-j4yhcg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=432&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489066/original/file-20221010-12-j4yhcg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=432&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489066/original/file-20221010-12-j4yhcg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=432&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489066/original/file-20221010-12-j4yhcg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=543&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489066/original/file-20221010-12-j4yhcg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=543&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489066/original/file-20221010-12-j4yhcg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=543&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Activist and author Rachel Carson, whose book ‘Silent Spring’ triggered a reassessment of pesticide use, testifies before a Senate Government Operations Subcommittee in Washington, D.C., June 4, 1963.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/SilentSpringAuthorTestifies/7b45b46735fb4021b0c2e4c9f882fa34/photo">AP Photo/Charles Gorry</a></span>
</figcaption>
</figure>
<p>This approach put Carson at odds with the fledgling organic movement, which totally rejected synthetic pesticides and fertilizers. Early organic advocates claimed Carson as a supporter nonetheless, but Carson kept them at arm’s length. “The organic farming movement was suspect in Carson’s eyes because most of its early leaders were not scientists,” Paarlberg observes. </p>
<p>This divergence has echoes today in debates about whether organic production or steady improvements in conventional farming have more potential to feed a growing world population.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/would-rachel-carson-eat-organic-94967">Would Rachel Carson eat organic?</a>
</strong>
</em>
</p>
<hr>
<h2>2. Concerned cropdusters</h2>
<p>Well before “Silent Spring” was published, a crop-dusting industry developed on the Great Plains in the years after World War II to apply newly commercialized pesticides. “Chemical companies made broad promises about these ‘miracle’ products, with little discussion of risks. But pilots and scientists took <a href="https://theconversation.com/farmers-and-cropdusting-pilots-on-the-great-plains-worried-about-pesticide-risks-before-silent-spring-91976">a much more cautious approach</a>,” recounts University of Nebraska-Kearney historian <a href="https://scholar.google.com/citations?user=37kbK3MAAAAJ&hl=en">David Vail</a>. </p>
<p>As Vail’s research shows, many crop-dusting pilots and university agricultural scientists were well aware of how little they knew about how these new tools actually worked. They attended conferences, debated practices for applying pesticides and organized flight schools that taught agricultural science along with spraying techniques. When “Silent Spring” was published, many of these practitioners pushed back, arguing that they had developed strategies for managing pesticide risks.</p>
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<figcaption><span class="caption">Archival footage of crop-dusters spraying in California in the 1950s.</span></figcaption>
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<p>Today aerial spraying is still practiced on the Great Plains, but it’s also clear that insects and weeds rapidly evolve resistance to every new generation of pesticides, trapping farmers on what Vail calls “a chemical-pest treadmill.” Carson anticipated this effect in “Silent Spring,” and called for more research into alternative pest control methods – an approach that <a href="https://www.usda.gov/oce/pest/integrated-pest-management">has become mainstream today</a>.</p>
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Read more:
<a href="https://theconversation.com/farmers-and-cropdusting-pilots-on-the-great-plains-worried-about-pesticide-risks-before-silent-spring-91976">Farmers and cropdusting pilots on the Great Plains worried about pesticide risks before 'Silent Spring'</a>
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<h2>3. The osprey’s crash and recovery</h2>
<p>In “Silent Spring,” Carson described in detail how chlorinated hydrocarbon pesticides persisted in the environment long after they were sprayed, rising through the food chain and building up in the bodies of predators. Populations of fish-eating <a href="https://raptor.umn.edu/about-raptors/learn-about-raptors">raptors</a>, such as bald eagles and ospreys, were ravaged by these chemicals, which thinned the shells of the birds’ eggs so that they broke in the nest before they could hatch. </p>
<p>“Up to 1950, ospreys were one of the most widespread and abundant hawks in North America,” writes Cornell University research associate <a href="https://academy.allaboutbirds.org/person/alan-poole/">Alan Poole</a>. “By the mid-1960s, the number of ospreys breeding along the Atlantic coast between New York City and Boston <a href="https://theconversation.com/ospreys-recovery-from-pollution-and-shooting-is-a-global-conservation-success-story-111907">had fallen by 90%</a>.”</p>
<p>Bans on DDT and other highly persistent pesticides opened the door to recovery. But by the 1970s, many former osprey nesting sites had been developed. To compensate, concerned naturalists built nesting poles along shorelines. Ospreys also learned to colonize light posts, cell towers and other human-made structures.</p>
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<figcaption><span class="caption">Wildlife monitors band young ospreys in New York City’s Jamaica Bay to monitor their lives and movements.</span></figcaption>
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<p>Today, “Along the shores of the Chesapeake Bay, nearly 20,000 ospreys now arrive to nest each spring – the largest concentration of breeding pairs in the world. Two-thirds of them nest on buoys and channel markers maintained by the U.S. Coast Guard, who have become de facto osprey guardians,” writes Poole. “To have robust numbers of this species back again is a reward for all who value wild animals, and a reminder of how nature can rebound if we address the key threats.”</p>
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Read more:
<a href="https://theconversation.com/ospreys-recovery-from-pollution-and-shooting-is-a-global-conservation-success-story-111907">Ospreys' recovery from pollution and shooting is a global conservation success story</a>
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<h2>4. New concerns</h2>
<p>Pesticide application techniques have become much more targeted in the 60 years since “Silent Spring” was published. One prominent example: crop seeds coated with neonicotinoids, the world’s most widely used class of insecticides. Coating the seeds makes it possible to introduce pesticides into the environment at the point where they are needed, without spraying a drop. </p>
<p>But a growing body of research indicates that even though coated seeds are highly targeted, much of their pesticide load washes off into nearby streams and lakes. “Studies show that neonicotinoids are <a href="https://theconversation.com/farmers-are-overusing-insecticide-coated-seeds-with-mounting-harmful-effects-on-nature-176109">poisoning and killing aquatic invertebrates</a> that are vital food sources for fish, birds and other wildlife,” writes Penn State entomologist <a href="https://scholar.google.com/citations?user=AAdZM1UAAAAJ&hl=en">John Tooker</a>.</p>
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<p>In multiple studies, Tooker and colleagues have found that using coated seeds reduces populations of beneficial insects that prey on crop-destroying pests like slugs. </p>
<p>“As I see it, neonicotinoids can provide good value in controlling critical pest species, particularly in vegetable and fruit production, and managing invasive species like the spotted lanternfly. However, I believe the time has come to rein in their use as seed coatings in field crops like corn and soybeans, where they are providing little benefit and where the scale of their use is causing the most critical environmental problems,” Tooker writes.</p>
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Read more:
<a href="https://theconversation.com/farmers-are-overusing-insecticide-coated-seeds-with-mounting-harmful-effects-on-nature-176109">Farmers are overusing insecticide-coated seeds, with mounting harmful effects on nature</a>
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<p><em>Editor’s note: This story is a roundup of articles from The Conversation’s archive.</em></p><img src="https://counter.theconversation.com/content/192232/count.gif" alt="The Conversation" width="1" height="1" />
Published in 1962, ‘Silent Spring’ called attention to collateral damage from widespread use of synthetic pesticides. Many problems the book anticipated persist today in new forms.Jennifer Weeks, Senior Environment + Cities Editor, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1828112022-05-18T13:29:01Z2022-05-18T13:29:01ZHerbicides threaten edible weeds in Zambia – that may be bad news for local food security<figure><img src="https://images.theconversation.com/files/462690/original/file-20220512-19-l240fy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A woman cuts "bodwe", an edible weed that is often sold at markets in Lusaka, Zambia.</span> <span class="attribution"><span class="source">Alysha Vehre</span></span></figcaption></figure><p>The use of herbicides – substances that control unwanted plants – is on the rise across Africa. This trend has been referred to by some researchers as the “<a href="https://link.springer.com/article/10.1057/s41287-017-0090-7?msclkid=05756e62d06011ec869a121ce95f557d">herbicide revolution</a>”. This trend is driven by cheap herbicides flooding into the continent from Asia and global agrochemical companies discovering Africa’s emerging markets. Also, rural wages have risen due to rural-urban migration and structural transformation. </p>
<p>Herbicides may help to raise yields, thereby contributing to food security. They also reduce the large labour burden associated with manual weeding, which is often done by women and children. <a href="https://link.springer.com/article/10.1007/s13593-017-0453-7">Studies</a> suggest that herbicides can reduce labour use for weeding by 90%. <a href="https://ageconsearch.umn.edu/record/54464?ln=en">A study</a> in Zambia suggests that herbicide can reduce labour use for weeding from up to 70 to 10 days per hectare.</p>
<p>However, herbicides may also have negative effects on environmental and human health, particularly when substances are not carefully handled and no protective equipment is used. Unintentional pesticide poisoning kills 11,000 people every year, according to a <a href="https://link.springer.com/article/10.1186/s12889-020-09939-0">global study</a>.</p>
<p>In the quest to assess these trade-offs one aspect has received limited attention: the role of edible weeds, which can be key elements of rural food baskets, yet are targeted by herbicides.</p>
<p>In a <a href="https://tandfonline.com/doi/full/10.1080/14735903.2022.2065949">new study</a>, we explored the role of edible weeds in rural diets in Zambia and how herbicides affect their consumption. Edible weeds are an integral part of the daily diets of many Zambian farm families, in particular during the “hunger months” and during droughts, which will become more severe with the climate crisis. The herbicide revolution reduces the availability of edible weeds, which may undermine food and nutrition security as an important part of families’ diets is becoming under threat. </p>
<p>It’s up to individual farmers and societies at large to decide how much they want to use herbicides. But informed decisions should be made acknowledging all potential trade-offs, including those regarding edible weeds and food and nutrition security.</p>
<h2>Nutritious and useful</h2>
<p>For our study we surveyed or interviewed 158 randomly selected households in rural parts of eastern and southern Zambia where most families depend of farming. We also used qualitative methods such as field walks, focus group discussions, and stakeholder interviews.</p>
<p>All the households collected edible weeds from their fields. The most important species were spiny amaranth, nalta jute and plants from the aster family. Edible weeds provide important nutrients. <em>Amaranthus hybridus</em>, which is consumed by 88% of all households, contains high levels of vitamin A, iron, zinc, and protein. <em>Bidens pilosa</em> (or black-jack) is frequently used in Zambia to treat anaemia. </p>
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Read more:
<a href="https://theconversation.com/kenyas-push-to-promote-traditional-food-is-good-for-nutrition-and-cultural-heritage-176384">Kenya's push to promote traditional food is good for nutrition and cultural heritage</a>
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<p>Edible weeds are consumed by households regardless of wealth or the age and gender of the household head, underscoring how embedded they are in the area’s food culture. In the hunger months between December and March, after the previous year’s harvest has dwindled, many households consumed edible weeds every day.</p>
<p>Edible weeds are mostly eaten fresh but also preserved through drying. Between one and five types of these plants were preserved by 87% of the households. Nearly all of the households that preserved edible weeds did so to ensure future food security. The edible weed known as “bondwe” from the leafy <em>Amaranthaceae</em> family is also traded and sold in supermarkets in the capital, Lusaka.</p>
<h2>Households’ experiences</h2>
<p>Herbicide use in Zambia is slowly but steadily climbing. According to <a href="https://www.iapri.org.zm/rural-agricultural-livelihoods-survey-2019-report/?msclkid=0ddfc03bd06411ec9a316f6f870ca67c">a national survey</a> by the Zambian Indaba Agricultural Policy Research Institute, 28% of Zambian farmers use herbicides – up from 14% in 2015.</p>
<p>Herbicides are specifically designed to eradicate weeds. In contrast to manual weeding, herbicides are less selective and allow “clean weeding” where all weeds are destroyed. That’s why increased use of herbicides may cause edible weeds to disappear from food baskets.</p>
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<img alt="A woman in a bright blue and green dress stoops to collect edible weeds with two small children" src="https://images.theconversation.com/files/462691/original/file-20220512-13-69ahjt.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462691/original/file-20220512-13-69ahjt.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462691/original/file-20220512-13-69ahjt.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462691/original/file-20220512-13-69ahjt.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462691/original/file-20220512-13-69ahjt.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462691/original/file-20220512-13-69ahjt.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462691/original/file-20220512-13-69ahjt.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Families in the study area eat a variety of edible weeds.</span>
<span class="attribution"><span class="source">Alysha Vehre</span></span>
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<p>We found that the rise of herbicides, as measured by the share of plots sprayed, has not yet affected consumption of weeds. Households using herbicides can still access edible weeds from non-sprayed plots and from outside their farms. </p>
<p>However, households that have already been using herbicides for some time consume fewer edible weeds and many households themselves perceived trade-offs between herbicide use and edible weed availability. Close to 50% of the respondents perceived that fewer edible weeds were available.</p>
<h2>Trade-offs</h2>
<p>While edible weeds haven’t vanished entirely from the area we studied, it’s clear that their numbers are dropping. In the coming years, households will have to manoeuvre the trade-offs between herbicides and edible weeds. It is possible, for instance, that herbicides may contribute to higher agricultural production for these families – and that the additional revenues from increased harvests may be used to buy nutritious food and counterbalance the loss of edible weeds.</p>
<p>Whatever individual households decide, it’s crucial that they are given all the information about these trade-offs so they can collectively make informed decisions.</p><img src="https://counter.theconversation.com/content/182811/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Daum receives funding from the German Federal Ministry of Economic Cooperation and Development (BMZ).</span></em></p><p class="fine-print"><em><span>The data was collected as part of my master's thesis. In order to be able to carry out my master's thesis, I received a scholarship from fiat panis.</span></em></p><p class="fine-print"><em><span>Christoph Schunko does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The herbicide revolution reduces the availability of edible weeds, which may undermine food and nutrition security.Thomas Daum, Agricultural Economist, University of HohenheimCarolin Schweizerhof, Research fellow, University of HohenheimChristoph Schunko, Assistant scientist, University of Natural Resources and Life Science (BOKU)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1741812022-01-26T13:27:04Z2022-01-26T13:27:04ZThe herbicide dicamba was supposed to solve farmers’ weed problems – instead, it’s making farming harder for many of them<figure><img src="https://images.theconversation.com/files/442064/original/file-20220122-25-9rovsg.jpg?ixlib=rb-1.1.0&rect=51%2C0%2C5760%2C3794&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Soybean plants on an Arkansas farm. Those at left show signs of damage from dicamba; others at right were planted later in the season.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/at-david-wildys-soybean-fields-on-the-left-soybean-plants-news-photo/842398912">Washington Post via Getty Images</a></span></figcaption></figure><p>In October 2021 I was a guest on a popular podcast to discuss my recently published book, “<a href="https://wwnorton.com/books/9781324002048">Seed Money: Monsanto’s Past and Our Food Future</a>,” which examines the agribusiness giant’s influence on the global food system. After the show, I got a lot of calls from around the world, but one really stood out to me: A farmer speaking on his cellphone from the seat of his combine in South Dakota as he harvested soybeans.</p>
<p>Farmers don’t like to stop tractors on good-weather days in the fall, but this was important. The caller wanted to talk about a chemical weedkiller called <a href="http://npic.orst.edu/factsheets/dicamba_gen.html">dicamba</a> that had been sprayed on neighboring fields. He claimed it was damaging his crops. And he wasn’t alone.</p>
<p>In 2021, <a href="https://www.regulations.gov/document/EPA-HQ-OPP-2020-0492-0021">thousands of U.S. growers</a> reported to the Environmental Protection Agency that dicamba sprayed by other farmers – sometimes <a href="https://investigatemidwest.org/2020/10/29/epa-documents-show-dicamba-damage-worse-than-previously-thought/">up to a mile and a half away</a> – damaged crops in their fields. Complaints came from all over the country.</p>
<p><a href="https://www.regulations.gov/document/EPA-HQ-OPP-2020-0492-0021">The list</a> of affected plants was astounding: sycamore, oak and elm trees; azaleas, black-eyed Susans and roses; garden tomatoes, peppers and peas. <a href="https://www.regulations.gov/document/EPA-HQ-OPP-2020-0492-0003">According to an EPA memorandum</a>, there were 2,700 “dicamba incidents,” affecting about 3.6 million acres, in 2017. Two years later, the number of incidents ballooned to 3,300. </p>
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<figcaption><span class="caption">Farmers describe their concerns about dicamba damage in 2017.</span></figcaption>
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<p>This problem has been building for over five years, and the EPA acknowledges that the modest controls it has required, such as creating buffer zones around fields, <a href="https://www.epa.gov/pesticides/epa-releases-summary-dicamba-related-incident-reports-2021-growing-season">aren’t working</a>. But tighter curbs on use of dicamba aren’t likely before the 2022 growing season starts in the spring, because they would require a <a href="https://www.epa.gov/pesticides/epa-releases-summary-dicamba-related-incident-reports-2021-growing-season">complicated legal process</a>. </p>
<p>Why is it so hard to address this national problem? Answering that question requires looking back to 1996, when a revolution transformed American agriculture.</p>
<h2>From Roundup to dicamba</h2>
<p>Weeds have always been an expensive headache for farmers. A 2016 study estimated that if left uncontrolled, weeds would cut corn and soybean yields in North America roughly in half, causing <a href="https://wssa.net/wssa/weed/croploss-2/">US$43 billion in yearly economic losses</a> just from those two crops. One of the problems farmers face is that weeds are very good at evolving resistance to chemical products used to kill them, so herbicides lose their effectiveness over time.</p>
<p>Weed problems became especially bad in the late 1980s and early 1990s as widely used herbicides called ALS inhibitors <a href="https://doi.org/10.1177/074823379901500120">became less and less effective</a>. That’s why farmers were enthusiastic about Monsanto’s “Roundup Ready” crops, first introduced in 1996. </p>
<p>These plants were engineered to resist heavy spraying of Monsanto’s <a href="https://www.nytimes.com/2001/08/02/business/the-power-of-roundup-a-weed-killer-is-a-block-for-monsanto-to-build-on.html">blockbuster herbicide, Roundup</a>. Monsanto had developed and patented glyphosate, Roundup’s active ingredient, in the 1970s, but the advent of Roundup Ready seeds made glyphosate sales explode.</p>
<p>It seemed like a magical system: Farmers could treat fields with glyphosate throughout the growing season without hurting their crops. For a few years, overall herbicide use dropped: Farmers used glyphosate in huge quantities, but stopped buying most other herbicides. </p>
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<figure><figcaption><span class="caption">Use of glyphosate has increased dramatically since the introduction of Roundup Ready seeds starting in 1996 (move slider to compare 1995 and 2019 usage).</span></figcaption></figure>
<p><a href="https://web.archive.org/web/19970714063108/http://www.monsanto.com/monpub/environment/monsantoear96/96earall.pdf">Monsanto asserted</a> that this approach would <a href="http://extension.agron.iastate.edu/weeds/weednews/roundupcottonad.htm">make farming more sustainable</a> by reducing long-term use of herbicides and pesticides – especially older, more toxic brands. Soon, however, the system started to falter. </p>
<p>In the early 2000s, scientists began reporting that weeds were <a href="https://doi.org/10.1002/ps.4760">evolving resistance to Roundup</a>. In response, Monsanto rolled out a new generation of genetically engineered seeds that would make crops resistant to a wider array of older herbicides. Farmers could use these older products along with Roundup, improving their chances of killing most weeds.</p>
<p>One of the chemicals Monsanto bet on was dicamba, first introduced in the 1960s. In 2015 and 2016, the company began producing seeds <a href="https://www.roundupreadyxtend.com/products/pages/default.aspx">branded “Roundup Ready Xtend</a>” that were engineered to tolerate heavy spraying of both dicamba and glyphosate. The logic was that dicamba would eliminate glyphosate-resistant weeds, and glyphosate would wipe out all other unwanted vegetation.</p>
<h2>A solution becomes a problem</h2>
<p>It quickly became clear that this fix was seriously flawed. Dicamba is <a href="https://extension.umn.edu/herbicides/uncovering-dicambas-wayward-ways">one of the most volatile herbicides on the market</a>, meaning that it changes readily from a liquid to a vapor in warm temperatures. When farmers sprayed dicamba on hot days, it tended to vaporize and drift off target, spreading to fields and farms that often were not planted with crops genetically engineered to tolerate it. The South Dakota farmer who called me from his combine was harvesting organic soybeans that did not contain Monsanto’s Xtend traits. </p>
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<p>Maddeningly for farmers, Monsanto had seen this coming. In a 2020 federal court case, <a href="https://casetext.com/case/bader-farms-inc-v-monsanto-co-18">Bader Farms v. Monsanto</a>, confidential company documents revealed that the firm was aware that dicamba sprayed on Xtend crops would likely drift off target. Monsanto sales representatives even called this a sales point for dicamba-tolerant seeds. “Push ‘protection from your neighbor,’” one <a href="https://usrtk.org/wp-content/uploads/2020/02/dicamba-PLTF-22.pdf">slide in an internal 2013 sales presentation suggested</a>. </p>
<p>Farmers started complaining about dicamba drift soon after Monsanto introduced its first Xtend seeds. The Trump administration ordered farmers not to spray dicamba in buffer zones around fields, and to <a href="https://www.epa.gov/sites/default/files/2020-10/documents/dicamba-decision_10-27-2020.pdf">restrict dicamba application to particular times of day</a>, but this had little effect. </p>
<p>Amid this controversy, the EPA extended approval in 2018 for three dicamba-based herbicides. But the U.S. Ninth Circuit Court of Appeals <a href="https://www.centerforfoodsafety.org/files/125--dicamba-opinion_35970.pdf">revoked this decision in June 2020</a>, ruling that the agency had ignored or downplayed evidence of damage from dicamba and failed to consider how its licensed use would “tear the social fabric of farming communities.” In response, EPA approved new dicamba licenses with some <a href="https://www.epa.gov/newsreleases/epa-announces-2020-dicamba-registration-decision">additional control measures</a> that it asserted met the court’s concerns.</p>
<h2>A chemical arms race</h2>
<p>Now the Biden administration is weighing how to address dicamba – and none too soon. Farmers reportedly are seeing weeds that have <a href="https://www.dtnpf.com/agriculture/web/ag/crops/article/2021/07/03/weed-resistance-dicamba-2-4-d-rise">developed resistance to dicamba and other herbicides</a> recommended for use with a new generation of genetically engineered seeds. According to weed specialists, this is happening precisely because farmers are <a href="https://www.nytimes.com/2021/08/18/magazine/superweeds-monsanto.html">using such large quantities of these chemicals</a> during the growing season. </p>
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<p>Seed companies like the German firm Bayer, which now owns Monsanto’s product portfolio, say one solution is for farmers to buy seeds that can tolerate a wider array of weedkillers. Recently, for example, Bayer sought approval for a new line of seeds that would make crops resistant to <a href="https://civileats.com/2020/07/01/bayer-forges-ahead-with-new-crops-resistant-to-5-herbicides-glyphosate-dicamba-2-4-d-glufosinate-quizalofop/">five different types of herbicides</a>.</p>
<p>For farmers, this will mean greater reliance on an expanding array of petrochemicals, and therefore higher costs. Today, U.S. farmers <a href="https://www.nytimes.com/2016/10/30/business/gmo-promise-falls-short.html">use more than twice as much herbicide</a> to grow soybeans as they did before Roundup Ready crops were introduced. </p>
<p>I see dicamba drift as a symptom of a larger petrochemical dependency that threatens the viability of the U.S. food system. My research in this area makes clear that if federal agencies really want to help farmers solve weed problems, they would do well to look to agricultural innovators who are demonstrating that <a href="https://doi.org/10.1038/nplants.2017.8">crops can be grown productively and profitably</a> without relying so heavily on synthetic pesticides. </p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>In the U.S. and around the world, farmers are seeking alternative ways to deal with weeds. Some are <a href="https://doi.org/10.1371/journal.pone.0219847">diversifying what they grow</a>, using time-honored practices like <a href="https://www.farmers.gov/blog/conservation/discover-cover-managing-cover-crops-suppress-weeds-and-save-money-herbicides">cover cropping</a>, and looking to innovative methods coming out of a resurgent <a href="https://theconversation.com/regenerative-agriculture-can-make-farmers-stewards-of-the-land-again-110570">regenerative farming movement</a>. </p>
<p>If these tools can create a future agricultural economy less reliant on petrochemicals derived from finite resources, I believe it would be welcome news not just to farmers but also to those of us who depend on them for our food.</p><img src="https://counter.theconversation.com/content/174181/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bart Elmore receives funding from the New America Foundation in Washington, DC, and the Nieman Foundation for Journalism at Harvard University and Columbia's University's School of Journalism.</span></em></p>Farmers are stuck in a chemical war against weeds, which have developed resistance to many widely used herbicides. Seed companies’ answer – using more varied herbicides – is causing new problems.Bart Elmore, Associate Professor of History and Core Faculty in the Sustainability Institute, The Ohio State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1725822022-01-01T13:09:31Z2022-01-01T13:09:31Z‘Sallets’ – how to eat healthily the 1600s way<figure><img src="https://images.theconversation.com/files/438097/original/file-20211216-21-3dgn0e.jpg?ixlib=rb-1.1.0&rect=27%2C9%2C5979%2C3980&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/search/salad+with+flowers"> Geo-grafika/Shutterstock</a></span></figcaption></figure><p>When we think of food in the past, it is often images of Henry VIII with a table groaning with meat dishes that springs to mind. But in fact our ancestors knew more about the health benefits of eating salads – normally thought of as a cold dish of herbs or vegetables – than we might think. </p>
<p>By looking back to the sustainable self-sufficiency of the past, we find there is a lot we can learn about the variety of the historical salad dish, which costs next to nothing, has no carbon footprint and might even be beneficial to our health.</p>
<p>The diarist, writer, and gardener <a href="https://en.wikipedia.org/wiki/John_Evelyn">John Evelyn</a> (1620-1706) pursued his interest in salads in the mid-to-late 17th century. His model both defined the dish very broadly and showed how you could live on home-grown salads all year round. </p>
<p>To Evelyn, the ideal kitchen garden was full of vegetables and fruits that could be grown simply and in great variety. Evelyn even published a whole guide to growing and preparing salads, <em><a href="https://www.gutenberg.org/files/15517/15517-h/15517-h.htm">Acetaria</a></em>, A Discourse on Sallets in 1699. The words “sallet” came into English from the French “salade” in the 1300s and was in common use by the 1600s. </p>
<p>In <em>Acetaria</em>, Evelyn promotes a low-meat diet, insisting that those who live on herbs and roots live to a ripe old age. He cites classical philosophy to back up his arguments about the “<a href="https://www.gutenberg.org/files/15517/15517-h/15517-h.htm#page98">the Wholeſomness of the Herby-Diet</a>” – citing Plato and Pythagoras as examples of great thinkers who banished “flesh” from their tables. Evelyn was not interested in converting people to vegetarianism as such, declaring: </p>
<blockquote>
<p>But this is not my Buſineſs, further than to ſhew how possible it is by so many instances and examples, to live on wholeſome vegetables, both long and happily.</p>
</blockquote>
<p>In the past year, gardening and growing vegetables has enjoyed a resurgence as a family-friendly, outdoor pastime that can also help ease concerns over food shortages. While becoming totally self-sufficient is unlikely, Evelyn’s <em>Acetaria</em> has some tips that the green-fingered grower can use to feed their families and some advice that could help expand their harvests in an unlikely way. </p>
<h2>The gardener’s year</h2>
<p>The centrality of salads to the diet in Evelyn’s manifesto is underpinned with the verse from <em>Acetaria</em>:</p>
<blockquote>
<p>Bread, Wine and wholſome Sallets you may buy,<br>
What Nature adds beſides is Luxury.</p>
</blockquote>
<p>While the rhyme refers to buying salads, Evelyn points out that such plants are easy to grow, have no fuel requirement in their preparation, are near at hand and importantly easy to digest.</p>
<figure class="align-left ">
<img alt="Painting of a young man with a skull." src="https://images.theconversation.com/files/438086/original/file-20211216-13-nigchl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/438086/original/file-20211216-13-nigchl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=821&fit=crop&dpr=1 600w, https://images.theconversation.com/files/438086/original/file-20211216-13-nigchl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=821&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/438086/original/file-20211216-13-nigchl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=821&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/438086/original/file-20211216-13-nigchl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1031&fit=crop&dpr=1 754w, https://images.theconversation.com/files/438086/original/file-20211216-13-nigchl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1031&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/438086/original/file-20211216-13-nigchl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1031&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">John Evelyn promoted a healthy diet and the consumption of sallets.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/John_Evelyn#/media/File:Walker,_Robert_John_-_Evelyn.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>And nature aids all sorts of things, as highlighted in another work of Evelyn’s, Directions for the Gardener, written about his garden at <a href="https://en.wikipedia.org/wiki/Sayes_Court">Sayes Court</a> in southeast London. This book contained helpful hints and tips for growing produce for the kitchen table. It’s not just the expected salad items such as cucumber and lettuce that Evelyn remarks on though. He offers daisies, dandelions and docks as part of the bounty, as well as cowslips (a type of primrose). These and many other plants that even flourish on compost heaps and waste ground could help the gardener be more self-sufficient – and at no real cost. </p>
<p>Many of the “weeds” have to be picked at the optimum time, and sometimes the roots and stems are boiled to remove the bitterness. In any case, early moderns were wary of raw vegetables because it was believed that if eaten in too great a quantity they could upset the body. But the key point is that he has a much broader definition of what might be included in the salad family, such as the kind of foraged plants that are making a come-back in some high-end <a href="https://foodtank.com/news/2018/10/21-chefs-bringing-foraged-ingredients-to-the-table/">restaurants</a>. </p>
<p>Some of what Evelyn recommends were new spins on familiar ingredients. So why not pickle the seed-pods of a radish to make an attractive addition to your salad dish rather than just using the root? Or cook the stalks of a turnip (before it runs to seed) and eat them boiled and covered in butter, like asparagus. </p>
<h2>A salad “fitted for a City Feast”</h2>
<p>This is a <a href="https://www.gutenberg.org/files/15517/15517-h/15517-h.htm#noteref-90">flamboyant recipe</a> that Evelyn gives us that upends our view of what a salad can be. </p>
<p><strong>Ingredients</strong><br>
Blanched almonds <em>sliced, and soaked in cold water</em><br>
Pickled cucumbers<br>
Olives<br>
Cornelians (a kind of cherry which Evelyn claims when pickled can pass for an olive)<br>
Capers<br>
Berberries (barberries)<br>
Red-Beet (beetroot)<br>
Nasturtium buds<br>
Broom<br>
Purslane stalks<br>
Samphire<br>
Ash keys<br>
Walnuts<br>
Pickled mushrooms<br>
Raisins of the Sun<br>
Citron and Orange peel<br>
Corinth (currants) <em>well cleansed and dried</em> </p>
<p><strong>Method</strong><br>
Chop all these ingredients, add in some roasted maroons (sweet chestnuts), pistachios, pine-kernels, lots more almonds, and decorate with candied flowers, and sprinkle with rose water. Accompany with a side dish of pickled flowers in vinegar.</p>
<p>The message of Evelyn’s book is to use what nature provides. The medicinal garden (called the apothecary or physic garden) brought into sharp focus the beneficial properties of various plants, which they thought able to cure all sorts of complaints. Evelyn would have been proud to see a nation of gardeners and cooks today taking up this self-sufficiency that was so natural to him back in the 1600s. Something for us to reflect on as we enter another new year.</p><img src="https://counter.theconversation.com/content/172582/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Taking lessons from the past could help enrich our diets for little costCatie Gill, Lecturer in English, Loughborough UniversitySara Read, Lecturer in English, Loughborough UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1678832021-10-04T19:06:35Z2021-10-04T19:06:35ZRosemary in roundabouts, lemons over the fence: how to go urban foraging safely, respectfully and cleverly<figure><img src="https://images.theconversation.com/files/424373/original/file-20211004-19-19r21tk.jpg?ixlib=rb-1.1.0&rect=46%2C26%2C4360%2C2853&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>Does anything beat the experience of finding a wild mulberry tree and stuffing a handful of fresh juicy berries in your mouth? Have you ever roasted potatoes with a sprig of rosemary taken from an overgrown nature strip? </p>
<p>COVID lockdowns have encouraged more people to explore their neighbourhoods and appreciate <a href="https://theconversation.com/spending-time-in-nature-has-always-been-important-but-now-its-an-essential-part-of-coping-with-the-pandemic-153073">their local green spaces</a>, where edible plants are often growing freely. Alongside the joy in eating something freely harvested, foraging can help us learn about plants, become better environmental stewards, and bring together communities. </p>
<p>It can also help us notice changes in season, weather and climate. So with spring upon us, how do you forage safely, respectfully, and legally?</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Lmm51Cyf9_8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">12 Australian bushfoods.</span></figcaption>
</figure>
<h2>Wild, edible plants thrive in cities</h2>
<p>The locations of Sydney and Melbourne were chosen by colonists, in part, because they’re within large food basins. Many edible species existed well before colonisation, thanks to the favourable climate, shape of the coastline and custodianship of Country.</p>
<p>Edible native plants, from ground covering warrigal greens to the huge canopies of Illawarra plum trees, are still naturally growing all over southeast Australian cities. Further north, macadamias, lemon myrtles and finger limes thrive, and <a href="https://www.bhg.com.au/everything-about-pigface">pigface</a> is common on sand dunes along coastal towns.</p>
<p>Today, edible plants thrive despite the disturbances of soils and water from urbanisation. Fruit trees, for example, emerge spontaneously on the edges of park lands, in vacant lots and in people’s gardens.</p>
<p>In some cases, urbanisation is actually responsible for the growth and distribution of edible plants. </p>
<p>Birds, rats, bats broaden the trajectories of mulberry, loquat, and papaya seeds by eating them and expelling the seeds somewhere else. This is also how mulberries, which European settlers introduced to Australia, now grow in most Australian cities. </p>
<p>Kumquat, citrus, and fig trees are also very common in tropical and temperate climates. And keep an eye out for blackberry vines. They’ve created an immense environmental problem, although the fruit is delicious, and grow best in NSW, Victoria and Tasmania. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/424395/original/file-20211004-13-jkwhj5.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/424395/original/file-20211004-13-jkwhj5.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424395/original/file-20211004-13-jkwhj5.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424395/original/file-20211004-13-jkwhj5.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424395/original/file-20211004-13-jkwhj5.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424395/original/file-20211004-13-jkwhj5.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424395/original/file-20211004-13-jkwhj5.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424395/original/file-20211004-13-jkwhj5.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Not everyone likes it when you pick from their nature strip.</span>
<span class="attribution"><span class="source">Courtesy of Mapping Edges</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Think before you pick</h2>
<p>But foraging is not a free for all, and doing it safely and respectfully is important. </p>
<p>First and foremost, in Australia, wherever you walk, you are on Country. Take a moment to remember that although urban foraging may be new to you, Aboriginal people have always gathered native plants while caring for Country.</p>
<p>Foraging also carries possible risks to your own health. Some plants in urban areas are poisonous, such as the castor oil plant and many gum trees. Plants could also be contaminated from pollution in the air, water and soil, and by chemical sprays. </p>
<p>You can learn about some of the possible environmental contaminants in your neighbourhood <a href="https://www.mapmyenvironment.com/">here</a>, and there are a few services like <a href="https://www.360dustanalysis.com/">VegeSafe</a> that test soil samples for metals. </p>
<p>Always start by considering the past and current uses of the land where you’re foraging. Was the land once industrially zoned? Do dogs urinate there? Make sure you always wash foraged food.</p>
<p>Legally, plants are the property of whoever owns the land on which they’re growing. That means foraging for food on private land is legal, as long as you either own the land or have the owner’s permission. </p>
<p>But if food is accessible on public land — such as lemons or bananas hanging over a fence, or rosemary and parsley planted as ornamentals in a park or street shoulder — you can harvest them. Just take what you need, and leave plenty for others.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/our-land-abounds-in-nature-strips-surely-we-can-do-more-than-mow-a-third-of-urban-green-space-124781">Our land abounds in nature strips – surely we can do more than mow a third of urban green space</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/424394/original/file-20211004-23-1whq400.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/424394/original/file-20211004-23-1whq400.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424394/original/file-20211004-23-1whq400.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424394/original/file-20211004-23-1whq400.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424394/original/file-20211004-23-1whq400.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424394/original/file-20211004-23-1whq400.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424394/original/file-20211004-23-1whq400.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424394/original/file-20211004-23-1whq400.png?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">Make sure you wash foraged plants before you eat them.</span>
<span class="attribution"><span class="source">Courtesy of Mapping Edges</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Foraging respectfully</h2>
<p>There are different cultures around growing and sharing food, depending on the local area. For example, many neighbourhood nature strips are technically owned by the council, but planted and tended by residents. </p>
<p>Community gardens and even streets with nature strips may have their own harvesting rules. Some groups like <a href="https://www.cityofsydney.nsw.gov.au/community-gardens/green-square-growers">Green Square Growers</a> encourage spontaneous harvesting. Others, such as <a href="https://www.cityofsydney.nsw.gov.au/community-gardens/sydney-city-farm">Sydney City Farm</a>, donate produce to local charities.</p>
<p>Since 2016, we have been working in various suburbs of Sydney to <a href="https://www.mappingedges.org/projects/home-gardens-of-haberfield/">conduct research</a> on urban gardening. We discovered people often work with plants to develop a sense of place that goes well beyond what’s visible in their gardens. </p>
<p>We found networks of neighbours grow together with plants on street edges, through exchanging cuttings, seeds, tips, stories and produce. Coming across a row of trees heavy with olives on a nature strip may feel like a lucky discovery, but these plants are probably watered, pruned, and whitewashed for winter by one or more gardeners. </p>
<p>For someone who has carefully netted a fruit tree to protect it from bats and cockatoos, or who has patiently tended a vine for three years before their first passionfruit appears, there’s nothing more infuriating than a stranger harvesting. </p>
<p>On the other hand, helping yourself to a fragrant feijoa tree weighed down by ripe fruit makes sense, when the fruits would otherwise fall, rot and go to waste. </p>
<p>When possible, ask residents about the plants growing on or around their properties. Conversations about what’s growing in neighbourhoods build so-called “<a href="https://www.mappingedges.org/projects/the-green-square-atlas-of-civic-ecologies/what-are-civic-ecologies/">civic ecologies</a>” — actions that bring together environmental and civic values, building neighbourly connections around common interests and care for shared places.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/supermarket-shelves-stripped-bare-history-can-teach-us-to-make-do-with-food-135304">Supermarket shelves stripped bare? History can teach us to 'make do' with food</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/424377/original/file-20211004-13-1xgj4rn.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/424377/original/file-20211004-13-1xgj4rn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424377/original/file-20211004-13-1xgj4rn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=802&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424377/original/file-20211004-13-1xgj4rn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=802&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424377/original/file-20211004-13-1xgj4rn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=802&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424377/original/file-20211004-13-1xgj4rn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1008&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424377/original/file-20211004-13-1xgj4rn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1008&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424377/original/file-20211004-13-1xgj4rn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1008&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Foraging on nature strips can depend on local council rules.</span>
<span class="attribution"><span class="source">Courtesy of Mapping Edges</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Learn from foraging celebrities</h2>
<p>In Australia, a hand full of “foraging” celebrities have brought attention to this age old practice. They see foraging as an opportunity to learn about what’s growing where, and why. </p>
<p>In Sydney, Randwick Council Sustainability Educator Julian Lee, has created a Scrumper’s Delight <a href="https://www.google.com/maps/d/edit?mid=1z4E4KYaDZLVFs-ShpcF-WgYglHg&ie=UTF8&oe=UTF8&msa=0&ll=-33.91414914832107%2C151.20033552888276&z=21">participatory map</a> that records edible plants growing in public spaces. Sydney artist and activist Diego Bonetto — aka <a href="https://www.diegobonetto.com/about">The Weedy One</a> — brought a wealth of planty knowledge from Piedmont, Italy to Australia in the 1990s, and since then his passion has evolved to a public pedagogy about respectful foraging.</p>
<p><a href="https://www.milkwood.net/2018/11/06/the-right-to-roam-tips-for-first-time-foragers/">Milkwood Permaculture</a> offer tips, even on foraging sea weed. The <a href="https://www.instagram.com/melbourneforager/?hl=en">Melbourne Forager</a> on Instagram makes urban foraging hip. And a growing number of Indigenous businesses, such as <a href="https://www.indigigrow.com.au/">Indigigrow</a>, share Indigenous knowledge by selling plants people can recognise outside their gardens. </p>
<p>Foraging in cities is fun, it helps us remember we’re part of ecosystems, and we have a responsibility to care for Country. So keep in mind principles of reciprocity, and go forth and learn what’s growing in your city. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/farming-the-suburbs-why-cant-we-grow-food-wherever-we-want-80330">Farming the suburbs – why can’t we grow food wherever we want?</a>
</strong>
</em>
</p>
<hr>
<hr>
<p><em>Correction: A previous version of this article said Sydney City Farm allocates produce to volunteers. In fact, the produce is donated to local charities.</em></p><img src="https://counter.theconversation.com/content/167883/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Spring has settled in and fruit is starting to ripen. Read this before you start helping yourself to the edible plants growing in your neighbourhood.Alexandra Crosby, Associate Professor, School of Design, University of Technology SydneyIlaria Vanni, Associate Professor, International Studies and Global Societies, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1651652021-08-17T19:58:31Z2021-08-17T19:58:31ZPlanning to plant an Australian native like wattle? Read this first — you might be spreading a weed<figure><img src="https://images.theconversation.com/files/413656/original/file-20210729-19-1r6o346.jpg?ixlib=rb-1.1.0&rect=0%2C74%2C1712%2C2211&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Coastal wattle.</span> <span class="attribution"><span class="source">Dr David Chael</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Australian native plants are having a moment in the sun, with <a href="https://myplantlifebalance.com.au/wp-content/uploads/2019/12/PLB_Trend_Report_2020.pdf">more of us</a> seeking out <a href="http://aff.org.au/wp-content/uploads/AFF-Newsletter-Jan-2019-Final.pdf">and planting</a> native species than in the past. Our gardens — and our social media feeds — are brimming with beautiful Australian native blooms.</p>
<p>But not all Australian native species belong in all Australian environments. In fact, many have become pests in places far from their original homes.</p>
<p>They can crowd out other native endemic species, affect the local balance of insects and other animals, wreck soils and even increase fire risk.</p>
<p>Here are three Australian native plants that have become invasive species after ending up in places they don’t belong.</p>
<h2>Sydney golden wattle (<em>Acacia longifolia subspecies longifolia</em>)</h2>
<p>Originally extending from East Gippsland in Victoria up about as far as Brisbane in Queensland, this species is undoubtedly photogenic. It’s also an <a href="https://keyserver.lucidcentral.org/weeds/data/media/Html/acacia_longifolia_subsp._longifolia.htm">invasive weed</a> in parts of Victoria, South Australia and Western Australia.</p>
<p>It was spread across the nation by well-meaning gardeners who saw it as a charming ornamental plant. However, its seeds made their way into the wild and took off — it’s what’s known in my field as “<a href="https://keyserver.lucidcentral.org/weeds/data/media/Html/acacia_longifolia_subsp._longifolia.htm">a garden escapee</a>”.</p>
<p>Like many weeds, this species can capitalise on a natural disaster; after fire it can send out shoots from its base. Acacias are often one of the first species to sprout following a bushfire. They’re now completely dominant and spreading in many areas. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/413703/original/file-20210729-23-rhosgi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/413703/original/file-20210729-23-rhosgi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/413703/original/file-20210729-23-rhosgi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413703/original/file-20210729-23-rhosgi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413703/original/file-20210729-23-rhosgi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413703/original/file-20210729-23-rhosgi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413703/original/file-20210729-23-rhosgi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413703/original/file-20210729-23-rhosgi.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">Sydney golden wattle is an invasive weed in other parts of Victoria, South Australia and Western Australia.</span>
<span class="attribution"><span class="source">Gill Armstrong</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Seeds of Sydney golden wattle can last in the soil for many decades, long after the parent plants have died. The heat from a fire cracks the hard seed coat, allowing water to enter and germination to take off.</p>
<p>In the Grampians, in Victoria, Sydney golden wattle is causing terrible <a href="https://keyserver.lucidcentral.org/weeds/data/media/Html/acacia_longifolia_subsp._longifolia.htm">soil problems</a>. Many native plants endemic to this area don’t like high levels of soil nitrogen, but <em>Acacia longifolia subsp. longifolia</em> is a nitrogen-fixing plant.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/414082/original/file-20210802-61897-y8817k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Acacia longifolia subsp. longifolia has quite long, thin seed pods." src="https://images.theconversation.com/files/414082/original/file-20210802-61897-y8817k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/414082/original/file-20210802-61897-y8817k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414082/original/file-20210802-61897-y8817k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414082/original/file-20210802-61897-y8817k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414082/original/file-20210802-61897-y8817k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414082/original/file-20210802-61897-y8817k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414082/original/file-20210802-61897-y8817k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Acacia longifolia subsp. longifolia has quite long, thin seed pods.</span>
<span class="attribution"><span class="source">Gill Armstrong</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In other words, it increases the nitrogen in the soil and changes the soil nutrient status and even physical aspects of the soil. It can grow tall and produce a lot of foliage, which reduces the amount of light coming to the ground. That makes it harder for native species lower to the ground to survive.</p>
<p>This is a major challenge, especially in biodiversity-rich places like the Grampians.</p>
<h2>Coast wattle (<em>Acacia longifolia subspecies sophorae</em>)</h2>
<p>The blooms on <em>Acacia longifolia subspecies sophorae</em> (Coast wattle) look more or less the same as many other wattles, but the leaves are a bit shorter and stubbier.</p>
<p>Originally, Coast wattle occurred along the east coast from western Victoria — up about as far as Brisbane and down south as far as Tasmania (where Sydney golden wattle did not occur naturally).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/414078/original/file-20210802-30100-nsn5ct.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="_Acacia longifolia subsp. sophorae_, also known as 'Coastal Wattle', has shorter, stubby leaves." src="https://images.theconversation.com/files/414078/original/file-20210802-30100-nsn5ct.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414078/original/file-20210802-30100-nsn5ct.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414078/original/file-20210802-30100-nsn5ct.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414078/original/file-20210802-30100-nsn5ct.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414078/original/file-20210802-30100-nsn5ct.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414078/original/file-20210802-30100-nsn5ct.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414078/original/file-20210802-30100-nsn5ct.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">Acacia longifolia subsp. sophorae, also known as ‘Coastal Wattle’, has shorter, stubby leaves.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/tgerus/3911615361/in/photolist-6XE3Ya-723uAB-buVE8p-aeBu22-aeEhKJ-aeBsE6-aeBtA6-aeEhcy-E3Kf45-39gSmE">Tatters ✾/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>It was originally restricted to sandy sites at the top of beaches but has been <a href="https://keyserver.lucidcentral.org/weeds/data/media/Html/acacia_longifolia_subsp._sophorae.htm">deliberately planted</a> as a “sand-binder” in other sites. It’s also naturally spread into heathlands inland of the beaches and is now causing <a href="https://keyserver.lucidcentral.org/weeds/data/media/Html/acacia_longifolia_subsp._sophorae.htm">huge problems</a> around our coasts.</p>
<p>Like the earlier example, it dominates local ecosystems and displaces native species endemic to the area (particularly in our species-rich heathlands), which affects local insect habitats. It is also now modifying natural sand dune patterns.</p>
<p>It is increasing fire risk by changing heathland plant profiles from mostly short shrubs of limited bulk to tall, dense shrublands with much higher fuel levels.</p>
<h2>Coast teatree (<em>Leptospermum laevigatum</em>)</h2>
<p>As with Coast wattle, Coast teatree was formerly restricted to a narrow strip on sandy soils just above the beaches of south-eastern Australia. But it has now spread into nearby heathlands and woodlands. It’s even reached as far as <a href="https://florabase.dpaw.wa.gov.au/browse/profile/5850">Western Australia</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/414080/original/file-20210802-79549-1qrhadj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Coast teatree, Leptospermum laevigatum, is now an invasive species in some areas. It has small white flowers." src="https://images.theconversation.com/files/414080/original/file-20210802-79549-1qrhadj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414080/original/file-20210802-79549-1qrhadj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414080/original/file-20210802-79549-1qrhadj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414080/original/file-20210802-79549-1qrhadj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414080/original/file-20210802-79549-1qrhadj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414080/original/file-20210802-79549-1qrhadj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414080/original/file-20210802-79549-1qrhadj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Coast teatree, Leptospermum laevigatum, is now an invasive species in some areas.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/13639096@N06/9653264250/in/photolist-214BxdU-DfpVaq-CU5ZX5-DDUa5F-DfEcx7-DDV28M-EaPfGE-EdoAKX-ayVLZt-E2XQXm-nBXF6-cqz2FU-68k7gX-cqz3ss-27Z6bWs-26XXvs7-218qT8y-cqz35f-cqz28A-9ped6M-E5Upzw-215MFb9-6r39bn-9pegtx-htvyDT-fH2v9w-fH2xEq-bz3qqV-4DjuBi-4qMjA1-4DoKcq-37RRiT-4qHfxz-21XqGzk-4qHfCc-4DoN2E-22eZUcA-4Djvmn-4qMjYA-KVr9S5-4DoMjo-4qHfrT-JnUmhr-4qMjv1-4qMjQJ-KnwRVD-285CF8y-218sQ27-2aQsCRk-27hGtmq">Flickr/Margaret Donald</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>This <a href="https://pir.sa.gov.au/__data/assets/pdf_file/0011/289748/Coastal_TeaTree_Factsheet_Final.pdf">teatree plant</a> is now considered an invasive species in parts of Victoria and South Australia.</p>
<p>Although the mature plants are usually killed by fire, the seeds are abundant and very good at surviving; they pop out of their capsules after fires.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/413701/original/file-20210729-25-mn6ycm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Coast teatree" src="https://images.theconversation.com/files/413701/original/file-20210729-25-mn6ycm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/413701/original/file-20210729-25-mn6ycm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413701/original/file-20210729-25-mn6ycm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413701/original/file-20210729-25-mn6ycm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413701/original/file-20210729-25-mn6ycm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413701/original/file-20210729-25-mn6ycm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413701/original/file-20210729-25-mn6ycm.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">Coast teatree produces a lot of seeds.</span>
<span class="attribution"><span class="source">Dr David Chael</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>They are high-density plants that burn quickly in a fire. They are very quick to take over and push out endemic species.</p>
<p>For example, parts of the Wilson’s Prom National Park in Victoria, which was originally a Banksia woodland, have now been converted almost to a teatree monoculture. It is very sad.</p>
<h2>A call to action</h2>
<p>Authorities are trying their best to keep these and other native invasive species under control, but in some cases things may never go back to the way they were. Sometimes, the best you can hope for is just to strike a balance between native and invasive species.</p>
<p>When you do landcare restoration work or home gardening, I urge you to look up the plant history and see if the species you’re thinking of planting is listed as one that might cause problems in future.</p>
<p>When you go to purchase from a nursery or plant centre, be cautious. Think twice before you bring something into your garden. Too many species have “jumped the garden fence” and now cost us a great deal in control efforts and in native species loss.</p>
<p>Lots of apps, such as <a href="https://apps.apple.com/au/app/plantnet/id600547573">PlantNet</a>, can help you identify plants and see what is native to your area. </p>
<p>Australia has spent billions trying to control invasive species and environmental weeds. Anything you can do to help is a bonus.</p><img src="https://counter.theconversation.com/content/165165/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Singarayer Florentine has received funding from the ARC, the federal government and the Victorian government.</span></em></p>Not all Australian native species belong in all Australian environments. In fact, many Australian plant species have become pests in places far from their original homes. Could some be in your garden?Singarayer Florentine, Professor (Restoration Ecologist), Federation University AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1611562021-07-02T12:15:12Z2021-07-02T12:15:12ZWhile debate rages over glyphosate-based herbicides, farmers are spraying them all over the world<figure><img src="https://images.theconversation.com/files/408535/original/file-20210627-25-jd7j90.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5039%2C3382&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Containers of the herbicide glyphosate at a farm supply store in northeast Thailand in 2019.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/ThailandChemicalBan/da01ccda97714aad8cd2edf54a67f3ac/photo">AP Photo/Sakchai Lalit</a></span></figcaption></figure><p>As North America enters its peak summer growing season, gardeners are planting and weeding, and groundskeepers are mowing parks and playing fields. Many are using the popular weed killer Roundup, which is widely available at stores like <a href="https://www.homedepot.com/p/Roundup-Weed-and-Grass-Killer-III-with-Pump-N-Go-Ready-To-Use-2-1-Sprayer-510011435/100619041">Home Depot</a> and <a href="https://www.target.com/b/roundup/-/N-6dbu?Nao=0">Target</a>.</p>
<p>In the past two years, three U.S. juries have awarded <a href="https://www.courthousenews.com/roundup-cancer-trial-verdict-upheld-but-damages-slashed/">multimillion-dollar verdicts</a> to plaintiffs who asserted that glyphosate, the active ingredient in Roundup, gave them <a href="https://www.cancer.org/cancer/non-hodgkin-lymphoma/about/what-is-non-hodgkin-lymphoma.html">non-Hodgkin lymphoma</a>, a cancer of the immune system. Bayer, a German chemical company, <a href="https://www.businessinsider.com/monsanto-beyer-merge-drop-monsanto-name-2018-6">bought Roundup’s inventor, Monsanto, in 2018</a> and inherited some 125,000 pending lawsuits, of which it has settled all but about 30,000. The company is now considering ending U.S. retail sales of Roundup to reduce the risk of further lawsuits from residential users, who have been the <a href="https://www.reuters.com/business/healthcare-pharmaceuticals/us-judge-rejects-bayers-2-bln-deal-resolve-future-roundup-lawsuits-2021-05-26/">main source of legal claims</a>. </p>
<p>As scholars who study <a href="https://scholar.google.com/citations?user=EnsiK4gAAAAJ&hl=en">global trade</a>, <a href="https://scholar.google.com/citations?user=OZUSfzMAAAAJ&hl=en">food systems</a> and their <a href="https://scholar.google.com/citations?user=U73rXq8AAAAJ&hl=en">effects on the environment</a>, we see a bigger story: Generic glyphosate is ubiquitous around the globe. Farmers use it on <a href="https://doi.org/10.1016/j.scitotenv.2020.137167">a majority of the world’s agricultural fields</a>. Humans spray enough glyphosate to coat every acre of farmland in the world with <a href="https://doi.org/10.1186/s12302-016-0070-0">half a pound of it every year</a>.</p>
<p>Glyphosate is now showing up in humans, but scientists are <a href="https://www.sfpublicpress.org/scientists-split-over-herbicide-risk-leaving-public-in-lurch/">still debating its health effects</a>. One thing is clear, though: Because it’s an effective and very cheap weedkiller, it has become pervasive. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/trtgLoKJmns?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Research on glyphosate’s possible human health effects in inconclusive, but concern is rising over its heavy use worldwide.</span></figcaption>
</figure>
<h2>How glyphosate went global</h2>
<p>When glyphosate was commercialized under the Roundup brand name in 1974, it was widely viewed as safe. Monsanto scientists claimed that it would <a href="https://www.cabdirect.org/cabdirect/abstract/19972301931?gitCommit=4.13.20-5-ga6ad01a">not harm people or other nontarget organisms</a> and did not persist in <a href="https://www.cabdirect.org/cabdirect/abstract/19972301931?gitCommit=4.13.20-5-ga6ad01a">soil and water</a>. Scientific reviews determined that it <a href="https://doi.org/10.1006/rtph.1999.1371">did not build up</a> in animal tissue.</p>
<p>Glyphosate killed <a href="https://www.sciencedirect.com/book/9780123814951/a-history-of-weed-science-in-the-united-states">more target weed species than any other herbicide before or since</a>. Farmers started spraying it on fields to prepare for the next cropping cycle. </p>
<p>In the 1990s Monsanto began packaging glyphosate with crops that were genetically modified to be resistant to it, including corn, soybeans, cotton and canola. Farmers who used these “<a href="https://www.nytimes.com/2001/08/02/business/the-power-of-roundup-a-weed-killer-is-a-block-for-monsanto-to-build-on.html">Roundup Ready</a>” seeds could apply a single herbicide to manage weeds during the growing season, saving time and simplifying production decisions. Roundup became the <a href="https://doi.org/10.1002/(SICI)1526-4998(200004)56:4%3C309::AID-PS143%3E3.0.CO;2-C">highest-selling and most profitable herbicide</a> ever to appear on the global market. </p>
<p>In the late 1990s, as the last patents for glyphosate expired, the generic pesticide industry began to offer <a href="https://doi.org/10.1002/(SICI)1526-4998(200004)56:4%3C309::AID-PS143%3E3.0.CO;2-C">low-cost versions</a>. In Argentina, for example, prices dropped from <a href="https://repositorio.iica.int/handle/11324/12252">$40 per liter in the 1980s to $3 in 2000</a>.</p>
<p>In the mid-1990s, China began to manufacture pesticides. <a href="https://doi.org/10.1016/j.apgeog.2020.102244">Weak environmental, safety and health regulations</a> and energetic promotion policies initially made Chinese glyphosate very cheap. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/408536/original/file-20210627-15-1e2yvao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Man driving forklift loads pallets onto warehouse shelves." src="https://images.theconversation.com/files/408536/original/file-20210627-15-1e2yvao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/408536/original/file-20210627-15-1e2yvao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/408536/original/file-20210627-15-1e2yvao.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/408536/original/file-20210627-15-1e2yvao.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/408536/original/file-20210627-15-1e2yvao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/408536/original/file-20210627-15-1e2yvao.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/408536/original/file-20210627-15-1e2yvao.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">An employee arranging boxes of agricultural chemicals at a warehouse of Anhui Fengle Agrochemical Co. on Feb. 26, 2021, in Hefei, China.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/an-employee-drives-a-forklift-while-arranging-boxes-of-news-photo/1304299110">Ruan Xuefeng/VCG via Getty Images)</a></span>
</figcaption>
</figure>
<p>China still dominates the pesticide industry – it exported <a href="https://doi.org/10.1080/24694452.2021.1898322">46% of all herbicides worldwide</a> in 2018 – but now other countries are getting into the business, including Malaysia and India. Pesticides used to flow from Europe and North America to developing nations, but now developing countries export many pesticides to wealthy nations. More pesticide factories in more places leads to oversupply and even lower prices, with critical implications for human health and the environment. </p>
<h2>Health controversies</h2>
<p>Thanks to cheap globalized manufacturing, glyphosate has become ubiquitous on farmland worldwide – and in human bodies. Researchers have detected it in the urine of <a href="https://doi.org/10.1080/24694452.2020.1761285">children in remote villages in Laos</a> and <a href="https://doi.org/10.1186/s12940-020-00673-z">babies in New York and Seattle</a>.</p>
<p>The question of whether glyphosate causes cancer in humans has been hotly debated. In 2015 the International Agency for Research on Cancer, an agency of the World Health Organization, <a href="https://www.iarc.who.int/featured-news/media-centre-iarc-news-glyphosate/">classified it as a probable human carcinogen</a> based on “limited” evidence of cancer in humans from actual real-world exposures and “sufficient” evidence of cancer in experimental animals. </p>
<p>There also are questions about possible linkages between glyphosate and other human health problems. A 2019 study found that children whose mothers experienced prenatal exposure to glyphosate had a <a href="https://doi.org/10.1136/bmj.l962">significantly higher risk of autism spectrum disorder</a> than a control population. </p>
<p>Studies have found that glyphosate <a href="https://doi.org/10.1186/s12940-015-0056-1">causes liver and kidney damage in rats</a> and <a href="https://doi.org/10.1073/pnas.1803880115">alters honey bees’ gut microbiomes</a>. Mice exposed to it have shown increased disease, obesity and birth abnormalities <a href="https://doi.org/10.1038/s41598-019-42860-0">three generations after the exposure</a>. Although glyphosate breaks down in the environment relatively quickly, it is present in aquatic systems at a volume large enough to be detected in <a href="https://doi.org/10.1016/j.envint.2021.106493">blood samples from Florida manatees</a>. </p>
<p>However, the U.S. Environmental Protection Agency and the European Food Safety Authority maintain that glyphosate is unlikely to cause cancer in humans and <a href="https://www.epa.gov/ingredients-used-pesticide-products/glyphosate">does not threaten human health</a> when used according to the manufacturer’s directions. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1395040975333040133"}"></div></p>
<h2>A challenge for regulators</h2>
<p>In the 1990s and early 2000s, the world community adopted <a href="http://www.brsmeas.org/">several groundbreaking agreements</a> to restrict or monitor sales and use of hazardous pesticides. These agreements – the <a href="https://www.unido.org/our-focus-safeguarding-environment-implementation-multilateral-environmental-agreements/stockholm-convention">Stockholm</a> and <a href="https://treaties.un.org/pages/ViewDetails.aspx?src=TREATY&mtdsg_no=XXVII-14&chapter=27">Rotterdam</a> conventions – target compounds that are either acutely toxic or persist in the environment and accumulate in animals, including humans. Glyphosate does not appear to meet these criteria, but humans may be more exposed to it because of its ubiquity <a href="https://doi.org/10.1111/jawr.12159">in soil and water</a> and <a href="https://doi.org/10.1007/s11356-016-7425-3">on food</a>. </p>
<p>Today a handful of countries, including <a href="https://pan-international.org/pan-international-consolidated-list-of-banned-pesticides/">Luxembourg</a> and <a href="https://www.agweb.com/news/crops/corn/mexican-judge-rejects-industry-bid-halt-gmo-corn-glyphosate-ban">Mexico</a>, have banned or restricted the use of glyphosate, citing health concerns. In most countries, however, it remains legal with few restrictions. </p>
<p>Scientists are unlikely to reach consensus soon about glyphosate’s health and environmental impacts. But that has also been true of other pesticides. </p>
<p>For example, DDT – which is <a href="https://doi.org/10.1186/s12936-017-2050-2">still used in developing countries</a> to control mosquitoes that spread malaria and other diseases – was <a href="https://www.epa.gov/ingredients-used-pesticide-products/ddt-brief-history-and-status">banned in the U.S. in 1972</a> for its effects on wildlife and potential harm to humans. But it was not thought to cause cancer in humans until 2015, when scientists analyzed data from women whose mothers were exposed to DDT while pregnant in the 1960s, and found that these women were <a href="https://doi.org/10.1210/jc.2015-1841">more than four times as likely to develop breast cancer</a> than others who were not exposed. This study was published 65 years after the first congressional testimony on DDT’s human health impacts.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/zmslbUoPLEQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">In 1946, health officials who believed incorrectly that polio was spread by insects ordered widespread fogging with DDT in San Antonio, Texas, decades before the pesticide’s health and environmental effects were understood.</span></figcaption>
</figure>
<p>Science can take a long time to reach conclusive results. Given how widely glyphosate is used now, we expect that if it is definitively found to harm human health, its effects will be widespread, difficult to isolate and extremely challenging to regulate. </p>
<p>And finding a cheap silver bullet to safely replace it could be hard. Many substitutes on the market today are <a href="https://doi.org/10.1038/ncomms14865">more acutely toxic</a>. Nonetheless, there’s a need for better options, because weeds are <a href="http://dx.doi.org/10.1002/ps.4760">developing resistance to glyphosate</a>. </p>
<p>In our view, growing concerns about glyphosate’s effectiveness and possible health impacts should accelerate research into <a href="https://doi.org/10.1007/s13593-020-00631-6">alternative solutions</a> to chemical weed control. Without more public support for these efforts, farmers will turn to more toxic herbicides. Glyphosate looks cheap now, but its true costs could turn out to be much higher. </p>
<p><em>This article has been updated to remove a reference to glyphosate detection in breast milk, which was based on a study that was not peer-reviewed.</em></p><img src="https://counter.theconversation.com/content/161156/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marion Werner receives funding from the US National Science Foundation.</span></em></p><p class="fine-print"><em><span>Annie Shattuck is currently on the global advisory board for the Agroecology Fund, a multi-donor fund supporting agroecological practices and policies around the world. She has received past funding from the National Science Foundation.</span></em></p><p class="fine-print"><em><span>Ryan Galt receives funding from the US National Science Foundation and the John D. and Catherine T. MacArthur Foundation.</span></em></p>Roundup may be taking a beating in the US, where three juries have concluded that it gave plaintiffs cancer, but it’s still widely used around the globe.Marion Werner, Associate Professor of Geography, University at BuffaloAnnie Shattuck, Assistant Professor of Geography, Indiana UniversityRyan Galt, Professor of Geography, University of California, DavisLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1526092021-06-01T03:14:37Z2021-06-01T03:14:37ZWillow trees are notorious pests. But for freshwater animals, they could be unlikely climate heroes<figure><img src="https://images.theconversation.com/files/384396/original/file-20210216-14-1ncnf8a.jpg?ixlib=rb-1.1.0&rect=9%2C7%2C1268%2C950&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Willow invasion on Happy Valley Creek in north east Victoria</span> <span class="attribution"><span class="source">Author provided; Happy Valley Creek, Victoria</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Climate change will make Australia hotter and drier in future, and we’re starting to see the dangerous consequences of this in our rivers, lakes and streams.</p>
<p>As waters warm and flow patterns alter, the animals who call these waterways home may struggle to <a href="https://www.nature.com/articles/nclimate3382">survive</a>. Many are <a href="https://www.britannica.com/science/ectotherm">ectotherms</a> — meaning that unlike humans, these animals can’t regulate their body temperature, putting them at the mercy of ambient water temperature. And for animals that have evolved in cold water, such as some <a href="https://www.publish.csiro.au/mf/MF13189">native crayfish</a>, increased water temperatures can be lethal.</p>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S0301479721009336">new research paper</a> calls for a (possibly controversial) solution: take advantage of willow trees growing along the banks. They can create cool, shady refuges in these warming waterways. </p>
<p>Willows are not native and, in many places, are an invasive weed. But for temperature-sensitive animals, their dense, leafy canopy may make willows the lesser of two evils in a warming climate. </p>
<h2>The lesser evil</h2>
<p><a href="http://secure.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/wons/salix.html">Willows</a> belong to the genus <em>Salix</em>, and are natives of the northern hemisphere. They were introduced to Australia in the 19th century first as ornamental plants, then later planted to help stabilise river banks to combat erosion.</p>
<p>Today, they’re considered noxious weeds in Australia, South America and southern Africa, are <a href="https://www.journals.uchicago.edu/doi/abs/10.1086/692068">highly invasive</a> and have spread along waterways throughout temperate Australia.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/384386/original/file-20210216-14-148td5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384386/original/file-20210216-14-148td5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=270&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384386/original/file-20210216-14-148td5m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=270&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384386/original/file-20210216-14-148td5m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=270&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384386/original/file-20210216-14-148td5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=339&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384386/original/file-20210216-14-148td5m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=339&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384386/original/file-20210216-14-148td5m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=339&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Willows along waterways can prevent light from entering streams and cool water temperature.</span>
<span class="attribution"><span class="source">Author provided; Yackandandah Creek, Victoria</span></span>
</figcaption>
</figure>
<p>The <a href="https://link.springer.com/article/10.1007/s10530-016-1169-3">harms willows inflict</a> on aquatic ecosystems are well documented. For example, they alter energy dynamics in streams by dropping all their leaves into the water at once, which can reduce water quality and the amount of <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/fwb.12778">food for animals</a>. </p>
<p>Dense shading in summer reduces the amount of algae (an important food source) growing on <a href="https://link.springer.com/article/10.1007/s10750-015-2507-7">surfaces in streams</a>. Willows also out-shade and <a href="https://www.sciencedirect.com/science/article/pii/S0301479710003932?casa_token=Q9-AmkaQatsAAAAA:-uh4CtQJTcsiWKEACstna60YcR2mxWTqlZ_UWnR0pFMYWGk_E5DfCnPx-BIIDzxs1OEIdLEZvQc">use more water</a> than native plants, stopping them from re-colonising. </p>
<p>These reasons are why governments invest in removing willows from our waterways. But what if willows offer some benefits to their invaded ecosystems, too?</p>
<h2>Freshwater wildlife in peril</h2>
<p>As far as we know, the presence of willows hasn’t caused any extinctions. But in coming years, we can expect to see <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2001104">more animal extinctions</a> due to temperature increases from climate change.</p>
<p>To deal with climate change, temperature-sensitive animals are left with two options: either migrate upstream to cooler water or adapt to warmer water. Both alternatives are problematic. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403683/original/file-20210601-17-u2z781.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Willow trees on a river bank" src="https://images.theconversation.com/files/403683/original/file-20210601-17-u2z781.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403683/original/file-20210601-17-u2z781.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403683/original/file-20210601-17-u2z781.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403683/original/file-20210601-17-u2z781.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403683/original/file-20210601-17-u2z781.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403683/original/file-20210601-17-u2z781.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403683/original/file-20210601-17-u2z781.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Willow trees can out-shade native plants and stop them from re-colonising.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Some animals, such as <a href="https://link.springer.com/article/10.1007/s10452-012-9401-4">two-spined blackfish</a>, aren’t well suited to (or potentially even capable of) long distance travel to cooler water. And many of our rivers have barriers, such as dams, weirs and waterfalls, making migration impossible.</p>
<p>If animals stay put, Australia’s climate is now warming at such a fast rate, some may struggle to <a href="https://www.nature.com/articles/nclimate3382">adapt quickly enough</a>. The critically endangered <a href="https://www.environment.gov.au/biodiversity/threatened/recovery-plans/national-recovery-plan-barred-galaxias-galaxias-fuscus">barred galaxias</a> is another cool water adapted fish <a href="https://www.publish.csiro.au/MF/pdf/MF11139">unlikely to successfully migrate</a> to other habitats to escape warming climate, but remains at risk if it doesn’t.</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>To give wildlife a fighting chance at survival, we need to consider a patchwork of new and alternative approaches to stream management, such as creating “<a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2486.2010.02263.x?casa_token=_Tfd-3efci4AAAAA%3AahTnzYhH4IbvNvI5C0nj0Z0DXdFJQ5XBlAOR-gFkMknIdEMIqGUVxYxeCmxvcXZBjmq9x3pM9tmymXUv">climatic refugia</a>”. These are places where local climate is cooler than the regional climate, providing areas animals can escape to when temperatures get extreme.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/384409/original/file-20210216-14-hvcumi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384409/original/file-20210216-14-hvcumi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384409/original/file-20210216-14-hvcumi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384409/original/file-20210216-14-hvcumi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384409/original/file-20210216-14-hvcumi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384409/original/file-20210216-14-hvcumi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384409/original/file-20210216-14-hvcumi.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">
<figcaption>
<span class="caption">Warmer temperatures may cause the populations of some freshwater species, such as the Murray River turtle, to grow.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>Trees and shrubs growing along the edges of streams (<a href="https://www.water.vic.gov.au/__data/assets/pdf_file/0019/421390/Waterway-Veg-Fact-Sheet-Riparian-vegetation-FINAL-May19.pdf">riparian vegetation</a>) do this when they shade the water surface, helping to mediate water temperature. </p>
<p>This could make willows a useful tool for natural resource managers as we see increases in extreme heat days.</p>
<h2>Happy Valley Creek</h2>
<p>For our <a href="https://www.sciencedirect.com/science/article/pii/S0301479721009336">research paper</a>, we use a case study from north-east Victoria to illustrate how dense willow invasions can reduce stream water temperature and create climatic refugia.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-theres-a-lot-more-to-love-about-jacarandas-than-just-their-purple-flowers-150851">Why there's a lot more to love about jacarandas than just their purple flowers</a>
</strong>
</em>
</p>
<hr>
<p>We logged water temperature in Happy Valley Creek at three locations: at an upstream native forested site, a midstream site with no vegetation, and a downstream site that was heavily shaded by invasive willows. </p>
<p>We expected water temperature to increase with distance downstream as it moves from cool upland areas to warmer lowland areas. Instead, we found the water temperature at the willow shaded site could be a few degrees cooler than the midstream site, particularly during periods of extreme heat.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/403680/original/file-20210601-15-1gjrin9.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Fish among rocks" src="https://images.theconversation.com/files/403680/original/file-20210601-15-1gjrin9.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403680/original/file-20210601-15-1gjrin9.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403680/original/file-20210601-15-1gjrin9.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403680/original/file-20210601-15-1gjrin9.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403680/original/file-20210601-15-1gjrin9.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403680/original/file-20210601-15-1gjrin9.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403680/original/file-20210601-15-1gjrin9.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some animals, like the two-spined blackfish, are unlikley to migrate to cooler waters.</span>
<span class="attribution"><span class="source">Alan Couch/Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Many streams are fringed by native vegetation that provide comparable heat protection to animals as willows, and we should protect these from willow invasion.</p>
<p>But in locations where willow removal activities are unlikely to be successful in the long-term, it may be better to prioritise willow removal elsewhere. For example, if willows can’t be removed from upstream catchments, they’ll continue to recolonise downstream. And if there’s no funding for follow-up activities, willows may re-establish following removal.</p>
<p>Where willows are rampant, they may already be protecting populations of heat-sensitive animals from temperature extremes. Removing them could have unintended consequences for such animals.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/384398/original/file-20210216-18-1i1tqbi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384398/original/file-20210216-18-1i1tqbi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384398/original/file-20210216-18-1i1tqbi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384398/original/file-20210216-18-1i1tqbi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384398/original/file-20210216-18-1i1tqbi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384398/original/file-20210216-18-1i1tqbi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384398/original/file-20210216-18-1i1tqbi.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">
<figcaption>
<span class="caption">An absence of shade from bank-side vegetation can increase stream temperatures.</span>
<span class="attribution"><span class="source">Author provided; Happy Valley Creek, Victoria</span></span>
</figcaption>
</figure>
<h2>What’s the end goal?</h2>
<p>It’s important to clarify we’re not suggesting <a href="https://weeds.dpi.nsw.gov.au/Weeds/Willows">willow removal</a> activities should stop to prevent further widespread invasion. But as our climate changes, we need to objectively consider what ecosystems will be sustainable in the future, and prioritise our restoration efforts accordingly. </p>
<p>We need to decide what state we’re trying to manage our ecosystems to — the likely endpoint. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pulling-out-weeds-is-the-best-thing-you-can-do-to-help-nature-recover-from-the-fires-130296">Pulling out weeds is the best thing you can do to help nature recover from the fires</a>
</strong>
</em>
</p>
<hr>
<p>Given current river regulations, land-use and changing climate, restoring all ecosystems to a pre–European state may not be sustainable or even possible at this point.</p>
<p>For willow-dominated, degraded catchments, there may be more value in promoting willows as refuges from the temperature extremes of climate change, rather than pursuing an ideal that may not even be possible.</p><img src="https://counter.theconversation.com/content/152609/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul McInerney works for CSIRO. He receives funding from Murray-Darling Basin Authority and the Department of Agriculture, Water and the Environment</span></em></p><p class="fine-print"><em><span>Tanya Doody receives funding from the North East Catchment Management Authority and Water for Rivers. </span></em></p>For temperature-sensitive animals, the dense, leafy canopy of willow trees may make them the lesser of two evils in a warming climate.Paul McInerney, Research scientist, CSIROTanya Doody, Principle Research Scientist, CSIRO, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1586282021-04-18T20:08:08Z2021-04-18T20:08:08ZAttack of the alien invaders: pest plants and animals leave a frightening $1.7 trillion bill<figure><img src="https://images.theconversation.com/files/395272/original/file-20210415-14-jzhiyk.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C4193%2C2785&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>They’re one of the most <a href="http://ipbes.net">damaging environmental forces</a> on Earth. They’ve colonised pretty much every place humans have set foot on the planet. Yet you might not even know they exist.</p>
<p>We’re talking about alien species. Not little green extraterrestrials, but invasive plants and animals not native to an ecosystem and which become pests. They might be plants from South America, starfish from Africa, insects from Europe or birds from Asia. </p>
<p>These species can threaten the health of plants and animals, including humans. And they cause huge economic harm. <a href="https://www.nature.com/articles/s41586-021-03405-6">Our research</a>, recently published in the journal Nature, puts a figure on that damage. We found that globally, invasive species cost US$1.3 trillion (A$1.7 trillion) in money lost or spent between 1970 and 2017. </p>
<p>The cost is increasing exponentially over time. And troublingly, most of the cost relates to the damage and losses invasive species cause. Meanwhile, far cheaper control and prevention measures are often ignored.</p>
<figure class="align-center ">
<img alt="Yellow crazy ants attacking a gecko" src="https://images.theconversation.com/files/395275/original/file-20210415-15-1pn4p4y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395275/original/file-20210415-15-1pn4p4y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395275/original/file-20210415-15-1pn4p4y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395275/original/file-20210415-15-1pn4p4y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395275/original/file-20210415-15-1pn4p4y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395275/original/file-20210415-15-1pn4p4y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395275/original/file-20210415-15-1pn4p4y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Yellow crazy ants, such as these attacking a gecko, are among thousands of invasive species causing ecological and economic havoc.</span>
<span class="attribution"><span class="source">Dinakarr, CC0, Wikimedia Commons</span></span>
</figcaption>
</figure>
<h2>An expansive toll</h2>
<p>Invasive species have been invading foreign territories for <a href="https://www.nature.com/articles/ncomms14435">centuries</a>. They hail from habitats as diverse as tropical forests, dry savannas, temperate lakes and cold oceans. </p>
<p>They arrived because we brought them — as pets, ornamental plants or as stowaways on our holidays or via <a href="https://theconversation.com/global-trade-increases-exotic-species-incursion-4208">commercial trade</a>. </p>
<p>The problems they cause can be:</p>
<ul>
<li>ecological, such as causing the extinction of native species</li>
<li>human health-related, such as causing allergies and spreading disease</li>
<li>economic, such as reducing crop yields or destroying human-built infrastructure. </li>
</ul>
<p>In Australia, invasive species are one of our <a href="https://www.environment.gov.au/biodiversity/invasive-species/publications/factsheet-invasive-species-australia">most serious</a> environmental problems – and the biggest cause of extinctions.</p>
<p>Feral animals such as rabbits, goats, cattle, pigs and horses can degrade grazing areas and compact soil, damaging farm production. Feral rabbits take over the burrows of native animals, while <a href="https://theconversation.com/one-cat-one-year-110-native-animals-lock-up-your-pet-its-a-killing-machine-138412">feral cats</a> and <a href="https://theconversation.com/is-it-too-late-to-bring-the-red-fox-under-control-11299">foxes</a> hunt and kill native animals.</p>
<hr>
<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>
</strong>
</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/394171/original/file-20210409-13-1bznl7v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/394171/original/file-20210409-13-1bznl7v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/394171/original/file-20210409-13-1bznl7v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/394171/original/file-20210409-13-1bznl7v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/394171/original/file-20210409-13-1bznl7v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/394171/original/file-20210409-13-1bznl7v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/394171/original/file-20210409-13-1bznl7v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/394171/original/file-20210409-13-1bznl7v.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">Wetlands in the Northern Territory damaged by invasive swamp buffalo (<em>Bubalus bubalis</em>)</span>
<span class="attribution"><span class="source">Warren White</span></span>
</figcaption>
</figure>
<p>Introduced insects, such as <a href="https://theconversation.com/a-tiny-wasp-could-save-christmas-islands-spectacular-red-crabs-from-crazy-ants-69646">yellow crazy ants</a> on Christmas Island, pose a serious threat to a native species. Across Australia, <a href="https://www.environment.gov.au/biodiversity/invasive-species/insects-and-other-invertebrates/invasive-bees">feral honeybees</a> compete with native animals for nectar, pollen and habitat.</p>
<p><a href="https://www.dpi.nsw.gov.au/fishing/aquatic-biosecurity/pests-diseases/freshwater-pests">Invasive fish</a> compete with native species, disturb aquatic vegetation and introduce disease. Some, such as <a href="https://www.environment.nsw.gov.au/topics/animals-and-plants/threatened-species/nsw-threatened-species-scientific-committee/determinations/final-determinations/1996-1999/predation-by-the-plague-minnow-gambusia-holbrooki-key-threatening-process-listing">plague minnows</a>, prey on the eggs and tadpoles of frogs and attack native fish. </p>
<p><a href="http://www.anbg.gov.au/weeds/weeds.html">Environmental weeds</a> and invasive <a href="https://www.environment.gov.au/biodiversity/invasive-species/diseases-fungi-and-parasites">fungi and parasites</a> also cause major damage.</p>
<p>Of course, the problem is global – and examples abound. In Africa’s Lake Victoria, the huge, carnivorous <a href="https://www.invasivespeciesinfo.gov/aquatic/fish-and-other-vertebrates/nile-perch">Nile perch</a> — introduced to boost fisheries – has wiped out <a href="https://link.springer.com/article/10.1007/BF00004782">more than 200</a> of the 300 known species of <a href="https://www.britannica.com/animal/cichlid">cichlid fish</a> — prized by aquarium enthusiasts the world over.</p>
<p>And in the Florida Everglades, thousands of five metre-long <a href="https://doi.org/10.1073/pnas.1115226109">Burmese pythons</a> have gobbled up small, native mammals at alarming rates.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/invasive-predators-are-eating-the-worlds-animals-to-extinction-and-the-worst-is-close-to-home-64741">Invasive predators are eating the world's animals to extinction – and the worst is close to home</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="cichlid fish" src="https://images.theconversation.com/files/395273/original/file-20210415-17-uge3g9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395273/original/file-20210415-17-uge3g9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395273/original/file-20210415-17-uge3g9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395273/original/file-20210415-17-uge3g9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395273/original/file-20210415-17-uge3g9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395273/original/file-20210415-17-uge3g9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395273/original/file-20210415-17-uge3g9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In Africa, numbers of the beautiful cichlid fish have been decimated by Nile perch.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Money talks</h2>
<p>Despite the <a href="https://pubag.nal.usda.gov/catalog/61">serious threat</a> biological invasions pose, the problem receives little political, media or public attention.</p>
<p>Our research sought to reframe the problem of invasive species in terms of economic cost. But this was not an easy task. </p>
<p>The costs are diverse and not easily compared. Our analysis involved thousands of cost estimates, compiled and analysed over several years in our <a href="https://figshare.com/articles/dataset/InvaCost_References_and_description_of_economic_cost_estimates_associated_with_biological_invasions_worldwide_/12668570">still-growing</a> <a href="https://www.nature.com/articles/s41597-020-00586-z"><em>InvaCost</em></a> database. Economists and ecologists helped fine-tune the data.</p>
<p>The results were staggering. We discovered invasive species have cost the world US$1.3 trillion (A$1.7 trillion) lost or spent between 1970 and 2017. The cost largely involves damages and losses; the cost of preventing or controlling the invasions were ten to 100 times lower.</p>
<p>Clearly, getting on top of control and prevention would have helped avoid the massive damage bill. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/global-agriculture-study-finds-developing-countries-most-threatened-by-invasive-pest-species-61280">Global agriculture study finds developing countries most threatened by invasive pest species</a>
</strong>
</em>
</p>
<hr>
<p>Average costs have been increasing exponentially over time — trebling each decade since 1970. For 2017 alone, the estimated cost of invasive species was more than US$163 billion. That’s more than 20 times higher than the combined budgets of the <a href="https://www.who.int">World Health Organisation</a> and the <a href="https://www.un.org">United Nations</a> in the same year.</p>
<p>Perhaps more alarming, this massive cost is a conservative estimate and likely represents only the tip of the iceberg, for several reasons:</p>
<ul>
<li><p>we analysed only the most robust available data; had we included all published data, the cost figure would have been 33 times higher for the estimate in 2017</p></li>
<li><p>some damage caused by invasive species cannot be measured in dollars, such as carbon uptake and the loss of ecosystem services such as pollination</p></li>
<li><p><a href="https://doi.org/10.1016/j.scitotenv.2020.144441">most</a> of the impacts have not been properly estimated</p></li>
<li><p>most countries have little to no relevant data. </p></li>
</ul>
<figure class="align-center ">
<img alt="A bucket by a lake with a sign reading 'Biosecurity station. Please dip your feet and nets'" src="https://images.theconversation.com/files/395276/original/file-20210415-19-10m8e2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395276/original/file-20210415-19-10m8e2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=447&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395276/original/file-20210415-19-10m8e2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=447&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395276/original/file-20210415-19-10m8e2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=447&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395276/original/file-20210415-19-10m8e2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=562&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395276/original/file-20210415-19-10m8e2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=562&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395276/original/file-20210415-19-10m8e2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=562&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Prevention strategies, such as biosecurity controls, are a relatively cheap way to deal with invasive species.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Prevention is better than cure</h2>
<p>National regulations for dealing with invasive species are patently <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1111/geb.12517">insufficient</a>. And because alien species do not respect borders, the problem also requires a global approach.</p>
<p>International cooperation must include financial assistance for developing countries where invasions are expected to increase substantially in the coming decades, and where regulations and management are <a href="https://www.nature.com/articles/ncomms12485">most lacking</a>. </p>
<p>Proactive measures to prevent invasion must become a priority. As the old saying goes, an ounce of prevention is better than a pound of cure. And this must happen early – if we miss the start of an invasion, control in many cases is <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320702001611">impossible</a>. </p>
<p>More and better research on the economic costs of biological invasions is essential. Our current knowledge is fragmented, hampering our understanding of patterns and trends, and our capacity to manage the problem efficiently. </p>
<p>We hope quantifying the economic impacts of invasive species will mean political leaders start to take notice. Certainly, confirmation of a A$1.7 trillion bill should be enough to get the ball rolling.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/worried-about-earths-future-well-the-outlook-is-worse-than-even-scientists-can-grasp-153091">Worried about Earth's future? Well, the outlook is worse than even scientists can grasp</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/158628/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Corey J. A. Bradshaw receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Franck Courchamp a reçu des financements de Centre National de la Recherche Scientifique (CNRS) and AXA Research Fund</span></em></p><p class="fine-print"><em><span>Boris Leroy, Camille Bernery, and Christophe Diagne do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Invasive species have been invading foreign territories for centuries. By quantifying the mammoth economic impacts, we hope political leaders will start to take notice.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 UniversityBoris Leroy, Maître de conférences en écologie et biogéographie, Muséum national d’histoire naturelle (MNHN)Camille Bernery, Doctorante en écologie des invasions, Université Paris-SaclayChristophe Diagne, Chercheur post-doctorant en écologie des invasions, Université Paris-SaclayFranck Courchamp, Directeur de recherche CNRS, Université Paris-SaclayLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1542652021-02-17T19:12:27Z2021-02-17T19:12:27ZDon’t disturb the cockatoos on your lawn, they’re probably doing all your weeding for free<figure><img src="https://images.theconversation.com/files/384637/original/file-20210217-19-1b114rk.jpg?ixlib=rb-1.1.0&rect=8%2C0%2C5982%2C3988&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>Australians have a love-hate relationship with sulphur-crested cockatoos, <em>Cacatua galerita</em>. For some, the noisy parrots are pests that destroy crops or the garden, damage homes and <a href="https://www.wildlife.vic.gov.au/__data/assets/pdf_file/0022/90661/Guidelines-For-Reducing-Cockatoo-Damage-PDF.pdf">pull up turf</a> at sports ovals. </p>
<p>For others, they’re a bunch of larrikins who love to play and are quintessentially Australian. </p>
<p>Along with other scientists, I had a unique opportunity during the COVID-19 lockdowns to study things that had intrigued me closer to home, perhaps for years. While isolating in the suburbs of Melbourne, I wanted to find out why cockatoos return to the same places, and what they’re after. </p>
<p>The answer? Onion grass, reams of it. </p>
<p>Onion grass is a significant weed, and I estimated in a recent <a href="https://onlinelibrary.wiley.com/doi/10.1111/emr.12449?fbclid=IwAR0-0s3AJkhaQhWAqh9_RdjMLQ-bIvZs_I1M--KzoaAQACTXwU3ejEEL0O8https://onlinelibrary.wiley.com/doi/10.1111/emr.12449?fbclid=IwAR0-0s3AJkhaQhWAqh9_RdjMLQ-bIvZs_I1M--KzoaAQACTXwU3ejEEL0O8">paper</a> that one bird gorges on about 200 plants per hour. A flock of about 50 birds can consume 20,000 plants in a couple of hours. </p>
<p>This significantly reduces the weed level and may make expensive herbicide use unnecessary. So if you have a large amount of onion grass on your property and are regularly visited by sulphur-crested cockatoos, it would be wise to let them do their weeding first. </p>
<h2>When play verges on vandalism</h2>
<p>Most of us see cockies whether we live in rural communities or major cities, but how much do you really know about them? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/384632/original/file-20210217-13-qyo2ao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two sulphur-crested cockatoos sitting on a branch" src="https://images.theconversation.com/files/384632/original/file-20210217-13-qyo2ao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384632/original/file-20210217-13-qyo2ao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384632/original/file-20210217-13-qyo2ao.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384632/original/file-20210217-13-qyo2ao.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384632/original/file-20210217-13-qyo2ao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384632/original/file-20210217-13-qyo2ao.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384632/original/file-20210217-13-qyo2ao.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">Sulphur-crested cockatoos nest in old hollow trees.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>In late winter and early spring in many parts of Australia, flocks of sulphur–crested cockatoos can be seen grazing on the ground. They’re usually found close to water, nesting in woodlands with old hollow trees, such as <a href="http://theconversation.com/the-river-red-gum-is-an-icon-of-the-driest-continent-118839">river red gums</a>, <em>Eucalyptus camaldulensis</em>. </p>
<p>Where these forests and trees are being cleared, the number of cockies falls. But they are resilient and adaptable birds, and have spread their range to cities and the urban fringe, where <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.13295">numbers are increasing</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/birds-that-play-with-others-have-the-biggest-brains-and-the-same-may-go-for-humans-151079">Birds that play with others have the biggest brains - and the same may go for humans</a>
</strong>
</em>
</p>
<hr>
<p>The birds are known to play with fruits, hang upside down on branches or perform flying cartwheels by holding a small branch or powerline with their feet, flapping their wings as they do loop after loop. </p>
<p>Sometimes their play verges on vandalism as they follow tree planters, deftly pulling up just-planted trees and laying them neatly beside the hole. </p>
<p>While cockatoos feed on the fruits and seed of native species, they’ve adapted very quickly to the introduction of exotic species, such as onion grass from South Africa, which is plentiful and easy to harvest. </p>
<p>I observed flocks ranging from nine to 63 cockatoos at seven sites along the Maribyrnong River in Keilor last July and August. Onion grass was the only item on their menu.</p>
<h2>A pest for humans, a feast for birds</h2>
<p>Onion grass (<em>Romulea rosea</em>) is small and usually inconspicuous with grass-like leaves. It’s typically only noticed when it flowers in spring, producing pretty, pink and yellow-throated flowers. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/384634/original/file-20210217-17-1diaw6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Conspicuous onion grass with a small purple flower" src="https://images.theconversation.com/files/384634/original/file-20210217-17-1diaw6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384634/original/file-20210217-17-1diaw6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384634/original/file-20210217-17-1diaw6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384634/original/file-20210217-17-1diaw6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384634/original/file-20210217-17-1diaw6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384634/original/file-20210217-17-1diaw6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384634/original/file-20210217-17-1diaw6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Onion grass comes from South Africa, and is a big problem for native grasslands.</span>
<span class="attribution"><span class="source">Harry Rose/Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Onion grass can be a <a href="https://grasslands.ecolinc.vic.edu.au/fieldguide/flora/onion-grass#details">serious weed</a> that’s very difficult to control. It’s not only a problem for agricultural land, but also for recreational turf and native grasslands. </p>
<p>In some areas, there are nearly <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2494.2011.00838.x">5,000 onion grass plants</a> per square metre. This is a massive number requiring costly control measures, such as spraying or scraping away the upper layer of top soil.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-river-red-gum-is-an-icon-of-the-driest-continent-118839">The river red gum is an icon of the driest continent</a>
</strong>
</em>
</p>
<hr>
<p>Onion grass gets its name from its onion-like leaves. At the base is a small bulb, which works as a modified underground stem called a “corm”. The corm is what cockatoos will travel many kilometres for, to dig up and return to for days on end. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/384636/original/file-20210217-15-bansad.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A brown bulb with small roots coming out" src="https://images.theconversation.com/files/384636/original/file-20210217-15-bansad.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384636/original/file-20210217-15-bansad.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384636/original/file-20210217-15-bansad.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384636/original/file-20210217-15-bansad.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384636/original/file-20210217-15-bansad.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384636/original/file-20210217-15-bansad.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384636/original/file-20210217-15-bansad.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">When cockatoos eat onion grass corm, it prevents the weed from regenerating.</span>
<span class="attribution"><span class="source">Harry Rose/Wikimedia</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Their super weeding effort</h2>
<p>Like other native parrots, sulphur-crested cockatoos are famously <a href="https://www.abc.net.au/science/articles/2011/02/07/3131593.htm#">left-footed</a>. So it was interesting to observe them primarily use their powerful beaks to pull onion grass plants from the ground and dig up corms, using their left foot only occasionally to manipulate the plant.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/these-historic-grasslands-are-becoming-a-weed-choked-waste-it-could-be-one-of-the-worlds-great-parks-144208">These historic grasslands are becoming a weed-choked waste. It could be one of the world's great parks</a>
</strong>
</em>
</p>
<hr>
<p>The cockatoos fed for between 30 minutes and two and a half hours. At each feed, one or two sentry (or sentinel) birds, depending on the flock size, would keep watch and give raucous warning should danger threaten.</p>
<p>The cockies could remove a plant and corm from the ground in as little as six seconds, but sometimes it could take up to 30 seconds. They then removed and consumed a corm every 14 seconds on average in wet soil and every 18 seconds from harder, dry soil. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/384630/original/file-20210217-21-qt1ow6.jpg?ixlib=rb-1.1.0&rect=14%2C22%2C2481%2C1642&q=45&auto=format&w=1000&fit=clip"><img alt="Eight cockatoos on grass, with autumn leaves" src="https://images.theconversation.com/files/384630/original/file-20210217-21-qt1ow6.jpg?ixlib=rb-1.1.0&rect=14%2C22%2C2481%2C1642&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/384630/original/file-20210217-21-qt1ow6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/384630/original/file-20210217-21-qt1ow6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/384630/original/file-20210217-21-qt1ow6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/384630/original/file-20210217-21-qt1ow6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/384630/original/file-20210217-21-qt1ow6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/384630/original/file-20210217-21-qt1ow6.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">When flocks feed, one or two sentinel birds keep watch for danger.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This means a flock of 63 birds could remove more than 35,400 onion grass plants in a feeding session lasting two and half hours. This is a super weeding effort by any standard!</p>
<h2>Future partnerships</h2>
<p>My further investigation revealed most of the corms were within 20 millimetres of the soil surface, so the holes left in the soil by the birds extracting the onion grass were shallow and quite small. This shouldn’t give seeds from onion grass any great advantage. </p>
<p>And they’re very efficient: the birds eat over 87% of the corms they lift, which then won’t get a chance to generate in future years. So, if we’re going to try to eradicate onion grass, it may be better to let the cockies do their work first before we humans take a turn. </p>
<p>We have a lot to learn about how our native species interact with introduced weeds, and more research might reveal some very useful future partnerships. They might be birdbrains, but sulphur-crested cockatoos really know their onions when it comes to, well, onion grass.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/running-out-of-things-to-do-in-isolation-get-back-in-the-garden-with-these-ideas-from-4-experts-134229">Running out of things to do in isolation? Get back in the garden with these ideas from 4 experts</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/154265/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gregory Moore 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>I collected data about my neighbourhood sulphur-crested cockatoos while stuck home in Melbourne’s lockdown. I learned that each bird can eat 200 onion grass plants per hour.Gregory Moore, Doctor of Botany, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1522552020-12-23T17:34:09Z2020-12-23T17:34:09ZGoldenrod honey: misinformation is causing a biological invasion of this Canadian weed<figure><img src="https://images.theconversation.com/files/376105/original/file-20201221-17-j9o20i.jpg?ixlib=rb-1.1.0&rect=0%2C369%2C4050%2C2637&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/JMuJfLVWtN4">Jeffrey Hamilton/Unsplash</a>, <a class="license" href="http://artlibre.org/licence/lal/en">FAL</a></span></figcaption></figure><p><a href="https://theconversation.com/why-anti-vaccine-beliefs-and-ideas-spread-so-fast-on-the-internet-111431">Refusal of vaccines</a>, <a href="https://theconversation.com/pseudoscience-is-taking-over-social-media-and-putting-us-all-at-risk-121062">climate change denial</a>, the spread of <a href="https://theconversation.com/coronavirus-conspiracy-theories-are-dangerous-heres-how-to-stop-them-spreading-136564">coronavirus</a>, <a href="https://theconversation.com/misinformation-about-illicit-drugs-is-spreading-on-social-media-and-the-consequences-could-be-dangerous-146637">dangerous drug use</a> – all can be linked to the rapid spread of misinformation over the internet. Our recently published <a href="https://onlinelibrary.wiley.com/doi/10.1111/ele.13645">study</a> now adds a biological invasion to the list: Canadian goldenrod, a weed used to make a much-sought after honey.</p>
<p>Biological invasions occur when non-native species spread rapidly, out-competing native species and causing major ecosystem change and damage. <a href="http://www.issg.org/about_is.htm">Invasive species</a> are a major threat to biodiversity worldwide, threatening the diversity of plants, animals and insects where they spread.</p>
<p>Besides ecological harm, biological invasions also cause <a href="https://www.fws.gov/verobeach/PythonPDF/CostofInvasivesFactSheet.pdf">economic</a> harm. In the United States alone, the cost of invasive species is estimated to be <a href="https://nwrc.contentdm.oclc.org/digital/collection/NWRCPubs1/id/60547/rec/7">billions of dollars annually</a>, impacting agriculture, property values, fisheries and more.</p>
<p>History shows that a lack of understanding about a species which leads to unintended consequences isn’t new. The non-native Nile perch <a href="https://cdnsciencepub.com/doi/full/10.1139/cjfas-2017-0056">wreaked havoc</a> in Lake Victoria’s ecosystem decades after being introduced in the 1950s, most likely with a view to benefit the <a href="https://academic.oup.com/bioscience/article/55/9/780/286121">fishing industry</a>. Japan still suffers a <a href="https://www.smithsonianmag.com/smart-news/childrens-book-behind-japans-raccoon-problem-180954577/">raccoon pest problem</a> after a 1970s children’s television cartoon show inspired families to import racoons as pets. But the ease of spreading incomplete, or false, information via the internet magnifies the risk of far more devastating consequences.</p>
<h2>A dangerous fad</h2>
<p>In our study, the first to research the impact of online misinformation on biological invasions, we looked at Canadian goldenrod (<em>Solidago canadensis</em>), an incredibly <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320709000640?via%25253Dihub">harmful weed</a> due to its tendency to crowd out other plant species, thereby reducing biodiversity. Goldenrod has a high growth rate, and light, wind-dispersed seeds. It also <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/ddi.12902">changes soil properties</a> by releasing chemical substances into the soil which impact on <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2745.2008.01413.x">other plants</a>. Goldenrod is a herbaceous plant that produces plumes of fluffy yellow flowers in the summer. It is native to North America, but has now spread well beyond. The plant grows rapidly, and takes particular advantage of human modified habitats in urban and agricultural environments.</p>
<p>Many online stores and natural remedies websites and blogs tout goldenrod honey as a “superfood” for kidney disease or as beneficial in treating other ailments, from colds to the circulatory system to bad skin. We examined the scientific literature and found <a href="https://onlinelibrary.wiley.com/doi/10.1111/ele.13645">no proof</a> that goldenrod honey improves health or cures any disease. </p>
<p>Our research shows these scientifically unsupported claims have indeed spread faster and farther with the rise of social media and the internet. For example, Google search records from Poland show only a handful of searches (in Polish) for “goldenrod honey kidney” and “what goldenrod honey cures” in 2002, but 14,200 and 18,500 searches respectively in 2019.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/376366/original/file-20201222-17-10zg3j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing prevalence of goldenrod." src="https://images.theconversation.com/files/376366/original/file-20201222-17-10zg3j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376366/original/file-20201222-17-10zg3j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376366/original/file-20201222-17-10zg3j2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376366/original/file-20201222-17-10zg3j2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376366/original/file-20201222-17-10zg3j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=466&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376366/original/file-20201222-17-10zg3j2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=466&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376366/original/file-20201222-17-10zg3j2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=466&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 and introduced distribution map of goldenrod and goldenrod honey availability.</span>
<span class="attribution"><span class="source">Ecology Letters</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The spread of this misinformation has led to an increased demand for goldenrod honey, resulting in higher prices. From 2008-2018, we found that the availability and price of goldenrod honey rose sharply – from about £5 to £12 per kilogram – mirroring the rise we documented in searches for its purported health benefits. Goldenrod honey is sold online in 37 countries where goldenrod is not native, as far afield as Australia, New Zealand and South Africa.</p>
<p>Across 13 countries where Canadian goldenrod is considered invasive, we counted about 150,000 web pages with information on how to plant goldenrod for bees. In Poland we found more than 20,000 such web pages; especially popular is information about planting along rivers and railways, and in meadows and abandoned fields. Planting in these natural and <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0101297">semi-natural habitats</a> is concerning because these areas are <a href="https://www.sciencedirect.com/science/article/pii/S0925857417302379?via%25253Dihub">typically rich</a> in plant and pollinator biodiversity. In addition, <a href="http://www.ibot.cas.cz/personal/pysek/pdf/Cuda,%252520Rumlerova,%252520Bruna,%252520Skalova,%252520Pysek-Flood%252520effects%252520on%252520Impatiens%252520abundance_DiversityDistrib2017(online%252520early).pdf">flooding rivers</a> further spread this invasive species.</p>
<p>Laws against the import of alien invasive species seeds and seedlings do not stop beekeepers from purchasing and planting them. Canadian goldenrod is sold on platforms like Amazon, eBay and Etsy, even in countries where import is illegal, such as Australia and New Zealand.</p>
<figure class="align-center ">
<img alt="A field of goldenrod." src="https://images.theconversation.com/files/376187/original/file-20201221-21-1gxa0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376187/original/file-20201221-21-1gxa0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376187/original/file-20201221-21-1gxa0u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376187/original/file-20201221-21-1gxa0u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376187/original/file-20201221-21-1gxa0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376187/original/file-20201221-21-1gxa0u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376187/original/file-20201221-21-1gxa0u.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">
<figcaption>
<span class="caption">Goldenrod often takes over the local ecology.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/solidago-canadensis-known-canada-goldenrod-canadian-1457291744">Gabriela Beres/Shutterstock.com</a></span>
</figcaption>
</figure>
<h2>Harm to farmers, flora, and fauna</h2>
<p>For farmers and landowners, controlling <a href="https://bioone.org/journals/polish-journal-of-ecology/volume-64/issue-1/15052249PJE2016.64.1.003/Invasive-Solidago-Species--How-Large-Area-Do-They-Occupy/10.3161/15052249PJE2016.64.1.003.short">goldenrod</a> is costly. One <a href="https://bioone.org/journals/polish-journal-of-ecology/volume-64/issue-1/15052249PJE2016.64.1.003/Invasive-Solidago-Species--How-Large-Area-Do-They-Occupy/10.3161/15052249PJE2016.64.1.003.short">study</a> estimated that to remove Canadian goldenrod stands from 130,000 hectares in south-west Poland would cost more than £25 million.</p>
<p>Studies show multiple species of <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320709000640">pollinators</a>, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320709005382">birds</a> and <a href="https://link.springer.com/article/10.1007/s10530-013-0461-8">ants</a> rely on the species crowded out by non-native goldenrod.</p>
<p>We found that, ironically, planting Canadian goldenrod is detrimental to honeybees. Because Canadian goldenrod tends to quickly dominate the vegetation, nectar and pollen resources for honeybees decrease by 90% outside of late summer and autumn, when goldenrod flowers. This reduction in plant diversity therefore causes poor honeybee nutrition. In an experiment, we found worker honeybees fed only goldenrod honey had ten times lower survival probability than bees fed a mixed flower honey or sugar water diet.</p>
<figure class="align-center ">
<img alt="Graph showing low survival rates for bees fed on goldenrod honey" src="https://images.theconversation.com/files/376368/original/file-20201222-15-6ri9qk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/376368/original/file-20201222-15-6ri9qk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=316&fit=crop&dpr=1 600w, https://images.theconversation.com/files/376368/original/file-20201222-15-6ri9qk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=316&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/376368/original/file-20201222-15-6ri9qk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=316&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/376368/original/file-20201222-15-6ri9qk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=397&fit=crop&dpr=1 754w, https://images.theconversation.com/files/376368/original/file-20201222-15-6ri9qk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=397&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/376368/original/file-20201222-15-6ri9qk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=397&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Honeybee worker survival on diets of goldenrod honey, mixed flower honey and sugar water.</span>
<span class="attribution"><span class="source">Ecology Letters</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>To protect biodiversity, we believe that, outside North America, governments should review and update laws to explicitly ban the Canadian goldenrod trade. Many countries – including Germany, Poland, France, Slovenia, Hungary, the Czech Republic, Slovakia, Austria and the United Kingdom – have laws aimed at controlling <a href="https://ec.europa.eu/environment/nature/invasivealien/list/index_en.htm">invasive species</a>. In the same countries, scientists and government agencies consider Canadian goldenrod <a href="https://www.cabi.org/isc/datasheet/50599">invasive</a>. However, legislation doesn’t seem to have kept up with scientific advice as it doesn’t currently cover Canadian goldenrod. Seeds and seedlings are legally traded in these countries. </p>
<p>Governmental agencies and horticultural societies can help by increasing and promoting scientifically based guidance to the public. Circulating better information about invasive species and their environmental impacts can help beekeepers and consumers make better individual decisions that help – not harm – the environment.</p><img src="https://counter.theconversation.com/content/152255/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>During work on this study Magdalena Lenda was supported by Australian Research Council Centre of Excellence for Environmental Decisions CE11001000104,
Iuventus Plus, Polish Ministry of Science and Higher Education grant number: IP2012 029472,
Mobilnosc Plus, Polish Ministry of Science and Higher Education 1324/1/MOB/IV/15/2016/0
and Australian Government.</span></em></p><p class="fine-print"><em><span>Johannes M H Knops 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>Our study is the first to research the impact of online misinformation on biological invasions.Magdalena Lenda, Associate professor in Biology, Polish Academy of SciencesJohannes M H Knops, Professor & Head of Department Health and Environmental Sciences, Xi'an Jiaotong-Liverpool UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1489202020-11-23T19:03:09Z2020-11-23T19:03:09ZSilky oaks are older than dinosaurs and literally drip nectar – but watch out for the cyanide<figure><img src="https://images.theconversation.com/files/370726/original/file-20201123-19-x1qpx0.jpg?ixlib=rb-1.1.0&rect=83%2C251%2C3904%2C1988&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>As we come to the end of spring, look up from the footpath or at the park, and you may spot the fiery flowers of the silky oak, <em>Grevillea robusta</em>. </p>
<p>You may already be familiar with <a href="http://anpsa.org.au/APOL2009/mar09-s1.html">grevilleas</a> – perhaps you have low- growing ground cover and shrub species in your garden. </p>
<p>Some people love the brilliant red, yellow, orange or white flowers of grevilleas. They’re also nesting and roosting havens for small native birds, and so people may plant them to attract wildlife.</p>
<p>Of all the grevillias, the silky oak is the one that catches my eye. It’s the largest and tallest of the species, reaching up to 30 metres. They’re now blooming along the east coast and in some inland places – like huge orange light bulbs dominating the skyline.</p>
<figure class="align-center ">
<img alt="A bird feeding on silky oak flower" src="https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.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">Silky oaks flowers are a magnet for birds and insects.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Strong like oak</h2>
<p>Grevilleas have an ancestry older than dinosaurs. They originated on the super-continent Gondwana, and are closely related to banksias, waratahs and proteas.</p>
<p>Today, the 360 species of grevilleas occur in Indonesia and Australia and are a diverse group. Their colourful, distinctive flowers lack petals and instead consist of a long tube known as a “calyx”, which splits into four “lobes”.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/once-again-wattles-are-out-in-bloom-heres-what-makes-our-iconic-flowers-so-special-146109">Once again, wattles are out in bloom: here's what makes our iconic flowers so special</a>
</strong>
</em>
</p>
<hr>
<p>Like most other grevillea, silky oak possesses proteoid or cluster roots, which are dense and fine. These roots greatly increase the absorbing surface area and <a href="http://www.plantphysiol.org/content/121/2/317">allow plants to thrive</a> in nutrient-deprived soils.</p>
<p>The word “robusta” refers to the fact that the timber is strong like real oak. The freshly split wood has a silky texture, and a pattern and light colour resembling English oak – hence the common name “silky oak”.</p>
<figure class="align-center ">
<img alt="Silky oak timber" src="https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.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">Grevillia robusta has a silky texture when split for timber.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Watch out for the cyanide</h2>
<p>Grevilleas literally drip nectar, much to the delight of native birds and bees. <a href="https://www.rbg.vic.gov.au/documents/Top_10_Australian_bush_tucker_plants_FINAL.pdf">Aboriginal people enjoyed</a> the sweet nectar straight from the plant or mixed with water — the original lolly water. </p>
<p>But you have to know which species to taste as some, including the silky oak, <a href="https://landcare.nsw.gov.au/groups/maclean-landcare-group/projects/signs-plant-labels-fact-sheets-for-community-education/australian-native-plant-factsheets/Silky%20Oak.pdf">contain hydrogen cyanide</a> that could make you ill.</p>
<p>Like other grevilleas the silky oak also contains <a href="https://www.publish.csiro.au/ch/CH9682979">tridecyl resorcinol</a>, which causes an allergic reaction leading to contact dermatitis. The chemical is similar to the <a href="http://anpsa.org.au/APOL2009/mar09-s1.html">toxicodendron</a> in poison ivy. </p>
<p>So when working with silky oaks, you’d be wise to wear gloves, a face mask, protective eye wear (or face shield) and long sleeved clothing. Washing hands and showering at the end of the day is also recommended.</p>
<figure class="align-center ">
<img alt="gardening gloves" src="https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.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">Wear gardening gloves when handling silky oak, just to be one the safe side.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>A prized timber</h2>
<p>Silky oak timber was widely used in colonial times. Then it was <a href="http://www.agroforestry.net.au/main.asp?_=Silky%20Oak">marketed as</a> “lacewood”, and that name persists today among some who use it.</p>
<p>Silky oak veneer was used widely in colonial table tops and other furniture. Over the years, silky oak has also been used to make window frames because it is resistant to wood rot.</p>
<p>Overseas, silky oak timber is still <a href="https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/2918082">widely grown</a>, in timber plantations and as windbreaks.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/here-are-5-practical-ways-trees-can-help-us-survive-climate-change-129753">Here are 5 practical ways trees can help us survive climate change</a>
</strong>
</em>
</p>
<hr>
<p>But it’s not widely available in Australia, due to low market demand – the allergens and cyanide it contains means people are generally reluctant to work with it. However silky oak is still highly prized by those who make guitars, and wood turners who make bowls and cabinets.</p>
<figure class="align-center ">
<img alt="Painted silky oak window frames" src="https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.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">
<figcaption>
<span class="caption">Silky oak timber is rot-resistant and was often used in window frames.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>In the garden</h2>
<p>Although an evergreen tree, some specimens are almost semi-deciduous, losing most of their foliage just prior to flowering.</p>
<p>Some specimens of silky oak can be a bit scraggly in their canopy form. They can benefit enormously from a bit of formative pruning when they are young, and perhaps some structural pruning from a good arborist as they get older. A little attention at the right time will be amply rewarded with a safe and great looking tree that can live for 150 years or more.</p>
<p>Silky oak is <a href="https://www.cabi.org/isc/datasheet/25866">drought-tolerant</a>. In dry times they often flower a bit later than their usual October blooming, providing a big splash of colour in otherwise drab and difficult years. </p>
<p>The trees can be vulnerable to frost when young, but grow well once taller. This makes the silky oak a potential winner as climate change brings warmer, drier weather. </p>
<p>Silky oaks have been declared an <a href="https://weeds.dpi.nsw.gov.au/WeedImages/Details/1324">environmental weed</a> in parts of New South Wales and Victoria where it grows outside its native distribution range. They’re also considered an invasive or invader plant in Hawaii and South Africa. However <em>Grevillea robusta</em> <a href="https://keyserver.lucidcentral.org/weeds/data/media/Html/grevillea_robusta.htm">is declining</a> in its natural rainforest/wet forest habitat. </p>
<p>In some cities in China, silky oaks have been planted along roadsides with great success. The tree has also gained the <a href="https://en.wikipedia.org/wiki/Royal_Horticultural_Society">Royal Horticultural Society</a>’s <a href="https://en.wikipedia.org/wiki/Award_of_Garden_Merit">Award of Garden Merit</a> for its performance in growing under United Kingdom conditions. That just shows you how one person’s weed is another’s treasure.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-river-red-gum-is-an-icon-of-the-driest-continent-118839">The river red gum is an icon of the driest continent</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/148920/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gregory Moore 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>Silky oaks, or Grevillea robusta, are in bloom. These hardy, attractive trees light up the sky in late spring – but handle with care.Gregory Moore, Doctor of Botany, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1395452020-07-02T16:27:39Z2020-07-02T16:27:39ZHow to manage plant pests and diseases in your victory garden<figure><img src="https://images.theconversation.com/files/344936/original/file-20200701-54162-1evw3y8.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C3895%2C2216&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Entomologist Brian Lovett examines flea beetle-infested potatoes in Morgantown, West Virginia.</span> <span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Home gardening is having a boom year across the U.S. Whether they’re <a href="https://www.nytimes.com/2020/03/25/dining/victory-gardens-coronavirus.html">growing their own food</a> in response to the pandemic or just looking for a diversion, numerous aspiring gardeners have constructed their first raised beds, and seeds are flying off suppliers’ shelves. Now that gardens are largely planted, much of the work for the next several months revolves around keeping them healthy.</p>
<p>Contrary to the <a href="https://biblehub.com/galatians/6-7.htm">Biblical adage</a>, we do not necessarily reap what we sow. As researchers specializing in <a href="https://www.davis.wvu.edu/faculty-staff/directory/matthew-kasson">plant</a> <a href="https://plantpath.psu.edu/directory/ctb14">pathology</a> and <a href="https://www.lovettbr.com/about">entomology</a>, we have devoted our careers to understanding and managing plant pests and pathogens. We are also gardeners with varying levels of experience and have seen firsthand the damage these insects and disease-causing agents can inflict.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/345094/original/file-20200701-159785-e2sa5p.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/345094/original/file-20200701-159785-e2sa5p.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/345094/original/file-20200701-159785-e2sa5p.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345094/original/file-20200701-159785-e2sa5p.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345094/original/file-20200701-159785-e2sa5p.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345094/original/file-20200701-159785-e2sa5p.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345094/original/file-20200701-159785-e2sa5p.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345094/original/file-20200701-159785-e2sa5p.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">Plant pathologist Carolee Bull works in her home garden in State College, Pennsylvania.</span>
<span class="attribution"><span class="source">Carolee Bull</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Plant health is essential for seeing your garden succeed all the way to harvest. The United Nations General Assembly has declared 2020 as the <a href="https://www.apsnet.org/members/engagement/IYPH2020/Pages/default.aspx">International Year of Plant Health</a> to help bring needed attention to pests and diseases that threaten global food production. </p>
<p>Thousands of pests and pathogens are known to target commercial crops, but a few usual suspects are routinely responsible for havoc in gardens across the U.S. Although each organism’s preferences vary, a few common tactics can help you detect them and protect your plants.</p>
<h2>Start with prevention</h2>
<p>Just as preventive steps like maintaining a balanced diet help keep humans healthy, home growers can take many actions to help their gardens thrive.</p>
<p>One key step is assessing soil fertility – the ability of soil to sustain plant growth – which can vary widely depending on your location and soil type. Low soil fertility limits food production and predisposes plants to disease and pests. University extension <a href="https://soiltesting.wvu.edu/">soil testing labs</a> can help evaluate the quality of garden soil and identify nutrient deficiencies and acidic soils, often at no charge.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/345060/original/file-20200701-159781-ma23s6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/345060/original/file-20200701-159781-ma23s6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345060/original/file-20200701-159781-ma23s6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=505&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345060/original/file-20200701-159781-ma23s6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=505&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345060/original/file-20200701-159781-ma23s6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=505&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345060/original/file-20200701-159781-ma23s6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=634&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345060/original/file-20200701-159781-ma23s6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=634&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345060/original/file-20200701-159781-ma23s6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=634&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Using weed barrier landscape cloth for planting rows and mulching between rows is an effective way to suppress weeds.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Suppressing weeds, either through mulching or weeding by hand each week, increases air flow and reduces humidity around garden plants, making it harder for pests and pathogens to thrive. Weed control ensures that nutrients are available for the plants you want to grow.</p>
<p>Proper spacing between plants is also important. Crowding can contribute to disease and pest outbreaks, so check and follow recommendations on seed packs or online as you add and move plants throughout the season. You can always cull plants after they come up to help with spacing. In small gardens, fewer plants that are properly supported can produce a bigger harvest than many overcrowded plants. </p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklysmart">You can get our highlights each weekend</a>.]</p>
<p>And then there’s the weather. Frost, hail, drought and flooding all pose unique risks to plants. Inconsistent rainfall can kill thirsty plants more quickly than infertile soils. Both too little and too much water will stress plants and can make them more vulnerable to severe pest and pathogen outbreaks.</p>
<p>A general rule of thumb is to follow a consistent daily watering regimen – preferably first thing in the morning – and to avoid over-watering, which can encourage root pathogens in soil.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/344906/original/file-20200630-103688-p09cnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/344906/original/file-20200630-103688-p09cnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/344906/original/file-20200630-103688-p09cnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=739&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344906/original/file-20200630-103688-p09cnv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=739&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344906/original/file-20200630-103688-p09cnv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=739&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344906/original/file-20200630-103688-p09cnv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=929&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344906/original/file-20200630-103688-p09cnv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=929&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344906/original/file-20200630-103688-p09cnv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=929&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Frost-killed blackberries in Morgantown, West Virginia.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Diagnosing problems</h2>
<p>Common plant pathogens include <a href="https://www.apsnet.org/edcenter/disandpath/viral/introduction/Pages/PlantViruses.aspx">viruses</a>, <a href="https://www.apsnet.org/edcenter/disandpath/prokaryote/intro/Pages/Bacteria.aspx">bacteria</a>, <a href="https://www.apsnet.org/edcenter/disandpath/nematode/intro/Pages/IntroNematodes.aspx">nematodes</a>, <a href="https://www.apsnet.org/edcenter/disandpath/oomycete/introduction/Pages/IntroOomycetes.aspx#:%7E:text=The%20oomycetes%2C%20also%20known%20as,foliar%20blights%20and%20downy%20mildews.">oomycetes</a> and <a href="https://www.apsnet.org/edcenter/disandpath/fungalasco/intro/Pages/IntroFungi.aspx">fungi</a>. All of these microorganisms, especially at an early stage of infection, are too small to see. But when they proliferate, they cause changes in plants that we can recognize. </p>
<p>Unlike insects, which move around on six legs or on wings through the air, pathogens can move unseen and unchecked from leaf to leaf on the wind, through the soil or in droplets of water. Some microbes have even formed intimate relationships with insects and use them as vehicles to move from plant to plant, which makes these pathogens even more challenging to manage. Unfortunately, by the time some pathogens make their presence known, the damage is already done.</p>
<p>We recently conducted a <a href="https://twitter.com/kasson_wvu/status/1265989041725624323">Twitter poll</a> of gardeners nationwide to find out which culprits plagued their gardens. People named <a href="https://ento.psu.edu/extension/factsheets/aphids">aphids</a>, <a href="https://ento.psu.edu/extension/factsheets/squash-vine-borer">squash vine borers</a>, <a href="https://ento.psu.edu/extension/factsheets/squash-bug">squash bugs</a> and <a href="https://ento.psu.edu/extension/factsheets/flea-beetle">flea beetles</a> as the most problematic insect pests. Their most troublesome pathogens included <a href="https://extension.wvu.edu/lawn-gardening-pests/plant-disease/fruit-vegetable-diseases/powdery-mildew">powdery mildew</a>, <a href="https://plantpath.ifas.ufl.edu/rsol/Trainingmodules/BWTomato_Module.html">tomato bacterial wilt</a> and <a href="https://extension.wvu.edu/lawn-gardening-pests/plant-disease/fruit-vegetable-diseases/downy-mildew">cucurbit downy mildew</a>. </p>
<p>To manage such perennial challenges, the first step is to spend time closely looking at your plants. Do you notice any insects consistently hanging around, or molds colonizing leaves or other plant parts? How about symptoms such as blight, stunting, or leaves that are yellowing, browning or wilting? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/345054/original/file-20200701-159785-11vtyf8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/345054/original/file-20200701-159785-11vtyf8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345054/original/file-20200701-159785-11vtyf8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=453&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345054/original/file-20200701-159785-11vtyf8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=453&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345054/original/file-20200701-159785-11vtyf8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=453&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345054/original/file-20200701-159785-11vtyf8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=569&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345054/original/file-20200701-159785-11vtyf8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=569&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345054/original/file-20200701-159785-11vtyf8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=569&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 white fungal growth is an early sign of powdery mildew on a leaf of susceptible summer squash.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>There are countless resources online for keen-eyed and curious gardeners looking to identify and manage pests and diseases. Try uploading a photo to the <a href="https://www.inaturalist.org/">iNaturalist app</a> or a <a href="https://www.facebook.com/groups/StateCollegeGardens/?multi_permalinks=600704970572066%2C600705577238672%2C600746833901213%2C600249863950910%2C599671614008735&notif_id=1593225594524195&notif_t=group_activity&ref=notif">Facebook gardeners group</a> that can offer a community-sourced ID. Plant disease clinics in your state will also diagnose plant damage from diseases and pests <a href="https://www.npdn.org/home">for free or at low cost</a>.</p>
<p>Once you’ve identified a problem serious enough to intervene, the land grant extension system can provide solutions. Extension programs at land grant schools like <a href="https://extension.wvu.edu/lawn-gardening-pests">West Virginia University</a> and <a href="https://extension.psu.edu/insects-pests-and-diseases">Penn State University</a> offer critical information on agriculture and management of pests and diseases in multiple languages for commercial and home growers. </p>
<p>Their resources include information on safe and proper use of <a href="https://extension.wvu.edu/agriculture/farm-management/pesticide-education">pesticides</a> as part of <a href="https://www.entsoc.org/sites/default/files/files/Science-Policy/ESA-Factsheet-IPM.pdf">integrated pest management</a> strategies. This approach employs pesticides in a targeted way along with non-chemical control methods and <a href="https://landscapeipm.tamu.edu/what-is-ipm/ipm-practices/cultural-practices/#:%7E:text=In%20IPM%2C%20cultural%20and%20physical,watering%2C%20nutrient%20management%2C%20etc.">cultural practices</a>, such as choosing native plants. Our professional societies, including the <a href="https://www.apsnet.org/Pages/default.aspx">American Phytopathological Society</a>, also offer <a href="https://www.apsnet.org/apsstore/pages/oncompendia.aspx">a compendium series</a> to help users diagnose and treat pests and diseases.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1278028757362790400"}"></div></p>
<p>Those who are serious about learning and sharing their experience with others may want to consider <a href="https://mastergardener.extension.org/">Master Gardener programs</a>, which train and certify community members on the latest evidence-based gardening techniques, tailored to their growing area. Master Gardeners pay it forward by training new Master Gardeners and answering questions for any gardener.</p>
<p>Plant pests are a daily reminder that gardens do not exist in a vacuum, and gardeners shouldn’t struggle alone either. Joining the gardening community takes attentiveness and time, but we believe the investment required to become an active member of your local gardening community is well worth it. With experience, the nervous tightrope act of keeping pests at bay and food on the table becomes a delicate dance that can help us appreciate where our food comes from – and ultimately, our place in the global ecosystem.</p><img src="https://counter.theconversation.com/content/139545/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matt Kasson receives funding from USDA and The Ohrstrom Foundation. </span></em></p><p class="fine-print"><em><span>Carolee Bull receives funding from the USDA and from the mushroom industry, and matching funds from seed companies for her research projects. </span></em></p><p class="fine-print"><em><span>Brian Lovett does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The COVID-19 pandemic has boosted interest in home gardening. Three scientists who garden explain some basic methods for controlling common insects and microbes that can spoil your crop.Matt Kasson, Associate Professor of Plant Pathology and Mycology, West Virginia UniversityBrian Lovett, Postdoctoral Researcher in Mycology, West Virginia UniversityCarolee Bull, Professor of Plant Pathology and Systematic Bacteriology, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1338922020-06-05T12:04:17Z2020-06-05T12:04:17ZRain plays a surprising role in making some restored prairies healthier than others<figure><img src="https://images.theconversation.com/files/327388/original/file-20200412-6948-13gxbir.jpg?ixlib=rb-1.1.0&rect=48%2C42%2C3935%2C2951&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A restored prairie in southern Michigan.</span> <span class="attribution"><span class="source">Lars Brudvig</span></span></figcaption></figure><p>Prairies once covered an enormous area of North America, but today have been <a href="https://doi.org/10.2307/1312365">reduced to a small fraction</a> of this historical range. Imagine an area the size of Texas, the second largest state, shrinking over the course of decades to an area the size of Massachusetts, the sixth smallest state. </p>
<p>Prairie grasslands <a href="https://www.fs.fed.us/grasslands/ecoservices/index.shtml">produce a lot of benefits</a>, such as storing carbon in soil, providing habitat for wildlife and protecting the land from erosion. <a href="https://www.nps.gov/miss/learn/nature/prairesthome.htm">Government agencies</a>, <a href="https://www.americanprairie.org/restoring-the-prairie">conservation organizations</a> and <a href="https://e360.yale.edu/features/in_us_midwest_restoring_native_prairie_ecosystems_kessler">homeowners</a> are working to restore native prairie ecosystems in many parts of the central U.S., but it’s a daunting challenge. Often newly planted restoration sites end up covered with weeds.</p>
<p>I am an <a href="https://scholar.google.com/citations?user=FicmXq4AAAAJ&hl=en">ecologist</a> and have worked with other researchers for a decade to find the most effective ways of restoring prairies in the midwestern United States. <a href="https://doi.org/10.1038/s41598-020-62123-7">Research we published in 2020</a> points to a reason why planted prairies can fail, one that few had considered earlier: the weather during the year they are planted. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/e_-Qo7IBxEw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Neal Smith Wildlife Refuge in central Iowa is farmland that has been restored with native plants.</span></figcaption>
</figure>
<h2>Restoring ecosystems to solve environmental problems</h2>
<p><a href="https://www.ser.org/page/SERStandards/International-Standards-for-the-Practice-of-Ecological-Restoration.htm">Ecological restoration</a> improves the health of ecosystems that have been degraded – for example, <a href="https://theconversation.com/restoring-the-everglades-will-benefit-both-humans-and-nature-56052">returning water to drained wetlands</a> or <a href="https://theconversation.com/restoring-tropical-forests-isnt-meaningful-if-those-forests-only-stand-for-10-or-20-years-107880">replanting heavily logged forests</a>. It’s an important strategy for tackling many of the world’s most pressing environmental challenges.</p>
<p>Research shows that repairing damaged ecosystems provides <a href="http://dx.doi.org/10.1126/science.1172460">critical habitat for plants and animals</a>. It <a href="https://doi.org/10.1111/rec.12989">slows the impacts of climate change</a> by drawing down carbon dioxide levels in the atmosphere. It <a href="https://doi.org/10.1111/1365-2664.12257">enhances crop pollination</a>, prevents soil loss and <a href="https://doi.org/10.1073/pnas.1620229114">keeps fertilizers out of waterways</a>. For all these reasons, the United Nations recently declared 2021-2030 to be the <a href="https://www.unenvironment.org/news-and-stories/press-release/new-un-decade-ecosystem-restoration-offers-unparalleled-opportunity">Decade on Ecosystem Restoration</a>. </p>
<p>But these projects can produce widely inconsistent results, even on similar sites where similar techniques have been used. Researchers are starting to understand that <a href="https://doi.org/10.1111/1365-2664.12938">restoration success</a> depends on multiple factors, but why some projects succeed and others fail is largely still a mystery. We want to predict outcomes so that agencies can direct scarce funding to sites where the work is most likely to succeed. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/327392/original/file-20200412-186332-1rvlyx0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/327392/original/file-20200412-186332-1rvlyx0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/327392/original/file-20200412-186332-1rvlyx0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/327392/original/file-20200412-186332-1rvlyx0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/327392/original/file-20200412-186332-1rvlyx0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/327392/original/file-20200412-186332-1rvlyx0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/327392/original/file-20200412-186332-1rvlyx0.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">
<figcaption>
<span class="caption">An eastern tiger swallowtail butterfly visits a purple cone flower within a restored prairie in southern Michigan.</span>
<span class="attribution"><span class="source">Lars Brudvig</span></span>
</figcaption>
</figure>
<h2>Decimated prairies</h2>
<p>Before European settlement, prairies were the <a href="https://doi.org/10.2307/1312365">most expansive ecosystem in North America</a>, covering much of the Midwest and Plains. Today, however, most of them have been converted largely to farmland, thanks to their fertile soil. Prairie grasslands are nearly extinct east of the Mississippi River. </p>
<p>As a result, a huge number of plant and animal species that once thrived in those regions have little habitat remaining. Some, like <a href="https://www.fws.gov/midwest/endangered/insects/posk/index.html">Poweshiek Skipperling butterflies</a> and <a href="https://www.fws.gov/midwest/endangered/plants/prairief.html">prairie fringed orchids</a>, are now at risk of extinction.</p>
<p>By spreading the seeds of prairie plants onto old farmlands, land managers can restore these ecosystems. As new grasslands grow, managers periodically conduct prescribed fires and remove weeds with herbicides to promote the prairie plants. In time, insects and birds will return to restored prairies from nearby areas. </p>
<p>I’ve been to hundreds of restored prairies. Strikingly, no two have been the same. Some are rich communities of prairie plants, while others are packed with weeds – that is, nonprairie plant species. This variation can be vexing to land managers who are seeking to restore prairies in particular ways, for particular species. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/327391/original/file-20200412-174608-1y3q2cf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/327391/original/file-20200412-174608-1y3q2cf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/327391/original/file-20200412-174608-1y3q2cf.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/327391/original/file-20200412-174608-1y3q2cf.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/327391/original/file-20200412-174608-1y3q2cf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/327391/original/file-20200412-174608-1y3q2cf.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/327391/original/file-20200412-174608-1y3q2cf.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">
<figcaption>
<span class="caption">Seeding a prairie restoration on former farmland in southern Michigan in 2007.</span>
<span class="attribution"><span class="source">Jerry Stewart</span></span>
</figcaption>
</figure>
<p>In past studies, colleagues and I have identified a number of <a href="https://doi.org/10.1111/1365-2664.12135">factors explaining why no two prairies are alike</a>. They include specific soil type, the number of plant species spread as seed to initiate restoration and the frequency of prescribed fires. These findings show that although restoration outcomes vary, at least they do so for reasons that are either easily known or under land managers’ control. But our new research indicates that this isn’t always the case.</p>
<h2>Rainy planting years cause problems</h2>
<p>Land managers widely acknowledge that planting-year weather can affect a restoration, but up to now, <a href="https://doi.org/10.1111/j.1526-100X.2010.00714.x">few scientists had tested this idea</a>. Restorations planted during rainy years should be more successful, meaning that they will support a greater diversity and abundance of the native plants that we seed on the land. But it’s hard to test this hypothesis because it requires many study sites, planted under differing weather conditions.</p>
<p>Our team worked at 83 restored prairies in Illinois, Indiana and Michigan that had been planted two to 19 years earlier. We recorded which plant species lived within each site, and then determined the weather conditions that affected each prairie during the year it was planted. </p>
<p>Our results were surprising. We expected that rainy years would promote successful restorations, but instead they produced prairies with more abundant and diverse weeds. These effects were comparable to or larger than the influence of other important factors such as soil conditions, the length of time since the last prescribed fire and the age of the project. </p>
<p>Weeds were more abundant in prairies that had been restored during rainy years as much as 19 years earlier. These sites also had relatively fewer native prairie plant species. </p>
<p>Why would dry planting years ultimately lead to more successful restoration than wet years, even though native prairie plants <a href="https://doi.org/10.1111/rec.12708">perform better with more water</a>, as we showed in a previous study? Unfortunately, weeds are super-responders to water. We suspect that this explains why they gained dominance and suppressed prairie plants during wet planting years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/339633/original/file-20200603-130912-n64yd0.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/339633/original/file-20200603-130912-n64yd0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/339633/original/file-20200603-130912-n64yd0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/339633/original/file-20200603-130912-n64yd0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/339633/original/file-20200603-130912-n64yd0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/339633/original/file-20200603-130912-n64yd0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/339633/original/file-20200603-130912-n64yd0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/339633/original/file-20200603-130912-n64yd0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Projected changes in average precipitation across the Midwest for the middle of the current century (2041-2070) relative to the end of the last century (1971-2000) if greenhouse gas emissions remain at current levels.</span>
<span class="attribution"><a class="source" href="https://nca2014.globalchange.gov/report/regions/midwest">USGCRP</a></span>
</figcaption>
</figure>
<h2>Working around the weather</h2>
<p>Our results show that land managers need to guard against detrimental planting-year weather conditions – a challenge that is likely to become increasingly important in the future. Climate change is <a href="https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180001312.pdf">increasing springtime rainfall</a> in the Midwest, which may <a href="https://doi.org/10.1016/j.ppees.2011.07.002">particularly benefit weeds</a>. </p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-likethis">Sign up for The Conversation’s daily newsletter</a>.]</p>
<p>To manage the weed burden during wet planting years, managers can mow frequently, repeat seed-spreading in a later year or even avoid planting during anticipated high rainfall years. Humans can’t control the weather, but understanding how weather affects restoration can help managers maximize projects’ chances of success.</p>
<p><em><a href="https://www.discovermagazine.com/author/anna-funk">Anna Funk</a>, a former graduate student at Michigan State University, was lead author of the study on which much of this article is based.</em></p><img src="https://counter.theconversation.com/content/133892/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lars Brudvig receives funding from the United States National Science Foundation. </span></em></p>Restoring former prairies that have been plowed under for farming delivers land, wildlife and climate benefits. But a new study finds that the weather plays a surprising role.Lars Brudvig, Associate Professor of Plant Biology, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1393052020-06-05T03:56:14Z2020-06-05T03:56:14ZLet’s fix Australia’s environment with any pandemic recovery aid – the Kiwis are doing it<figure><img src="https://images.theconversation.com/files/339397/original/file-20200603-133924-rleruq.jpg?ixlib=rb-1.1.0&rect=0%2C431%2C5760%2C3397&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Leah Anne Thompson/Shutterstock</span></span></figcaption></figure><p>The COVID-19 pandemic is causing significant economic challenges for Australia. With April figures showing <a href="https://www.abs.gov.au/AUSSTATS/abs@.nsf/allprimarymainfeatures/6050C537617B613BCA25836800102753">more than 800,000</a> people <a href="https://theconversation.com/were-it-not-for-jobkeeper-unemployment-would-be-11-7-up-from-5-2-in-one-month-heres-how-the-numbers-pan-out-138268">unemployed</a> and last month <a href="https://www.pm.gov.au/media/press-conference-australian-parliament-house-act-17">1.6 million on JobSeeker</a> payments, a key focus will be job creation.</p>
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Read more:
<a href="https://theconversation.com/the-big-stimulus-spending-has-just-begun-heres-how-to-get-it-right-quickly-138414">The big stimulus spending has just begun. Here's how to get it right, quickly</a>
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<p>Lessons should be learned from what’s happening in New Zealand, where the government is funding projects that revive the environment. Unfortunately, Australia seems to be going the other way.</p>
<h2>New Zealand gets it</h2>
<p>As part of New Zealand’s innovative <a href="https://budget.govt.nz/budget/pdfs/wellbeing-budget/b20-wellbeing-budget.pdf">Wellbeing Budget</a> the government will invest NZ$50 billion in a direct COVID-19 recovery response.</p>
<p>Of that, NZ$1.1 billion will be spent on <a href="https://www.doc.govt.nz/news/media-releases/2020-media-releases/investment-to-create-11000-environment-jobs-in-our-regions/">creating 11,000 “nature jobs”</a> to combat unemployment and supplement pandemic-affected sectors.</p>
<p>This unique investment will be delivered in a number of targeted environmental programs.</p>
<p>These include NZ$433 million for regional environmental projects that will provide 4,000 jobs in conserving and managing waterways. This will help restore fragile ecosystems such as wetlands, rivers and catchments. </p>
<p>There’s NZ$315 million for weed and feral animal control, including possums, pigs, deer and wallabies. This will provide employment through partnerships between the community, Māori land managers and government departments.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/339408/original/file-20200603-130969-1lavkkk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/339408/original/file-20200603-130969-1lavkkk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/339408/original/file-20200603-130969-1lavkkk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/339408/original/file-20200603-130969-1lavkkk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/339408/original/file-20200603-130969-1lavkkk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/339408/original/file-20200603-130969-1lavkkk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/339408/original/file-20200603-130969-1lavkkk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/339408/original/file-20200603-130969-1lavkkk.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>
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<span class="caption">New Zealanders hate possums as they’re an invasive pest.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/geoftheref/9247046550/">Flickr/Geof Wilson</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
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<p>A further NZ$200 million will deliver jobs on public conservation land through the Department of Conservation for various management actions. These include predator control, restoration, regenerative planting and maintenance of tracks, huts and other assets.</p>
<p>Some of these investments will not only provide jobs but also conserve New Zealand’s environment. They will maintain agricultural productivity and advance existing environmental initiatives such as <a href="https://predatorfreenz.org/">Predator Free New Zealand</a>.</p>
<p>They will also provide households with income that will in turn help stimulate local economies.</p>
<p>This is a win for New Zealand’s environment and wildlife, particularly native fish species and unique birds. It’s also a win for people and the economy.</p>
<h2>Australia’s destructive COVID-19 recovery</h2>
<p>In contrast, the Australian federal and some state governments have resorted to environmentally destructive projects and policies to stimulate economic activity and support employment.</p>
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Read more:
<a href="https://theconversation.com/cutting-green-tape-may-be-good-politicking-but-its-bad-policy-here-are-5-examples-of-regulation-failure-137164">Cutting ‘green tape’ may be good politicking, but it’s bad policy. Here are 5 examples of regulation failure</a>
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<p>For example, the New South Wales government in March granted approval to extend <a href="https://www.theguardian.com/environment/2020/mar/31/fears-for-water-quality-after-nsw-allows-coalmining-extension-under-sydneys-worona-reservoir">coalmining under Sydney’s Woronora reservoir</a> and in May approved the controversial <a href="https://theconversation.com/nsw-has-approved-snowy-2-0-here-are-six-reasons-why-thats-a-bad-move-139112">Snowy Hydro 2.0 project</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/336635/original/file-20200521-102678-tg7uut.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/336635/original/file-20200521-102678-tg7uut.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/336635/original/file-20200521-102678-tg7uut.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/336635/original/file-20200521-102678-tg7uut.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/336635/original/file-20200521-102678-tg7uut.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/336635/original/file-20200521-102678-tg7uut.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/336635/original/file-20200521-102678-tg7uut.jpeg?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">
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<span class="caption">Snowy 2.0 threatens to pollute pristine Snowy Mountains rivers.</span>
<span class="attribution"><span class="source">Schopier/Wikimedia</span></span>
</figcaption>
</figure>
<p>In Victoria, the government delayed key <a href="https://www.epa.vic.gov.au/about-epa/news-media-and-updates/new-environment-protection-act-postponed-to-july-2021">improvements to environmental protection laws</a> and amended legislation to <a href="https://theconversation.com/victoria-quietly-lifted-its-gas-exploration-pause-but-banned-fracking-for-good-its-bad-news-for-the-climate-133923">allow onshore gas extraction</a>. </p>
<p>Federally, wider plans exist for an apparent <a href="https://www.abc.net.au/news/2020-05-13/coronavirus-recovery-to-push-australia-towards-gas-future/12239978">fossil-fuel-led national recovery</a> through gas expansion, fast-tracked by relaxing environmental regulations. This includes a proposed <a href="https://www.abc.net.au/news/2020-05-21/leaked-national-covid-commission-gas-manufacturing-report/12269100">exemption from additional approvals under the Environment Protection and Biodiversity Conservation Act</a>. </p>
<p>The relaxing of environmental legislation and protections (commonly referred to as cutting “<a href="https://theconversation.com/cutting-green-tape-may-be-good-politicking-but-its-bad-policy-here-are-5-examples-of-regulation-failure-137164">green tape</a>”) has been pushed by <a href="https://theconversation.com/be-worried-when-fossil-fuel-lobbyists-support-current-environmental-laws-138526">business and industry lobby groups</a> and some quarters of the media. </p>
<p>Even politicians such as <a href="https://www.theguardian.com/australia-news/2020/apr/23/coalition-is-aiming-to-change-australias-environment-laws-before-review-is-finished">federal Environment Minister Sussan Ley</a> see it as a way to promote economic recovery.</p>
<h2>A better way to recovery</h2>
<p><a href="https://invasives.org.au/wp-content/uploads/2020/04/Prime-Minister-re-Economic-Stimulus-in-conservation-and-land-managementatt-20-Apr-2020.pdf">Nature groups, environmental scientists, economists</a> and political parties <a href="https://greens.org.au/sites/default/files/2020-05/Greens-Recovery-Plan.pdf">such as the Greens</a> are proposing an alternative approach.</p>
<p>Some state and territory departments, including in the <a href="https://www.cmtedd.act.gov.au/open_government/inform/act_government_media_releases/gentleman/2020/environment-to-benefit-from-acts-covid-19-stimulus">ACT</a> and the <a href="https://business.nt.gov.au/__data/assets/pdf_file/0010/885358/operation-rebound-green-paper.pdf">Northern Territory</a>, recognise environmental management and protection as a source of high employment opportunity.</p>
<p>They all see investment in conservation and land management as a key feature of any economic recovery. </p>
<h2>An opportunity for Australia</h2>
<p>Economic stimulus through conservation and land management is not yet recognised as a way for Australia to respond to both the COVID-19 crisis and long-standing conservation needs.</p>
<p>Australian governments, if they invested similarly to New Zealand, could create jobs in the short term in any desired target region, based on economic and environmental need.</p>
<p>This flexibility would allow jobs to be created in regions with already fragile local economies, particularly those made worse by COVID-19. This includes regional areas that usually have high tourism, bushfire-affected communities, drought-affected regions, as well as Indigenous communities. </p>
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Read more:
<a href="https://theconversation.com/when-introduced-species-are-cute-and-loveable-culling-them-is-a-tricky-proposition-130471">When introduced species are cute and loveable, culling them is a tricky proposition</a>
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<p>Conservation and land management jobs could include dealing with <a href="https://www.environment.gov.au/biodiversity/invasive-species/feral-animals-australia">feral pests</a>, such as <a href="https://theconversation.com/why-australia-needs-to-kill-cats-116654">cats</a>, <a href="https://www.environment.gov.au/biodiversity/invasive-species/publications/factsheet-european-red-fox-vulpes-vulpes">foxes</a>, <a href="https://www.environment.gov.au/biodiversity/invasive-species/publications/factsheet-european-wild-rabbit-oryctolagus-cuniculus">rabbits</a>, <a href="https://www.environment.gov.au/biodiversity/invasive-species/feral-animals-australia/feral-pigs">pigs</a>, <a href="https://www.environment.gov.au/biodiversity/invasive-species/publications/factsheet-feral-deer">deer</a> and <a href="https://theconversation.com/double-trouble-as-feral-horse-numbers-gallop-past-25-000-in-the-australian-alps-128852">horses</a>.</p>
<p>It could feature restoration activities such as tree planting, weed removal, hazard-reduction burning, and wildlife restoration and monitoring.</p>
<p>This type of employment is hands-on, labour-intensive and has low overhead costs. Investment is likely to be cost-effective, with most of it going straight to the worker. </p>
<h2>Let’s stimulate the economy and the environment</h2>
<p>Projects can be up and running quickly, so the economic stimulus is immediate.</p>
<p>The <a href="https://www.tai.org.au/sites/default/files/Design%20Principles%20for%20Fiscal%20Policy%20in%20a%20Pandemic%20%5BWEB%5D.pdf">benefits</a> of direct household stimulus are well understood. This form of spending provides localised economic benefits as money is likely to stay in the local community.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/the-next-global-health-pandemic-could-easily-erupt-in-your-backyard-138861">The next global health pandemic could easily erupt in your backyard</a>
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<p>There is an opportunity to support the <a href="https://www.theguardian.com/australia-news/2020/apr/14/a-downward-spiral-coronavirus-spins-australian-universities-into-economic-crisis">hard-hit university sector</a>. It could get funds for research to design, monitor and assess the effectiveness of any interventions.</p>
<p>Such investment would have lasting and much-needed environmental benefits through the conservation of landscapes <a href="https://www.theguardian.com/environment/ng-interactive/2020/feb/11/counting-the-cost-of-australias-summer-of-dread">recently ravaged by bushfire</a> that contain unique and <a href="https://theconversation.com/scientists-re-counted-australias-extinct-species-and-the-result-is-devastating-127611">declining wildlife species</a>. </p>
<p>Could the much-hyped “new normal” be one where Australia’s environment and economy are not seen as incompatible?</p><img src="https://counter.theconversation.com/content/139305/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lachlan G. Howell is affiliated with the University of Newcastle and FAUNA Research Alliance, and is a member of Port Stephens Koala and Wildlife Preservation Society. </span></em></p><p class="fine-print"><em><span>John Clulow receives funding for biodiversity projects from industry, and government (state and local government) sources through the University of Newcastle. He is affiliated with FAUNABank and FAUNA Research Alliance. </span></em></p><p class="fine-print"><em><span>John Rodger has received funding from the ARC and CRC Program. He is affiliated with FAUNA Research Alliance.
</span></em></p><p class="fine-print"><em><span>Ryan R. Witt receives funding from Taronga Conservation Society Australia and has received funding from the Holsworth Wildlife Research Endowment and the Ecological Society of Australia. He is affiliated with the University of Newcastle, FAUNA Research Alliance and is a member of Port Stephens Koala and Wildlife Preservation Society.</span></em></p>New Zealand is pumping millions of dollars into environment projects as part of its COVID-19 recovery. Australia’s recovery plan seems more destructive than reconstructive.Lachlan G. Howell, PhD Candidate | School of Environmental and Life Sciences, University of NewcastleJohn Clulow, Associate Professor, University of NewcastleJohn Rodger, Emeritus Professor, University of Newcastle & CEO FAUNA Research Alliance, University of NewcastleRyan R. Witt, Conjoint Lecturer | School of Environmental and Life Sciences, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1307022020-02-05T02:04:49Z2020-02-05T02:04:49ZNot all weeds are villains. After a fire, some plants – even weeds – can be better than none<figure><img src="https://images.theconversation.com/files/313195/original/file-20200203-41503-qjgnd5.jpg?ixlib=rb-1.1.0&rect=19%2C38%2C6470%2C4281&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 Invasive Species Council and other observers have argued for weed control <a href="https://invasives.org.au/media-releases/bushfire-and-ferals-a-recipe-for-disaster/">as a major priority</a> following bushfires, to promote the recovery of wildlife and damaged ecosystems. The time is right, some <a href="https://theconversation.com/pulling-out-weeds-is-the-best-thing-you-can-do-to-help-nature-recover-from-the-fires-130296">say</a>, to wage a serious offensive against weeds before they re-establish and this opportunity is lost. </p>
<p>But perhaps we shouldn’t be so hasty to villainise all weeds. There is <a href="https://www.brown.edu/Research/Sax_Research_Lab/Documents/PDFs/Schlaepfer%20et%20al.%202011%20-%20conservation%20value%20of%20non-natives.pdf">growing recognition</a> that weeds can, in some cases, support a range of critical ecological functions. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/hold-the-spray-some-garden-weeds-are-helping-native-wildlife-47848">Hold the spray: some garden weeds are helping native wildlife</a>
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<h2>Who decides what’s a weed?</h2>
<p>There are official lists of <a href="http://www.environment.gov.au/cgi-bin/biodiversity/invasive/weeds/weedspeciesindex.pl?id=701">weeds</a> in Australia. But for many, the term “weed” is vague, non-scientific and highly subjective. Weeds can be non-native or <a href="http://www.environment.gov.au/biodiversity/invasive/weeds/weeds/what.html">native species</a>. They’re generally considered to be plants that are growing in places, or ways (for example, in high abundance), that are undesirable.</p>
<p>Their “undesirability” may be traced to a wide range of economic, social, cultural, aesthetic and political reasons. From an ecological perspective, weeds are <a href="https://theconversation.com/pulling-out-weeds-is-the-best-thing-you-can-do-to-help-nature-recover-from-the-fires-130296">often blamed</a> for stifling native plant growth, altering wildlife habitat and changing ecological processes. Many assume weed control will improve native plant growth, habitat quality and ecosystem function.</p>
<p>In some situations, however, weeds provide valuable ecological functions by, for example, offering food and habitat for wildlife, protecting soils and landforms from erosion and slowing down the movement of water through catchments.</p>
<p>Exotic chinee apple trees (<em>Ziziphus mauritiana</em>) in north-west Australia, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/aec.12454">for example</a>, protect the burrow systems of native rodents from habitat damage by feral horses.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/313207/original/file-20200203-41485-ecyupl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/313207/original/file-20200203-41485-ecyupl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313207/original/file-20200203-41485-ecyupl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313207/original/file-20200203-41485-ecyupl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313207/original/file-20200203-41485-ecyupl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313207/original/file-20200203-41485-ecyupl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313207/original/file-20200203-41485-ecyupl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313207/original/file-20200203-41485-ecyupl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">One study found invasive chinee apple trees (Ziziphus mauritiana) provide critical refuge habitat for native rodents.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Chinee_Apple_(Zizyphus_mauritiana)_fruit_and_leaves.jpg">Chris Gardiner CC BY-SA/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>This kind of benefit is especially likely in very disturbed habitats, such as areas that have been cleared. Other areas of high functional importance in the landscape such as <a href="https://www.thesolutionsjournal.com/article/turning-new-leaf-role-novel-riparian-ecosystems-catchment-management/">riparian zones</a> – land alongside creeks, streams, gullies, rivers and wetlands - can benefit from some weeds.</p>
<p>Riparian weeds can support rivers and streams by trapping sediments and contaminants washing into channels via run-off. Exotic riparian willows (<em>Salix spp.</em>) can also provide <a href="https://scialert.net/fulltextmobile/?doi=ajbs.2011.428.444">habitat</a> and <a href="https://onlinelibrary.wiley.com/doi/full/10.1046/j.1442-9993.1999.01008.x">food sources</a> for aquatic fauna.</p>
<p>This may be particularly important for <a href="https://theconversation.com/the-sweet-relief-of-rain-after-bushfires-threatens-disaster-for-our-rivers-129449">aquatic ecosystem health</a> following fire.</p>
<p>Weeds may also promote regeneration of native plants by helping stabilise soil, providing shade and protecting seedlings from being eaten by animals and pests.</p>
<p>At larger scales, weeds can also enhance the dispersal of native plant seeds. In highly cleared parts of north-eastern New South Wales, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320705004933">for example</a>, camphor laurel trees (<em>Cinnamomum camphora</em>) – an introduced species – can provide habitats for fruit-eating birds that disperse and establish native rainforest plants.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/313194/original/file-20200202-41532-1n1631u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/313194/original/file-20200202-41532-1n1631u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313194/original/file-20200202-41532-1n1631u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313194/original/file-20200202-41532-1n1631u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313194/original/file-20200202-41532-1n1631u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313194/original/file-20200202-41532-1n1631u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313194/original/file-20200202-41532-1n1631u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313194/original/file-20200202-41532-1n1631u.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">Camphor laurel trees can provide bird habitats in areas where a lot of native trees have been cleared.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>There’s a lot we don’t know about weeds</h2>
<p>In some cases, weeds may be the only plants that grow back well after fires. And some plants – even weeds – may be better than none. </p>
<p>We can’t always assume that the presence of weeds is limiting native plant growth. The fact is we <a href="https://esajournals.onlinelibrary.wiley.com/doi/10.1890/04-0669">don’t really know</a>, in most cases, if removing weeds actually results in higher native plant diversity. </p>
<p>What we do know is that ecosystem functions, such as carbon storage and nutrient cycling, tend to increase where more species are present. And this <a href="https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/11-1014.1">holds true</a> even in weed-infested forests, which often contain more species than their equivalent native ecosystems. </p>
<p><a href="https://theconversation.com/pulling-out-weeds-is-the-best-thing-you-can-do-to-help-nature-recover-from-the-fires-130296">Many assume</a> weeds will flourish in our post-fire landscapes. </p>
<p>Some see this early establishment period as a unique opportunity to banish “undesirable” plants by weeding before they set seed.</p>
<p>There is surprisingly little evidence, however, regarding the effectiveness of most weed control methods over the longer-term. Many weeds can quickly re-establish from soil seed banks, suckers or plant fragments dispersed by wind, water or birds. </p>
<p>We also know very little about how <a href="https://onlinelibrary.wiley.com/doi/10.1046/j.1526-100X.2002.01051.x">weed control methods</a> themselves might affect ecological processes through soil disturbance and herbicides.</p>
<p>Even where these methods kill one weed, other, potentially more noxious plants may spring up in its place.</p>
<h2>When it comes to weeds, question your assumptions</h2>
<p>There is much at stake in Australia as we make decisions regarding the restoration of our unique ecosystems after the recent bushfire crisis. </p>
<p>Importantly, however, we can learn by not blindly acting on assumptions and ideologies. We can test assumptions through robust, long term ecological experiments.</p>
<p>Obviously, not all weeds should be retained. Non-native species can and do have negative effects. </p>
<p>However, we now face an opportunity to embark on a more nuanced and open approach to conservation and restoration. </p>
<p>Indeed, in a future that looks little like the past, we must never stop questioning our land management practices.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pulling-out-weeds-is-the-best-thing-you-can-do-to-help-nature-recover-from-the-fires-130296">Pulling out weeds is the best thing you can do to help nature recover from the fires</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/130702/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samantha Capon has consulted for and/or received funding from the Department of Environment and Energy, the Murray-Darling Basin Authority, the Victorian Department of Environment, Land, Water and Planning and the Cotton Research & Development Corporation. She also sits on scientific advisory panels for the Australian Landscape Science Institute and Healthy Land & Water.</span></em></p><p class="fine-print"><em><span>Gary Palmer has consulted for and received funding from the Department of Environment and Energy. He also receives funding from the Defense Advanced Research Projects Agency. </span></em></p>Weeds can play an important role supporting ecosystem recovery after fire.Samantha Capon, Associate professor, Griffith UniversityGary Palmer, Post-doctoral Research Fellow, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1302962020-01-27T18:58:14Z2020-01-27T18:58:14ZPulling out weeds is the best thing you can do to help nature recover from the fires<figure><img src="https://images.theconversation.com/files/311539/original/file-20200123-162232-xs4vf3.jpg?ixlib=rb-1.1.0&rect=23%2C0%2C3867%2C2444&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Australians are keen to help nature recover after a season of devastating bushfires.</span> <span class="attribution"><span class="source">Darren England/AAP</span></span></figcaption></figure><p>Many Australians feel compelled to help our damaged wildlife after this season’s terrible bushfires. Suggested actions have included <a href="https://www.wwf.org.au/get-involved/bushfire-emergency">donating money</a>, <a href="https://theconversation.com/you-can-leave-water-out-for-wildlife-without-attracting-mosquitoes-if-you-take-a-few-precautions-128631">leaving water out</a> for thirsty animals, and learning how to <a href="https://www.marieclaire.com.au/how-to-help-animals-australian-bushfires">help the injured</a>. But there is an equally, if not more, important way to assist: weeding.</p>
<p>An army of volunteers is needed to help land owners with judicious weed removal. This will help burnt habitats recover more quickly, providing expanded, healthy habitat for native fauna. </p>
<p>Other emergency responses, such as culling feral animals and <a href="https://www.smh.com.au/environment/conservation/massive-food-drop-to-help-save-endangered-wallabies-in-fire-affected-areas-20200112-p53qss.html">dropping emergency food from aeroplanes</a>, are obviously jobs for specialists. But volunteer weeding does not require any prior expertise – just a willingness to get your hands dirty and take your lead from those in the know. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/311544/original/file-20200123-162190-4qhus3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311544/original/file-20200123-162190-4qhus3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311544/original/file-20200123-162190-4qhus3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311544/original/file-20200123-162190-4qhus3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311544/original/file-20200123-162190-4qhus3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311544/original/file-20200123-162190-4qhus3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311544/original/file-20200123-162190-4qhus3.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">Volunteer weeding will help burnt habitats recover more quickly.</span>
<span class="attribution"><span class="source">Silje Polland/Flickr</span></span>
</figcaption>
</figure>
<h2>Why is weeding so critical?</h2>
<p>The recent bushfires burned many areas in national parks and reserves which were infested with weeds. Some weeds are killed in a blaze, but fire also stimulates their seed banks to germinate.</p>
<p>Weed seedlings will spring up en masse and establish dense stands that out-compete native plants by blocking access to sunlight. Native seedlings will die without setting seed, wasting this chance for them to recover and to provide habitat for a diverse range of native species.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/many-of-our-plants-and-animals-have-adapted-to-fires-but-now-the-fires-are-changing-129754">Many of our plants and animals have adapted to fires, but now the fires are changing</a>
</strong>
</em>
</p>
<hr>
<p>This mass weed germination is also an opportunity to improve the outlook for biodiversity. With a coordinated volunteer effort, these weeds can be taken out before they seed – leaving only a residual seed bank with no adult weeds to create more seed and creating space for native plants to flourish.</p>
<p>With follow-up weeding, we can leave our national parks and reserves – and even bushland on farms - in a better state than they were before the fires.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/311542/original/file-20200123-162221-1l3qp1w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311542/original/file-20200123-162221-1l3qp1w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311542/original/file-20200123-162221-1l3qp1w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311542/original/file-20200123-162221-1l3qp1w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311542/original/file-20200123-162221-1l3qp1w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311542/original/file-20200123-162221-1l3qp1w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311542/original/file-20200123-162221-1l3qp1w.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">
<figcaption>
<span class="caption">Bush regeneration groups are well placed to restore forests after fire, but need volunteers.</span>
<span class="attribution"><span class="source">Flickr</span></span>
</figcaption>
</figure>
<h2>Weeding works</h2>
<p>In January 1994, fire burned most of Lane Cove National Park in Sydney. Within a few months of the fire, <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2005.00225.x">volunteer bush regeneration groups were set up to help tackle regenerating weeds</a>.</p>
<p>Their efforts eradicated weeds from areas where the problem previously seemed intractable and prevented further weed expansion. Key to success in this case was the provision of funding for coordination, an engaged community which produced passionate volunteers and enough resources to train them.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/conservation-scientists-are-grieving-after-the-bushfires-but-we-must-not-give-up-130195">Conservation scientists are grieving after the bushfires -- but we must not give up</a>
</strong>
</em>
</p>
<hr>
<p>Following recent fires in the Victorian high country, volunteers will be critical to controlling weeds, <a href="https://bie.ala.org.au/species/http://id.biodiversity.org.au/node/apni/2897651">particularly broom (Scotch broom and related species), which occurs throughout fire-affected areas </a>. </p>
<p>Fire typically kills these woody shrubs but also stimulates seed germination. Without intervention, broom will form dense stands which <a href="https://link.springer.com/content/pdf/10.1007/s11258-005-9046-7.pdf">out-compete native plant species </a>.</p>
<p>However, swift action now can prevent this. Mass germination <a href="https://www.researchgate.net/publication/299041169">reduces the broom’s seedbank to as low as 8% of pre-fire levels, and around half of the remaining seeds die each year</a>. Further, broom usually takes three years to flower and replenish its seedbank. So with no new seeds being produced and the seedbank low and shrinking, this three-year window offers an important opportunity to restore previously infested areas.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/311540/original/file-20200123-162199-1bukveg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311540/original/file-20200123-162199-1bukveg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311540/original/file-20200123-162199-1bukveg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311540/original/file-20200123-162199-1bukveg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311540/original/file-20200123-162199-1bukveg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311540/original/file-20200123-162199-1bukveg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311540/original/file-20200123-162199-1bukveg.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">
<figcaption>
<span class="caption">Scotch broom, a native shrub of Western Europe, has infested vast swathes of Australia.</span>
<span class="attribution"><span class="source">Gunter Maywald-CSIRO/Wikimedia</span></span>
</figcaption>
</figure>
<p>Parks Victoria took up this opportunity after the 2003 fires in the Alpine National Park. They rallied agencies, natural resource management groups and local landholders to <a href="http://www.aabr.org.au/images/stories/resources/ManagementGuides/WeedGuides/wmg_brooms.pdf">sweep up broom </a>. Herbicide trials at that time revealed that to get the best outcome for their money, it was critical to spray broom seedlings early, within the <a href="https://www.researchgate.net/publication/259323125_Best-practice_chemical_control_of_English_broom_Cytisus_scoparius_evaluated_in_Alpine_National_Park_Victoria_through_an_adaptive_experimental_management_program">first year and a half</a>. </p>
<p>Broom management also needs to use a range of approaches, <a href="https://www.parkconnect.vic.gov.au/Volunteer/public-planned-activity/?id=446c9d83-53b6-e811-a966-000d3ad1c6f2">including using volunteers to spread a biological control agent</a>. </p>
<h2>Plenty of work to do</h2>
<p>Parks Victoria continue to <a href="https://www.parkconnect.vic.gov.au/Volunteer/">engage community groups in park management</a> and will coordinate fire response actions when parks are safe to enter. Similar programs can be found in <a href="https://www.nationalparks.nsw.gov.au/conservation-and-heritage/volunteer-programs">New South Wales</a>, <a href="https://www.dbca.wa.gov.au/parks-and-wildlife-service/volunteering-with-parks-and-wildlife">Western Australia</a>, <a href="https://www.parks.sa.gov.au/volunteer">South Australia</a>, <a href="https://www.qld.gov.au/environment/parks/park-volunteers/start-volunteering">Queensland</a>, <a href="https://parks.tas.gov.au/be-involved/volunteer">Tasmania</a>, <a href="https://nt.gov.au/leisure/parks-reserves/learn-and-be-involved/volunteers-in-parks">the Northern Territory</a>, and the <a href="https://www.environment.act.gov.au/parks-conservation/parks-and-reserves/get-involved/the-ParkCare-initiative">ACT</a>.</p>
<p>A <a href="https://www.researchgate.net/profile/Kevin_Taylor16/publication/331247014_Fire_Weeds_and_the_Native_Vegetation_of_New_South_Wales_A_report_prepared_by_the_Hotspots_Fire_Project/links/5c6e1fa94585156b570d4c51/Fire-Weeds-and-the-Native-Vegetation-of-New-South-Wales-A-report-prepared-by-the-Hotspots-Fire-Project.pdf">wide range of weeds expand after fire</a> and warrant a rapid response. They include <a href="https://www.environment.gov.au/biodiversity/invasive/weeds/publications/guidelines/wons/pubs/l-camara.pdf">lantana</a>, <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0128482">bitou bush</a>, and
<a href="http://caws.org.nz/old-site/awc/2006/awc200612111.pdf">blackberry</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/yes-native-plants-can-flourish-after-bushfire-but-theres-only-so-much-hardship-they-can-take-129748">Yes, native plants can flourish after bushfire. But there’s only so much hardship they can take</a>
</strong>
</em>
</p>
<hr>
<p>Managing weeds after fire is currently a high priority at many sites. At the edges of the World Heritage Gondwana rainforests of southwest Queensland and northern and central NSW, there is a window to more effectively control <a href="https://www.abc.net.au/science/articles/2011/12/12/3387436.htm">lantana</a>. In many forested areas in NSW, Victoria and South Australia, fire has created an opportunity to address important weed problems.</p>
<p>State government agencies have the mapping capacity to locate these places. Hopefully they can make these resources easy for the public to access soon, so community groups can self-organise and connect with park managers. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/311545/original/file-20200123-162240-brb21w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/311545/original/file-20200123-162240-brb21w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/311545/original/file-20200123-162240-brb21w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/311545/original/file-20200123-162240-brb21w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/311545/original/file-20200123-162240-brb21w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=486&fit=crop&dpr=1 754w, https://images.theconversation.com/files/311545/original/file-20200123-162240-brb21w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=486&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/311545/original/file-20200123-162240-brb21w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=486&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A koala badly injured during the Canberra bushfires before it was returned to the wild.</span>
<span class="attribution"><span class="source">ALAN PORRIT/AAP</span></span>
</figcaption>
</figure>
<h2>All this needs money</h2>
<p>Emergency funding is now essential to enable community-based weed control programs at the scale needed to have a substantial impact. Specifically, funding is needed for group coordinators, trainers and equipment.</p>
<p>While emergency work is needed to control regenerating weeds in the next 6-18 months, <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2005.00225.x">ongoing work is needed after that</a> to consolidate success and prevent reinfestations from the small, but still present, seed bank.</p>
<p><a href="https://vnpa.org.au/wp-content/uploads/2017/02/Assessment-of-the-Weed-Management-program-in-land-managed-by-Parks-Victoria.pdf">Ongoing government funding is needed</a> to enable this work, and prepare for a similar response to the next mega-fires.</p>
<h2>Want to act immediately?</h2>
<p>You can volunteer to do your bit for fire recovery right now. In addition to state-agency volunteer websites, there are many existing park care, bush care and “friends of” groups coordinated by local governments. They’re waiting for you to join so they can start planning the restoration task in fire-affected areas.</p>
<p>Contact them directly or <a href="http://www.aabr.org.au/do/post-fire-wildlife-habitat-recovery-response/">register your interest with the Australian Association of Bush Regenerators</a> who can link you with the appropriate organisations. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/you-can-leave-water-out-for-wildlife-without-attracting-mosquitoes-if-you-take-a-few-precautions-128631">You can leave water out for wildlife without attracting mosquitoes, if you take a few precautions</a>
</strong>
</em>
</p>
<hr>
<p>If we do nothing now, the quality of our national parks will decline as weeds take over and native species are lost. But if you channel your fire-response energy and commitment to help manage weeds, our national parks could come out in front from this climate-change induced calamity.</p>
<p>By all means, rescue an injured koala. But by pulling out weeds, you could also help rescue a whole ecosystem.</p>
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<p><em>Dr Tein McDonald, president of the Australian Association of Bush Regenerators, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/130296/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Don Driscoll receives funding from the Herman Slade Foundation, OEH NSW Environmental Grants program, DELWP Vic, National Geographic, Rufford Foundation and Bushfire and Natural Hazards CRC. He is Past President of the Ecological Society of Australia, Director of the Centre of Integrative Ecology and Director of the TechnEcology Research Network at Deakin University. Don is a member of the Ecological Society of Australia and Society for Conservation Biology.</span></em></p>By all means, rescue an injured koala. But by pulling out weeds after the fires, you could also help rescue a whole ecosystem.Don Driscoll, Professor in Terrestrial Ecology, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.